The Interfacial Electric Field Strategy for Improving the Performance of Perovskite X-ray Detectors

Abstract

X-ray detection technologies are indispensable tools across diverse fields, including medical diagnostics, industrial inspection, environmental monitoring, and security screening. The emerging perovskite materials are a prospective substitute for traditional ones to develop higher performance X-ray detectors, which are distinguished by their large atomic numbers, configurable bandgap, better charge carrier mobility, and extended carrier diffusion length. However, high sensitivity, low detection limits, quick reaction times, and long-term operating stability are still major challenges for perovskite X-ray detectors. The main cause of this problem is the ineffective use of photogenerated charge carriers, including their creation, separation, transport, collection, and recombination minimization. Notably, these charge carrier dynamics in perovskite Xray detectors are fundamentally driven by the interfacial electric field (IEF). Therefore, a comprehensive and deep understanding of the the IEF's crucial role in the performance of perovskite X-ray detectors is of paramount importance in their rational design. In this review, we first elucidate the basic principles of IEF formation at various interfaces within perovskite detector devices, and the profound impact of IEF on enhancing charge separation efficiency, promoting carrier transport, and suppressing recombination pathways, and ultimately reducing dark current and improving signal-to-noise ratio. Subsequently, we systematically summarize recent advances in modulating the IEF through various strategies, including heterojunction engineering, energy level alignment via interfacial dipole layers and functional layer modifications. Finally, perspectives are given on the existing challenges and future opportunities in IEF engineering, aiming to stimulate new fundamental understanding and guide the rational design of high-performance perovskite X-ray detectors.