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Title: See-through amorphous silicon solar cells with selectively transparent and conducting photonic crystal back reflectors for building integrated photovoltaics

Abstract

Thin semi-transparent hydrogenated amorphous silicon (a-Si:H) solar cells with selectively transparent and conducting photonic crystal (STCPC) back-reflectors are demonstrated. Short circuit current density of a 135 nm thick a-Si:H cell with a given STCPC back-reflector is enhanced by as much as 23% in comparison to a reference cell with an ITO film functioning as its rear contact. Concurrently, solar irradiance of 295 W/m{sup 2} and illuminance of 3480 lux are transmitted through the cell with a given STCPC back reflector under AM1.5 Global tilt illumination, indicating its utility as a source of space heating and lighting, respectively, in building integrated photovoltaic applications.

Authors:
 [1];  [2];  [3];  [4];  [1];  [3]
  1. The Edward S. Rogers Sr. Department of Electrical and Computer Engineering, University of Toronto, 10 King's College Road, Room GB254B, Toronto, Ontario M5S 3G4 (Canada)
  2. Department of Materials Science and Engineering, University of Toronto, 184 College Street, Room 140, Toronto, Ontario M5S 3E4 (Canada)
  3. (Canada)
  4. Materials Chemistry Research Group, Department of Chemistry, University of Toronto, 80 St. George Street, Toronto, Ontario M5S 3H6 (Canada)
Publication Date:
OSTI Identifier:
22253941
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 103; Journal Issue: 22; Other Information: (c) 2013 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; CRYSTALS; CURRENT DENSITY; ELECTRICAL FAULTS; HYDROGENATION; PHOTOVOLTAIC EFFECT; RADIANT FLUX DENSITY; SILICON; SILICON SOLAR CELLS; SPACE HEATING

