TiO 2 nanoribbons were synthesized hydrothermally via the reaction of TiO 2 particles and NaOH solution. Their photovoltaic properties were studied by surface photovoltage spectroscopy (SPS) and electric field-induced...TiO 2 nanoribbons were synthesized hydrothermally via the reaction of TiO 2 particles and NaOH solution. Their photovoltaic properties were studied by surface photovoltage spectroscopy (SPS) and electric field-induced surface photovoltage spectroscopy (FISPS). Under the external field, new photovoltaic response bands were found from 375 nm to 550 nm. It is suggested that these response bands resulted from the surface states, which can be ascribed to the formation of steps and kinks in the TiO 2 nanoribbons.展开更多
Surface photovoltage spectrum(SPS), field-induced surface photovoltage spectrum(FISPS) and gas probe techniques are used together to study surface photovoltage(SPV) property of ZnO nanoparticles. The SPS of ZnO nanopa...Surface photovoltage spectrum(SPS), field-induced surface photovoltage spectrum(FISPS) and gas probe techniques are used together to study surface photovoltage(SPV) property of ZnO nanoparticles. The SPS of ZnO nanoparticles consists of two parts, band-to-band transition(P1,P2) and surface states transition(P3). The result shows that the SPV response is mostly attributed to the built-in field formed by active adsorbates, most of which is O 2. Competitive adsorption of O 2 and H 2O exists on ZnO surface. They play different roles in the influence on SPS. The Adsorption of O 2 weakens P3, whereas H 2O enhances P3. And the velocity of adsorption and desorption of O 2 on the surface is significantly faster than H 2O. The adsorption and desorption of H 2O may be correlated with the adjustment of surface structure.展开更多
The photo-generated charge property of TiO 2 nanoparticles annealed at different temperatures was studied by the field induced surface photovoltage spectrum (FISPS) technique. The powder of TiO 2 was prepared and anne...The photo-generated charge property of TiO 2 nanoparticles annealed at different temperatures was studied by the field induced surface photovoltage spectrum (FISPS) technique. The powder of TiO 2 was prepared and annealed at 400, 600 and 800 ℃, respectively. The crystalline of TiO 2 transformed from anatase to rutile with the annealing temperature increasesing. And the photo-generated charges property of TiO 2 behaves differently after it was annealed at different temperatures. When the powder was annealed at 400 ℃, the particle size is so small that the energy band can not be formed completely, so the bound exciton state was formed when it was illuminated by the proper incident light, and it inverse antisymmetrically under external field for locatization effect. While, the powder was annealed at 600 ℃, the surface phtovoltaic response presents the characteristics of homojunction for different crystalline interfaces. After being annealed at 800 ℃, the energy band was formed completely and the larger particle size(36 nm) was got. Consequently, a band for the dissociation of free exciton emerged in the band edge of the surface photovotaic response distinguished from the band-band transition, and the direction of the photovoltaic response resulted from the free excition is consistent with the external field, that is positive under positive field, and it inverse symmetrically under external field.展开更多
文摘TiO 2 nanoribbons were synthesized hydrothermally via the reaction of TiO 2 particles and NaOH solution. Their photovoltaic properties were studied by surface photovoltage spectroscopy (SPS) and electric field-induced surface photovoltage spectroscopy (FISPS). Under the external field, new photovoltaic response bands were found from 375 nm to 550 nm. It is suggested that these response bands resulted from the surface states, which can be ascribed to the formation of steps and kinks in the TiO 2 nanoribbons.
文摘Surface photovoltage spectrum(SPS), field-induced surface photovoltage spectrum(FISPS) and gas probe techniques are used together to study surface photovoltage(SPV) property of ZnO nanoparticles. The SPS of ZnO nanoparticles consists of two parts, band-to-band transition(P1,P2) and surface states transition(P3). The result shows that the SPV response is mostly attributed to the built-in field formed by active adsorbates, most of which is O 2. Competitive adsorption of O 2 and H 2O exists on ZnO surface. They play different roles in the influence on SPS. The Adsorption of O 2 weakens P3, whereas H 2O enhances P3. And the velocity of adsorption and desorption of O 2 on the surface is significantly faster than H 2O. The adsorption and desorption of H 2O may be correlated with the adjustment of surface structure.
文摘The photo-generated charge property of TiO 2 nanoparticles annealed at different temperatures was studied by the field induced surface photovoltage spectrum (FISPS) technique. The powder of TiO 2 was prepared and annealed at 400, 600 and 800 ℃, respectively. The crystalline of TiO 2 transformed from anatase to rutile with the annealing temperature increasesing. And the photo-generated charges property of TiO 2 behaves differently after it was annealed at different temperatures. When the powder was annealed at 400 ℃, the particle size is so small that the energy band can not be formed completely, so the bound exciton state was formed when it was illuminated by the proper incident light, and it inverse antisymmetrically under external field for locatization effect. While, the powder was annealed at 600 ℃, the surface phtovoltaic response presents the characteristics of homojunction for different crystalline interfaces. After being annealed at 800 ℃, the energy band was formed completely and the larger particle size(36 nm) was got. Consequently, a band for the dissociation of free exciton emerged in the band edge of the surface photovotaic response distinguished from the band-band transition, and the direction of the photovoltaic response resulted from the free excition is consistent with the external field, that is positive under positive field, and it inverse symmetrically under external field.
