Stimuli-responsive photoluminescent (PL) materials have attracted considerable attention in recent years owing to their potential applications in anti-counterfeiting, information encryption, and sensing. Further investigations of the transformation mechanism and potential applications of stimulus-responsive PL materials are considerably important. In the current study, an organic–inorganic metal halide, C 9 H 15 N 3 SbCl 5 ([C 9 H 13 N 3 ] 2+ is a 1-(2-pyridyl) piperazine cation) is obtained, which exhibits a 0D structure with P- 1 space group. At room temperature, when excited by UV light, the C 9 H 15 N 3 SbCl 5 single crystals exhibit unimodal blue light emission at 405 nm, and grinding or hydrostatic pressure induces double-peak emissions at 405 and 650 nm. Interestingly, double-emission samples can be restored to single-emission samples by short annealing or storage in air for 2 weeks, and this process is reversible. Luminescence response to mechanical stimuli can also be achieved in the presence of hydrochloric acid and water. Spectral analysis and the analysis of the microstructural changes revealed that the structural modifications of the inorganic group play a pivotal role in the response to the stimulus. Finally, a composite film device based on C 9 H 15 N 3 SbCl 5 is prepared to demonstrate the potential of these smart materials in anti-counterfeiting and sensing applications.
Nan Li,Yu Xia,Xiao-Ying He,Jia-Cheng Li,Kai-Li Wang,Jing Chen,Chun-Hao Chen,Lei Huang,Yu-Tong Yang,Xin Chen,Yan-Hui Lou,Zhao-Kui Wang
The operational stability of mixed-halide blue perovskite light-emitting diodes (PeLEDs) is fundamentally constrained by intrinsic halide ion migration. Employing single-halide perovskite systems represents a viable route to circumvent this issue, yet solution-processed pure-bromide perovskites typically exhibit undesirable green emission, impeding attainment of high-color-purity blue electroluminescence. Herein, this challenge is addressed through the strategic incorporation of Mg 2+ into the B-site of the pure bromine-based perovskite lattice. This substitution induces a substantial spectral blueshift and promotes phase homogenization by facilitating efficient energy transfer from small-n to large-n phases. Notably, the first systematic investigation and mechanistic elucidation of the origin of bimodal emission in blue PeLEDs is presented. Consequently, the champion PeLED delivers stable deep-blue emission at 464 nm with a maximum external quantum efficiency of 4.76%. This study presents a definitive paradigm for achieving spectrally stable and efficient deep-blue emission from single-halide perovskites. The elucidated mechanism underlying emission bimodality provides critical guidance for future development of blue PeLEDs.
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