Solvent Doping Organic Single Crystal Enables High‐Performance Optoelectronic Devices

Abstract Organic doping has become an effective method to improve the performance of organic optoelectronic devices. However, the understanding of organic doping mechanism is limited by the difficulty in obtaining highly ordered molecular packing structure. Herein, a new donor‐acceptor type triphenylamine‐acetylene‐based isoindigo derivative, (E)‐6,6′‐bis((4‐(diphenylamino)phenyl)ethynyl)‐[3,3′‐biindolinylidene]‐2,2′‐dione (BDPEBD), is successfully designed and synthesized. The tetrahydrofuran solvent doped BDPEBD single crystal with a mass fraction of 4.33% is easily obtained through a solvent evaporation method. Tetrahydrofuran, as a dopant in its single crystal, effectively reduces the dihedral angle of BDPEBD molecules by forming strong intermolecular hydrogen bonds with BDPEBD molecules, which enhances the π–π intermolecular interaction between BDPEBD molecules, thereby resulting in excellent optoelectronic properties of its single crystal. Its phototransistors show the highest mobility of 0.3 cm 2 V −1 s −1 , wide spectral response from 254 to 790 nm, UV sensitivity, and a response time of 40 ms, the highest photoresponsivity exceeds 7.44 × 10 6 A W −1 .