Citation Formats

Yang, Yang, O’Brien, Paul G., Materials Chemistry Research Group, Department of Chemistry, University of Toronto, 80 St. George Street, Toronto, Ontario M5S 3H6, Ozin, Geoffrey A., E-mail: gozin@chem.utoronto.ca, E-mail: kherani@ecf.utoronto.ca, Kherani, Nazir P., E-mail: gozin@chem.utoronto.ca, E-mail: kherani@ecf.utoronto.ca, and Department of Materials Science and Engineering, University of Toronto, 184 College Street, Room 140, Toronto, Ontario M5S 3E4. See-through amorphous silicon solar cells with selectively transparent and conducting photonic crystal back reflectors for building integrated photovoltaics. United States: N. p., 2013. Web. doi:10.1063/1.4833542.
Yang, Yang, O’Brien, Paul G., Materials Chemistry Research Group, Department of Chemistry, University of Toronto, 80 St. George Street, Toronto, Ontario M5S 3H6, Ozin, Geoffrey A., E-mail: gozin@chem.utoronto.ca, E-mail: kherani@ecf.utoronto.ca, Kherani, Nazir P., E-mail: gozin@chem.utoronto.ca, E-mail: kherani@ecf.utoronto.ca, & Department of Materials Science and Engineering, University of Toronto, 184 College Street, Room 140, Toronto, Ontario M5S 3E4. See-through amorphous silicon solar cells with selectively transparent and conducting photonic crystal back reflectors for building integrated photovoltaics. United States. doi:10.1063/1.4833542.
Yang, Yang, O’Brien, Paul G., Materials Chemistry Research Group, Department of Chemistry, University of Toronto, 80 St. George Street, Toronto, Ontario M5S 3H6, Ozin, Geoffrey A., E-mail: gozin@chem.utoronto.ca, E-mail: kherani@ecf.utoronto.ca, Kherani, Nazir P., E-mail: gozin@chem.utoronto.ca, E-mail: kherani@ecf.utoronto.ca, and Department of Materials Science and Engineering, University of Toronto, 184 College Street, Room 140, Toronto, Ontario M5S 3E4. Mon . "See-through amorphous silicon solar cells with selectively transparent and conducting photonic crystal back reflectors for building integrated photovoltaics". United States. doi:10.1063/1.4833542.
@article{osti_22253941,
title = {See-through amorphous silicon solar cells with selectively transparent and conducting photonic crystal back reflectors for building integrated photovoltaics},
author = {Yang, Yang and O’Brien, Paul G. and Materials Chemistry Research Group, Department of Chemistry, University of Toronto, 80 St. George Street, Toronto, Ontario M5S 3H6 and Ozin, Geoffrey A., E-mail: gozin@chem.utoronto.ca, E-mail: kherani@ecf.utoronto.ca and Kherani, Nazir P., E-mail: gozin@chem.utoronto.ca, E-mail: kherani@ecf.utoronto.ca and Department of Materials Science and Engineering, University of Toronto, 184 College Street, Room 140, Toronto, Ontario M5S 3E4},
abstractNote = {Thin semi-transparent hydrogenated amorphous silicon (a-Si:H) solar cells with selectively transparent and conducting photonic crystal (STCPC) back-reflectors are demonstrated. Short circuit current density of a 135 nm thick a-Si:H cell with a given STCPC back-reflector is enhanced by as much as 23% in comparison to a reference cell with an ITO film functioning as its rear contact. Concurrently, solar irradiance of 295 W/m{sup 2} and illuminance of 3480 lux are transmitted through the cell with a given STCPC back reflector under AM1.5 Global tilt illumination, indicating its utility as a source of space heating and lighting, respectively, in building integrated photovoltaic applications.},
doi = {10.1063/1.4833542},
journal = {Applied Physics Letters},
number = 22,
volume = 103,
place = {United States},
year = {Mon Nov 25 00:00:00 EST 2013},
month = {Mon Nov 25 00:00:00 EST 2013}
}
  • For thin-film silicon solar cells (TFSC), a one-dimensional photonic crystal (1D PC) is a good back reflector (BR) because it increases the total internal reflection at the back surface. We used the plane-wave expansion method and the finite difference time domain (FDTD) algorithm to simulate and analyze the photonic bandgap (PBG), the reflection and the absorption properties of a 1D PC and to further explore the optimal 1D PC design for use in hydrogenated amorphous silicon (a-Si:H) solar cells. With identified refractive index contrast and period thickness, we found that the PBG and the reflection of a 1D PC aremore » strongly influenced by the contrast in bilayer thickness. Additionally, light coupled to the top three periods of the 1D PC and was absorbed if one of the bilayers was absorptive. By decreasing the thickness contrast of the absorptive layer relative to the non-absorptive layer, an average reflectivity of 96.7% was achieved for a 1D PC alternatively stacked with a-Si:H and SiO{sub 2} in five periods. This reflectivity was superior to a distributed Bragg reflector (DBR) structure with 93.5% and an Ag film with 93.4%. n-i-p a-Si:H solar cells with an optimal 1D PC-based BR offer a higher short-circuit current density than those with a DBR-based BR or an AZO/Ag-based BR. These results provide new design rules for photonic structures in TFSC.« less
  • An efficient light trapping scheme named as textured conductive photonic crystal (TCPC) has been proposed and then applied as a back-reflector (BR) in n-i-p hydrogenated amorphous silicon (a-Si:H) solar cell. This TCPC BR combined a flat one-dimensional photonic crystal and a randomly textured surface of chemically etched ZnO:Al. Total efficiency enhancement was obtained thanks to the sufficient conductivity, high reflectivity and strong light scattering of the TCPC BR. Unwanted intrinsic losses of surface plasmon modes are avoided. An initial efficiency of 9.66% for a-Si:H solar cell was obtained with short-circuit current density of 14.74 mA/cm{sup 2}, fill factor of 70.3%, andmore » open-circuit voltage of 0.932 V.« less
  • The stability of various textured tin oxide and zinc oxide transparent conductors was evaluated against annealing in air, in vacuum or exposed to hydrogen plasma. Only fluorine-doped zinc oxide deposited by atmospheric pressure chemical vapor deposition (APCVD) had stable electrical and optical properties under all conditions. Thin layers of ZnO or TiO{sub 2} greatly improved the plasma resistance of SnO{sub 2}. A new TCO material, niobium-doped titanium dioxide (TiO{sub 2}:Nb) was able to withstand hydrogen plasmas with only slight increases in its optical absorption and conductivity. Composite TCO{close_quote}s consisting of glass/SnO{sub 2}:F/TiO{sub 2}:Nb were shown to provide good electrical contactmore » to amorphous silicon solar cells. {copyright} {ital 1996 American Institute of Physics.}« less
  • We investigate the effect of sputtered transparent conducting oxide (TCO) contacts on the device performance of ss/n-i-p/TCO and glass/SnO {sub 2}/p-i-n/TCO/Ag solar cells. TCO materials ITO and ZnO are compared, and found to have very similar transparency at the same sheet resistance. Sputtering ZnO with O{sub 2} in the Ar reduces FF for ss/n-i-p/ZnO devices, compared to sputtering without O{sub 2}. This is attributed to an interface not bulk effect. Sputtering ITO with O{sub 2} on the same devices increases J{sub SC} due to higher ITO transparency, compared to sputtering without O{sub 2} , but has no effect on FF.more » Based on curvature in the J(V) curve around V{sub OC}, the ZnO/p layer contact appears to be non-ohmic. For p-i-n/TCO/Ag devices, {mu}c-Si n-layers have much higher V{sub OC}, J{sub SC}, and FF for all variations of TCO/Ag back reflectors compared to an a-Si n-layer. Devices with ITO/Ag have lower V{sub OC} and J{sub SC} compared to devices with ZnO/Ag. Sputtering ZnO with O{sub 2} has no detrimental effect on devices with {mu}c-Si n-layers but severely reduces FF in devices with a-Si n-layers. {copyright} {ital 1997 American Institute of Physics.}« less
  • The role of back reflectors in enhancing the absorption of weakly absorbing, long-wavelength light has been investigated as applied to amorphous silicon alloy solar cells. The reflectance and scattering properties of various types of back reflectors have been studied. The performance of {ital p}-{ital i}-{ital n} amorphous silicon alloy solar cells deposited on different back reflectors has been analyzed. The studies elucidate the role of back reflectors in improving the short-circuit current density and thereby the efficiency of the cell.