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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.