películas absorbedoras para celdas solares por depósito ...pkn/solace2008tutorial.pdf · research...
TRANSCRIPT
TutorialJanuary 20, 2008
Cochin University of Science and Technology
Research in chemically deposited solar cells
P. Karunakaran Nair
Centro de Investigación en EnergíaUniversidad Nacional Autónoma de México
Temixco, Morelos 62580, Mé[email protected]
In Collaboration with:
M. T. S. Nair, Harumi Moreno, Sarah Messina, D. Avellaneda, Jose Campos, O. GomezDaza, Ma. Luisa Ramon G.
Pilkington-Toledo OH, BHEL-Gurgaon
Funding: CONACYT, Mexico; DGAPA-UNAM
Solace2008, Kochi
Outline
1. PV fundamentals and material issues - just how
many solar cell technologies..?
2. Chemical deposition and scope for low efficiency
solar cells
3. Chemically deposited photovoltaic structures
4. Prospects
PV fundamentals and material issues just how many solar cell
technologies..?
Borrowed from David E. Carlson talk, March 2006
Borrowed from David E. Carlson talk, March 2006
Just how many solar cell technologies..?
1950 1960 1970 1980 1990 2000
5
10
15
20
25E
ffici
ency
(%)
Year
crystalline Siamorphous Sinano TiO2CIS/CIGSCdTe
Nathan S. Lewis, www.caltech.edu
Just how many solar cell technologies..?
Worst day insolation map (kWh/m2/day ) PV sellers’ strategic web map
Just how many solar cell technologies..?
6 Boxes at 3.3 TW each; Nathan S. Lewis, www.caltech.edu
Just how many solar cell technologies..?
Just how many solar cell technologies..?Semicond. Mexican
Production (2004)
William W. Porterfield, Inorganic Chemistry: a united approach, Academic 1993 San Diego, p. 9.
Ag (3,000 ton)
www.inegi.gob.mx
Chalcogenide Absorbers
Most investigated:
• CdTe - Eg, 1.47 eV; α > 105 cm-1 (vis)solar cells: η ~ 16.5%
• Chalcopyrite - Cu(In1-xGax)Se2 (CIGS) Eg, 1.04 – 1.37 eV; α >105 cm-1
solar cells: η ~ 19.5% (x = 0.3)
Cd2SnO4/Zn2SnO4/CdS/CdTe/CuTe:HgTe-doped graphite paste
CTO – rf magnetron sputtering, low resistivity;ZTO – Buffer, high resistivity;CdS – Chemical bath;CdTe- Close-space sublimation (css)
Voc, 845 mV; Jsc, 25.88 mA/cm2; FF, 75.51%; 1.032 cm2
NREL: X. Wu et al, Preprint NCPV Program Review Meeting, Lakewood, CO, Oct 2001
η ~ 16.5%
Mo/CuIn1-xGaxSe2/CdS/ZnO-Al2O3 dopedZnO/Ni-Al grid/MgF2
• Mo-sputter coating• CIGS (2-4 µm)- evaporation,
three-stage process: (In-Ga)2Se, react with Cu & Se,
• Evaporation of In and Ga in the presence of Se;
• CdS (50 nm) – chemical bath;• ZnO (90 nm)-Al2O3 coated
ZnO (120 nm) – sputter coating, 60-70 Ω/;
• MgF2 (100 nm)- electron beam evaporation
• CIGS: x ~ 0.3; Eg, ~1.14 eV • η ~ 19.5%- area, 0.41 cm2
• Voc, 693 mV; • Jsc, 35.34 mA/cm2; • FF, 79.4 %.
K. Ramanathan et al, Thin Solid Films 480-481 (2005) 499-502;
Contreras et al, Prog. Photovolt : Res. Appl. 13 (2005) 209-216
Abundance: Cd, 0.1 ppm; Te, 0.005 ppm; In, 0.05 ppm; Ga,15 ppm; Ru, 0.0001ppm
At system efficy. of 10%, for 100,000 TWh/yr PV electricity
Solar cell Mater. req. Total req.
