Optical Properties of a CsMnBr3 Single Crystal

Lead-free perovskite materials with good stability are promising for various applications. In order to explore their application in optoelectronic devices, it is essential to investigate their fundamental optical properties. In this work, we have synthesized a CsMnBr3 single crystal (SC) with red emission at similar to 621 nm and studied their optical properties. Through the measurement of temperature-dependent photoluminescence (PL) spectra, it is found that a phase transition occurs at approximately 100 K in the SC, which is absent in the CsMnBr3 nanocrystals (NCs). Furthermore, the SC exhibits stronger electron and longitudinal optical phonon coupling strength than that of the NCs at low temperatures. In addition, under the resonant excitation at 600 nm, the SC possesses strong saturable absorption property, with a modulation depth of similar to 27%. Interestingly, the SC also exhibits a large two-photon absorption coefficient of similar to 0.035 cm GW-1 at 800 nm and an excellent optical limiting behavior. The experimental results indicate that the CsMnBr3 SC is a class of excellent environmentally friendly optoelectronic materials.