the growth of bismuth sulfide nanorods from spherical-shaped

Hindawi Publishing CorporationJournal of NanoparticlesVolume 2013 Article ID 367812 11 pageshttpdxdoiorg1011552013367812

Research ArticleThe Growth of Bismuth Sulfide Nanorods fromSpherical-Shaped Amorphous Precursor Particles underHydrothermal Condition

Pravas Kumar Panigrahi and Amita Pathak

Department of Chemistry Indian Institute of Technology Kharagpur Kharagpur West Bengal 721302 India

Correspondence should be addressed to Amita Pathak amichemiitkgpernetin

Received 22 October 2012 Accepted 3 January 2013

Academic Editor Fabien Grasset

Copyright copy 2013 P K Panigrahi and A PathakThis is an open access article distributed under theCreative CommonsAttributionLicense which permits unrestricted use distribution and reproduction in anymedium provided the originalwork is properly cited

A surfactantsolid-template-free hydrothermal process has been developed for the synthesis of single-crystalline nanorods ofbismuth sulfide (Bi

2S3) using triethanolamine as a complexing agent for the Bi3+ ions and elemental sulfur solubilized in

monoethanolamine as the sulfur source X-ray diffraction and morphological studies of a series of samples synthesized at differentreaction conditions suggest that the growth of nanorods occurred at the expense of the low-crystalline spherical precursor particlesof aminium compounds of bismuth sulfide or bismuth sulfate formed at room temperature In the process the reaction conditionis optimized for obtaining crystalline nanorods of pure Bi

2S3with high aspect ratio From the XRD XPS and HRTEM analysis

of the samples the growth of nanorods was assessed to be due to the cooperative effects of solid-solution-solid transformationand controlled oriented attachment The hydrothermal process parameters and the presence of water in the reaction system havebeen found to play a crucial role in the formation of high aspect ratio nanorods The optical band gap of the synthesized sample atoptimized conditions is found to be 146 eV as calculated from its diffused reflectance spectrum at room temperature

1 Introduction

Bismuth sulfide (Bi2S3) is a direct band gap semiconductor

with large absorption coefficient high band gap energy (13ndash17 eV) [1] and having energy conversion efficiency close totheoretical maximum attainable value These qualities makeBi2S3potentially suitable for the fabrication of optoelectronic

and thermoelectric devices as well as applications in photo-voltaic thermoelectric transport photoconductivity electri-cal photoresponse and field emission [2ndash7] Nanostructuresof Bi2S3 especially the one-dimensional (1D) nanostruc-

tures (such as wires rods tubes and ribbons) are in factconsidered to be the best contenders for these applicationsdue to quantum confinement effect [8 9] Due to quantumconfinement of the charge carriers in 1D nanostructure thethermoelectric efficiency of a material is enhanced throughthe increase in its figure-of-merit value brought about bythe increase in the Seebeck coefficient and the decrease in

the coefficient of thermal conductivity through boundaryscattering of the heat carriers [10] Similarly the electrontransport in crystalline nanowires is expected to be severalfolds faster than through a polycrystalline structure It isbecause of these reasons that the optoelectronic propertiesof single-crystalline 1D nanostructures of Bi

2S3have been

widely studied for the design and fabrication of fastminiatur-ized optoelectronic devices (such as optical switches and pho-todiode arrays) [11 12] or for augmenting the performance ofexisting ones

Due to the immense technological importance of 1Dnanostructured Bi

2S3in nanoscale devices fabrication there

has been a surge of interest in their synthesis There hasbeen a variety of synthetic approaches reported so farfor their synthesis which include evaporation-condensationroute [1] molecular precursor decomposition route [13]solventless synthesis route [14] electrochemical depositionroute [15] solvothermalhydrothermal route [16 17] and

2 Journal of Nanoparticles

ionic liquid-assisted route [18] Among these processessolvothermalhydrothermal method is one of the most stud-ied solution-based synthesis route for the fabrication of 1Dnanostructures of Bi

2S3because this technique allows the

opportunities to control the morphology of the final prod-ucts through the variation of different reaction parameterswhich include reaction temperature reaction time reactionmedium (or solvent) bismuth and sulfur sources complexingagent and surfactant [19ndash21] Besides in the context ofthe possibilities to modify the growth behaviour of Bi

2S3

crystal to anisotropic one the use of soft templates (suchas surfactant complexing agent and block copolymer) asgrowth-directing agent has received significant amount ofresearch interest in the recent past Among various growth-directing agents the use of a complexing agent to change thegrowth behaviour (ie both nucleation and growth rate) andto confine it in a desired direction remained an interestingaspect The complexing agents are generally polyfunctionalligands that coordinate to the surface of either the ions orthe nanoparticles formed modify the particle surface energyand thereby enforce the unidirectional growth of the crystalThese bi- or multidentate ligands in some cases also act as asoft template in the growth process

There are a number of reports on the synthesis of 1Dnanostructured Bi

2S3by using organic ligands such as long

chain amines alcohols and acids as complexing agents Yu etal for example reported the use of EDTA as a coordinatingagent for the preparation of Bi

2S3nanorods [22] EDTA plays

multiple roles as a coordinating agent for Bi3+ as well as asoft template for the growth of nanorods under solvothermalcondition [23] On the other hand Ota and Srivastava [24]utilized amultifunctional organicmolecule (ie tartaric acid)as a capping agent for producing nanorods of Bi

2S3 Similarly

Chen et al [25] synthesized highly crystalline Bi2S3nanorods

using bismuth citrate and thiourea as precursor materialsin the presence of cetyltrimethylammonium bromide Theyclaimed that the growth of nanorods is assisted by linearbismuth citrate polymer template In addition a number ofpolyols for example ethylene glycol [26] diethylene glycol(DEG) [27] and so forth have been reported to assist in thedirection-arrested one-dimensional growth of Bi

2S3 In this

process the multiple ndashOH groups cap the formed particlesof Bi2S3and make them stable These polyols could also

exist in long chains due to the effective hydrogen bondingbetween them that serves as a template for growth of Bi

2S3

nuclei to form nanorods [27] Triethanolamine (TEA) isanother important tetradentate chelating ligand containingthree ndashOH and one amine group which like diethyleneglycol exists as a long chain polymeric framework in thepresence of water due to the effective hydrogen bonding [28]Moreover TEA is miscible with water in all proportions andcan be used in hydrothermal process successfully Henceit is expected that the use of this organic ligand can bean alternative route for the synthesis of Bi

2S3nanorods

However the use of TEA for the synthesis of 1Dnanostructureof Bi2S3powders is limited only to a few reports [29]

Therefore the present work aims at synthesizing nano-rods of Bi

2S3by using TEA as a complexing agent under

hydrothermal condition In the developed process a noveland inexpensive sulfur source that is elemental sulfur sol-ubilized in monoethanolamine (MEA) has been used Theessence of this work lies in the formation of amorphousspherical precursors at room temperature and subsequentlytheir transformation into nanorods under hydrothermalcondition A growth mechanism is also proposed

2 Experimental Details

21 Materials Bismuth nitrate (Bi(NO3)3sdot5H2O) triethanol-

amine (HOC2H4)3N) monoethanolamine (HOC

2H4NH2)

and elemental sulfur were purchased fromMerck India andused as received without further purification

22 Synthesis In a typical preparation 1 g of bismuth nitratewas solubilized in a mixture of 20mL of TEA and 120mLof distilled water by stirring continuously for 1 h The clearsolution was obtained possibly through the formation of[Bi(TEA)

119909

3+] complex [29 30] Elemental sulfur (0132 g)was separately dissolved in 10mL of MEA and it was thenpoured into the solution of [Bi(TEA)

119909]3+ complex A brown

precipitate was obtained immediately which turned graywithin few seconds The entire solution mixture containingthe gray colored solid precursor (ie the precursor sol) wasthen transferred to a Teflon-lined stainless steel autoclave andsubjected to hydrothermal reaction at 160∘C After coolingthe autoclave naturally to room temperature the precipitateswere collected washedwithwater for several times andfinallywith ethanol and dried For the investigation of the reactionmechanism the precursor sol formed at room temperature(prior to hydrothermal treatment) was also collected sep-arately and characterized This sample was referred to asldquoprecursor samplerdquo in the later part of the paper

23 Characterization The phase and structure analysis ofthe synthesized samples were carried out on Philips PW1729 X-ray diffractometer using Co K

120572radiation (120582 =

179 A) X-ray photoelectron spectroscopy (XPS) studies ofthe samples were carried out on an XPS system made byOmicron NanoTechnology using Mg K

