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Multi-color fluorescent anti-counterfeiting technology possesses a wide range of application prospects. However, there is still a challenge on the development of new single-component multi-color fluorescent materials related to the excitation wavelength. Herein, we report an efficient multi-peak luminescent material, Sb3+, Mn2+ co-doped CsCdCl 3 , which emission with a long afterglow is related to the excitation wavelength. There are two independent energy transfer channels of Mn2+ under short- and long-wave excitation. Under 357 nm excitation, dual-emission is observed at 506 and 590 nm attributed to the 3P 1 –1S 0 and 4T 1 -6A 1 transitions of [SbCl 6 ]3- and Mn2+ ions, respectively. Under 254 nm excitation, the microcrystals have orange emission. Excitation wavelength-dependent and tunable dual-emission associated with the host self-captured excitons and [SbCl 6 ]3- to Mn2+ energy transfer. The microcrystal's afterglow time at room temperature is 3500 s, which is attributed to the modulation of the trap for Mn2+. These results indicate that the material has potential applications in the field of multicolor fluorescent anti-counterfeiting. [ABSTRACT FROM AUTHOR]

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]

[Display omitted] • Bi-bridge BiPO 4 /CdS heterojunction (BiPO 4 /Bi/CdS) with oxygen vacancy was fabricated. • BiPO 4 /Bi/CdS displayed high intersystem crossing efficiency. • The effective intersystem crossing from singlet to triplet excitons facilitated 1O 2 production. • BiPO 4 /Bi/CdS exhibits excellent photocatalytic activity in ofloxacin degradation. • Mechanism of type-II heterojunction based on exciton energy transfer was first set forth. The separation of photogenerated charge carriers has been widely investigated, but exciton effects in type-II heterojunctions are often overlooked. Herein, the Bi-bridge BiPO 4 /CdS type-II heterojunction (BiPO 4 /Bi/CdS) with oxygen vacancy was successfully fabricated. BiPO 4 /Bi/CdS displayed stronger phosphorescence emission than BiPO 4 /Bi, suggesting the higher efficiency of intersystem crossing. The effective intersystem crossing from singlet to triplet excitons facilitated the activation of O 2 to singlet oxygen (1O 2), which was the product of energy transfer from the triplet excitons to the ground-state O 2 molecule. The synergies between oxygen vacancy, surface plasmon resonance of Bi and heterojunction-construction promoted charge carrier separation and the generation of 1O 2. As a result, BiPO 4 /Bi/CdS exhibited excellent photocatalytic activity in ofloxacin degradation with 93% degradation efficiency and 55% mineralization efficiency under the joint action of 1O 2 and h+ as reactive species. More importantly, the mechanism of BiPO 4 /Bi/CdS type-II heterojunction was set forth from the coupling of charge carriers and exciton effects. This work sheds new light on the regulation of excitonic effects in type-II heterojunction and provides unique insight into 1O 2 production. [ABSTRACT FROM AUTHOR]

• A series of Mn-doped A 2 PbBr 4 2D perovskites are synthesized and the luminescence properties of Mn2+ ions in related to the A-site cations is explored. • The highest efficiency of the energy transfer from excitons to Mn2+ reaches as high as 78.08 % in (PPA) 2 PbBr 4 :60 % Mn2+ 2D perovskite. • The luminescence mechanism of Mn-doped (PPA) 2 PbBr 4 perovskite with different Mn2+ concentrations are investigated by temperature dependent PL spectra. The incorporation of Mn2+ ions has been widely used to modulate optical properties of two-dimensional (2D) organic-inorganic hybrid perovskites (OIHPs). However, the luminescence mechanism of Mn2+ ions that is related to the A-site cations remains largely unexplored. Herein, we report the synthesis of a series of Mn-doped A 2 PbBr 4 (A = C 6 H 5 (CH 2) n NH 3 , n = 1,2,3,4,) 2D perovskites. The (C 6 H 5 (CH 2) 3 NH 3) 2 PbBr 4 ((PPA) 2 PbBr 4) 2D perovskite exhibited a maximum photoluminescence (PL) quantum yield of 67 %, a prolonged PL lifetime of 0.75 ms, and the highest energy transfer efficiency of 78.07 %. Furthermore, we systematically investigated the luminescence properties of Mn-doped (PPA) 2 PbBr 4 perovskite with different Mn2+ concentrations. The temperature dependent PL spectra indicate a thermalized de-trap process of self-trapped exciton at high temperatures and the presence of permanently shallow defect states in highly doped samples with lower activation energy. We reported the luminescence properties of Mn-doped 2D organic-inorganic hybrid perovskites, with a particular focus on the (PPA) 2 PbBr 4 perovskite material. [Display omitted] [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]