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Title: Metal-oxide broken-gap tunnel junction for copper indium gallium diselenide tandem solar cells

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Publication Date:
Sponsoring Org.:
OSTI Identifier:
Grant/Contract Number:
EE0005319; RL-0003-12
Resource Type:
Journal Article: Publisher's Accepted Manuscript
Journal Name:
Solar Energy Materials and Solar Cells
Additional Journal Information:
Journal Volume: 133; Journal Issue: C; Related Information: CHORUS Timestamp: 2016-09-04 16:10:39; Journal ID: ISSN 0927-0248
Country of Publication:

Citation Formats

Ho Song, Sang, Aydil, Eray S., and Campbell, Stephen A.. Metal-oxide broken-gap tunnel junction for copper indium gallium diselenide tandem solar cells. Netherlands: N. p., 2015. Web. doi:10.1016/j.solmat.2014.10.046.
Ho Song, Sang, Aydil, Eray S., & Campbell, Stephen A.. Metal-oxide broken-gap tunnel junction for copper indium gallium diselenide tandem solar cells. Netherlands. doi:10.1016/j.solmat.2014.10.046.
Ho Song, Sang, Aydil, Eray S., and Campbell, Stephen A.. 2015. "Metal-oxide broken-gap tunnel junction for copper indium gallium diselenide tandem solar cells". Netherlands. doi:10.1016/j.solmat.2014.10.046.
title = {Metal-oxide broken-gap tunnel junction for copper indium gallium diselenide tandem solar cells},
author = {Ho Song, Sang and Aydil, Eray S. and Campbell, Stephen A.},
abstractNote = {},
doi = {10.1016/j.solmat.2014.10.046},
journal = {Solar Energy Materials and Solar Cells},
number = C,
volume = 133,
place = {Netherlands},
year = 2015,
month = 2

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record at 10.1016/j.solmat.2014.10.046

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Cited by: 8works
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  • The influence of Cu(In,Ga)Se{sub 2} (CIGSe) surface roughness on the photovoltaic parameters of state of the art devices is reported, highlighting the importance of the roughness of the as-grown CIGSe absorbers on solar cell efficiencies. As-grown CIGSe surface is progressively smoothed using a chemical etch, and characterized by SEM, AFM, XPS, {mu}-Raman spectroscopy, x-ray diffraction (XRD), and reflectivity. The decrease of roughness has no marked influence on crystal structure and surface composition of the absorber. The main effect is that the total reflectivity of the CIGSe surface increases with decreasing roughness. The samples are processed into solar cells and characterizedmore » by current-voltage measurements. While the open circuit voltage (V{sub oc}) and fill factor remain constant, the short circuit current (J{sub sc}) decreases markedly with decreasing roughness, resulting in a reduction of the solar cell efficiency from 14% down to 11%, which exceeds the expected decrease from increased reflectivity. Quantum efficiency and reflectivity measurements on complete cells are performed to analyze those effects. The influence of surface roughness on the theorical effective space charge region and diffusion length is based on a simple theoretical model. This paper discusses the comparison of CIGSe solar cells with n-i-p structures.« less
  • In this study, we present a physics-based analytical model for copper indium gallium diselenide (CIGS) solar cells that describes the illumination- and temperature-dependent current-voltage (I-V) characteristics and accounts for the statistical shunt variation of each cell. The model is derived by solving the drift-diffusion transport equation so that its parameters are physical and, therefore, can be obtained from independent characterization experiments. The model is validated against CIGS I-V characteristics as a function of temperature and illumination intensity. This physics-based model can be integrated into a large-scale simulation framework to optimize the performance of solar modules, as well as predict themore » long-term output yields of photovoltaic farms under different environmental conditions.« less
  • Textured transparent conductors are widely used in thin-film silicon solar cells. They lower the reflectivity at interfaces between different layers in the cell and/or cause an increase in the path length of photons in the Si absorber layer, which both result in an increase in the number of absorbed photons and, consequently, an increase in short-circuit current density (J{sub sc}) and cell efficiency. Through optical simulations, we recently obtained strong indications that texturing of the transparent conductor in copper indium gallium (di-)selenide (CIGS) solar cells is also optically advantageous. Here, we experimentally demonstrate that the J{sub sc} and efficiency ofmore » CIGS solar cells with an absorber layer thickness (d{sub CIGS}) of 0.85 μm, 1.00 μm and 2.00 μm increase through application of a moth-eye textured resist with a refractive index that is sufficiently similar to AZO (n{sub resist} = 1.792 vs. n{sub AZO} = 1.913 at 633 nm) to avoid large optical losses at the resist-AZO interface. On average, J{sub sc} increases by 7.2%, which matches the average reduction in reflection of 7.0%. The average relative increase in efficiency is slightly lower (6.0%). No trend towards a larger relative increase in J{sub sc} with decreasing d{sub CIGS} was observed. Ergo, the increase in J{sub sc} can be fully explained by the reduction in reflection, and we did not observe any increase in J{sub sc} based on an increased photon path length.« less
  • A photovoltaic cell exhibiting an overall conversion efficiency of 13.6% is prepared from a copper-indium-gallium-diselenide precursor thin film. The film is fabricated by first simultaneously electrodepositing copper, indium, gallium, and selenium onto a glass/molybdenum substrate (12/14). The electrodeposition voltage is a high frequency AC voltage superimposed upon a DC voltage to improve the morphology and growth rate of the film. The electrodeposition is followed by physical vapor deposition to adjust the final stoichiometry of the thin film to approximately Cu(In.sub.1-n Ga.sub.x)Se.sub.2, with the ratio of Ga/(In+Ga) being approximately 0.39.