Total req/ resources
CdTe (1.5 µm) 4.7 g/m2 of Te 2,400,000 m.tons
110
CuIn0.75Ga0.25Se2 (2 µm) 2.9 g/m2 of In 1,400,000 m.tons
650
Potential to reduce materials exists: only 0.5 µm of CIGS and 1.0 µm of CdTeare needed to absorb 90% of the photons
B. A. Andersson, et al, Energy, 23 (1998) 407 – 411; Energy Policy 28 (2000) 1037-1049
CdTe & CIGS cells
Material constraints are unlikely to affect production prior to 2015
Could serve as bridging technologies so that other solar cell technologies can emerge
Abundant use of these cells would:(i) prepare the electricity market for solar cells in
general(ii) be beneficial for the emergence of the solar cell
industry as a whole
Just how many solar cell technologies..?
A Statement of Understanding
• Photovoltaic technologies meeting the future demand for photovoltaic modules would complement each other.
• There is room for developing distinct technologies making use of local/regional raw materials and appropriate technologies to satisfy local need.
Chemical depositionscope for low efficiency solar cells
Chemical deposition – by flotation
Optimization of: 1. composition of bath mixture
2. quantity of bath per surface area of the substrate
3. duration and temperature of deposition
4. post deposition processing and/or multilayer deposition
Chemical deposition – solar radiation control and low-efficiency solar cells..
Heat transfer - G. Alvarez, et al: Solar Energy 78 (2005) 113
Mechanical - J. O. Aguilar, et al: Surf. Coat. Technol. 200 (2005) 2557
Tvis 20%, Tsol 13%, Rsol 16%, Asol 71%
End use saving 40%, PV gen 5%
a great step forward!
Chemical deposition – by immersion
Chemical deposition – scope for low efficiency solar cells..
980 W/m2
180 W/m2
Chemical deposition – scope for low efficiency solar cells..
www.sunwize.com grid-tieD. E. Carlson talk, 2006
Create comfort space with a solar roof; the value added is welcome!
Then 5% PV/solar control roof too has a role to play!
chemical deposition:scope for low efficiency solar cells
PV cells inside cellular plastic sheets – no lamination or
support structures
Sheet area: 15 sheets x 1.5 square meter: 22.5 sq mPV power @ 5% efficiency ≈ 1 kWe
And we also just created 22.5 sq m of valuable comfort zone underneath!
Hu, Nair, PET: J. Cryst.Growth 152(1995)150; Nair et al, Polyethersulfone: Thin Solid Films, 401 (2001) 243; J. Cardoso et al, polyimide: Semicond Sci. Technol. 16 (2001) 123
Chemically deposited photovoltaic structures
Chemically deposited photovoltaic structures…
Chemical deposition: a brief history1835 Liebig ‘silver mirror’1869 PbS, CuS, Sb2S3 thin films from chemical solutions1884 Emerson-Reynolds - PbS thin films, J. Chem. Soc. 45:162, 18841906 Rosenheim et al – Chemically deposited PbS IR detectors1940’s Chemically deposited PbS y PbSe detectors in missile heads
1960-2006 II-VI: CdS, ZnS; IV-VI: PbS,SnS; V-VI: Sb2S3; I-VI:CuS;I-III-VI: CuInS2; I-V-VI: CuSbS2; III-V: InAs, InSb; I-II-IV-VI: Cu2ZnSnS4 and the selenides
1990’s Chemically deposited CdS thin films in high efficiency solar cells2000’s Nano-technology
Gary Hodes: Chemical Solution Deposition of Semiconductor Films, Marcel Dekker 2003
Chemically deposited photovoltaic structures…
CdS direct ~ 2.45 eVZnS direct ~ 3.7 eVZnSe direct ~ 2.7 eV
CdSe direct ~ 1.7 - 2.0 eVSb2S3 direct ~ 1.7 - 1.8 eVSnS direct ~ 1.6 eV
CuSe, Cu2-xSe direct ~ 2.1 – 2.3 eV; indirect, ~ 1.2 - 1.4 eV
CuS, Cu1.8S, Cu1.96S direct, ~ 1.55 - 1.4 eV
Bi2S3 direct ~ 1.4 – 1.5 eVSb2Se3 indirect? ~ 1 – 1.2 eVTl2S direct ~ 1.12 eV, Bi2Se3 direct ~ 1.08-1.06 eV Ag2S direct ~ 1 eVPbS direct ~ 0.4 – 0.7 eV PbSe direct ~ 0.6 eV(?)