120572(12536 eV) as the

excitation source The morphologies of the samples werestudied by using JEOL JSM-5800 model and Zeiss EVO-60 model scanning electron microscope The chemical com-positions of the samples were confirmed through energydispersive analysis by X-ray (EDAX) using Oxford INCAelectron microprobe attached to scanning electron micro-scope JEOL JEM-2100 model high-resolution transmissionelectron microscope (HRTEM) was used to examine themicrostructural details of the prepared samples Raman spec-troscopy was performed using Renishaw RM-1000 modelinstrument equipped with an Ar ion laser of wavelength5144 nmThediffuse reflectance spectra of the as-synthesizedpowders were recorded at room temperature using VarianCary 5000 UV-Vis-NIR spectrophotometer

Journal of Nanoparticles 3

10 20 30 40 50 60 70 80

Inte

nsity

(au

)

522

171

242

16106

135

122

216

006

043

100

252

0421

141

041231

240

311

410

221

211

021

130

101

220

12002

0

310

2120579 (deg)

Figure 1 XRD pattern of the Bi2S3sample obtained after 18 h of

hydrothermal treatment at a temperature of 160∘C

3 Results and Discussion

The XRD analysis of the product obtained after 18 h ofhydrothermal treatment at 160∘C is displayed in Figure 1The positions and relative intensities of all the peaks arein good agreement with those of the orthorhombic crystalstructure of Bi

2S3and are indexed according to JCPDS file

number 17-0320 The calculated cell parameters (a = 11133 Ab = 11304 A and c = 3977 A) are also found to be wellmatched with the standard values (ie a = 1114 A b =1130 A and c = 398 A) Within the detection limit of theXRD method no unidentified peaks in the diffractogramare noticed suggesting that the final product is free fromimpurities Energy dispersive analysis byX-ray (EDAX) of thesample reveals S-to-Bi atomic ratio as 145 against the idealvalue of 15 for pure Bi

2S3

The composition of this sample was also verified by X-ray photoelectron spectroscopy (XPS) (Figure 2) The surveyspectrum (Figure 2(a)) reveals the presence of elements suchas Bi S O and C which indicates the high purity of theresulting product The peak for O arises possibly due tothe adsorbed gases andor oxides of C on the surfaces ofthe samples [29] This observation is common in case ofultrafine powder samples when exposed to atmosphere Thehigh resolution XPS spectra in Bi region (Figure 2(b)) showstwo peaks at 1577 and 163 eV which can be assignablerespectively to the binding energies of Bi 4f

72and Bi 4f

52

in Bi2S3 The broad peak at around 2249 eV (Figure 2(c))

corresponds to the binding energy of S 2s The observedvalues are found to be in close agreement with the datareported by Grigas et al [31] Raman spectroscopy studieswere carried out to further validate the composition ofthe samples Room-temperature Raman spectrum (recordedbetween 200 and 1400 cmminus1) for the sample obtained after 18 hof hydrothermal treatment at 160∘C is displayed in Figure 3The spectrum depicts five distinct vibrational peaks at about260 306 422 606 and 965 cmminus1 which corresponds to the

characteristic Raman bands of crystalline Bi2S3samples [24]

These are also in good agreement with the nanoparticles ofBi2S3reported by Rabin et al [7 32]

The particle morphologies of the synthesized Bi2S3pow-

ders were studied by electron microscopy RepresentativeSEM and bright field TEM micrographs of the sampleobtained after 18 h of hydrothermal treatment at 160∘C areshown in Figures 4(a) and 4(b) respectivelyThemicrographsreveal the formation of nanorods of Bi

2S3with average diam-

eters and lengths ranging between 70 and 170 nm and 0550ndash3 120583m respectively TEM image of a typical nanorod havingdiameter of 90 nm and length of 25 120583m and its detailedlattice fringe pattern are illustrated in Figures 4(c) and 4(d)respectively The calculated fringe width of 056 nm (shownin Figure 4(d)) matches with the d-spacing of the (200)planes of the orthorhombic Bi

2S3crystal [12] suggesting

that the growth of the nanorods of Bi2S3occurred along the

preferential [001] (c-axis) direction Furthermore the spottedpattern of the selected area electron diffraction (SAED) ofthe selected nanorod (shown as an inset in Figure 4(d)) inferssingle-crystalline nature of the synthesized sample

In order to investigate the possible growth mecha-nism and the chemistry involved in the synthesis of Bi

2S3

nanorods a series of samples were synthesized at differentreaction conditions and were analyzed by XRD and electronmicroscopy Figure 5 represents the XRD patterns of theroom-temperature precipitate that was separated prior tohydrothermal treatment and the samples obtained after 1 3and 12 h of hydrothermal treatment at a fixed temperatureof 160∘C XRD pattern in Figure 5(a) showed broad anddiffused peaks centered at around 2120579 = 3088∘ 3523∘ and5173∘ indicating the precursor sample to be predominantlyamorphous The positions of these diffused peaks are slightlyshifted from the standard values of major peaks reported forthe orthorhombic Bi

2S3phase (JCPDS file no 17-0320) but

could not be assigned to any compound reported in the avail-able literature These unidentified broad peaks were howeverobserved to diminish in intensity and eventually disappearedto give way to diffraction lines characteristic of the pureBi2S3phase This could be achieved through hydrothermal

treatment of the precursors at temperaturesge160∘C and incu-bation periodsge6 h (see Figure S1 in SupplementaryMaterialavailable online at httpdxdoiorg1011552013367812) Itwas interesting to note that though the orthorhombic phaseof Bi2S3was realized through hydrothermal processing of the

precursors at temperatures as low as 120∘C and incubationperiod of just 3 h but it was accompanied by the highestintense peak (at 2120579 asymp 3028∘) of the unidentified phase It wasalso realized that this peak persisted even though it prolongedthe incubation period to 24 h at a temperature of 120∘CThe peak however diminished in intensity with an increasein hydrothermal temperatures beyond 120∘C and in effectthe pure orthorhombic phase of Bi

2S3was accomplished

on hydrothermal processing of the precursors at 160∘C for12 h (Figure 5(d)) although the products after 1 and 3 h ofheating periods contain some amount of unidentified phase(as indicated by lowast in Figures 5(b) and 5(c)) On the basisof optimization studies however the pure and crystallinephases of Bi

2S3with relatively high aspect ratio were obtained


0 200 400 600 800O

1s

Bi 4

d

C 1sS 2s

Bi 4

f

Bi 5

d

Inte

nsity

(au

)

Binding energy (eV)

Bi4p32

Bi4p12

(a)

155 160 165 170

Inte

nsity

(au

)

Binding energy (eV)

4f72

4f52

(b)

220 224 228 232Binding energy (eV)

Inte

nsity

(au

)

S 2s

(c)

Figure 2 XPS analysis of Bi2S3synthesized after 18 h of hydrothermal treatment at a temperature of 160∘C (a) survey spectra (b) Bi region

and (c) S region

on hydrothermal processing of the precursors at 160∘C for18 h as depicted in Figure 1

It may thus be inferred that the broad peaks of theprecursors (at 2120579 = 3088∘ 3523∘ and 5173∘) correspond toan intermediate compound that are poorly crystalline anddecompose to Bi

2S3at hydrothermal processing temperatures

ge160∘C and incubation period ge6 h Liu et al [16] reportedthe formation of similar intermediates which decomposed togenerate Bi

2S3nanoribbons They assigned the broad peaks

located at 2120579 asymp 3057∘ 2962∘ and 5275∘ to cubic NaBiS2

which got formed through hydrothermal reaction betweenBi3+-glycerol complexes and elemental sulfurNa

2S2O3in

aqueous solution of NaOH Ota and Srivastava [33] alsopredicted the formation of Bi

2S3nanotubes via decom-

position of NH4BiS2intermediates that were claimed to

be produced from the reaction of [Bi(TEA)119909]3+ complex

with CS2and NH

3in presence of Triton X-100 under

hydrothermal condition It was noted that the observed 2120579values of our precursors were slightly shifted from thosereported for the cubic NaBiS

2phase Therefore based on

these observations and drawing analogies with the reportedliterature in conjunction with the knowledge of the reagentsinvolved in the present preparation we can rationally predictthe intermediates (precursors) to be aminium compoundsof bismuth sulfide [(BiS

2)minus] or thiosulfate [[Bi(S

2O3)]3minus]

