Both 2D perovskite Cs 2 PbI 4 and phosphorus are significant optoelectronic semiconductor materials, the optical-electrical characters between both contact interfaces are interesting topics. In present work, we demonstrate comparative investigation of optoelectronic properties for two kinds of electrical contact interfaces. i.e. Pb-I and Cs-I interfaces with black phosphorus contacts. The carrier transport, charge transferring and optical properties for both cases are investigated by using first principle calculation. Both contact interfaces exhibit type II band alignment with direct band gap. Charge carrier migration from Cs-I interface to black phosphorus is more strong than that of Pb-I interface by considering differential charge density and bader charge between distinct electrical contact interfaces. Besides, electron-hole effective masses of heterojunctions for both cases along different direction are investigated. Optical absorption coefficients of both cases are compared with those of free-standing Cs 2 PbI 4 and black phosphorus in the visible spectrum. We systematically compared advantages and disadvantages of two kinds of contact interfaces for photovoltaic application, and the results reveal interfacial engineering of 2D heterojunction plays a important role in tuning optoelectronic properties.

The present work discusses conditions of comparable microstructure and compressive behaviours of powder metallurgy (PM) Ti-46Al-(Cr,Nb,W,B) (at.-%) alloy prepared by hot isostatic pressing (HIP) and pseudo-HIP technology respectively. A PM route based on pseudo-HIP of alloy powder prepared by plasma rotating electrode process was used for the rapid fabrication of high quality TiAl alloys. The pseudo-hipped alloy shows a fine grained microstructure which is significantly finer than that of the hipped alloy consolidated under similar conditions. The pseudo-hipped alloy exhibits more excellent compression properties than that of the hipped alloy at elevated temperatures. By using the kinetic rate equation, the stress exponent n and the apparent activation energy Q are determined and discussed respectively. The influence of microstructure on the flow behaviour during the total hot compressive deformation was studied. The role of submicrocrystalline forming and dynamic recrystallisation due to mechanical twinning and grain matrix deformation will be discussed.