Song Chenlu

Simulation of scattering in dense medium by Monte Carlo method

We present a Monte Carlo (MC) method to simulate the scattering for medium within randomly distributed particles, discuss the convergence of this method by varying the size parameter ka, volume parameter η and calculation parameter Ni, then compare this method with the classical iteration method with the same parameters. The calculation results showed that this method has good convergence and accords with the iteration method while consuming less CPU time. At the end of this paper, this method is used to discuss the visual light scatter in the c-Si/α-Si films.

First-principles study of the influences of oxygen defects upon the electronic properties of Nb-doped TiO2 by GGA + U methods

The influence of oxygen defects upon the electronic properties of Nb-doped TiO2 has been studied by using the general gradient approximation (GGA)+U method. Four independent models (i.e., an undoped anatase cell, an anatase cell with a Nb dopant at Ti site (NbTi), an anatase cell with a Nb-dopant and an oxygen vacancy (NbTi+VO), and an anatase cell with a Nb-dopant and an interstitial oxygen (NbTi+Oi)) were considered. The density of states, effective mass, Bader charge, charge density, and electron localization function were calculated. The results show that in the NbTi+VO cell both eg and t2g levels of Ti 3d orbits make contributions to the electronic conductivity, and the oxygen vacancies (VO) collaborate with Nb-dopants to favor the high electrical conductivity by inducing the Nb-dopants to release more excess charges. In NbTi+Oi, an unoccupied impurity level appears in the band gap, which served as an acceptor level and suppressed the electronic conductivity. The results qualitatively coincide with experimental results and possibly provide insights into the preparation of TCOs with desirable conductivity.

柱状晶形貌TiO 2 膜厚对FTO/TiO 2 镀膜玻璃光催化活性影响

采用溶胶-凝胶法, 在FTO(SnO 2 :F)低辐射镀膜玻璃衬底上制备了柱状晶体结构的TiO 2 薄膜, 获得双层结构FTO/TiO 2 镀膜玻璃样品. 研究了TiO 2 薄膜厚度对FTO/TiO 2 镀膜玻璃样品的光催化活性、低辐射性能以及透光性能的影响. 结果表明, FTO/TiO 2 镀膜玻璃样品光催化活性随着TiO 2 薄膜厚度的增加先升高后下降, 在TiO 2 薄膜厚度为300 nm时光催化活性最佳; 低辐射性能随着TiO 2 薄膜厚度的增加而下降, 但TiO 2 薄膜厚度为300 nm时仍然具备一定的低辐射性能; 透光性能与TiO 2 薄膜膜厚的关系不大, 可见光透射比保持在72%左右; 表面平均粗糙度约为1 nm, 表面光滑, 不易沾染油污灰尘. 该镀膜玻璃在保证低辐射建筑节能和透光的前提下, 兼具光催化自清洁功能, 具有很好的应用前景.采用溶胶-凝胶法, 在FTO(SnO 2 :F)低辐射镀膜玻璃衬底上制备了柱状晶体结构的TiO 2 薄膜, 获得双层结构FTO/TiO 2 镀膜玻璃样品. 研究了TiO 2 薄膜厚度对FTO/TiO 2 镀膜玻璃样品的光催化活性、低辐射性能以及透光性能的影响. 结果表明, FTO/TiO 2 镀膜玻璃样品光催化活性随着TiO 2 薄膜厚度的增加先升高后下降, 在TiO 2 薄膜厚度为300 nm时光催化活性最佳; 低辐射性能随着TiO 2 薄膜厚度的增加而下降, 但TiO 2 薄膜厚度为300 nm时仍然具备一定的低辐射性能; 透光性能与TiO 2 薄膜膜厚的关系不大, 可见光透射比保持在72%左右; 表面平均粗糙度约为1 nm, 表面光滑, 不易沾染油污灰尘. 该镀膜玻璃在保证低辐射建筑节能和透光的前提下, 兼具光催化自清洁功能, 具有很好的应用前景.Columnar crystal structured TiO2 thin films were prepared on the FTO (SnO2: F) low-emissivity coated glass substrates, obtaining double-layer structure FTO/TiO2 coated glass samples. The effect of TiO2 film thickness on the photocatalytic activity, the low-emissivity performance and light transmission properties of the FTO/TiO2 coated glass samples was investigated. The results showed that the photocatalytic activity of the samples increased firstly and then decrease with the increase of the film thickness. The best catalytic activity was observed for the sample coated with 300 nm TiO2 film. The low-emissivity properties of the samples declined as the TiO2 film thickness increased. The sample still have some low-emissivity performance when the TiO2 film thickness is 300 nm, while the light transmittance of the samples have little relations with the TiO2 films thickness. The visible light transmittances of the samples remain at about 72% with a smooth surface. The average surface roughness of the sample is about 1 nm. The FTO/TiO2 coated glass has photocatalytic self-cleaning properties with excellent low emissive performance and light transmittance property, thus guaranteeing good application prospects.