Solution-Processed Ultrathin Cu-TCPP Metal−Organic Framework Films for Self-Powered Organic Photodetectors

Abstract

Metal−organic framework films have attracted increasing interest as functional materials and interfacial layers in optoelectronic devices, but their solution processing and integration into thin-film devices remain challenging. Here, we report a precursor-mediated method for preparing ultrathin Cu-TCPP MOF films by spin-coating and rapid thermal annealing. Cu(NO3)2·2H2O and H2TCPP were co-dissolved in DMSO to form a homogeneous coordination precursor solution, with Cu2+−H2TCPP interactions indicated by fluorescence quenching. Subsequent thermal treatment promotes the formation of the Cu-TCPP coordination framework, yielding continuous films with a thickness of approximately 10 nm. The resulting Cu-TCPP film was integrated into a self-powered organic photodetector. The device exhibits a pronounced UV photoresponse, with a peak responsivity of 0.119 A W−1 and a shot-noise-limited estimated specific detectivity of 5.62 × 1012 Jones at 355 nm. The introduction of the Cu-TCPP film suppresses the dark current and improves the external quantum efficiency (EQE). In addition, the spectral response can be modulated by changing the Cu-TCPP precursor concentration, accompanied by concentration-dependent changes in the optical absorption, film thickness, and nanoscale morphology of the MOF layer. This work demonstrates a simple precursor-mediated strategy for solution processing of ultrathin Cu-TCPP MOF films and their integration into self-powered organic photodetectors.