Donor-Node-Acceptor Type Hole-Transporting Materials Based on Conjugated Polymers with Perylene Diimide Pendants for High-Performance Vertical-Structure Perovskite Photodetectors

A series of donor-node-acceptor (D-n-A) type polymers containing linear conjugated backbone as donor and various contents of tetrachloronated perylene diimide (4Cl-PDI) pendant as acceptor are synthesized for the application as hole-transporting layers (HTLs) in n-i-p structured perovskite photodetectors (PDs). The strong aggregation behaviors of the linear conjugated backbone endow the polymers excellent hole transporting properties, and the strong electron affinity of 4Cl-PDI pendant enables easily trapping of free electrons. Besides, the 4Cl-PDI pendants in polymers suppress the intrinsic face-on orientation of conjugated backbone. Both of the electron-trapping property of 4Cl-PDI pendant and the favorable edge-on orientation of the conjugated backbone are benefits for restraining the dark current in perovskite PDs. Based on such D-n-A type hole-transporting materials, durable vertical-structure perovskite PDs are successfully demonstrated with superior performance of high responsivity of 0.32 A W-1, high detectivity of 2.2 x 10(12) ones, and fast response speed in microsecond scales.

Automated summary

A series of donor-node-acceptor (D-n-A) polymers with linear conjugated backbone as donor and tetrachloronated perylene diimide (4Cl-PDI) pendant as acceptor have been synthesized for use as hole-transporting layers (HTLs) in perovskite photodetectors (PDs). The polymers exhibit excellent hole transporting properties due to the aggregation behavior of the conjugated backbone and easily trap free electrons due to the electron affinity of the 4Cl-PDI pendant. The presence of the 4Cl-PDI pendant in the polymers also suppresses the face-on orientation of the conjugated backbone, thus reducing dark current in the perovskite PDs. Based on these D-n-A type hole-transporting materials, durable perovskite PDs with high responsivity, detectivity, and fast response speed have been successfully demonstrated.