Hydrothermal processing of these precursors probably gen-erates nanorods of Bi

2S3 It however needs to be mentioned

that though Na3Bi(S2O3)3sdotnH2O and NaBiS

2are reported in

the literature [16 34] the existence of aminiumammoniumintermediates is difficult to establish through XRD studiesbecause of their poor crystalline nature and nonavailabilityof the standard literature claiming their formation in thecrystalline form

In order to substantiate the prediction fromXRDanalysisthe composition of the precursor sample (collected prior tohydrothermal treatment) was further studied by XPS Thesurvey spectrum shown in Figure 6(a) reveals the presenceof Bi S O N and C Here C 1s with standard bindingenergy (BE) value of 2846 eV is taken as a reference AsC 1s peak in Figure 6(a) lies at 2855 eV instead of its ideal


200 400 600 800 1000 1200 14000

10000

20000

30000

40000

Inte

nsity

(au

)

Raman shift (cmminus1)

965

606

306

42226

0

Figure 3 Raman spectra of the Bi2S3sample synthesized through hydrothermal process at 160∘C and incubation time period of 18 h

5 120583m

(a) (b)

[001]

(c)

056 nm

(d)

Figure 4 Bi2S3sample obtained through hydrothermal process at 160∘C after 18 h of incubation period (a) SEM image (b) corresponding

TEM image (c) TEM image of a selected nanorod and (d) HRTEM image of the selected nanorod with the corresponding SAED pattern(inset)

value of 2846 eV all the observed BEs in the XPS analysisare corrected accordingly [35 36] The small peak around400 eV in survey spectrum may be attributed to N 1s ofamine analogue [37 38] present in the precursor sample thatis aminium compounds of (BiS

2)minus and [Bi(S

2O3)3]3minus The

standard 2s binding energy for sulfur in their elemental stateis reported to be 229 eV [39] which is lowered by 3 eV forS2minus state in Bi

2S3[31] So the peak at 228 eV in Figure 6(b)

may be assigned to 2s BE for S2minus state in (BiS2)minus species On

the other hand the peak at 2315 eV which is higher than 2sBE for S0 but lower than S6+ state in sulfate ion [38] maybe assigned to the presence of S

2O3

2minus species (S2+ state) inthe precursor sample In addition the strong peak for O 1sin the survey spectrum (Figure 6(a)) could be deconvolutedinto two peaks (5311 and 5336 eV) These two deconvolutedpeaks could respectively be assigned to S

2O3

2minus species and


10 20 30 40 50 60 70 80 90

Inte

nsity

(au

) (d)

(c)

(b)

(a)

lowast

lowast

2120579 (deg)65

181

027

1

310

171

242

061

161421

520 00

2 431

060 35

116

0

141

22212

0 220

101

130

021

211

221

410

311 24

023

1 04102

0

Figure 5 XRD patterns of the samples synthesized at differentconditions (a) at room temperature after hydrothermal treatmentat 160∘C for (b) 1 h (c) 3 h and (d) 12 h

to adsorbed CO2in the sample [38] The peak pair at 1595

and 1645 eV (in Figure 6(c)) is close to binding energies of Bi4f72

and Bi 4f52

in Bi2S3[13] and can be assigned to Bi3+

in (BiS2)minus or [Bi(S

2O3)3]3minus species This is because Bi3+ is

not very sensitive to chemical environment therefore (BiS2)minus

or [Bi(S2O3)3]3minus species are expected to show ionization

potential values comparable to Bi2S3

Based on the above experimental results the possiblechemistry involved in the preparation of Bi

2S3can be pro-

posed As it is already discussed in our previous paper [40]that the disproportionation reaction of solution of elemen-tal sulfur in MEA generates a number of ions includingthiosulfate (S

2O3

2minus) and HSminus ions in the presence of OHminusions in the reaction mixture The TEA chelated complexes ofbismuth ions react then with the S2minus and S

2O3

2minus ions at roomtemperature to produce aminium compounds of bismuthsulfide and thiosulfate (ie (BiS

2)minus and [Bi(S

2O3)]3minus) as per

reactions (1) and (2)

Bi3+ + 2S2minus 999445999468 [BiS2]minus (1)

Bi3+ + 3S2O32minus999445999468 [Bi(S2O3)3]

3minus (2)

Under hydrothermal processing the aminium compoundsof [Bi(S

2O3)]3minus are first converted into the corresponding

(BiS2)minus which subsequently undergoes decomposition to

generate Bi2S3nanocrystals These nanocrystals probably

grow into 1D nanostructures of Bi2S3with increasing the

incubation period The whole process thus can be summa-rized through the following set of chemical reactions

Bi S O 33minus Hydrothermal processing

BiS minus (3)

BiS minusHydrothermal processing

Bi S nanocrystals S2minus

(4)

Bi Shydrothermal

Bi S (5)

To further study the possible growth mechanism of theformation of one-dimensional structures of Bi

2S3 the effect

of reaction temperature and reaction time on the morpholo-gies of the samples were studied exhaustively by electronmicroscopy Figure 7(a) depicts TEM image of the precursorsample obtained prior to hydrothermal treatment which sug-gests the presence of mostly aggregation of nearly sphericalnanoparticles of diameters in the range of 20ndash40 nm Theseaggregates are amorphous in nature as indicated from its dif-fused SAEDpatterns (inset of Figure 7(a))This finding is alsosupported by XRD analysis (Figure 5(a)) Figure 7(b) revealsthat the nanorod-shaped morphologies get formed evenafter 1 h of hydrothermal processing at 160∘C though someagglomerated spherical particles are still present With theincrease of the incubation to 12 h the number of rod-shapedparticles of Bi

2S3increased while the spherical aggregates

reduced drastically (Figure 7(c)) Pure crystalline nanorodsof Bi2S3were eventually realized on increasing the incubation

period to 18 h at the hydrothermal reaction temperature of160∘C (as shown in Figure 4(a)) It is interesting to note thaton increasing the heating period to 24 h a few nanowires ofBi2S3(indicated by arrows in Figure 7(d)) are also formed

amidst a pool of nanorodsThe effect of reaction temperature on the morphology of

the synthesized Bi2S3sample was also investigated by varying

the reaction temperature in the range of 120ndash180∘C for afixed incubation period (ie 6 h) The SEM images of thesynthesized samples at hydrothermal temperatures 120 140160 and 180∘C (Figure S2 Supporting Information) suggestthat rod-like morphologies with diameters in nanometerrange are formed after 6 h of incubation period irrespectiveof the hydrothermal reaction temperature However someaggregatedmasseswere visible when the reactionwas carriedout at a lower temperature which gradually disappeared asthe temperature was increased It can thus be inferred thatthe growth of nanorods occurs probably at the expense ofamorphous spherical particles

Based on the morphological findings and other experi-mental observations it is thus possible to propose a growthmechanism for the preparation of Bi

2S3 As it was already

mentioned earlier a large numbers of Bi2S3nuclei are

generated as a result of the decomposition of the precursorsat the initial stage of the hydrothermal reactionThese freshlyformednanocrystals or nuclei in the solution are unstable dueto the presence of a large number of dangling bonds defectsor traps on the nuclei surfaces Hence under hydrothermal


0 200 400 600 800

Bi 4

p

O 1

s

C 1s

S 2s

Bi 4

f (S

2p)

Bi 5

p

Bi 5

d

Inte

nsity

(au

)

Binding energy (eV)Bi

4p32

Bi4d52

Bi4d32

(a)

225 230 235 240

Inte

nsity

(au

)

Binding energy (eV)

S2minus 2s

S2+ 2s

(b)

155 160 165 170

Inte

nsity

(au

)

Binding energy (eV)

Bi 4f72 Bi 4f52

(c)

Figure 6 XPS analysis of the precursor sample (a) survey spectra (b) S region and (c) Bi region

condition the smaller Bi2S3nanocrystals precipitate onto

comparatively larger particles leading to growth of thecrystals along the energetically favorable direction (ie c-direction) to form the nanorods of Bi

2S3 The proposed

growth mechanism agrees with the morphological findingswhere it is evident that with the increase in the incubationperiod the Bi

2S3particles grew more rapidly along the

length compared to the diameters This oriented crystalgrowth can be attributed to the typical anisotropic layeredstructure of Bi

2S3 The process is also thermodynamically

driven by the decrease in the total interfacial energy of theparticles as a result of merging An analogous mechanismwas suggested by Zhu et al [41] for the growth of nanorodsfrom the initially formed Bi

