Charge Photogeneration and Recombination Dynamics in PTQ10:Y6 Solar Cells

Abstract

In this work, charge photogeneration dynamics in PTQ10:Y6 solar cells were studied by steady-state and time-resolved spectroscopies. For neat donor and acceptor films, we determined the exciton diffusion coefficients of PTQ10 and Y6 as 1.3 × 10−3 cm2·s−1 and 6.8 × 10−3 cm2·s−1, respectively. Furthermore, we find the LUMO and HOMO level offsets of 0.14 eV and 0.11 eV are sufficient for the dissociation of donor and acceptor excitons, respectively. For PTQ10:Y6 blend films, we find DIO additive could increase the scales of acceptor and donor phases. The acceptor phase increased slightly from 17.2 nm to 20.0 nm, while the donor phase increased from 2.3 nm to 5.8 nm. In addition, we find bimolecular recombination is a critical form for carrier recombination and DIO additive can significantly suppress the carrier recombination rate of PTQ10:Y6 active layer in an ultrafast time scale. This work is helpful for understanding the charge photogeneration processes in non-fullerene polymer solar cells.