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A precise understanding of the intrinsic photoluminescence (PL) and photocarrier dynamics of lead halide perovskites remains elusive, largely due to the heterogeneities at multiple length scales associated with the solution-processed sample preparation. We report the slow solvent-evaporation-assisted crystallization, yielding a high-quality CH3NH3PbI3single crystal with crack-free flat pristine surfaces. The single crystal demonstrated photoluminescence as a function of wavelength with two components, which represent the bulk- and surface-specific emissions, respectively. By time-resolved photoluminescence analysis as a function of probed wavelengths, we revealed distinctive bulk- versus surface-specific photocarrier dynamics. The remarkably long and dominating photocarrier lifetime of ∼2.4 μs probed at the bulk-PL peak position, as opposed the counterpart associated with the surface-PL peak, strongly indicated a much delocalized physical scheme for photocarrier dynamics in the lattice interior, as opposed to the periphery. The lattice-periphery-induced local confinement effect on the photocarrier dynamics was further verified with a polycrystalline thin film sample, which demonstrated much shorter photocarrier lifetimes.

Hydrogenation saturation of naphthalene (NL) is a critical step for upgrading the quality of transportation fuels. The Ni nanoparticles supported by YP80 were prepared with a wet impregnation method using alkanol solvents, which help modify the Ni0particle sizes and Ni dispersion of the Ni/YP80-X catalysts. The relatively high specific surface area and the hydrophobicity of YP80 promote the infiltration of impregnation solvents into the pores of the support. Under the conditions of 180 °C, 1 h, and 2.0 MPa H2, a complete conversion of NL and a high decalin yield of 100% were achieved by the Ni/YP80-EG catalyst. The Ni/YP80-EG catalyst exhibits high efficiency, high selectivity, and excellent stability due to the well-dispersed Ni and small Ni nanoparticles of the catalyst. This work contributes to understanding how to tune the particle sizes of catalysts and optimize the reaction conditions for improving the NL hydrogenation.