水热合成法制备非晶态α-Fe_2O_3薄膜及其光吸收性能

Preparation and Optical Absorption Properties of Non-crystallineα-Fe_2O_3 Thin Film by Hydrothermal Synthesis Method

以K9玻璃为基片,在柠檬酸存在的碱性体系内,采用水热合成法制备了非晶态α-Fe2O3薄膜,并对样品进行了XRD、SEM、FT-IR、UV-Vis表征。研究结果表明,随着反应体系初始pH值升高及Fe3+初始质量浓度增大,所得样品的结晶度略有增大。水热反应体系初始pH值从9.5升高至10.5,薄膜表面沉积颗粒增大,薄膜逐渐致密。但当pH值继续升高至11时,沉积颗粒减小,且存在较大孔隙。水热体系中Fe3+初始质量浓度增大至1.2g/L时,薄膜表面沉积颗粒最大,颗粒间孔隙较大。Fe3+质量浓度继续增大,颗粒减小,薄膜表面致密、均匀。反应体系初始pH值较低时,有少量柠檬酸随非晶态α-Fe2O3沉积,反应过程中非晶态α-Fe2O3与玻璃基底有化学键力的结合。水热反应初始pH值为11时,薄膜对紫外光的吸光度最大。当Fe3+初始质量浓度为1.5g/L时,薄膜对紫外光的吸光度最高,当Fe3+初始质量浓度为1.2g/L时,薄膜对可见光的吸光度最低,反射率最高。

Non-crystalline α-Fe2O3 thin films were prepared on the K9 glass substrate by hydrothermal synthe sis method in the citric acid-alkalic condition, and the samples were characterized by XRD, SEM, FT-IR and UV-Vis. The results show that the crystallinities of the samples are slightly increased with the increasing of the initial pH and initial concentration of reaction system. When pH increased from 9.5 to 10. 5, the deposited particles increased and the thin films were compact. However, samller grain size and bigger porosity were presented at the pH value of 11. At Fe^3＋ initial concentration of 1.2 g/L, the grains and the porosities were the biggest. With the increase of Fe^3＋ ini tial concentration, the nano-particles get smaller, and the film surface were compact and uniform. Moreover, a little of citric acid deposited with α-Fe2O3 particles at low initial pH value. Non-crystallineα-Fe2O3was connected with glass- substrate by chemical bond. Meanwhile, the ultraviolet-light absorbance of the film was the hightest at initial pH of 11 and Fe^3＋ initial concentration of 1.5 g/L. When Fe^3＋ initial concentration was 1.2 g/L, the visible light absorbance of the film was the lowest, and reflectivity was the hightest.