Coexistence of Mo4+ and Mo3+ in stannum-based halide perovskites for stable ultra-wide dual-band near-infrared emission (800–1630 nm)

Metal halide ionic octahedra, serving as the fundamental optoelectronic unit in halide perovskites, enable near-infrared (NIR) luminescence via transition-metal ion incorporation. However, their intrinsically low radiative efficiency and inadequate operational stability have posed significant challenges for practical implementation. In this work, we report the first successful synthesis of a highly stable Mo-doped Sn-based perovskite NIR emitter via a one-step hydrothermal approach, which exhibits unprecedented dual broadband NIR emission (800–1630 nm). The oxidation of Sn 2+ induces the formation of mixed Mo 4+ / 3+ valence states, while the synergy of lattice distortion, spin–orbit coupling, and vibronic coupling activates multiple d-d transitions. Specifically, they promote the 1 T 2g / 1 E g → 3 T 1g transition of Mo 4+ and the Γ 8 ( 2 T 1g ) → Γ 8 ( 4 A 2g ) transition of Mo 3+ , achieving a high photoluminescence quantum yield (PLQY) of 68% at room temperature. Notably, this NIR-emitting halide maintains 88% of its room-temperature emission intensity at 423 K, demonstrating exceptionally low thermal quenching. Moreover, the precise control of Mo doping level and the introduction of Sn 2+ enable the systematic tailoring of the NIR-I/II luminescence. This breakthrough not only provides fundamental design principles for developing next-generation broadband NIR-I and II emitting material but also establishes a new application platform in night-vision and vascular imaging for optoelectronic devices with superior performance.