Halide perovskite-based photovoltaics are the fastest-growing solar technology in nowadays. Because of the low production costs, perovskite-based photovoltaics are competitive for commercial applications in the marketplace. Additionally, due to the remarkable optoelectronic properties, perovskites are also promising for other optoelectronics, including photodetector, light emitting diode and laser. However, for commercial applications in optoelectronics, there are still several crucial obstacles: (i) a robustness patterning technique is missing for nanofabrication of perovskite devices, (ii) hysteresis effect exits in perovskite devices, and (iii) the stability issue of perovskite. To address these problems, we have performed the fundamental study on perovskite from four aspects: orthogonal patterning, metal contact, carrier transport, and light emission stability.
Due to the ionic nature, halide perovskite can be easily dissolved by most of the commonly used organic solvents, which means conventional lithography patternings are not applicable for perovskite, limiting the extensive applications of perovskite electronics. To adress this, we introduced chlorobenzene and hexane and proposed an orthogonal electron beam lithography method for fabrication of perovskite nanodevices without damaging their electrical and optical properties. By this orthogonal method, we fabricated a two-dimensional single crystalline (C6H5C2H4NH3)2PbI4 photodetector with device channel length of few hundred nanometers and outstanding photosensing capability.
The hysteresis effect in perovskite is highly related to the interfacial recombination and ionic transport, which requires abundant fundamental understanding on perovskite contact and transport to help to solve this issue. In this study, we performed the lithography patterning method and the transfer length measurement on cm-sized single crystalline perovskite bulk single crystal for indicating the metal contact interface and charge transport, which are requared for efficienct device design and improving the device performance.
For stable light emission, we fabricated perovskite nanowires in the nanopores of anodic aluminum oxide substrate using an inkjet printing technique. Lasing behaviors and color-tunable light emission of perovskite nanowires are demonstrated in this study, and the photostability is much better than reported all-inorganic perovskite quantum dots.
We believe these fundamental studies provide solutions to some critical issues in current perovskite technology, thus paving the way for future optoelectronic applications.
|Date of Award||Apr 2019|
|Original language||English (US)|
- Computer, Electrical and Mathematical Sciences and Engineering
|Supervisor||Jr-Hau He (Supervisor)|