One-dimensional luminescent tetrabutylammonium lead halide perovskite synthesized with deep eutectic solvents

Abstract

One-dimensional (1D) luminescent tetrabutylammonium lead halide perovskites (TBA)₄Pb₅Br_14−xCl_x·HBr(Cl)·2H₂O and TBAPbI₃ (TBA = tetrabutylammonium) were synthesized with deep eutectic solvents (DESs) for the first time. Temperature-dependent photoluminescence (PL) spectroscopy and differential scanning calorimetry (DSC) show that these materials undergo order–disorder phase transitions near room temperature. The perovskite with bromine shows double emission at low temperature, with a peak of approximately 506 nm originating from free excitons (FEs) and a peak of 547 nm due to self-trapped excitons (STEs). In addition, the PL intensity does not decrease but increases in the first 6 h at 100 °C. This may be due to the continuous expansion of the volume of TBA⁺ at 100 °C, resulting in continuous lattice distortion and more STEs emission. This work opens up new avenues for the sustainable synthesis of good thermally stable perovskites using DESs. The successful design of new 1D perovskite materials offers new ideas for high-performance perovskite optoelectronic devices.