Highly Sensitive Broadband Photodetectors Based on Donor–Acceptor 2D Conjugated Coordination Polymers

ABSTRACT Two‐dimensional (2D) semiconductors are highly desirable for broadband photodetection but are often constrained by their limited optical absorption and inefficient exciton dissociation. In this study, we report a donor–acceptor‐engineered 2D conjugated coordination polymer (c‐CP), Ni‐TABQ (TABQ = tetraaminobenzoquinone), as a narrow‐bandgap semiconductor. The TABQ ligands integrate electron‐rich amino donors and electron‐deficient quinone carbonyl acceptors within the same molecular backbone, endowing the Ni‐TABQ lattice with strong intramolecular charge‐transfer absorption and a built‐in driving force for charge separation. Benefiting from strong broadband absorption and high charge‐carrier mobility, the vapor‐phase‐grown Ni‐TABQ thin films enable photodetection from 350 to 1400 nm under a 3 V bias, with a measurable response tail above 1150 nm, further achieving a responsivity of up to 3.1 A W −1 , a specific detectivity of up to 6.58 × 10 10 Jones (625 nm at ∼85 µW cm −2 ), and a response time of ∼206 µs, while maintaining stable operation at 3 V over 8500 s of continuous cycling. These metrics compare favorably with state‐of‐the‐art broadband photodetectors based on standalone 2D materials, establishing donor–acceptor molecular engineering within the 2D metal‐organic lattice as an effective strategy for advancing high‐performance 2D optoelectronic devices.