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Centimeter-size 2D layered Pb-free (CH3NH3)2MnCl4 single crystal was grown by using different ways and proved to have good luminous via fabricating LED device.

The redox state of cerium and elimination of defects were synergistically regulated by a protected-annealing treatment in Ce:YAG transparent ceramics.

The optoelectronic performances of MAPbI 3 are related to film morphology and crystal orientation. However, it is difficult to directly quantify the optoelectronic anisotropy in thin films because controlling growth-oriented grains and measuring the optoelectronic difference within micro−nono regions have great technological challenges. Here, taking advantages of the pseudo-cubic morphology of MAPbI 3 single crystals (SCs) exposed with ( 110), (002), and (200) facets, the optoelectronic anisotropies are compared. It reveals that the periodic positive and negative potential distributions at the outermost (110) surface, the orientations of MA + dipoles, and the stacking of PbI 6 octahedrons ensure (110) planes have lower defect densities (V I + , V MA − , I − , MA + , or I i − , etc.), which therefore enhance photo recycling, deduce the dark current, and increase the photocurrent. Besides, the periodic MA + and I − arrangements at the (110) surface also restrict ion migrations compared to those of (200) planes. In addition, by comparing the optoelectronic properties of (200) planes of the pseudo-cubic and rhombic dodecahedral MAPbI 3 SCs, it is found that the roomtemperature-grown pseudo-cubic MAPbI 3 SC possesses lower intrinsic defect densities and thus enhances the photo response.

Excellent optoelectronic performances of [010] orientated super long CsPbBr3 MSCs can be controlled growing through elaborating nucleation and layer-by-layer growth.

The fully inorganic perovskite lead cesium bromide single crystal (CsPbBr3 SC) is considered as an excellent candidate semiconductor for photodetectors because of its superior humidity resistance, thermal stability, and light stability compared with organic–inorganic hybrid perovskites as well as its photoelectric properties such as large light absorption coefficient and ultralong carrier migration distance. In this Letter, we utilize the inverse temperature solubility of CsPbBr3 in ternary solvents to grow large-sized CsPbBr3 SCs. By the use of the (101) plane, CsPbBr3 SC-based photodetectors are fabricated, which exhibit excellent polarized light response characteristics. The photocurrent relies on the polarization angle in a sinusoidal fashion and shows strong anisotropic optoelectronic properties. The photodetection performance perpendicular to the y axis is significantly higher than that parallel to the y axis, and the dichroic ratio under 405 nm illumination at a bias voltage of 1 V reaches 2.65. The experimental results are consistent with the results of first-principles calculations.

The existence of the organic component (MA) in MAPbBr 3 guarantees its cubic crystal lattice stabilities to satisfy the tolerance factor but increases the chemical instability risk when encountering moisture, oxidation, and heat. Mixed cations, particularly when using cesium cation (Cs + ), prove to be an effective way of improving both stability and optoelectronic performances of hybrid perovskite films applied in solar cells. However, the intrinsic effect of Cs + on the crystal structure, lattice defects, and optoelectronic properties of MAPbBr 3 is still unclear till now because grain boundary numbers and interface defect densities in films increase complexity; so, it is not easy to explore the intrinsic nature of how Cs + affects the optoelectronic properties of MAPbBr 3 . Single crystals (SCs) of MAPbBr 3 provide an ideal medium to investigate the influence of Cs + on the crystal structure and optoelectronic performances. Herein, we grew a series of MA 1−x Cs x PbBr 3 SCs. This reveals that Cs + inhibits the growth of MAPbBr 3 SCs, causes crystal lattice shrinkage, decreases crystal defects, and therefore reduces the dark currents, decreases the trap densities, and optimizes the optoelectronic properties. Our work provides a reference for the relationship between the composition of the mixed lead halide perovskites and the optoelectronic properties.

MAPbI3, one of the archetypical metal halide perovskites, is an exciting semiconductor for a variety of optoelectronic applications. The photoexcited charge-carrier diffusion and recombination are important metrics in optoelectronic devices. Defects in grain interiors and boundaries of MAPbI3 films cause significant nonradiative recombination energy losses. Besides defect impact, carrier diffusion and recombination anisotropy introduced by structural and electronic discrepancies related to the crystal orientation are vital topics. Here, large-sized MAPbI3 single crystals (SCs) were grown, with the (110), (112), (100), and (001) crystal planes simultaneously exposed through the adjusting ratios of PbI2 to methylammonium iodide (MAI). Such MAPbI3 SCs exhibit a weak n-type semiconductor character, and the Fermi levels of these planes were slightly different, causing a homophylic p–n junction at crystal ledges. Utilizing MAPbI3 SCs, the photoexcited carrier diffusion and recombination within the crystal planes and around the crystal ledges were investigated through time-resolved fluorescence microscope. It is revealed that both the (110) and (001) planes were facilitated to be exposed with more MAI in the growth solutions, and the photoluminescence (PL) of these planes manifesting a red-shift, longer carrier lifetime, and diffusion length compared with the (100) and (112) planes. A longer carrier diffusion length promoted photorecycling. However, excessive MAI-assisted grown MAPbI3 SCs could increase the radiative recombination. In addition, it revealed that the carrier excited within the (001) and (112) planes was inclined to diffuse toward each other and was favorable to be extracted out of the grain boundaries or crystal ledges.