Type‐II Perovskite Quantum Dots Heterostructures for Highly Sensitive, Stable, Flexible Self‐Powered Photodetectors

Abstract Flexible self‐powered photodetectors (PDs) are highly desirable for next‐generation portable and wearable optoelectronics, but it still remains a huge challenge to realize high sensitivity, operational stability, and mechanical flexibility. In this work, a novel Type‐II CsPbI 3 :Nd 3+ @Cs 2 SnI 6 perovskite quantum dots (PQDs) heterostructures is employed as photosensitive layers, which can significantly enhance charge separation and transport, reduce trap density, and suppress interface carrier recombination. Compared to the pristine CsPbI 3 PQDs PDs, the flexible self‐powered PDs based on Type‐II CsPbI 3 :Nd 3+ @Cs 2 SnI 6 PQDs heterostructures exhibit exceptional performance with the responsivity (R) of 416.1 mA W −1 , detectivity (D * ) of 3.75 × 10 12 Jones, and external quantum efficiency (EQE) of 85.3%, respectively. Furthermore, the flexible self‐powered PDs show remarkable enhanced long‐term and operational stability. The responsivity of the device maintains 84.3% and 85.6% of its original value after 30 days of storage and two thousand bending cycles, respectively. This work highlights a new attempt for designing Type‐II PQD heterostructures self‐powered PDs, which has application potential in optoelectronic devices.