Temperature-Dependent Double Exciton Competition Emission in One Dimensional Copper-Based Organic–Inorganic Hybrid Perovskites

Organic–inorganic hybrid perovskites with temperature-dependent dual emission are attracting more attention due to their promising application in fluorescence intensity ratio technology. Herein, we report a Cu-based organic–inorganic hybrid perovskite (BDA)Cu2Br4 (BDA = C4H12N22+) with dimeric clusters ([Cu2Br6]4–) and organic cations (BDA) periodically arranged in a one-dimensional structure. This structure enables lattice self-trapping and strong coupling between electrons and phonons. The difference in the degree of lattice distortion affected by the temperature decrease leads to the mutual competition between two different self-trapped excitons, thus causing the two self-trapped emissions, resulting in the emission changes from the blue light to the orange-red light. Furthermore, these change in emission color can reverse while the temperature increases. This property potentially enables applications in temperature sensing, blue LEDs, and solid-state lighting.