The ultraviolet (UV) emission from the Au-coated ZnO films was greatly enhanced and the visible emission was significantly suppressed compared with the un-coated ZnO films. Great changes in photoluminescence of ZnO films are attributed to the electron transfer between conduction band and defect levels through the localized surface plasmons. The increase of electron density in conduction band causes enhanced UV emission, while the decrease in electron density in defect level leads to the suppression of the visible emission. Such ZnO films with enhanced UV emission have potential applications in the highly efficient solid state emitters.

Electrical properties of TiO₂/CH₃NH₃PbI₃heterojunction solar cells.

The electrical transport through nanoscale contacts of ZnO nanowires bridging the interdigitated Au electrodes shows the negative differential resistance (NDR) effect. The NDR peaks strongly depend on the starting sweep voltage. The origin of NDR through nanoscale contacts between ZnO nanowires and metal electrodes is the electron charging and discharging of the parasitic capacitor due to the weak contact, rather than the conventional resonant tunneling mechanism.