Phase Engineering of Cesium Manganese Bromides Nanocrystals with Color-Tunable Emission

For display applications, it is highly desirable to obtain tunable red/green/blue emission. However, lead-free perovskite nanocrystals (NCs) generally exhibit broadband emission with poor color purity. Herein, we developed a unique phase transition strategy to engineer the emission color of lead-free cesium manganese bromides NCs and we can achieve a tunable red/green/blue emission with high color purity in these NCs. Such phase transition can be triggered by isopropanol: from one dimensional (1D) CsMnBr3 NCs (red-color emission) to zero dimensional (0D) Cs3MnBr5 NCs (green-color emission). Furthermore, in a humid environment both 1D CsMnBr3 NCs and 0D Cs3MnBr5 NCs can be transformed into 0D Cs2MnBr4.2 H2O NCs (blue-color emission). Cs2MnBr4.2 H2O NCs could inversely transform into the mixture of CsMnBr3 and Cs3MnBr5 phase during the thermal annealing dehydration step. Our work highlights the tunable optical properties in single component NCs via phase engineering and provides a new avenue for future endeavors in light-emitting devices.

Automated summary

The study introduced a unique phase transition strategy to engineer the emission color of lead-free cesium manganese bromides nanocrystals, achieving tunable red/green/blue emission with high color purity. Under humid conditions, both 1D and 0D nanocrystals can transform into 0D Cs2MnBr4.2 H2O nanocrystals, which can inversely transform back into a mixture of phases. This work highlights the tunable optical properties in single component nanocrystals through phase engineering, providing a new direction for future light-emitting devices.