Submicrowatt-driven near-infrared luminescence from perovskite-fluoride quantum-cutting heterostructures for gas sensing.

The pursuit of wideband tunable near-infrared (NIR) light sources has reached fever pitch due to advances in photonic chips, optical communications, and molecular trace detection. Lanthanide ions (Ln3+), renowned for their characteristic NIR luminescence, have nevertheless been stymied by the challenges of an extremely low molar extinction coefficient and linear absorption. Herein, a senitization methodology is presented that capitalizes on the quantum cutting-engineered heterostructure nanoparticles (CsPbX3: Yb3+-NaYF4: Yb3+, Ln3+), to achieve multi-wavelength NIR luminescence spanning the 900-2200 nm spectrum. The designed heterostructure exhibits an unprecedented absorption bandwidth (200-690 nm) across the UV-visible spectrum, with an exceptionally low stimulation threshold at the sub-microwatt level (50 µW cm-2). The NIR luminescent wavelengths can be precisely modulated by meticulously adjusting the dopant Ln3+ ions leveraging Yb3+-mediated quantum cutting processes. Spectroscopic analysis reveals a directed energy transfer pathway at the perovskite-fluoride heterogeneous interface: perovskite host→Yb3+ (perovskite) →Yb3+ (NaYF4) → Ln3+. This architecture demonstrates multiplexed gas detection capabilities under AI-assisted analysis, facilitating the simultaneous identification and monitoring of multiple marker gases in complex environments. Our work provides a scalable strategy for constructing ultra-broadband NIR light sources, with implications for high-throughput spectroscopic sensing.