2021 Adv. Mater. (If 30.849): Nearly 19% Organic Solar Cells! New Method of Photoactive Layer Modulation

　　Advanced Materials (IF 30.849) recently reported that with the aid of solid additives, organic solar cells can achieve significant power conversion efficiency (PCE).

 　　One of the important challenges of high-efficiency organic solar cells is to control the self-assembly of organic semiconductors to form good nanoscale phase separation. In particular, the similar anisotropic conjugated structure between the non-fullerene acceptor and the p-type organic semiconductor donor increases the complexity of achieving phase separation. In this research, scientists used the synergistic effect of volatile solid additives (dithieno[3,2-b:2′,3′-d]thiophene, DTT) and solvent additives (1-chloronaphthalene, CN) to develop a new method to adjust the photosensitive layer. In the film casting process, DTT can limit the excessive self-assembly of non-fullerene acceptors, allowing acceptors to undergo phase separation and refinement of molecular accumulation with the volatilization of DTT under thermal annealing.

　　Ternary organic solar cells (OSCs) based on PTQ10:m-BTP-PhC6:PC71BM are verified by the treatment of dual additives of CN and DTT. The use of Enlitech’s solar simulator and QE-R quantum efficiency measurement system verified a significant power conversion efficiency of 18.89% and fill factor (FF) of 80.6%. In addition to the EQE (External Quantum Efficiency) spectrum analysis of organic solar cells, the quantum efficiency measurement system also provides a comparison of Jsc (short-circuit current density) for the short-circuit current of the solar cell under the solar simulator. Prove the authenticity of the experiment. At the same time, Enlitech’s solar simulator and the KA-6000 software provide monitoring of the short-circuit current to prove the stability of the solar cell!