Lead-Free Cs3MnCl5 and CsMnCl3 Crystals: Rapid on-chip Crystallization, Phase Transition and Fluorescence Sensing Applications

Abstract

Manganese based perovskites have attracted tremendous interest due to their structural diversity, tunable emissions and low toxicity. In this work, manganese perovskite crystals, Cs3MnCl5 and CsMnCl3, are successfully fabricated through proposed on chip rapid crystallization strategy. Fabrication of Cs3MnCl5 and CsMnCl3 crystals can be finely controlled by adjusting the crystallization rate of precursor solution. The formation mechanisms of CsMnCl3 and Cs3MnCl5 crystals are clarified based on the classical crystal nucleation and growth theory. The morphology and phase structure of obtained Cs3MnCl5 and CsMnCl3 crystals are determined through scanning electron microscope (SEM) and X-ray diffraction (XRD) characterizations. Luminescent properties of Cs3MnCl5 and CsMnCl3 crystals are analyzed by UV-Vis absorption, steady and time-resolved photoluminescence spectra. The observed green and red emissions for Cs3MnCl5 and CsMnCl3 crystals are well explained according to varied coordination surroundings of Mn 2+ cations. Besides, phase transformation from Cs3MnCl5to CsMnCl3 with fluorescence converting from green to red. Furthermore, red luminescence of CsMnCl3 would be quenched under high relative humidity and fully recovered after heating, which makes it possible for applying in humidity detection.After 15 cycles of quenching-recovery test, the maximum fluorescence intensity of CsMnCl3 can still retain 75% of its initial value, showing high operation stability and potential application in fluorescence-based sensors.