CuSbS2, Cu3SbS4, AgSbSe2, Cu3BiS3, Cu4SnS4, Cu2SnS3,
TlSbS2, TlSbS2
P. K. Nair, et al, Sol. Energy Mater. Sol. Cells, 52, 313 (1998)….more than 70 compound semiconductors to work with!
Chemically deposited photovoltaic structures..
0.5 1.0 1 .5 2. 0 2.5 3.0 3.5 4.0102
103
104
105
106
CdS(cub)2.45 eV
Sb2(S/Se)
3
1 eV
Sb2 S3 1.7 eV
Optical Absorption Coeff ic ients of Chemically Deposited Thin Filims
PbS0.6 eV
ZnS3.45 eV
ZnO3.4 eV
CdS( hex)2.6 eV
SnS(cub)1.75 eV
Bi2S3 1.6 eV
α (c
m)-1
hυ (eV)
95% abs, 300 nm
For quantum size effects...G. Hodes, Phys. Chem. Chem. Phys. 9(2007) 2181-2196
Optical Conversion Efficiency: (i) photon absorption and e-h generation;(ii) Separation of e-h across the depletion region (iii) collection and work
Optical
Effic. %
Optical band gap Eg(eV)
Carrier multiplication at hν > 2Eg and super efficiencies ..? G. Nair, M. Bawendi, Phys. Rev. B 76, 081304(R) (2007)
Chemically deposited photovoltaic structures…
SnO2:F-CdS-SnS(A)-CuS-AgCdS (100 nm) - 0.1 M cadmium nitrate,1 M sodium citrate,
ammonia (aq), 1M thiourea,; 80 oC, 3h; predominantly hexagonal; photoconductive with conductivity σ~ 10-3 – 10-2 (Ω cm)-1, can be doped n-type; Eg ~ 2.6 eV
SnS - (Bath A) (100 nm)
CuS – 0.5 M CuCl2, 3.7 M triethanolamine, 30% NH3 (aq),1 M NaOH1 M thiourea; 30 oC, 30 min - 1 h; covellite (hexagonal); p-type conductivity, σ ~ 103 (Ω cm)-1; Eg indir. ~ 1.55 eV
315 oC in 300 mTorr Nitrogen
Avellaneda, Nair, Nair, Thin-Film Compound Semiconductor Photovoltaics—2007, MRS. Symp. Proc. Volume 1012 (2007), 1012-Y12-29 (on line)
Chemically deposited SnS thin films
(Bath A): 0.1 M Sn(II) in acetic acid and HCl, 10 ml; 3.7 M triethanolamine, 30 ml; 30% NH3 (aq), 16 ml; 0.1M thioacetamide, 10 ml; 20 to 25 oC, 6 h (100 nm); zinc blende, photoconductive, σ ~10-6 (Ω cm)-1; Eg dir. 1.7 eV
(Bath B): 1 g SnCl2 dissolved in acetone, of 3.7 M triethanolamine, 12 ml; 1 M thioacetamide, 8 ml; 4 M NH3 (aq), 10 ml; 55 oC, 8 h (400 nm); orthorhombic; photoconductive, σ ~ 10-4 (Ω cm)-1; Eg indir. ~ 1.1eV
..