2S3particles through a dynamic

equilibrium 2Bi3+ + 3S2minus harr Bi2S3 They proposed that the

Bi3+ and S2minus ions which were in equilibrium in solutionprecipitated onto larger particles thereby decreasing the totalinterfacial energy between the particles and the solution

Liu et al [16] recognized a similar growth sequence for thefabrication of Bi

2S3nanoribbons from NaBiS

2precursors

through solvothermal process but they choose to call themechanism as ldquosolid-solution-solid (SSS) transformationrdquoGates et al [42] also proposed the synthesis of single-crystalnanowires of selenium from spherical colloidal particles ofamorphous selenium in aqueous solution through similarmechanism and called it to be SSS transformation Based onthe discussion the formation and the overall growth processof the Bi

2S3nanorods through hydrothermal process can be

schematically represented by a sketch as shown in Figure 8On the other hand the formation of longer rods or

wires of Bi2S3(as shown in Figure 7(d)) probably occurred

at the expense of small rod-shaped particles which mergedto reduce the net interfacial energy of the particles Thisprediction is supported by bright field TEM images obtainedfor the sample synthesized at a hydrothermal temperature of160∘C for a period of 18 h (Figure 9) The contrast variation


(a)

2 120583m

(b)

5 120583m

(c)

1 120583m

(d)

Figure 7 (a) TEM image of precursor sample and the corresponding SAED pattern (inset) and SEM images of the sample obtained throughhydrothermal treatment at 160∘C (b) after 1 h (c) after 12 h and (d) after 24 h

Roomtemperature

Hydrothermal

Hydrothermal

Amorphousprecursors

Bi3+ + S2minus

160∘C for 18 h

160∘C for 1 h

Figure 8 Schematic representation of the growth of Bi2S3nanorods from spherical nanoparticles of precursors through hydrothermal

process

of TEM images (shown in Figures 9(a) and 9(b)) clearlydepicts the joining of a pair of Bi

2S3nanorods It can be

seen from the images that rods are continuous across theconnected part barring at some portions For further insightinto the microstructure at the junction the encircled portionof the TEM image was magnified (Figure 9(c)) which showsthe lattice planes at the joint Lattice spacing calculatedfrom the fringe pattern of the HRTEM image is found tobe 0476 nm corresponding to (120) plane of orthorhombicphase of Bi

2S3 It can be seen from images that fringes are

almost continuous across the joint with disrupted continuityonly at selected areaThe disrupted portion is indicated by anarrow in Figure 9(c)

It can thus be predicted that under hydrothermal condi-tions fusion of the particles at the interface takes place onlywhen joining particles are suitably positioned so as to share acommon crystallographic orientation A similar morpholog-ical sequence has also been observed by Yu et al [43] for the

synthesis of nanowires of Bi2S3from spherical crystals They

suggested that the formation of nanowires of Bi2S3occurred

via merging of short nanorods under hydrothermal reactionat 180∘C (for 3 days) of the solution containing sphericalcrystals of Bi

2S3 Deng et al [23] explained the fabrication of

sheet rods of Bi2Te3on the basis of EDTA-assisted controlling

oriented attachment of individual sheets They too proposedthat the joining process was thermodynamically driven by thereduction in the net surface energy of the particles and thejoining of particleswas possible onlywhen they had commoncrystallographic orientation On the basis of the present dis-cussion it can thus be inferred that both controlled orientedattachment and SSSmechanism cooperate in the formation ofnanorodswires of Bi

2S3from smaller rodsspherical particles

in the hydrothermal processIn the developed process TEA which serves as a sta-

bilizing agent for retaining the bismuth ions in solutionthrough complex formation as well as an efficient capping


(a) (b)

(120) 0476 nm

(c)

Figure 9 TEM images showing the joining of a pair of Bi2S3rods (marked by circles) (a) at low resolution (b) high resolution of image of

the encircled portion in (b) and (c) high resolution of image showing the fringe patterns at the joint

200 400 600 800 1000

0

10

20

30

40

50

60

Wavelength (nm)

Diff

use r

eflec

tion

()

Figure 10 Diffuse reflectance spectra of the Bi2S3samples synthe-

sized through hydrothermal process at a temperature of 160∘C andincubation period of 18 h

agent [44 45] also plays another important role in theformation of shape-controlled 1D structures of Bi

2S3 TEA

is a tetradentate ligand with three ndashOH groups and oneamine group that effectively coordinates to the ions orparticles and thereby modifies the surface energy states ofthe particles making them to grow in one dimension In theaqueous reactionmixture the unchelated free TEA probablyforms long chain polymeric framework [28] due to hydrogenbondingThese structuresmay help in assembling the initiallyformed nearly spherical particles to grow in one dimensionunder hydrothermal condition leading to the generation ofuniformly sized pure and crystalline 1D structures of Bi

2S3

To investigate the role of water in this mechanism furtherexperiments were carried out by heating a reaction mixturecontaining only TEA as a solvent (ie without water) in an

autoclave at 160∘C for 6 h and studying the morphology ofthe synthesized sample In this case Bi

2S3nanorods with

diameters and lengths in the range of 77ndash575 nm and 1200ndash3700 nm respectively (Figure S3 Supporting Information)were obtained in contrast to the nanorods (diameters andlengths in the range of 44ndash140 nm and 945ndash2150 nm resp)produced under similar reaction conditions with TEA andwater as reaction medium The results validated the utility ofwater in the reactionmedium for the generation of uniformlysized nanorods with high aspect ratio

Bi2S3has moderately high band gap energy (119864

119892) com-

pared to the other sulfides of the same group making themimportant materials for various optoelectronic applicationsSo the diffuse reflectance spectrum of the Bi

2S3sample

prepared at optimized hydrothermal reaction conditions (ieat 160∘C for 18 h) has been carried out at room temperatureand the result is depicted in Figure 10 The optical band gapwas calculated from the point of intersection of the tangentof the absorption edge and the extrapolated line of the diffusereflectance at lower wavelength and the value was found tobe 146 eV This calculated value lies in the band gap rangereported for bulk Bi

2S3 which may be attributed to their

larger average particle diameters compared to the excitonBohr radius of Bi

2S3(298 nm) [46]

4 Conclusions

Uniformly sized single-crystalline Bi2S3nanorods with aver-

age diameters and lengths in the range of 70ndash170 nmand 055ndash3120583m respectively have been synthesized throughhydrothermal reaction at a temperature as low as 160∘CThese nanorods have been found to be of pure orthorhom-bic phase as evident from XRD XPS and Raman spec-troscopy Nanorods of Bi

2S3have been generated at the

expense of the amorphous precursor precipitates formedat room temperature which has been found to consist ofaminium compounds of [Bi(S

2O3)]3minus and (BiS

2)minus The pre-

cursors undergo decomposition and subsequent growth into


nanorodswires through SSS as well as oriented-aggregation-growth process under hydrothermal conditions It is foundthat Bi

2S3nanorods with relatively good aspect ratio and

smooth surfaces are produced only when all the reactionconditions such as hydrothermal temperature incubationperiod and solvents are tuned

Acknowledgments

The authors acknowledge their sincere thanks to ProfessorB Viswanathan and Dr K Thirunavukkarasu of the IndianInstitute of Technology Madras for their help in character-izing the samples by XPS They also express their gratitudeto Professor M K Panigrahi of the Indian Institute ofTechnology Kharagpur for obtaining Raman spectra

References

[1] C Ye G Meng Z Jiang Y Wang G Wang and L ZhangldquoRational growth of Bi

2S3

nanotubes from quasi-two-dimensional precursorsrdquo Journal of the American ChemicalSociety vol 124 no 51 pp 15180ndash15181 2002

[2] S K Batabyal C Basu A R Das and G S Sanyal ldquoNanostruc-tures of bismuth sulphide synthesis and electrical propertiesrdquoJournal of Nanoscience and Nanotechnology vol 7 no 2 pp565ndash569 2007

[3] J D Desai and C D Lokhande ldquoChemical deposition of Bi2S3

thin films from thioacetamide bathrdquo Materials Chemistry andPhysics vol 41 no 2 pp 98ndash103 1995

[4] M T S Nair and P K Nair ldquoPhotoconductive bismuth sulphidethin films by chemical depositionrdquo Semiconductor Science andTechnology vol 5 no 12 pp 1225ndash1230 1990

[5] G Konstantatos L Levina J Tang and E H Sergeant ldquoSensi-tive solution-processed Bi

