Intense Broadband Emission in the Unconventional 3D Hybrid Metal Halide via High‐Pressure Engineering

Abstract

Developing hybrid metal halides with self‐trapped exciton (STE) emission is a powerful and promising approach to achieve single‐component phosphors for wide‐color‐gamut display and illumination. Nevertheless, it is difficult to generate STEs and broadband emission in the classical and widely used 3D systems, owing to the great structural connectivity of metal‐halogen networks. Here, high pressure is implemented to achieve dual emission and dramatical emission enhancement in 3D metal halide of [Pb3Br4][O2C(CH2)2CO2]. The pressure‐induced new emission is ascribed to the radiation recombination of STEs from the Pb2Br2O2 tetrahedra with the promoted distortion through the isostructural phase transition. Furthermore, the wide range of emission chromaticity can be regulated by controlling the distortion order of different polyhedral units upon compression. This work not only constructs the relationship between structure and optical behavior of [Pb3Br4][O2C(CH2)2CO2], but also provides new strategies for optimizing broadband emission toward potential applications in solid‐state lighting.

Self-Trapped Exciton Emission Enhancement in 3D Cationic Lead Halide Hybrids Via Phase Transition Engineering

“…As illustrated in Figure e, the PL intensity exhibited a marginal increase below 8.0 GPa and then a substantial surge upon 10.5 GPa. This nonlinear continuous enhancement indicated a discontinuous change in the structure . Previous studies have demonstrated that the STE emission is influenced by the electron–phonon coupling, related to the crystal structural distortion of hybrid materials. , The multiple variations in the PL intensity indicated that there may be a structural phase transition with an intensified lattice distortion.…”