Long-Term Stabilization of Organic Solar Cells using UV Absorbers

We are reporting on the successful implementation of UV absorbers for the long-term stabilization of organic photovoltaic devices (OPV). A set of six commercially available representatives of main UV absorber classes, commonly used for insulating plastics, were ternary-blended into the active layer, and the OPV performances were recorded under International Summit on OPV Stability standards (ISOS-3) degradation conditions. An improvement in the long-term performance of the OPV devices, manifested in the accumulated power generation (APG) increase for over a factor of 3, was found for 2-(4,6-diphenyl-1,3,5-triazin-2-yl)-5-[(hexyl)oxy]-phenol. This improvement is governed by a significantly decreased PCE loss during the burn-in period. Fourier transform infrared spectroscopy (FTIR) spectroscopy, used to trace chemical degradation over time, indicates that the stabilization of the active layer occurs due to a reduced formation of radicals facilitated by the UV screening properties of the additive.