Unraveling the cause of degradation in Cu(In,Ga)Se2 photovoltaics under potential induced degradation

Zeel Purohit,Abhiram Gundimeda,Harsh Chaliyawala,Michaël Daenen,Shubhendra K Jain,Govind Gupta,Brijesh Tripathi,Jorne Carolus

doi:10.1002/nano.202100122

Abstract

AbstractCopper indium gallium diselenide (CIGS) based technology is actively competing in the global photovoltaic market with high conversion efficiency. Commercial CIGS modules are anticipated to perform on rated output in the field condition for 20 years. Potential induced degradation (PID) is considered as one of the critical concerns among all the current reliability assessment issues. PID accelerated tests have been performed on pre‐commercial CIGS modules to investigate reduction in electrical performance. We report the severe reduction in electrical performance after PID is correlated to the microstructural and chemical properties of the constituent materials. Under extreme PID stress, the cell surface reveals various defects including crater formation. The aim of this article is to explore the consequences of PID induced craters on the efficiency of CIGS solar cells by investigating material degradation kinetics. In this perspective, we present the root cause of PID in CIGS thin‐film modules in relation to microstructural defects by detailed investigation using J‐V analysis, field emission scanning electron microscope (FESEM), Raman spectroscopy, X‐Ray diffraction (XRD), X‐ray photoelectron spectroscopy (XPS) and photoluminescence spectroscopy (PL). This analysis can provide more effective and sustainable research strategies to cultivate more efficient and reliable CIGS technologies in the long run.

Highlights

Over the last few decades, chalcopyrite copper indium gallium diselenide (CIGS) based thin film technologies have shown significant developments and penetration in the commercial global market.[1]
The potential induced degradation (PID)-treated CIGS solar cell shows a dramatic deterioration in electrical performance as compared to the initial performance
The PID treated solar cell demonstrated a drastic reduction in performance as VOC was reduced from 0.67 to 0.15 V, FF decreased from 66% to 37% and η was reduced to 1.6% after 70 hours

Summary

Introduction

Over the last few decades, chalcopyrite copper indium gallium diselenide (CIGS) based thin film technologies have shown significant developments and penetration in the commercial global market.[1]. Extreme environmental impact and high voltage stress conditions, modules undergo mid-life failure which leads to significant loss of efficiency within a short period of time (much lower than rated warranty period). This effect is known as potential induced degradation (PID).[5,6,7] The coercive issues of PID mid-life failures raise a warning alarm for industries to reveal the degradation mechanism to constrain its larger impact on global PV investments. In order to make the CIGS module-based solar industry much more competitive in a sustainable manner, PID analysis is required to be investigated in-depth

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Conclusion