Predicting thermal stability of organic solar cells through an easy and fast capacitance measurement
By Marta Tessarolo and Antonio Guerrero and Desta Gedefaw and Margherita Bolognesi and Mario Prosa and Xiaofeng Xu and Mahdi Mansour and Ergang Wang and Mirko Seri and Mats R. Andersson and Michele Muccini and Germ
Published in Solar Energy Materials and Solar Cells
2015
Abstract
Degradation of organic photovoltaic (OPV) devices is currently a topic under intense research as it is one of the main limitations towards the commercialization of this technology. Morphological changes at both active layer and interfaces with the outer contacts are believed to determine main key issues to be overcome. In-line techniques are essential to rule out any effect arising during sample fabrication. Unfortunately, the number of physical techniques able to provide morphological information on complete and operational devices is certainly limited. In this work, we study the thermal degradation of bulk heterojunction (BHJ) solar cells composed by different donor polymers with techniques developed to provide in-situ information on operational devices. Capacitance measurement as a function of temperature monitors the electrical integrity of the active layer and provides the threshold temperature (TMAX) at which the whole device becomes thermally unstable. We found a direct correlation between the threshold temperature TMAX, obtained by capacitance