Theoretical and Experimental Photovoltaic Behaviors of an s-Tetrazine Based D-A Copolymer

Abstract

A published theoretical approach for forecasting the photovoltaic behavior of D-A copolymers, relying on the frontier levels of donor–acceptor (D–A) type copolymer was tested experimentally. The pair [5,11-bis(2-ethylhexyl) dihydroindolo [3,2-b]-carbazole] (D)/ [3,6-Bis(4-octylthiophen-2-yl)-1,2,4,5-tetrazine] (A) was chosen to prepare the DA copolymer (PIC-TTz), based on an extensive theoretical study that has considered 2080 DA possible combinations. The energy levels, estimated by cyclic voltammetry joined with absorption spectra revealed that the polymer have appropriate energy levels for organic photovoltaic application. Polymer photovoltaic devices based on blends of the copolymer and PC₇₁BM showed a high open-circuit voltage (>0.9 V) under the illumination of AM 1.5 (100 mWcm^-2). The determined power conversion efficiency (PCE) was 1.12%, and this result is discussed in light of the photophysical behavior not considered in the theoretical approach. It was demonstrated that although promising, the theory can be used as a guide, but not enough to substitute bench work.