Enhancing the efficiency of non-fullerene organic solar cells by using a volatilizable solid additive system†

The morphology of the active layer mostly affects the photovoltaic efficiency of organic solar cells (OSCs). Optimizing the configuration of the bulk heterojunction (BHJ) is a very effective approach to enhancing the donor–acceptor network in the active layer. This work aims to examine the influence of a gallium (Ga) doped ZnO electron transport layer (ETL) and a solid additive 1,4-diiodobenzene (DIB) on the nanomorphology and performance of an inverted OSC. Nevertheless, the challenge of selecting appropriate solid additives for device optimization is arduous due to the extensive range of organic photovoltaic materials obtainable. This study presents the utilization of DIB as a solid additive to enhance the efficiency of OSCs. The utilization of modified ETL and DIB as solvent additives has been found to enhance the development of a desirable nanomorphology characterized by a bi-continuous interpenetrating network of donor and acceptor. Devices treated with DIB have significantly enhanced performance compared to control devices. In the case of non-fullerene OSCs, the power conversion efficiency (PCE) achieved a value of 16.67%. Additionally, employing DIB in the production of OSCs results in enhanced charge transport and extraction, improved crystallinity, reduced charge recombination, and superior phase separation. We provide evidence that the utilization of additive engineering is a very efficient approach for improving the efficiency of organic solar cells.