22 June 2018 Critical design criteria for silicon nanocrystals downshifting layers enhancement in CIGS solar cells
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Abstract
Conventional Cu  (  In  ,  Ga  )  Se2 (CIGS) solar cells suffer poor response in the short-wavelength region (280 to 520 nm) due to the parasitic absorption in the ZnO transparent conductive oxide and inefficient collection of generated electron–hole pairs in the CdS layer. The short-wavelength response can be enhanced using a downshifting (DS) layer mounted on the top surface of the solar cell. The performance effects of coupling silicon nanocrystals DS layer to a CIGS solar cell are analyzed using numerical simulations. Measured photoluminescence of fabricated Si-nC using plasma-enhanced chemical vapor deposition is used to calibrate the model. A 13.9% relative enhancement of the conversion efficiency is observed when a DS layer with a photoluminescence quantum yield (PLQY) of 20% is added. The relative enhancement increases to 17.8% when the DS layer has a PLQY of 100%. The results are further analyzed to decouple and quantify the surface reflectance effect and the DS effect using a passive cell. The surface reflectance effect is dominant for DS layers with PLQY of 20% and accounts for 13.6% relative enhancement. Whereas the DS effect dominates when the PLQY is >70  %   and reaches 17.1% relative enhancement for a DS layer with PLQY of 100%. Overall, cells with poor UV spectral responses are found to benefit the most from the coupling of a DS layer, albeit only for a very high PLQY.
© 2018 Society of Photo-Optical Instrumentation Engineers (SPIE)
Ahmed M. Gabr, Ahmed M. Gabr, Alexandre W. Walker, Alexandre W. Walker, Karin Hinzer, Karin Hinzer, } "Critical design criteria for silicon nanocrystals downshifting layers enhancement in CIGS solar cells," Journal of Photonics for Energy 8(2), 025502 (22 June 2018). https://doi.org/10.1117/1.JPE.8.025502 . Submission: Received: 9 April 2018; Accepted: 31 May 2018
Received: 9 April 2018; Accepted: 31 May 2018; Published: 22 June 2018
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