Bandgap of thin film solar cell absorbers: A comparison of various determination methods

THIN SOLID FILMS

卷:669

Article; Proceedings Paper

Carron, Romain¹  Andres, Christian¹  Avancini, Enrico¹  Feurer, Thomas¹  Nishiwaki, Shiro¹  Pisoni, Stefano¹  Fu, Fan¹  Lingg, Martina¹  Romanyuk, Yaroslav E.¹  Buecheler, Stephan¹  Tiwari, Ayodhya N.¹ 

[1] Empa Swiss Fed Labs Mat Sci & Technol, Lab Thin Films & Photovolta, Uberlandstr 129, CH-8600 Dubendorf, Switzerland

关键词: Bandgap;    External quantum efficiency;    Thin film solar cell;    Open circuit voltage deficit;    Band gap;    Derivative;    External radiative efficiency;   

DOI  :  10.1016/j.tsf.2018.11.017

来源: Elsevier

【 摘 要 】

Knowledge of the absorber bandgap is often needed for assessing the junction quality of a thin film solar cell, for example when computing the open-circuit voltage deficit. The bandgap is typically estimated from the routine measurement of the external quantum efficiency (EQE) of finished devices. However the extraction becomes ambiguous in the case of very thin absorbers, or in presence of bandgap gradients or collection issues of charge carriers. This work reviews several methods for the determination of the bandgap from EQE measurements and discusses their validity conditions. The numerical results are compared based on experimental EQE of several different thin film solar cells such as CuInGaSe2, CuInSe2, CdTe, CuZnSnSe and perovskite, and systematic trends are identified. Numerical simulations are also performed to illustrate the behavior of the different bandgap extraction methods in presence of a bandgap gradient and different magnitudes of the exponential tail states.

【 授权许可】

Free