(A):D. Avellaneda, G. Delgado, M. T. S. Nair, P. K. Nair, Thin Solid Films 515(2007) 5771-5776; (B): Semicond. Sci. Technol. 6 (1991) 132-134
20 30 40 50 600
255075
100
2 θ (deg)
SnS- herzenbergite PDF# 39-0354
a)
(%)
X-ra
y in
tens
ity(r
elat
ive)
b)
c)
0255075
100
(222
)
(311
)
(220
)
(200
)Zinc Blende (a = 5.7911)
(111
)
Structural data on SnS thin films
XRD patterns of a) acetone bath, b)acetic acid bath, ZB as prepared, c)SnS ZB annealed in N2, 1h 300 mTorr, 350ºC
Ref:E. C. Greyson, et al, “ Tetrahedral Zinc Blende Tin Sulfide Nanoand Microcrystals", Small 2 (2006) 368-371.
Anneal: Changes in Composition
a)SnS+Se annealed at 300 ºC, N2 along with the standard pattern of SnSe (PDF 38105); c)SnS+200 mg of S, annealed at 300 ºC, N2; d)SnS annealed in air at 400 ºC; e)SnS annealed in air at 550 ºC,
1,5 2,0 2,50
1
2
3
4
5
hν (eV)
(αhν
)2/3 (
103 c
m-2
/3eV
2/3 )
1.7 eV1.6 eV
After heating
Before heating
Optical properties of SnS ZB thin films annealed in air at differenttemperatures, and in the presence of Se, and S.
500 1000 1500 2000 25000
20
40
60
80
100
0
20
40
60
80
100
R %
W avelength (nm)
T %
550º 500º 400º 300ºC As prepared
Optical properties
SnO2:F-CdS-SnS(A)-CuS-Ag
-0,2 0,0 0,2 0,4
-1,5
-1,0
-0,5
0,0
0,5C
urre
nt (
10-4
A) Voltage (V)
Cu2SnS3
SnS
luz
CdS
Pintura de plata
SnO2:F
0.36FF6 kΩRp
300 ΩRs
200 mVVm
340 mVVoc
3.0A
3.7 mA/cm2Jm
6.0 mA/cm2Jsc
6.4 mA/cm2Jp
5x10-2 mA/cm2Jo
0.36FF6 kΩRp
300 ΩRs
200 mVVm
340 mVVoc
3.0A
3.7 mA/cm2Jm
6.0 mA/cm2Jsc
6.4 mA/cm2Jp
5x10-2 mA/cm2Jo
J = Jo [ exp(q(Voc-JRS)/AkBT) – 1] + [(V-JRS)/RP ] - JP
FF= Jm Vm/ Jsc Voc, Lambert W function used.
MRS Proc. Volume 1012, 2007, 1012-Y12-29
SnOSnO22:F /CdS/SnS(1,2)/:F /CdS/SnS(1,2)/CuSCuS//AgAg
-0.2 0.0 0.2 0.4 0.6 0.8
-7.7
-3.8
0.0
3.8
7.7
11.5
15.4
19.2
23.1 DARK LIGHT
J sc (m
A/cm
2 )
Voltage (V)
VOC = 380 mVJSC = 7.7 mA/cm2
Vm = 220 mVJm = 4.53 mA/cm2
FF = 0.34Eff. = 1%
SnS (1)SnS (2)
IL= 850 W/m2
SnO2:F
CuS
CdS
SnO2:F/CdS/SnS/PbS/Ag
-0,2 0,0 0,2 0,4
-8
-6
-4
-2
0
2
Voltage (V)
Cur
rent
(10-6
A)
0.27FF
70 kΩRp
90 ΩRs
160 mVVm
300 mVVoc
2.7A
0.247 mA/cm2Jm
0.484 mA/cm2Jsc
0.485 mA/cm2Jp
1x10-3 mA/cm2Jo
0.27FF
70 kΩRp
90 ΩRs
160 mVVm
300 mVVoc
2.7A
0.247 mA/cm2Jm
0.484 mA/cm2Jsc
0.485 mA/cm2Jp
1x10-3 mA/cm2Jo
