Broadband Emission Origin in Metal Halide Perovskites: Are Self-Trapped Excitons or Ions?

It has always been a goal to realize high efficiency and broadband emission in the single-component materials. The appearance of metal halide perovskites makes it possible. Their soft lattice characteristics and significant electron-phonon coupling synergistically generate the self-trapped excitons (STEs), contributing to the broadband emission with a large Stokes shift. Meanwhile, their structural/compositional diversity provides suitable active sites and coordination environments for ns 2 ions doping, allowing 3 P n (n = 0, 1, 2) → 1 S 0 transitions toward the broadband emission. The ns 2 ions emission is phenomenologically similar to that of the STE emission, preventing people from in-depth understanding their emission origin, thus failure to meeting the design requirements to serve the various sectors of practical applications. In this scenario, we deploy this review by summarizing the fundamentals and development of such two emission mechanisms, to establish a clear and comprehensive understanding of the broadband emission phenomenon, which may pave the way to an ideal customization of broadband-emission metal halide perovskites. This article is protected by copyright. All rights reserved.