Preparation Of Semiconductor Nano-materials And Their Photoelectric Properties

Semiconductor nano-materials are important part of nano-materials, closely linked with optoelectronics and materials science. Compared with conventional semiconductor materials, semiconductor nanoparticles are quite different in optical properties, photoelectric conversion characteristics and electrical properties. With the continuously deepening understanding of the semiconductor nano-materials, they have been applied to many traditional subjects and emerging areas, such as photocatalysis, magnetic materials, optical applications and biomedicine. Today, they become hot front of nano-materials science. Especially in recent years, with the sustained and rapid economic development of the world, the problems of energy and environment have been more and more serious. People are looking for alternative sources of energy and new methods to solve environmental problems. Due to the unique properties, semiconductor nano-materials have great potential for easing the current crisis.There are many researches about semiconductor nano-materials, such as ZnO, Cu2O, CdS, etc. We studied two kinds of inorganic semiconductor nano-materials, Bi2S3 and TiO2. The detailed investigations are as follows:1. Bi2S3 is a very important semiconductor material, which has been prepared in nanowires, nanorods, nanotubes and other morphology. Because of its small band gap, Bi2S3 is a good photosensitive material and very sensitive to light, and has good application foreground in the photoelectric and thermoelectric effect applications. Without any template, we prepared Bi2S3 nanoflowers and nanorods through simply one step hydrothermal synthesize with the assistance of KI. We studied the mechanism of assistant KI and the growth process of Bi2S3, and tested their photoresponsive properties. With the effect of KI, Bi2S3 gradually build the structure of nanorods. The response to light of the nanorods was more sensitive than the nanoflowers, and the samples of regular mophology had better stability.2. TiO2 is stable, non-toxic and inexpensive, and has been widely used due to its photocatalysis and UV absorption properties. Dye-sensitized TiO2 can be used to build dye-sensitized nanocrystalline solar cells, with simple and low cost production process. In this way, the solar radiation energy can be directly converted to electrical energy. Under laboratory conditions, the efficiency is more than 11%. We synthesized a large specific surface area TiO2,The specific surface area was many times great than P25, which indicated that the TiO2 had the great ability to load more dye and could substantially increase the photocurrent of solar cells.