-0,2 0,0 0,2 0,4
-2
-1
0
1
Cur
rent
(10-5
A)
Voltage (V)
0.28FF
22 k ΩRp
650 Ω (Area 1 mm2)
Rs
180 mVVm
320 mVVoc
2.2A
0.83 mA/cm2Jm
1.6 mA/cm2Jsc
1.7 mA/cm2Jp
1x10-3 mA/cm2Jo
0.28FF
22 k ΩRp
650 Ω (Area 1 mm2)
Rs
180 mVVm
320 mVVoc
2.2A
0.83 mA/cm2Jm
1.6 mA/cm2Jsc
1.7 mA/cm2Jp
1x10-3 mA/cm2JoSnS(A)
SnS(B)
PbS:1 M lead nitrate, 1 M NaOH, 1 M thiourea, 1 M triethanolamine; 40 oC, 2 h
Sb2S3 and Sb2SxSe3-xSb2S3 (i) Thin FilmsSbCl3 650 mgAcetone 2.5 mlNa2S2O3 25 ml
Sb2S3 (ii) Thin FilmsPotasium antimony tartrate 0.1 M,TEA 50% , Ammonia aq.Thioacetamide 0.1 M
Selenium Thin FilmsNa2SeSO3 → Se (@ pH 4.5)
0 1 2 3 4 5 6 7 8 9 100
100
200
300
400
500
600
700
Growth curve of Sb2S3 at diferent temperature
Thic
knes
s (n
m)
Deposition duration (h)
-3 °C 1 °C 5°C 10 °C
(i) M T S Nair, Y Peña, J Campos, V M García, P K Nair J. Electrochem. Soc. 145 (1998) 2113(ii) O Savadogo, and K C Mandal, Solar Energy Materials 26 (1991) 117
(Se) K. Bindu, M. Lakshmi, S. Bini, C. Sudha Kartha, K. P. Vijayakumar, T. Abe, Y. Kashiwaba, Semicond. Sci. Technol., 17 (2002) 270.
Sb2S3-xSex formationx=0.75, calculated from XRD data
XRD: Sb2S3 film heated in contact with Se film, 300oC
Eg direct (forbidden), 1.3 eV (?); orthorhombic: a =11.81 Å, b=11.47 Å, c=3.71 Åα , 105 cm-1 in the visible; conductivity, ≈ 10-8 Ω-1cm-1
1 0 2 0 3 0 4 0 5 0
1 0 2 0 3 0 4 0 5 0
S b2S
xS e
3 -x
(211
)
(420
)
(301
)
(221
)
θ = 0 .5 °
(230
)
b )
θ = 1 .5 °
(420
)
Inte
nsity
[a.u
.]
2 θ [d e g re e s ]
S b 2S 3
P D F # 4 2 -1 3 9 3
(120
)
a )
(520
)
(301
)
(140
)
(211
)
(320
)
(200
)
(310
)
(220
)
(110
)
(130
)(3
10)
(120
)
(020
)
S b 2S e 3 P D F # 1 5 -0 6 8 1
(520
)
(321
)
Sb2S3 and Sb2(S/Se)3absorber thin films
1.5 2.0 2.5 3.00.0
5.0x103
hν [eV]
(αhν
)2/3 [e
V cm
-1]2/
3
Eg=1.76 eV
1.0 1.5 2.0 2.50
1000
2000
3000
4000
5000
1.0 1.5 2.0 2.50
1000
2000
3000
4000
5000
Eg=1,38
Se+Sb2S3 horneado a 300°C en N2
(αhν
)2/3 [e
Vcm
-1]2/
3
hν [eV]
Eg=1,31
Sb2S3 + Se horneado a 300°C en N2
(αhν
)2/3 [e
Vcm
-1]2/
3
hν [eV]
500 1000 1500 2000 25000
20
40
60
80
100500 1000 1500 2000 2500
0
50
Tran
smitt
ance
(%)
Wavelength (nm)
Sb2S3
Sb2(S/Se)3
Ref
lect
ance
(%)
Photocurrent response of Sb2SxSe3-x
60 120 180 2401E-12
1E-11
1E-10
1E-9
1E-8
1E-7
bias 50 V
Sb2S3 + Se 300°C air
