Aggregation-Induced Emission Features of Organometal Halide Perovskites and Their Fluorescence Probe Applications

Organometal hybrid perovskites exhibit tunable absorption and photoluminescence spectra that originate from the adjustable excitons of the self-assembled quantum-well structures. The aggregation-induced emission (AIE) features of (RNH₃)₂PbI₄ (R = alkyl, C_nH_2n+1, n = 4, 12, 16, 18) as well as their reversible photoluminescence response to pH value are demonstrated. This interesting phenomenon correlates with the formation of quantum-well structure, which is a novel AIE mechanism. The temperature sensors based on organometal hybrid perovskites are also investigated. The combination of high sensitivity (1.3% K^-1) and good reversibility (>500 cycles) of organometal halide perovskites to temperature in a large temperature range (0-80 °C) makes them to be versatile systems for the temperature sensor applications. Furthermore, as a proof of concept, the application of organometal hybrid perovskites in 2D spatial imaging and NIR light detection is also presented. Organometal halide perovskites obtained by a fast precipitation technique with an obvious excitonic characteristic are demonstrated to have aggregation-induced emission (AIE) features which can be explained by the "turn-on" of exciton recombination during self-assembly, and temperature-induced photoluminescence quenching features, which make them suitable reversible pH and temperature fluorescent probes.