Metastability in Dark Current Diode Characteristics of Chalcogenide Photovoltaic Modules

Abstract

While present trends in commercial PV are set on a‐Si/c‐Si heterojunctions and promising perovskites, the chalcogenides still attract interest as an excellent candidate for coming multi‐ and heterojunction devices with perovskites. Continuously enhanced over the years, typical metastabilities in thin film devices still remain, causing issues under outdoor operation. Unfortunately, qualitative assessment in commercial PV is solely focused on data at the maximum power point of its operation, whether in simple on‐site PV plant monitoring or following latest standards for certified laboratory testing, thus metastabilities merely register as undefined power fluctuations. We show in this study that dark current characteristics are a simple and yet field‐fit method, to identify metastable changes and take suitable counter measures. With this study, using commercial CdTe and CIGS showcase modules of various manufacturers and production generations, we demonstrate how dark current characteristics allow to pin‐point physical changes of the individual module, between its pristine state, outdoor operation, dark degradation and stabilization, like a fingerprint. Using the two‐diode model, we show that alterations to respective regimes of the characteristic can be assigned to typical defects, defining the module’s current state, and be used to it as a guide to evaluate its recuperation via preconditioning treatments.This article is protected by copyright. All rights reserved.