Sb2S3 300°C air
Sb2S3 + Se 300°C N2
Sb2S3 300°C N2
curre
nt [A
]
time [s]
Sarah Messina, 2007
Chemically deposited photovoltaic structures…
Sarah Messina, Nair, Nair, Communicated 2007
Chemically deposited photovoltaic structures…
Sarah Messina, Nair, Nair Communicated 2007
Chemically deposited photovoltaic structures…
Sarah Messina, Nair, Nair Communicated 2007
500 1000 1500 2000 25000
20
40
60
80
100
TCO-CdS-(Sb2S
3+Se)-PbS
TCO-CdS-Sb2S
3+ Se
TCO-CdS-Sb2S
3
TCO-CdS
Tran
smitt
ance
[%]
Wavelength [nm]
SnOSnO22:F/:F/CdS(CubCdS(Cub, , hexhex)/Sb)/Sb22(S/Se)(S/Se)33/PbS/PbS--AgAg
0.0 0.2 0.4 0.6
-10
0
10 Ag PbS (200 nm)Sb
2(S/Se)
3 (250 nm)
CdS (cub) (90 nm)
SnO2:F
Voc=480 mVJsc=6 mA/cm2
FF= 0.38η= 1.4 %
Cur
rent
Den
sity
(mA/
cm2 )
Voltage (V)
0.0 0.2 0.4 0.6 0.8 1.0
-10
-5
0
5
10
15
AgPbS (200 nm)Sb2(S/Se)3 (500 nm)
CdS(hex) (200 nm)
Voc=640 mVJsc=7.5 mA/cm2
FF=0.26η=1.56%
Cur
rent
Den
sity
(mA
/cm
2 )Voltage (V)
Sb2(S/Se)3:D.Y. Suárez-Sandoval et al., J. Electrochem. Soc. 153 (2006) C91-C96.
SnO2:F/CdS/Sb2S3 /SnS/CuS-Ag
-0.2 0.0 0.2 0.4 0.6
-6.0x10-5
-4.0x10-5
-2.0x10-5
0.0
2.0x10-5
Curva I-V de la estructura FV SnO2-CdS-Sb2S3-SnS-CuS
Voc= 450 mVIsc = 40 µA; Jsc= 4 mA/cm2
A = 1 mm2
IL = 1 kW/m2
corr
ient
e [A
]
voltaje [V]
-0.6 -0.4 -0.2 0.0 0.2 0.4 0.6
-5.0x10-7
0.0
5.0x10-7
1.0x10-6
1.5x10-6
2.0x10-6
2.5x10-6
Curva IV de la estructura FV SnO2-CdS-Sb2S3-SnS-CuS
corr
ient
e [A
]
voltaje [V]
CdS
SnO2
SnS
IL=1000W/m2
silver print
Sb2S3
CuS
Voltage (V)
Voltage (V)
Current (A) Current (A)
Photoconductivity in CdS and PbS thin films
0 60 120 1801E-12
1E-11
1E-10
1E-9
1E-8
1E-7
1E-6
1E-5σ = 0.1 (Ωcm)-1
σ = 10-7 (Ωcm)-1
CdS (Cubic)
100 nm60 nm
bias 10 V
Cur
rent
(A)
Time (s)
-0.2 0.0 0.2 0.4 0.6
-1.0x10-5
0.0
1.0x10-5
2.0x10-5
3.0x10-5
4.0x10-5
5.0x10-5
6.0x10-5
-0.2 0.0 0.2 0.4
-2.0x10-5
-1.0x10-5
0.0
1.0x10-5
Curva IV de la estructura fotovoltaica CdS-PbS IL=1 kW/m2
Voc = 297 mVIsc = 13 µA; 0.3 mA/cm2 A = 4 mm2
IL = 1 kW/m2 tung-hal
Cor
rient
e (A
)
Voltaje (V)
+-
Lost generation cells...? CdS(100 nm)/ PbS(250nm)S. Watanabe, Y. Mita, J. Electrochem. Soc. 166 (1969) 989
dark Voltage (V)
Voltage (V)
Cur
rent
(A)
Cur
rent
(A)
dark
photo
n-CdS Eg : 2.5 eV dir - windowp-PbS Eg : 0.4 eV ind –absorb.
