Metal

Metallurgy

Materials science

Atomic physics

Broadband

Photoluminescence

Inorganic chemistry

Quantum yield

Metal halides

Laser

Physics

Nanotechnology

Exciton

Optics

Fluorescence

Condensed matter physics

Excited state

Chemistry

Light emission

Optoelectronics

Halide

Spontaneous emission

Advanced Materials

Self‐trapped excitons (STEs) have recently attracted tremendous interest due to their broadband emission, high photoluminescence quantum yield, and self‐absorption‐free properties, which enable a large range of optoelectronic applications such as lighting, displays, radiation detection, and special sensors. Unlike free excitons, the formation of STEs requires strong coupling between excited state excitons and the soft lattice in low electronic dimensional materials. The chemical and structural diversity of metal halides provides an ideal platform for developing efficient STE emission materials. Herein, an overview of recent progress on STE emission materials for optoelectronic applications is presented. The relationships between the fundamental emission mechanisms, chemical compositions, and device performances are systematically reviewed. On this basis, currently existing challenges and possible development opportunities in this field are presented.

Light Emission of Self‐Trapped Excitons in Inorganic Metal Halides for Optoelectronic Applications