Monofluorine substitution achieved high-Tc dielectric transition in a one-dimensional lead bromide hybrid photoluminescent perovskite semiconductor

High-Tc phase transition materials are essential for practical applications in energy and data storage, etc. Compared with the traditional deuterium isotope effect and newly discovered stress engineering, monofluorine substitution as a simple and universal method demonstrates many advantages over the above to enhance the Tc. In this report, we synthesized a one-dimensional hybrid lead bromide perovskite of (FTEA)PbBr3 (FTEA = Et3NCH2CH2F) by the monofluorine substitution of (Et4N)PbBr3. After fluoridation, (FTEA)PbBr3 retains the crystal symmetry unchanged and shows similar phase transition behavior with an Aizu notation of 6/mmmF2/m. The origin of the phase transition continues to be the order–disorder transition of a monofluorine substituted organic cation. However, the Tc experiences a significant enhancement of 16 K. Therefore, fluorine substitution provides a broad application range to improve the Tc. Moreover, (FTEA)PbBr3 undergoes excellent switchable dielectric transition coupled with semiconducting properties with an indirect bandgap of 3.48 eV. Unexpectedly, the title compound demonstrates a bright red emission under a UV lamp. Monofluorine substitution achieved significant Tc enhancement and the observation of multiple coupling of the switchable dielectric, semiconducting, and photoluminescent properties in a one-dimensional lead bromide halide perovskite will promote the further development of phase transition materials.