2S3nanocrystalline photodetectorsrdquo

Nano Letters vol 8 no 11 pp 4002ndash4006 2008[6] S C Liufu L D Chen Q Yao and C F Wang ldquoAssembly

of one-dimensional nanorods into Bi2S3films with enhanced

thermoelectric transport propertiesrdquo Applied Physics Lettersvol 90 Article ID 112106 3 pages 2007

[7] X Yu andC Cao ldquoPhotoresponse and field-emission propertiesof bismuth sulfide nanoflowersrdquo Crystal Growth amp Design vol8 pp 3951ndash3955 2008

[8] R S Mane B R Sankapal and C D Lokhande ldquoPhotoelectro-chemical cells based on chemically deposited nanocrystallineBi2S3thin filmsrdquoMaterials Chemistry and Physics vol 60 no 2

pp 196ndash203 1999[9] R Suarez P K Nair and P V Kamat ldquoPhotoelectrochemical

behavior of Bi2S3nanoclusters and nanostructured thin filmsrdquo

Langmuir vol 14 no 12 pp 3236ndash3241 1998[10] M S Dresselhaus G Chen M Y Tang et al ldquoNew directions

for low-dimensional thermoelectricmaterialsrdquoAdvancedMate-rials vol 19 no 8 pp 1043ndash1053 2007

[11] H Bao X Cui C M Li G Ye J Zhang and J Guo ldquoPho-toswitchable semiconductor bismuth sulfide (Bi

2S3) nanowires

and their self-supported nanowire arraysrdquoThe Journal of Phys-ical Chemistry C vol 111 no 33 pp 12279ndash12283 2007

[12] H Bao C M Li X Cui Q Song H Yang and J Guo ldquoSin-gle-crystalline Bi

2S3nanowire network film and its optical

switchesrdquo Nanotechnology vol 19 no 33 Article ID 3353022008

[13] Y W Koh C S Lai A Y Du E R T Tiekink and K PLoh ldquoGrowth of bismuth sulfide nanowire using bismuthtrisxanthate single source precursorsrdquo Chemistry of Materialsvol 15 no 24 pp 4544ndash4554 2003

[14] M B Sigman Jr and B A Korgel ldquoSolventless synthesis ofBi2S3(bismuthinite) nanorods nanowires and nanofabricrdquo

Chemistry of Materials vol 17 pp 1655ndash1660 2005[15] X S Peng G W Meng J Zhang et al ldquoElectrochemical fabri-

cation of ordered Bi2S3nanowire arraysrdquo Journal of Physics D

vol 34 no 22 pp 3224ndash3228 2001[16] Z P Liu J B Liang S Li S Peng and Y T Qian ldquoSynthesis and

growth mechanism of Bi2S3nanoribbonsrdquo European Journal of

Chemistry vol 10 no 3 pp 634ndash640 2004[17] H Zhang Y Ji X Y Ma J Xu and D Yang ldquoLong Bi

2S3

nanowires prepared by a simple hydrothermal methodrdquo Nan-otechnology vol 14 no 9 pp 974ndash977 2003

[18] J Jiang S H Yu W T Yao H Ge and G Z Zhang ldquoMor-phogenesis and crystallization of Bi

2S3nanostructures by an

ionic liquid-assisted templating route synthesis formationmechanism and propertiesrdquo Chemistry of Materials vol 17 no24 pp 6094ndash6100 2005

[19] T Thongtem A Phuruangrat S Wannapop and S ThongtemldquoCharacterization of Bi

2S3with different morphologies synthe-

sized using microwave radiationrdquoMaterials Letters vol 64 no2 pp 122ndash124 2010

[20] L Tian H Y Tan and J J Vittal ldquoMorphology-controlledsynthesis of Bi

2S3nanomaterials via single- andmultiple-source

approachesrdquoCrystal GrowthampDesign vol 8 no 2 pp 734ndash7382008

[21] J Wu F Qin G Cheng et al ldquoLarge-scale synthesis of bismuthsulfide nanorods by microwave irradiationrdquo Journal of Alloysand Compounds vol 509 no 5 pp 2116ndash2126 2011

[22] H S Yu J Yang Y S Wu Z H Han Y Xie and Y T QianldquoHydrothermal preparation and characterization of rod-likeultrafine powders of bismuth sulfiderdquo Materials Research Bul-letin vol 33 no 11 pp 1661ndash1666 1998

[23] Y Deng C W Nan and L Guo ldquoA novel approach to Bi2Te3

nanorods by controlling oriented attachmentrdquoChemical PhysicsLetters vol 383 no 5-6 pp 572ndash576 2004

[24] J R Ota and S K Srivastava ldquoPolypyrrole coating of Tartaricacid-assisted synthesized Bi

2S3nanorodsrdquoThe Journal of Physi-

cal Chemistry C vol 111 no 33 pp 12260ndash12264 2007[25] R ChenMH So CM Che andH Sun ldquoControlled synthesis

of high crystalline bismuth sulfide nanorods using bismuthcitrate as a precursorrdquo Journal of Materials Chemistry vol 15no 42 pp 4540ndash4545 2005

[26] G Z Shen D Chen K B Tang F Q Li and Y T QianldquoLarge-scale synthesis of uniform urchin-like patterns of Bi

2S3

nanorods through a rapid polyol processrdquo Chemical PhysicsLetters vol 370 no 3-4 pp 334ndash337 2003

[27] H Zhang and LWang ldquoSynthesis and characterization of Bi2S3

nanorods by solvothermal method in polyol mediardquo MaterialsLetters vol 61 no 8-9 pp 1667ndash1670 2007

[28] A Pathak S Mohapatra S Mohapatra et al ldquoPreparation ofnanosized mixed-oxide powdersrdquo American Ceramic SocietyBulletin vol 83 no 8 pp 9301ndash9306 2004

[29] H Wang J J Zhu J M Zhu and H Y Chen ldquoSonochemicalmethod for the preparation of bismuth sulfide nanorodsrdquo TheJournal of Physical Chemistry B vol 106 no 15 pp 3848ndash38542002


[30] A Jana C Bhattacharya S Sinha and J Datta ldquoStudy of theoptimal condition for electroplating of Bi

2S3thin films and their

photoelectrochemical characteristicsrdquoThe Journal of Solid StateElectrochemistry vol 13 no 9 pp 1339ndash1350 2009

[31] J Grigas E Talik and V Lazauskas ldquoX-ray photoemissionspectra and electronic structure of Bi

2S3crystalsrdquo Physica Status

Solidi B vol 232 pp 220ndash230 2002[32] O Rabin J M Perez J Grimm G Wojtkiewicz and R

Weissleder ldquoAn X-ray computed tomography imaging agentbased on long-circulating bismuth sulphide nanoparticlesrdquoNature Materials vol 5 pp 118ndash122 2006

[33] J R Ota and S K Srivastava ldquoLow temperature micelle-template assisted growth of Bi

2S3nanotubesrdquo Nanotechnology

vol 16 pp 2415ndash2419 2005[34] M S Bhadraver ldquoPhysico-chemical studies on the composition

of thiosulfates of metals I Thermometric studies of bismuththiosulfate complexesrdquo Bulletin of the Chemical Society of Japanvol 35 no 11 pp 1768ndash1770 1962

[35] X H Liao H Wang J J Zhu and H Y Chen ldquoPreparation ofBi2S3nanorods by microwave irradiationrdquo Materials Research

Bulletin vol 36 no 13-14 pp 2339ndash2346 2001[36] W B Zhao J J Zhu Y Zhao and H Y Chen ldquoPhotochemical

synthesis and characterization of Bi2S3nanofibersrdquo Materials

Science and Engineering B vol 110 no 3 pp 307ndash313 2004[37] W F Egelhoff Jr ldquoN

2on Ni(100) angular dependence of the

N1s XPS peaksrdquo Surface Science vol 141 no 2-3 pp L324ndashL3281984

[38] R Malakooti L Cademartiri Y Akcakir S Petrov A Miglioriand G A Ozin ldquoShape-Controlled Bi

2S3anocrystals and their

plasma polymerization into flexible filmsrdquo Advanced Materialsvol 18 no 16 pp 2189ndash2194 2006

[39] C D Wagner W M Riggs L E Davis and J F MoulderHandbook of X-Ray Photoelectron Spectroscopy Edited by G EMulenberg Perkin-Elmer Minneapolis Minn USA 1979

[40] P K Panigrahi and A Pathak ldquoMicrowave-assisted synthesis ofWS2nanowires through tetrathiotungstate precursorsrdquo Science

and Technology of Advanced Materials vol 9 no 4 Article ID045008 2008

[41] G Q Zhu P Liu J P Zhou et al ldquoEffect of mixed solventon the morphologies of nanostructured Bi