CdS: M.T.S. Nair, P.K. Nair, J.Campos Thin Solid Films 161 (1988) 21-34
PbS: P.K. Nair, M.T.S. Nair J. Phys. D: Appl. Phys 23 (1990) 150-155
Glass/plastic
SnO2:F/CdS(hex 100 nm)/PbS(250 nm)/Ag
-200 0 200 400 600 800 1000
-10
-5
0
5
10
15
20
J (m
A/cm
2 )
Voltage (mV)
Dark
-200 0 200 400 600
-3.5
-3.0
-2.5
-2.0
-1.5
-1.0
-0.5
0.0
0.5
1.0 Light
VOC = 0.5 VJSC = 2.3 mA/cm2
A = 1mm2
L = 850 W/m2J
(mA
/cm
2 )
Voltage (mV)
+-
SnO2:F
CdSPbS
850 W/m2
-300 -200 -100 0 100 200 300 400 500 600
-30
-25
-20
-15
-10
-5
0
5
10
15
20
25
TCO-CdS(hexagonal)-Bi2S3-PbS
J SC
(mA
/cm
2 )
Voltaje (mV)
Oscuridad Iluminacion
VCA = 340 mVJCS = 10 mA/cm2
A= 1.3 mm2
SnOSnO22:F/:F/CdS(CubCdS(Cub, , hexhex)/)/BiBi22SS33 /PbS/PbS--AgAg
PbS
SnO2:F CdSBiBi22SS33
Chemically deposited photovoltaic structures…
Chemically deposited photovoltaic structures..
-100 0 100 20 0 300 400 500
-8000
-6000
-4000
-2000
0
2000
-
24 mm 2
Ag + 200 nm
60 nm
PbS
SnO2:F
Bi 2S3
80 nmZnO-
B
A
A (1000 W/m2)V
OC = 2 20 mV
JSC
= 6.2 mA/cm2
B (3000 W/m2)V
OC = 300 mV
JSC
= 21 mA/cm2
I (µA
)
V (mV)
Prospects
Sulfosalts
Glass-Mo/Sn-Sb-S/CdS/ZnOVoc, 208 mV; Jsc, 13 mA/cm2
FF, 38%; η, 1.05%
H. Dittrich et al, Thin Solid Films 515 (2007) 5745Recent developments in thin film solar cells,
Solace 2008
M. Ichimura et al:Photochemically and electrochemically deposited solar cells:
Solace 2008
Cu2ZnSnS4 thin film solar cellCu2ZnSnS4: Eg, 1.45 eV; α, 104 cm-1
RF co-sputtering of ZnS, SnS, Cu; followed by sulfurization in N2+H2S (20%), at 580oC;
Cu/(Zn+Sn) = 0.87: Zn/Sn=1.15
ZnO:Al2O3/CdS/CZTS/Mo/glass: η, 5.74%
Voc, 662 mV; Jsc, 15.7 mA/cm2; FF, 0.55Katagiri and coworkers:
Thin Solid Films 515 (2007) 5997-5999
Photo-accelerated chemical depositionProspects..
Nair, Nair on CdS: Solar Energy Mater 15 (1987) 431
Nair et al on PbS: J. Phys. D. Appl. Phys. 24 (1991) 1466; Adv. Mater. Optics Electr. 1 (1992) 117; Semicond. Sci. Technol. 7 (1992) 239
Nair et al on Bi2S3: J. Electrochem. Soc. 140 (1993) 1085
PbS: bluish purple on goldenArt work by
Adrian Oskamsunlight
Bi2S3: Purple on golden golden on purple
Solace 2008, Kochi
Some Conclusions
Photovoltaic technologies meeting the future demand for photovoltaic modules would complement each other
There is room for developing distinct technologies making use of local/regional raw materials to satisfy local needs
Easy scale-up and low-capital intensive production are basic features of all-chemically deposited photovoltaic structures – promising for photovoltaic technology
Solace 2008, Kochi