Interface regulation toward high-performance narrow-bandgap perovskite photodetectors: mechanisms and challenges.

Narrow-bandgap perovskite photodetectors (PPDs) have emerged as promising candidates for broadband photodetection due to their extended spectral response from the visible to near-infrared region, high sensitivity, and low-cost solution processability. However, limitations such as instability, slow response speed, and insufficient spectral selectivity continue to restrict their practical application. This review critically examines the latest advances in interface engineering strategies for near-infrared PPDs, with a particular focus on optimizing carrier transport layers and structural technology, as well as defect passivation methods. We systematically analyze the potential mechanisms through which interface modulation affects charge extraction, defect density, energy level alignment, and carrier recombination dynamics. In addition, we compared different interface design methods to highlight their advantages, limitations, and potential synergies in multi-scale regulation. By identifying the current research bottlenecks and proposing targeted solutions, and summarizing the future development direction, this review provides a theoretical and technical basis for the development of high-performance narrow-bandgap PPDs.