2S3prepared by

solvothermal synthesisrdquo Materials Letters vol 62 no 15 pp2335ndash2338 2008

[42] B Gates Y Yin and Y Xia ldquoA solution-phase approach to thesynthesis of uniform nanowires of crystalline selenium withlateral dimensions in the range of 10ndash30 nmrdquo Journal of theAmerican Chemical Society vol 122 no 50 pp 12582ndash125832000

[43] Y Yu C H Jin R H Wang Q Chen and L M PengldquoHigh-quality ultralong Bi

2S3nanowires structure growth and

propertiesrdquoThe Journal of Physical Chemistry B vol 109 no 40pp 18772ndash18776 2005

[44] A K Singh V Viswanath and V C Janu ldquoSynthesis effectof capping agents structural optical and photoluminescenceproperties of ZnO nanoparticlesrdquo Journal of Luminescence vol129 no 8 pp 874ndash878 2009

[45] M S Mohajerani M Mazloumi A Lak A Kajbafvala SZanganeh and S K Sadrnezhaad ldquoSelf-assembled zinc oxidenanostructures via a rapidmicrowave-assisted routerdquo Journal ofCrystal Growth vol 310 no 15 pp 3621ndash3625 2008

[46] B Pejova and I Grozdanov ldquoStructural and optical properties ofchemically deposited thin films of quantum-sized bismuth(III)

sulfiderdquoMaterials Chemistry and Physics vol 99 no 1 pp 39ndash49 2006

Submit your manuscripts athttpwwwhindawicom

ScientificaHindawi Publishing Corporationhttpwwwhindawicom Volume 2013

CorrosionInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2013


Polymer ScienceInternational Journal of

ISRN Corrosion



CompositesJournal of

Advances in

Materials Science and EngineeringHindawi Publishing Corporationhttpwwwhindawicom Volume 2013

International Journal of

BiomaterialsHindawi Publishing Corporationhttpwwwhindawicom Volume 2013

ISRN Ceramics


Hindawi Publishing Corporationhttpwwwhindawicom

Volume 2013

MaterialsJournal of

NanotechnologyHindawi Publishing Corporationhttpwwwhindawicom Volume 2013

Journal of

ISRN Materials Science


Hindawi Publishing Corporation httpwwwhindawicom Volume 2013Hindawi Publishing Corporation httpwwwhindawicom Volume 2013

The Scientific World Journal

ISRN Nanotechnology


NanoparticlesJournal of


Smart Materials Research



MetallurgyJournal of

BioMed Research International


ISRN Polymer Science


Na

nom

ate

ria

ls


Journal ofNanomaterials


ionic liquid-assisted route [18] Among these processessolvothermalhydrothermal method is one of the most stud-ied solution-based synthesis route for the fabrication of 1Dnanostructures of Bi

2S3because this technique allows the

opportunities to control the morphology of the final prod-ucts through the variation of different reaction parameterswhich include reaction temperature reaction time reactionmedium (or solvent) bismuth and sulfur sources complexingagent and surfactant [19ndash21] Besides in the context ofthe possibilities to modify the growth behaviour of Bi

2S3

crystal to anisotropic one the use of soft templates (suchas surfactant complexing agent and block copolymer) asgrowth-directing agent has received significant amount ofresearch interest in the recent past Among various growth-directing agents the use of a complexing agent to change thegrowth behaviour (ie both nucleation and growth rate) andto confine it in a desired direction remained an interestingaspect The complexing agents are generally polyfunctionalligands that coordinate to the surface of either the ions orthe nanoparticles formed modify the particle surface energyand thereby enforce the unidirectional growth of the crystalThese bi- or multidentate ligands in some cases also act as asoft template in the growth process

There are a number of reports on the synthesis of 1Dnanostructured Bi

2S3by using organic ligands such as long

chain amines alcohols and acids as complexing agents Yu etal for example reported the use of EDTA as a coordinatingagent for the preparation of Bi

2S3nanorods [22] EDTA plays

multiple roles as a coordinating agent for Bi3+ as well as asoft template for the growth of nanorods under solvothermalcondition [23] On the other hand Ota and Srivastava [24]utilized amultifunctional organicmolecule (ie tartaric acid)as a capping agent for producing nanorods of Bi

2S3 Similarly

Chen et al [25] synthesized highly crystalline Bi2S3nanorods

using bismuth citrate and thiourea as precursor materialsin the presence of cetyltrimethylammonium bromide Theyclaimed that the growth of nanorods is assisted by linearbismuth citrate polymer template In addition a number ofpolyols for example ethylene glycol [26] diethylene glycol(DEG) [27] and so forth have been reported to assist in thedirection-arrested one-dimensional growth of Bi

2S3 In this

process the multiple ndashOH groups cap the formed particlesof Bi2S3and make them stable These polyols could also

exist in long chains due to the effective hydrogen bondingbetween them that serves as a template for growth of Bi

2S3

nuclei to form nanorods [27] Triethanolamine (TEA) isanother important tetradentate chelating ligand containingthree ndashOH and one amine group which like diethyleneglycol exists as a long chain polymeric framework in thepresence of water due to the effective hydrogen bonding [28]Moreover TEA is miscible with water in all proportions andcan be used in hydrothermal process successfully Henceit is expected that the use of this organic ligand can bean alternative route for the synthesis of Bi

2S3nanorods

However the use of TEA for the synthesis of 1Dnanostructureof Bi2S3powders is limited only to a few reports [29]

Therefore the present work aims at synthesizing nano-rods of Bi

2S3by using TEA as a complexing agent under

hydrothermal condition In the developed process a noveland inexpensive sulfur source that is elemental sulfur sol-ubilized in monoethanolamine (MEA) has been used Theessence of this work lies in the formation of amorphousspherical precursors at room temperature and subsequentlytheir transformation into nanorods under hydrothermalcondition A growth mechanism is also proposed

2 Experimental Details

21 Materials Bismuth nitrate (Bi(NO3)3sdot5H2O) triethanol-

amine (HOC2H4)3N) monoethanolamine (HOC

2H4NH2)

and elemental sulfur were purchased fromMerck India andused as received without further purification

22 Synthesis In a typical preparation 1 g of bismuth nitratewas solubilized in a mixture of 20mL of TEA and 120mLof distilled water by stirring continuously for 1 h The clearsolution was obtained possibly through the formation of[Bi(TEA)

119909

3+] complex [29 30] Elemental sulfur (0132 g)was separately dissolved in 10mL of MEA and it was thenpoured into the solution of [Bi(TEA)

119909]3+ complex A brown

precipitate was obtained immediately which turned graywithin few seconds The entire solution mixture containingthe gray colored solid precursor (ie the precursor sol) wasthen transferred to a Teflon-lined stainless steel autoclave andsubjected to hydrothermal reaction at 160∘C After coolingthe autoclave naturally to room temperature the precipitateswere collected washedwithwater for several times andfinallywith ethanol and dried For the investigation of the reactionmechanism the precursor sol formed at room temperature(prior to hydrothermal treatment) was also collected sep-arately and characterized This sample was referred to asldquoprecursor samplerdquo in the later part of the paper

23 Characterization The phase and structure analysis ofthe synthesized samples were carried out on Philips PW1729 X-ray diffractometer using Co K

120572radiation (120582 =

179 A) X-ray photoelectron spectroscopy (XPS) studies ofthe samples were carried out on an XPS system made byOmicron NanoTechnology using Mg K

120572(12536 eV) as the

excitation source The morphologies of the samples werestudied by using JEOL JSM-5800 model and Zeiss EVO-60 model scanning electron microscope The chemical com-positions of the samples were confirmed through energydispersive analysis by X-ray (EDAX) using Oxford INCAelectron microprobe attached to scanning electron micro-scope JEOL JEM-2100 model high-resolution transmissionelectron microscope (HRTEM) was used to examine themicrostructural details of the prepared samples Raman spec-troscopy was performed using Renishaw RM-1000 modelinstrument equipped with an Ar ion laser of wavelength5144 nmThediffuse reflectance spectra of the as-synthesizedpowders were recorded at room temperature using VarianCary 5000 UV-Vis-NIR spectrophotometer


10 20 30 40 50 60 70 80

Inte

nsity

(au

)

522

171

242

16106

135

122

216

006

043

100

252

0421

141

041231

240

311

410

221

211

021

130

101

220

12002

0

310

2120579 (deg)







