介质温度对Zn-MOF薄膜光学气体吸附性能的影响

Effect of medium temperature on optical gas adsorption properties of Zn-MOF thin films

合成温度会影响金属有机骨架(Metal organic frameworks,MOFs)的结构、孔径和产率等诸多特性。为制备高性能气体吸附MOFs薄膜,在不同介质温度(30~45℃)下采用原位生长法,在锡掺杂玻璃光波导表面制备[Zn_(2)-(bdc)_(2)-(dpNDI)]_(n)(Zn-MOF)薄膜;利用X射线光电子能谱(XPS)、扫描电镜(SEM)、分光光度计、椭圆偏振仪和光波导(OWG)测试系统等研究了介质温度对Zn-MOF薄膜表面形貌、光学特性(吸光度、折射率、光传播损失)及气体吸附性能的影响。结果表明:介质温度的升高有利于薄膜生长,且有效地缩短了薄膜的生长时间。介质温度在30~45℃范围内,薄膜表面形貌由球形结构转变为蜂窝状和层状结构;薄膜均透明,折射率高,光传播损失小,且对二甲苯气体表现出较大的吸附响应。40℃下生长10 h的Zn-MOF薄膜的性能最优。

The synthesis temperature will affect the structure,pore size and yield of metal organic frameworks(MOFs).In order to prepare high-performance gas adsorbed MOFs thin films,[Zn_(2)-(bdc)_(2)-(dpNDI)]_(n)(Zn-MOF)thin films were prepared on the surface of tin-doped glass optical waveguides by in-situ growth at different medium temperatures(30-45℃),and the effect of medium temperature on surface morphology,optical properties(absorbance,refractive index,light propagation loss)and gas adsorption properties of the Zn-MOF thin films was studied by means of X-ray photoelectron spectroscopy(XPS),scanning electron microscopy(SEM),spectrophotometer,ellipsometer and optical waveguide(OWG)testing system.The results show that the increase of medium temperature is conducive to the growth of the thin films and effectively shortens the growth time of the thin films.When the medium temperature is in the range of 30-45℃,the surface morphology of the films changes from spherical structure to honeycomb and layered structure.The thin films are transparent,have high refractive index,small light propagation loss,and exhibit large adsorption response to xylene gas.The performance of the Zn-MOF thin films grown at 40℃for 10 h is the best.