Organic-inorganic hybrid perovskite materials have been receiving considerable attention due to their promising applications in many optoelectronic fields. However, some of the fundamental properties of perovskite materials are still disputed, because most of them are derived from a thin-film state. To comprehend the intrinsic characteristics in a single crystal, herein we report, for the first time, the bulk crystal growth of CH 3 NH 3 PbI 3 . Single crystals of tetragonal CH 3 NH 3 PbI 3 with dimensions of 10 mm × 10 mm × 8 mm were grown by a temperature-lowering method in HI solution. Studies in to the refinement and orientations of the CH 3 NH 3 PbI 3 single crystal structure were conducted based on a high quality crystal.The absorption edge of a CH 3 NH 3 PbI 3 single crystal was located at about 836 nm, indicating that the band gap of CH 3 NH 3 PbI 3 is approximately 1.48 eV, which is close to the theoretical results and smaller than those derived from polycrystalline and thin-films. CH 3 NH 3 PbI 3 crystal exhibits a relatively wide absorption (from 250 nm to 800 nm) and a relatively good thermal stability. CrystEngCommThis journal is † Electronic supplementary information (ESI) available. CCDC 1029776; the images of white MAI, white with yellow MAI and residue light yellow PbI 2 ; powder X-ray diffraction patterns for MAI; 1 H-NMR and 13 C-NMR spectra of MAI; selected bond lengthIJÅ) and bond anglesIJdeg) for β-MAPbI 3 , isotropic and anisotropic displacement parameters of MAPbI 3 . See

Nanocrystalline SnO 2 particles have been synthesized by a simple sol-gel method. The structural and optical properties of these SnO 2 particles are investigated using X-ray powder diffraction, transmission electron microscopy, UV-visible absorption, and photoluminescence spectroscopy. The oxygen-vacancies-related photoluminescence of pure, cerium-, and manganese-doped SnO 2 nanoparticles was systematically investigated. The origin of the luminescence is assigned to the recombination of electrons in a conduction band with holes in the V o •• center. Experimental results reveal that increasing calcining temperature can decrease the oxygenvacancies-related luminescence intensity of the sample. After introducing Ce 3+ /Mn 2+ ions into the host, the oxygen-vacancies-related luminescence has been enhanced remarkably resulting from the formation of many more oxygen vacancies. The dependence of the oxygen-vacancies-related luminescence intensity on the Ce 3+ / Mn 2+ concentration is also discussed.

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In this paper, Dy3+ -doped ZnO nanocrystals have been synthesized via a simple combustion method. The as-prepared cuboid-like ZnO nanocrystals appear to be single hexagonal crystalline phase with an average diameter of 20 nm. The characteristic luminescence of doped Dy3+ ions has been evaluated, and the highly enhanced photoluminescence of Dy3+ ions can be obtained by Li+ doping.

Ternary metal halides with large exciton binding energy have recently gained considerable attention in the optoelectronic field due to their high photoluminescence quantum yield and large Stokes shift. Here, efficient scintillators are designed based on these advantageous properties. For the first time, bulk Cs3Cu2I5 is grown using a melt method other than the intensively reported solution growth, and behaved as an intrinsic scintillator, emitting bright blue (∼450 nm) light under X-ray and γ-ray irradiation. Successful Tl doping at Cs sites tune the emission band over the entire visible range (400–700 nm) due to the synergetic effects of self-trapped excitons (STEs) and Tl centers. Notably, after doping with 1% Tl+, the scintillation light yield of Cs3Cu2I5 increases by nearly three times to 51 000 ± 2000 ph/MeV (Cs-137, 662 keV). Cs3Cu2I5:Tl shows a higher energy resolution of 4.5% at 662 keV than that of NaI:Tl and an excellent nonproportionality (<3%) in the γ-ray energy range of 60–1275 keV. A model of energy relaxation in Cs3Cu2I5:Tl scintillators is proposed and discussed. In particular, it is the first Cu-based halide scintillator that has air stability, good stopping power, and the ability to grow large bulk single crystals for practical application. This work provides a strategy for tuning and broadening the spectral range of STE emitters, and bridges the lead-free halide derivatives with scintillators.