2S3


72and Bi 4f

52













2S3






2S3was accomplished




0 200 400 600 800O

1s

Bi 4

d

C 1sS 2s

Bi 4

f

Bi 5

d

Inte

nsity

(au

)

Binding energy (eV)

Bi4p32

Bi4p12

(a)

155 160 165 170

Inte

nsity

(au

)

Binding energy (eV)

4f72

4f52

(b)


Inte

nsity

(au

)

S 2s

(c)


and (c) S region








2S2O3in





with CS2and NH






2O3)]3minus]




2are reported in




200 400 600 800 1000 1200 14000

10000

20000

30000

40000

Inte

nsity

(au

)


965

606

306

42226

0


5 120583m

(a) (b)

[001]

(c)

056 nm

(d)




2)minus and [Bi(S

2O3)3]3minus The





2O3


2O3

2minus species and


10 20 30 40 50 60 70 80 90

Inte

nsity

(au

) (d)

(c)

(b)

(a)

lowast

lowast

2120579 (deg)65

181

027

1

310

171

242

061

161421

520 00

2 431

060 35

116

0

141

22212

0 220

101

130

021

211

221

410

311 24

023

1 04102

0




and Bi 4f52








2S3can be pro-


2O3


2O3


2)minus and [Bi(S

2O3)]3minus) as per



Bi3+ + 3S2O32minus999445999468 [Bi(S2O3)3]

3minus (2)








BiS minus (3)



(4)

Bi Shydrothermal

Bi S (5)


2S3 the effect













0 200 400 600 800

Bi 4

p

O 1

s

C 1s

S 2s

Bi 4

f (S

2p)

Bi 5

p

Bi 5

d

Inte

nsity

(au

)


4p32

Bi4d52

Bi4d32

(a)

225 230 235 240

Inte

nsity

(au

)

Binding energy (eV)

S2minus 2s

S2+ 2s

(b)

155 160 165 170

Inte

nsity

(au

)

Binding energy (eV)

Bi 4f72 Bi 4f52

(c)




2S3 The proposed











2precursors







(a)

2 120583m

(b)

5 120583m

(c)

1 120583m

(d)


Roomtemperature

Hydrothermal

Hydrothermal

Amorphousprecursors

Bi3+ + S2minus

160∘C for 18 h

160∘C for 1 h


process

















(a) (b)

(120) 0476 nm

(c)



200 400 600 800 1000

0

10

20

30

40

50

60

Wavelength (nm)

Diff

use r

eflec

tion

()




2S3 TEA


2S3



2S3nanorods with



119892) com-


2S3sample




2S3(298 nm) [46]

4 Conclusions






2)minus The pre-






Acknowledgments


References


2S3


















2S3) nanowires












2S3




















2S3































2S3prepared by
















ISRN Corrosion




Advances in




ISRN Ceramics



Volume 2013

MaterialsJournal of


Journal of





ISRN Nanotechnology












Na

nom

ate

ria

ls




10 20 30 40 50 60 70 80

Inte

nsity

(au

)

522

171

242

16106

135

122

216

006

043

100

252

0421

141

041231

240

311

410

221

211

021

130

101

220

12002

0

310

2120579 (deg)







2S3


72and Bi 4f

52













2S3






2S3was accomplished




0 200 400 600 800O

1s

Bi 4

d

C 1sS 2s

Bi 4

f

Bi 5

d

Inte

nsity

(au

)

Binding energy (eV)

Bi4p32

Bi4p12

(a)

155 160 165 170

Inte

nsity

(au

)

Binding energy (eV)

4f72

4f52

(b)


Inte

nsity

(au

)

S 2s

(c)


and (c) S region








2S2O3in





with CS2and NH






2O3)]3minus]




2are reported in




200 400 600 800 1000 1200 14000

10000

20000

30000

40000

Inte

nsity

(au

)


965

606

306

42226

0


5 120583m

(a) (b)

[001]

(c)

056 nm

(d)




2)minus and [Bi(S

2O3)3]3minus The





2O3


2O3

2minus species and


10 20 30 40 50 60 70 80 90

Inte

nsity

(au

) (d)

(c)

(b)

(a)

lowast

lowast

2120579 (deg)65

181

027

1

310

171

242

061

161421

520 00

2 431

060 35

116

0

141

22212

0 220

101

130

021

211

221

410

311 24

023

1 04102

0




and Bi 4f52








2S3can be pro-


2O3


2O3


2)minus and [Bi(S

2O3)]3minus) as per



Bi3+ + 3S2O32minus999445999468 [Bi(S2O3)3]

3minus (2)








BiS minus (3)



(4)

Bi Shydrothermal

Bi S (5)


2S3 the effect













0 200 400 600 800

Bi 4

p

O 1

s

C 1s

S 2s

Bi 4

f (S

2p)

Bi 5

p

Bi 5

d

Inte

nsity

(au

)


4p32

Bi4d52

Bi4d32

(a)

225 230 235 240

Inte

nsity

(au

)

Binding energy (eV)

S2minus 2s

S2+ 2s

(b)

155 160 165 170

Inte

nsity

(au

)

Binding energy (eV)

Bi 4f72 Bi 4f52

(c)




2S3 The proposed











2precursors







(a)

2 120583m

(b)

5 120583m

(c)

1 120583m

(d)


Roomtemperature

Hydrothermal

Hydrothermal

Amorphousprecursors

Bi3+ + S2minus

160∘C for 18 h

160∘C for 1 h


process

















(a) (b)

(120) 0476 nm

(c)



200 400 600 800 1000

0

10

20

30

40

50

60

Wavelength (nm)

Diff

use r

eflec

tion

()




2S3 TEA


2S3



2S3nanorods with



119892) com-


2S3sample




2S3(298 nm) [46]

4 Conclusions






2)minus The pre-






Acknowledgments


References


2S3


















2S3) nanowires












2S3




















2S3































2S3prepared by
















ISRN Corrosion




Advances in




ISRN Ceramics



Volume 2013

MaterialsJournal of


Journal of





ISRN Nanotechnology












Na

nom

ate

ria

ls




0 200 400 600 800O

1s

Bi 4

d

C 1sS 2s

Bi 4

f

Bi 5

d

Inte

nsity

(au

)

Binding energy (eV)

Bi4p32

Bi4p12

(a)

155 160 165 170

Inte

nsity

(au

)

Binding energy (eV)

4f72

4f52

(b)


Inte

nsity

(au

)

S 2s

(c)


and (c) S region








2S2O3in





with CS2and NH






2O3)]3minus]




2are reported in




200 400 600 800 1000 1200 14000

10000

20000

30000

40000

Inte

nsity

(au

)


965

606

306

42226

0


5 120583m

(a) (b)

[001]

(c)

056 nm

(d)




2)minus and [Bi(S

2O3)3]3minus The





2O3


2O3

2minus species and


10 20 30 40 50 60 70 80 90

Inte

nsity

(au

) (d)

(c)

(b)

(a)

lowast

lowast

2120579 (deg)65

181

027

1

310

171

242

061

161421

520 00

2 431

060 35

116

0

141

22212

0 220

101

130

021

211

221

410

311 24

023

1 04102

0




and Bi 4f52








2S3can be pro-


2O3


2O3


2)minus and [Bi(S

2O3)]3minus) as per



Bi3+ + 3S2O32minus999445999468 [Bi(S2O3)3]

3minus (2)








BiS minus (3)



(4)

Bi Shydrothermal

Bi S (5)


2S3 the effect













0 200 400 600 800

Bi 4

p

O 1

s

C 1s

S 2s

Bi 4

f (S

2p)

Bi 5

p

Bi 5

d

Inte

nsity

(au

)


4p32

Bi4d52

Bi4d32

(a)

225 230 235 240

Inte

nsity

(au

)

Binding energy (eV)

S2minus 2s

S2+ 2s

(b)

155 160 165 170

Inte

nsity

(au

)

Binding energy (eV)

Bi 4f72 Bi 4f52

(c)




2S3 The proposed











2precursors







(a)

2 120583m

(b)

5 120583m

(c)

1 120583m

(d)


Roomtemperature

Hydrothermal

Hydrothermal

Amorphousprecursors

Bi3+ + S2minus

160∘C for 18 h

160∘C for 1 h


process

















(a) (b)

(120) 0476 nm

(c)



200 400 600 800 1000

0

10

20

30

40

50

60

Wavelength (nm)

Diff

use r

eflec

tion

()




