关键词: 光电流谱, 光致发光光谱, 紫外可见吸收光谱, 纳米半导体

Abstract:

The electronic structures and properties of nano-semiconductors are quite different from those of bulk semiconductors due to the nano-size effect (such as quantum size effect). Moreover, when the nano-semiconductor materials are deposited onto the substrate to construct a device, their electronic properties are also affected by the substrate or other components, which may lead to different performances of nano-semiconductors based photoelectric devices, and consequently, different corresponding characterization methods are needed. The combination of photocurrent spectroscopy, photoluminescence spectroscopy with UV-Vis absorption spectroscopy can provide a more comprehensive characterization for the electronic properties and photoelectrochemical performances of nano-semiconductors in photoelectric devices. Our research group has long devoted to the studies in the preparations and characterizations of different nano-semiconductors for photoelectric devices. In this review, we firstly introduce the main different features in electronic properties of nano-semiconductors and the corresponding characterization methods, and then describe how to combine the abovementioned three spectroscopic methods to investigate the electronic properties and photoelectrochemical performances of the nano-semiconductors for photovoltaic cells, electroluminescent diodes, and other photocatalytic systems by detailed examples. Photoluminescence spectroscopy is a common method to characterize the surface states of the semiconductors, while photocurrent spectroscopy can provide the supplementary information of surface states. Especially, the photoluminescence efficiency is low for the nonradiactive recombination dominated materials such as indirect-bandgap semiconductors. The results of photocurrent spectroscopy are more useful under these circumstances. Furthermore, the combined characterization in surface states of the nano-semiconductors by photocurrent spectroscopy with photoluminescence spectroscopy is specially discussed. The combined applications of these three spectroscopic methods for the nano-semiconductors in photoeltric devices are not only beneficial to obtain intensive understanding the electric properties and the photo-induced charge transfer mechanism at the interface of the nano-semiconductors, but also useful to guide the preparation of nano-semiconductor materials for photoelectric devices and optimal to the photoelectrochemical performances.

Key words: photocurrent spectroscopy, photoluminescence spectroscopy, UV-Vis absorption spectroscopy, nano-semiconductors