Sb3+-doped terbium-based metal halide with efficient dual band emission for ratiometric temperature sensing

Low-dimensional organic-inorganic hybrid metal halides (HMH) have attracted widespread attention due to their tunable chemical composition and exceptional optoelectronic properties. However, there are only limited numbers of reports about lanthanide elements-based metal halides. Herein, we synthesize a zero-dimensional (0D) metal halide, (DFPD) 4 TbCl 7 (DFPD = 4,4-difluoropiperidinium), which exhibits intrinsic emission from the lanthanide ion (Tb 3+ ). Interestingly, by doping a small amount of Sb 3+ , an additional emission peak emerged at 625 nm. Apart from the dual band photoluminescence (PL), the photoluminescence quantum yield (PLQY) is increased from ~40% to near unity (99.6%) after doping (DFPD) 4 TbCl 7 HMH with Sb 3+ . To reveal the enhanced PLQY and dual band emission in (DFPD) 4 TbCl 7 :Sb 3+ , we carried out temperature-dependent PL measurements and density functional theory (DFT) calculation. We found the observed dual-band emission originated from intrinsic emission of Tb and self-trapped exciton (STEs) emission, which is introduced by the [SbCl 6 ] 3− octahedron. The extra radiative channel introduced by STEs contributes to the enhanced PLQY. Taking advantage of the efficient PL and high stability of (DFPD) 4 TbCl 7 :Sb 3+ , we fabricated a stable white-light-emitting diode with a color rendering index of 93. Furthermore, the temperature dependent PL of (DFPD) 4 TbCl 7 :Sb 3+ ensures its application as active material for optical thermometry. Our work provides a new strategy for developing lanthanide-based HMH with high performance for light emitting applications. We synthesized a 0D organic-inorganic terbium-based metal halide with dual emission by incorporating Sb 3+ . Temperature-dependent PL spectra and calculations reveal emissions from Tb 3+ and STEs of [SbCl₆] 3− units, with a near-unity PLQY. The distinct temperature response of the two emission bands enables ratiometric temperature sensing. WLEDs fabricated using this material exhibit excellent thermal stability, demonstrating its potential for both luminescent and sensing applications. • A 0D Tb-based metal halide with Sb 3+ doping exhibits efficient dual-band emission. • Distinct temperature-dependent emissions enable ratiometric optical thermometry. • Sb 3+ doping enhances PLQY to near unity via self-trapped exciton formation. • The material demonstrates excellent air and photo stability for optoelectronics. • A WLED device with high CRI of 92.5 was fabricated using the developed material.