2S3 TEA


2S3



2S3nanorods with



119892) com-


2S3sample




2S3(298 nm) [46]

4 Conclusions






2)minus The pre-






Acknowledgments


References


2S3


















2S3) nanowires












2S3




















2S3































2S3prepared by
















ISRN Corrosion




Advances in




ISRN Ceramics



Volume 2013

MaterialsJournal of


Journal of





ISRN Nanotechnology












Na

nom

ate

ria

ls




200 400 600 800 1000 1200 14000

10000

20000

30000

40000

Inte

nsity

(au

)


965

606

306

42226

0


5 120583m

(a) (b)

[001]

(c)

056 nm

(d)




2)minus and [Bi(S

2O3)3]3minus The





2O3


2O3

2minus species and


10 20 30 40 50 60 70 80 90

Inte

nsity

(au

) (d)

(c)

(b)

(a)

lowast

lowast

2120579 (deg)65

181

027

1

310

171

242

061

161421

520 00

2 431

060 35

116

0

141

22212

0 220

101

130

021

211

221

410

311 24

023

1 04102

0




and Bi 4f52








2S3can be pro-


2O3


2O3


2)minus and [Bi(S

2O3)]3minus) as per



Bi3+ + 3S2O32minus999445999468 [Bi(S2O3)3]

3minus (2)








BiS minus (3)



(4)

Bi Shydrothermal

Bi S (5)


2S3 the effect













0 200 400 600 800

Bi 4

p

O 1

s

C 1s

S 2s

Bi 4

f (S

2p)

Bi 5

p

Bi 5

d

Inte

nsity

(au

)


4p32

Bi4d52

Bi4d32

(a)

225 230 235 240

Inte

nsity

(au

)

Binding energy (eV)

S2minus 2s

S2+ 2s

(b)

155 160 165 170

Inte

nsity

(au

)

Binding energy (eV)

Bi 4f72 Bi 4f52

(c)




2S3 The proposed











2precursors







(a)

2 120583m

(b)

5 120583m

(c)

1 120583m

(d)


Roomtemperature

Hydrothermal

Hydrothermal

Amorphousprecursors

Bi3+ + S2minus

160∘C for 18 h

160∘C for 1 h


process

















(a) (b)

(120) 0476 nm

(c)



200 400 600 800 1000

0

10

20

30

40

50

60

Wavelength (nm)

Diff

use r

eflec

tion

()




2S3 TEA


2S3



2S3nanorods with



119892) com-


2S3sample




2S3(298 nm) [46]

4 Conclusions






2)minus The pre-






Acknowledgments


References


2S3


















2S3) nanowires












2S3




















2S3































2S3prepared by
















ISRN Corrosion




Advances in




ISRN Ceramics



Volume 2013

MaterialsJournal of


Journal of





ISRN Nanotechnology












Na

nom

ate

ria

ls




10 20 30 40 50 60 70 80 90

Inte

nsity

(au

) (d)

(c)

(b)

(a)

lowast

lowast

2120579 (deg)65

181

027

1

310

171

242

061

161421

520 00

2 431

060 35

116

0

141

22212

0 220

101

130

021

211

221

410

311 24

023

1 04102

0




and Bi 4f52








2S3can be pro-


2O3


2O3


2)minus and [Bi(S

2O3)]3minus) as per



Bi3+ + 3S2O32minus999445999468 [Bi(S2O3)3]

3minus (2)








BiS minus (3)



(4)

Bi Shydrothermal

Bi S (5)


2S3 the effect













0 200 400 600 800

Bi 4

p

O 1

s

C 1s

S 2s

Bi 4

f (S

2p)

Bi 5

p

Bi 5

d

Inte

nsity

(au

)


4p32

Bi4d52

Bi4d32

(a)

225 230 235 240

Inte

nsity

(au

)

Binding energy (eV)

S2minus 2s

S2+ 2s

(b)

155 160 165 170

Inte

nsity

(au

)

Binding energy (eV)

Bi 4f72 Bi 4f52

(c)




2S3 The proposed











2precursors







(a)

2 120583m

(b)

5 120583m

(c)

1 120583m

(d)


Roomtemperature

Hydrothermal

Hydrothermal

Amorphousprecursors

Bi3+ + S2minus

160∘C for 18 h

160∘C for 1 h


process

















(a) (b)

(120) 0476 nm

(c)



200 400 600 800 1000

0

10

20

30

40

50

60

Wavelength (nm)

Diff

use r

eflec

tion

()




2S3 TEA


2S3



2S3nanorods with



119892) com-


2S3sample




2S3(298 nm) [46]

4 Conclusions






2)minus The pre-






Acknowledgments


References


2S3


















2S3) nanowires












2S3




















2S3































2S3prepared by
















ISRN Corrosion




Advances in




ISRN Ceramics



Volume 2013

MaterialsJournal of


Journal of





ISRN Nanotechnology












Na

nom

ate

ria

ls




0 200 400 600 800

Bi 4

p

O 1

s

C 1s

S 2s

Bi 4

f (S

2p)

Bi 5

p

Bi 5

d

Inte

nsity

(au

)


4p32

Bi4d52

Bi4d32

(a)

225 230 235 240

Inte

nsity

(au

)

Binding energy (eV)

S2minus 2s

S2+ 2s

(b)

155 160 165 170

Inte

nsity

(au

)

Binding energy (eV)

Bi 4f72 Bi 4f52

(c)




2S3 The proposed











2precursors







(a)

2 120583m

(b)

5 120583m

(c)

1 120583m

(d)


Roomtemperature

Hydrothermal

Hydrothermal

Amorphousprecursors

Bi3+ + S2minus

160∘C for 18 h

160∘C for 1 h


process

















(a) (b)

(120) 0476 nm

(c)



200 400 600 800 1000

0

10

20

30

40

50

60

Wavelength (nm)

Diff

use r

eflec

tion

()




2S3 TEA


2S3



2S3nanorods with



119892) com-


2S3sample




2S3(298 nm) [46]

4 Conclusions






2)minus The pre-






Acknowledgments


References


2S3


















2S3) nanowires












2S3




















2S3































2S3prepared by
















ISRN Corrosion




Advances in




ISRN Ceramics



Volume 2013

MaterialsJournal of


Journal of





ISRN Nanotechnology












Na

nom

ate

ria

ls




(a)

2 120583m

(b)

5 120583m

(c)

1 120583m

(d)


Roomtemperature

Hydrothermal

Hydrothermal

Amorphousprecursors

Bi3+ + S2minus

160∘C for 18 h

160∘C for 1 h


process

















(a) (b)

(120) 0476 nm

(c)



200 400 600 800 1000

0

10

20

30

40

50

60

Wavelength (nm)

Diff

use r

eflec

tion

()




2S3 TEA


2S3



2S3nanorods with



119892) com-


2S3sample




2S3(298 nm) [46]

4 Conclusions






2)minus The pre-






Acknowledgments


References


2S3


















2S3) nanowires












2S3




















2S3































2S3prepared by
















ISRN Corrosion




Advances in




ISRN Ceramics



Volume 2013

MaterialsJournal of


Journal of





ISRN Nanotechnology












Na

nom

ate

ria

ls




(a) (b)

(120) 0476 nm

(c)



200 400 600 800 1000

0

10

20

30

40

50

60

Wavelength (nm)

Diff

use r

eflec

tion

()




2S3 TEA


2S3



2S3nanorods with



119892) com-


2S3sample




2S3(298 nm) [46]

4 Conclusions






2)minus The pre-






Acknowledgments


References


2S3


















2S3) nanowires












2S3




















2S3































2S3prepared by
















ISRN Corrosion




Advances in




ISRN Ceramics



Volume 2013

MaterialsJournal of


Journal of





ISRN Nanotechnology












Na

nom

ate

ria

ls







Acknowledgments


References


2S3


















2S3) nanowires












2S3




















2S3































2S3prepared by
















ISRN Corrosion




Advances in




ISRN Ceramics



Volume 2013

MaterialsJournal of


Journal of





ISRN Nanotechnology












Na

nom

ate

ria

ls




























2S3prepared by
















ISRN Corrosion




Advances in




ISRN Ceramics



Volume 2013

MaterialsJournal of


Journal of





ISRN Nanotechnology












Na

nom

ate

ria

ls









ISRN Corrosion




Advances in




ISRN Ceramics



Volume 2013

MaterialsJournal of


Journal of





ISRN Nanotechnology












Na

nom

ate

ria

ls



the growth of bismuth sulfide nanorods from spherical-shaped

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