Approaching 20% Efficiency in Ortho-Xylene Processed Organic Solar Cells by a Benzo[a]phenazine-Core-Based 3D Network Acceptor with Large Electronic Coupling and Long Exciton Diffusion Length.

High-performance organic solar cells often rely on halogen-containing solvents, which restrict the photovoltaic industry. Therefore, it is imperative to develop efficient organic photovoltaic materials compatible with halogen-free solvents. Herein, a series of benzo[a]phenazine (BP)-core-based small-molecule acceptors (SMAs) achieved through an isomerization chlorination strategy is presented, comprising unchlorinated NA1, 10-chlorine substituted NA2, 8-chlorine substituted NA3, and 7-chlorine substituted NA4.

Precise Methylation Yields Acceptor with Hydrogen-Bonding Network for High-Efficiency and Thermally Stable Polymer Solar Cells.

Utilizing intermolecular hydrogen-bonding interactions stands for an effective approach in advancing the efficiency and stability of small-molecule acceptors (SMAs) for polymer solar cells. Herein, we synthesized three SMAs (Qo1, Qo2, and Qo3) using indeno[1,2-b]quinoxalin-11-one (Qox) as the electron-deficient group, with the incorporation of a methylation strategy. Through crystallographic analysis, it is observed that two Qox-based methylated acceptors (Qo2 and Qo3) exhibit multiple hydrogen bond-assisted 3D network transport structures, in contrast to the 2D transport structure observed in gem-dichlorinated counterpart (Qo4).