Effect of phase transition stress on the photoluminescence of perovskite CH3NH3PbI3 microwires
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CH3NH3PbI3 (MAPbI3) exhibits distinctive properties for applications in photovoltaics, light emitting devices, photodetectors, and fuel cells. The working temperature of an optoelectronic device affects the photophysical properties of the active material, which is closely related to the device performance. In MAPbI3, these properties are intimately connected with its crystalline structure which is temperature dependent. Here, we study the photoluminescence (PL) behavior of MAPbI3 microwires (MWs) under recursive tetragonal-to-cubic and cubic-to-tetragonal phase transitions induced by temperature cycles from 40 °C (tetragonal phase) to 80 °C (cubic phase). MWs emission exhibited an initial redshift in wavelength by increasing the temperature from the tetragonal to the cubic phase, but after several thermal cycles, this trend reversed and the emission blueshifted. In both phases independently, the emission blueshifted and became stronger with increasing the cycles. The results indicate a thermal cycling-dependent PL and a gradual crystalline structure deformation due to a reiterated change in the MWs lattice, which implies variation in the electronic bandgap along the heating–cooling process. The alteration of the electronic band structure was corroborated by thermal cycling-reflectance measurements. The awareness behavior of material properties upon phase transitions and temperature fluctuations is of great importance for the optimization of optoelectronic devices.
This work was financially supported by the National Natural Science Foundation of China (Nos. 21473046, 21203046 and 11374074) and the New Faculty Start-up Funds from Harbin Institute of Technology.
BG and RS conceived idea. RS, LD, HJ, and PM carried out the experiments. RS and BG wrote the manuscript. XS, HS, and BG supervised the project. All authors contributed to data analysis and scientific discussion.
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Conflicts of interest
The authors declare that they have no conflict of interest.
- 13.International Electrotechnical Commission, IEC 61215 (2016) Terrestrial photovoltaic (PV) modules-design qualification and type approval, 1st edn. https://webstore.iec.ch/publication/24312