Ultrabroadband tunable emission in hybrid Zr-perovskite via Sb³⁺ doping: Harnessing singlet-triplet energy transfer and self-trapped excitons

Organic-inorganic hybrid metal halide perovskites (MHPs) are emerging as innovative and promising optical functional materials due to their tunable structures and impressive emission properties. However, it still remains an intriguing challenge to achieve multi-response excitation and spectrally tunable emission in single-component-based MHPs. Herein, we obtain component-, excitation-, temperature-dependent luminescence with broadband tunable emission in an organic-inorganic hybrid MHP, (ETP)₂ZrCl₆ (ETP = ethyl triphenylphosphine) with Sb³⁺ activation, in which the isolated [ZrCl₆]^2- metal-halide units are separated by ETP cations. The experimental studies indicate that energy transfer between the singlet and triplet of organic-inorganic hybrid MHPs, and doping-induced self-trapped excitons (STEs) result in multi-response broadband photoluminescence spanning deep UV to deep red. Zr⁴⁺ in the host could modulate room-temperature phosphorescence and ultraviolet B (280–315 nm) luminescence by regulating intersystem crossing and reverse intersystem crossing processes. The Sb³⁺ activator could extend luminescence to red region, achieving a photoluminescence quantum yield of up to 78.8 %. This multi-mode luminescence in organic-inorganic hybrid (ETP)₂ZrCl₆ shows its potential in multifunctional applications including advanced anti-counterfeiting, spatial-time-resolved coding, and low-temperature sensing.