Feedback between radiation and transport in photovoltaics. (4th December 2022)

• Record Type: Journal Article
• Authors: Irvin, Nicholas P.; Babcock, Sean J.; Chen, Eric Y.; King, Richard R.; Honsberg, Christiana B.
• Is Part Of: Progress in photovoltaics. Volume 31:Number 3(2023)
• Page Start: 283
• Page End: 301
• Publication Date: 2022-12-04
• Subjects: absorptance -- carrier transport -- detailed balance -- diffusion model -- EQE -- photon recycling -- photon recycling diffusion -- quasi‐Fermi‐level splitting -- radiative recombination -- solar cells; Solar cells -- Periodicals; Photovoltaic cells -- Periodicals; Solar power plants -- Periodicals; 621.31245
• DOI: 10.1002/pip.3640
• Languages: English
• ISSNs: 1062-7995

Abstract

Abstract: By building on the generalized Hovel model, this work develops an analytical solution to unify photon recycling, light trapping, and carrier transport in solar cells. Enhanced transport due to photon recycling diffusion is considered. While photon recycling diffusion is often negligible, it can significantly support transport in cases where charge diffusion is low but radiative efficiency is high. Next, the diffusion equation is solved to determine carrier collection for planar and textured cells. Results elucidate novel features in the external quantum efficiency (EQE) curve that occur for textured cells with high absorption and limited transport. Then, the effect of limited transport on the radiative recombination of solar cells is investigated in detail. While the traditional treatment of detailed balance uses the applied voltage to calculate a cell's radiative recombination, the present approach uses the spatially resolved quasi‐Fermi‐level splitting (QFLS). The discrepancy between the models is shown to be inconsequential to performance for cells with low radiative recombination (Si) or with high mobilities (lowly doped GaAs). However, for cells with high radiative recombination and low mobility (highly doped GaAs, polycrystalline CdTe, and thin‐film perovskites), incorporating variation in QFLS in the determination of radiative recombination can become necessary for accurate photovoltaic modeling. Abstract : An analytical diffusion model is developed to be broadly compatible with detailed balance theory under various levels of light trapping. It is seen that the relations between photon recycling and carrier transport alter the impact of phenomena such as photon recycling diffusion and the radiative recombination rate of transport‐limited materials.