Reducing Voltage Losses of Organic Solar Cells against Energetics Modifications by Thermal Stress.

Voltage losses are one of the main obstacles for further improvement in the power conversion efficiency of organic solar cells. In this work, we investigate the effect of thermal stress on voltage losses in various material systems by multiple spectroscopic measurements on both devices and thin films. The energetics of nonfullerene small molecules are more readily altered under thermal stress compared to all-polymer and fullerene-based systems, thereby strongly affecting open-circuit voltage.