Identification, Characterization, and Implications of Shadow Degradation in Thin Film Solar Cells

Sourabh Dongaonkar, Purdue University - Main Campus
Karthik Y, Indian Institute of Technology - Bombay
Dapeng Wang
Michel Frei
Souvik Mahapatra, Indian Institute of Technology - Bombay
Muhammad A. Alam, Network for Computational Nanotechnoloy, Birck Nanotechnology Center, School of Electrical and Computer Engineering, Purdue University

Date of this Version



Dongaonkar, S.; Alam, M.A.; Karthik, Y.; Mahapatra, S.; Dapeng Wang; Frei, M.; , "Identification, characterization, and implications of shadow degradation in thin film solar cells," Reliability Physics Symposium (IRPS), 2011 IEEE International , vol., no., pp.5E.4.1-5E.4.5, 10-14 April 2011


We describe a comprehensive study of intrinsicreliability issue arising from partial shadowing of photovoltaicpanels (e.g., a leaf fallen on it, a nearby tree casting a shadow,etc.). This can cause the shaded cells to be reverse biased, causingdark current degradation. In this paper, (1) we calculate thestatistical distribution of reverse bias stress arising from variousshading configurations, (2) identify the components of darkcurrent, and provide a scheme to isolate them, (3) characterizethe effect of reverse stress on the dark current of a-Si:H p-i-ncells, and (4) finally, combine these features of degradationprocess with shadowing statistics, to project ‘shadow-degradation’ (SD) over the operating lifetime of solar cells. Ourresults establish shadow degradation as an important intrinsicreliability concern for thin film solar cell.


Electronic Devices and Semiconductor Manufacturing