A Study On The Properties Of Photoinduced Charge Carriers By Surface Photovoltage Phase Spectroscopy

With the consumption of fossil fuels, the energy crisis and environmental problems are becoming more and more serious. Many researches focus on developing the clean renewable energy to take the place of fossil fuels.Solar energy has attracted much attention for its clean and renewable characteristics. To take advantage of solar energy, a great deal of photoelectric functional materials are developed which are used in solar cells, water splitting and photocatalytic degradation of organic pollutants. Tremendous progresses have been made already.Some semiconductors are excellent photoelectric function materials. Sub-band gap or band gap transition occurs when semiconductor photoelectric function materials are illuminated. The light energy is converted to electrical energy; the electron and hole transfer to water to split water into hydrogen and oxygen, light energy convers to chemical energy; the electron and hole transfer to organic molecules to decompose the organic molecules.The band model is introduced to research the semiconductor photoelectric function materials and great progresses have been made. A lot of optical, electrical and magnetic technologies are introduced at the same time. Surface photovoltage technology is used to research the character and behavior of photo generate charge, analysis the nature of the semiconductor optoelectronic functional materials Very great contribution has been made. Use Surface photovoltaic photovoltage phase spectroscopy and surface photovolgaic spectroscopy we can determine the direction of photogererate charge transfer.The theory,operation method and important notice of surface photovoltage spectroscopy and surface photovoltage phase spectroscopy that based on lock-in amplifier technique are introduced in this paper. The surface photovoltage phase spectroscopy, surface photovoltage spectroscopy and transient photovoltage technology are used as experimental methods to study photo-charge behavior of P25,anatase nano-powder, ZnWO4 nanorod was studied under different experimental condition.Details are as follows:(1) The importance of photoelectric function materials are introduced and the basic concepts are described. The concept and principle of surface photovoltaic spectroscopy and surface photovoltaic phase spectroscopy that based on lock-in technique are described in detail(2) The operation method and important notice of surface photovoltaic devices are introduced. And titanium oxide as a photoelectric function materials are also introduced. Bias and carbon monoxide atmosphere are introduced when we study the influence of contact with electrode. The surface state of P25 are also been studied.(3)Semiconductor will show different character when it is put into different gas atmosphere. Surface photovoltaic technique and surface photovoltaic phase technique are used to study anatase nanopowder that are stored in wet and relative dry environments. The influence caused by water is analyzed.We put one sample in different gas atmosphere:air, nitrogen, carbon monoxide and study the behavior of photogenerate electronic by surface photovoltage spectroscopy and surface photovoltaic phase spectroscopy at the same time.(4)Study the character and behavior of photogenerate electronic under different biases. Character of ZnWO4 and other sample will change when bias exist.