研究目的
Investigating the temperature-dependent phase transition of organic-inorganic halide perovskite single crystals through UV-Vis absorption and photoluminescence measurements.
研究成果
The study demonstrated that MAPbBr3?xIx single crystals exhibit abrupt changes in optical band gap, PL peak position, and intensity around 120 K - 170 K, indicating phase transition temperatures. MAPbBr3 was found to be more susceptible to temperature-induced phase transitions than MAPbI3. The temperature-dependent changes in absorption spectra were fully reversible, confirming the reversibility of the phase transition.
研究不足
The study focuses on the temperature-dependent optical properties and phase transition of MAPbBr3?xIx single crystals. The reversibility of the temperature-dependent changes was confirmed, but the time required for the samples to return to their initial state varied, indicating potential limitations in the stability and reversibility under thermal cycling.
1：Experimental Design and Method Selection:
The study utilized temperature-dependent UV-Vis absorption and photoluminescence (PL) measurements to investigate the phase transition in MAPbBr3?xIx single crystals. The optical band gap was extracted using derivation of absorption spectrum fitting (DASF) and Tauc plot methods.
2：Sample Selection and Data Sources:
MAPbBr3?xIx single crystals were synthesized with different mixing ratios (Br/I 3:0, Br/I 5:1, and Br/I 0:3) by the inverse temperature crystallization (ITC) method.
3：List of Experimental Equipment and Materials:
UV-Vis absorption was measured using a commercial spectrophotometer (V-670, JASCO). For PL measurement, a diode laser (λ = 405 nm) was used as an excitation source, and the PL signal was collected by a PMT detector. Temperature-dependent measurements were performed in a closed-cycle helium cryostat.
4：Experimental Procedures and Operational Workflow:
The temperature-dependent UV-Vis absorption and PL measurements were performed in the range of 10 to 300 K. A holding time of 30 minutes was provided at each temperature before measurement to ensure phase stabilization.
5：Data Analysis Methods:
The optical band gap was determined using DASF and Tauc's methods. PL spectra were analyzed using Gaussian peak fitting.
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