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Zero-dimensional organic-inorganic hybrid metal halides that can realize single-component white emission have attracted extensive attention due to the high-quality requirements of solid-state lighting technology. Although efficient white emission can be obtained in metal halides, the realization of tunable emission and high color rendering index of single-component white light remains a challenge. Herein, we report the binary halide (TEA) 2 (MnCl 4) 1- x (SbCl 5) x (TEA+ = tetraethylammonium, C 8 H 20 N+), realizing warm white emission with a photoluminescence quantum yield of 86.24 %. (TEA) 2 (MnCl 4) 1- x (SbCl 5) x halides with multiple optical polyhedral units ([SbCl 5 ]2- pyramid and [MnCl 4 ]2- tetrahedron) shows triple-peaked emission at 460 nm (free excitons emission), 520 nm (d – d transitions of Mn2+ ions), and 630 nm (self-trapped excitons emission). Interestingly, (TEA) 2 (MnCl 4) 1- x (SbCl 5) x halides exhibit emission color tunability by changing excitation energy and temperature, respectively. A comparison of lifetime spectra, as well as the temperature-variation spectra, was utilized to elucidate the energy transfer mechanism between Sb3+ and Mn2+ ions. The single-component white light-emitting diode fabricated by (TEA) 2 (MnCl 4) 0.92 (SbCl 5) 0.08 sample exhibits a high color rendering index of 92. This approach involving multiple emission mechanisms from different polyhedrons represents a promising avenue for designing single-component white-light emitters. • (TEA) 2 (MnCl 4) 1- x (SbCl 5) x halides showed high-performance white light emission (PLQY∼86.24 %). • The relationship between the host and guest has been established. • The unique energy transfer occurs from Sb3+ ions to Mn2+ ions has been confirmed. • High-efficiency luminescence (CRI∼92, CCT∼4253 K) of the fabricated WLED can be applied in the lighting field. [ABSTRACT FROM AUTHOR]

Ce+3 doped CsLaSiS 4 single crystals were synthesized using high-temperature flux synthesis. XRD analysis showed that the products are isostructural to CsLaSiS 4 and crystallize in orthorhombic space group Pnma. Absorption spectra were studied at room temperature, and photoluminescence properties were examined in the temperature range of 5–310 K. The energy of interband transitions E g = 3.75 eV was determined at room temperature in the Tauc model. At room temperature, only a non-elementary d → f emission band of Ce+3 ions was observed in the 520 nm region. The luminescence kinetics upon excitation by a pulsed cathode beam or X-ray synchrotron radiation exhibited a dominant nanosecond component. Decay time, as well as build-up time, decreased with increasing concentration of Ce+3 ions. Concentration quenching of Ce+3 emission was not observed up to 11.9 mol% of Ce+3 ions. At a low temperature of 5 K, new wide emission bands at 422 and 688 nm appeared in the photoluminescence spectrum. It is shown that the 422 nm band in the photoluminescence spectrum corresponds to host emission, specifically the luminescence of self-trapped excitons (STE). The 688 nm emission band corresponds to defect-related luminescence. STE emission is quenched according to the Mott law at temperatures above 26 K with an activation energy of 20 meV. An efficient energy transfer channel from the STE to the Ce+3 ion via the radiative resonance mechanism is observed. The emission of Ce+3 ions and defect-related luminescence can be excited by the intracenter way, due to electron-hole recombination, or by the creation of defect bound excitons. Based on the obtained spectroscopic data, a band scheme illustrating the processes of relaxation of electronic excitations at T = 5 K in Ce+3 doped CsLaSiS 4 crystals is proposed. [Display omitted] • Ce+3 doped CsLaSiS 4 single crystals were obtained through high-temperature flux synthesis. • Inter configurational d-f transitions in Ce3+ ions were studied upon both UV- and X-ray excitation. • Luminescence kinetic studies were conducted using a pulsed cathode beam and X-ray synchrotron radiation. • Self-trapped excitons, defect-bound excitons, and impurity luminescence were observed at T = 5 K. [ABSTRACT FROM AUTHOR]