First-Principles Calculation of Photoelectric Property in Upconversion Materials through In3+ Doping.

Multicolor turning holds great promise in optical intelligent recognition and optical imaging. Here, Er3+, Yb3+, and In codoped ZnO (Er/Yb/IZO) with a uniform block strucuture is obtained. The doping of In3+ ions enhances the multicolor upconversion luminescence (UCL) intensity of Er/Yb/IZO. Particularlly, the UCL of Er/Yb/I2ZO turns from red through yellow to dominant green emission via increasing density power from 2.54 to 10.19 W/cm2, thus realizing the power sensitiviy. First-principles theory is used to design a In3+, Yb3+, and Er3+ codoped ZnO. The band structure, total density of state and optical coefficient of Er/Yb/IZO have been studied via a generalized gradient approximation within density functional theory (DFT). The potential electron density and total electron density of the O atom increase with In3+ and Er3+/Yb3+ doping, which indicate that substitution of Zn2+ by In3+ and Er3+/Yb3+ generate positive vacancies on the surface. The band gap of Er/Yb/IZO decreases compare with that of pure ZnO. Furthermore, the optical coefficient of In3+ doping is enhanced compare with that of pure ZnO via using DFT calculations.