[1]Benzothieno[3,2‐b][1]benzothiophene‐Phthalocyanine Derivatives: A Subclass of Solution‐Processable Electron‐Rich Hole Transport Materials.

The [1]benzothieno[3,2‐b][1]benzothiophene (BTBT) planar system was used to functionalize the phthalocyanine ring aiming at synthesizing novel electron‐rich π‐conjugated macrocycles. The resulting ZnPc−BTBT and ZnPc−(BTBT)4 derivatives are the first two examples of a phthalocyanine subclass having potential use as solution‐processable p‐type organic semiconductors. In particular, the combination of experimental characterizations and theoretical calculations suggests compatible energy level alignments with mixed halide hybrid perovskite‐based devices. Furthermore, ZnPc−(BTBT)4 features a high aggregation tendency, a useful tool to design compact molecular films. When tested as hole transport materials in perovskite solar cells under 100 mA cm−2 standard AM 1.5G solar illumination, ZnPc−(BTBT)4 gave power conversion efficiencies as high as 14.13 %, irrespective of the doping process generally required to achieve high photovoltaic performances. This work is a first step toward a new phthalocyanine core engineerization to obtain robust, yet more efficient and cost‐effective materials for organic electronics and optoelectronics. [ABSTRACT FROM AUTHOR]