Rubrene∶MoO3混合薄膜的制备及光学和电学性质  

Preparation, optical, and electrical properties of rubrene∶MoO3 films

作　　者：李瑞东 邓金祥[1] 张浩 徐智洋 潘志伟 孙俊杰 王贵生 Li Rui-Dong;Deng Jin-Xiang;Zhang Hao;Xu Zhi-Yang;Pan Zhi-Wei;Sun Jun-Jie;Wang Gui-Sheng(College of Applied Science, Beijing University of Technology, Beijing 100124, China)

机构地区：[1]北京工业大学应用数理学院

出　　处：《物理学报》2019年第17期247-254,共8页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:60876006,60376007);北京市自然科学基金(批准号:4192016);北京市教育委员会科技计划重点项目(批准号:KZ201410005008)资助的课题~~

摘　　要：利用热蒸发技术在衬底温度为室温的硅衬底、氧化铟锡衬底和石英衬底上制备了红荧烯与氧化钼的混合薄膜.将两种材料放置于不同的坩埚中,通过控制蒸发源的温度来控制混合比例,制备了不同比例的混合薄膜.通过原子力显微镜对混合薄膜的表面形貌进行了测量,发现当红荧烯与氧化钼的比例为2:1时,薄膜表面的平整度最好;通过X射线衍射分析对混合薄膜的结晶性进行分析,发现不同浓度的混合薄膜均表现出非晶态特征.通过PL谱和吸收光谱研究了不同比例的混合薄膜的光学性质,从光致发光谱可以发现:混合薄膜在近红外区域有显著吸收,说明红荧烯在氧化钼诱导下产生中间能级,形成电荷转移络合物.从吸收谱知:除4:1外,其他比例的混合薄膜具有几乎相同的吸收峰.根据Tauc方程计算了混合薄膜的光学带隙,发现当红荧烯与氧化钼的比例为2:1时,混合薄膜的带隙最窄(-2.23 eV).制备了结构为Al/rubrene:MoO3/ITO的器件,测试了J-V特性,研究了混合薄膜的电学性质.发现当混合比例为4:1和2:1时,混合薄膜与金属电极的接触表现为欧姆接触.本研究显示出红荧烯和氧化钼的混合薄膜在近红外区域有潜在的应用前景,也为红荧烯和氧化钼的混合薄膜在有机光电器件的应用提供了基础.In this paper,the mixed films with different rubrene-to-MoO3 ratios are deposited on the substrates of Si,indium tin oxide and quartz glass by using the thermal evaporation technique.First,these films are characterized by atomic force microscopy and X-ray diffraction in order to identify their surface morphology and their structure properties.The results show that all the films are amorphous and the film has the best flatness when the rubrene-to-MoO3 ratio is 2:1.Second,the optical properties of the mixed films are investigated by both photoluminescence(PL)spectra and absorption spectra.The optical band gap of rubrene and MoO3 are 2.2 eV and 3.49 eV respectively and there is almost no absorption about rubrene and MoO3 in the near-infrared(NIR)region.However the PL spectrum shows a peak in NIR,region and it indicates that the interface between rubrene and MoO3 possesses an abrupt discontinuity at the vacuum level, resulting in electron wave functions overlapping and charge-transfer complex(CTC)forming.The intermediate state within the original band gap of rubrene with energy of 1.25 eV is induced by the CTC, which suggests the possibility of charge transfer exciton generated upon NIR excitation.The absorption spectra of the mixed films show that there is an obvious absorption.All the films have the same absorption peak except the film with a rubrene-toMoO3 ratio of 4:1 and it indicates that the concentration of MoO3 has almost no influence on the absorption of the mixed films.The optical band gaps of the mixed thin films are calculated in a spectral range of 345-1035 nm according to the Tauc equation,and the results show that the optical band gap of the film with a rubrene-toMoO3 ratio of 2:1 is narrowest(~2.23 eV).In order to study the electrical characteristics of the mixed films,an Al/rubrene:MoO3/ITO device is fabricated.The current,density-voltage(J-V)characteristic is also investigated.The analysis of the J-V measurement for the device indicates that the current conduction in the Al/rubrene:MoO3/ITO device i

关 键 词：rubrene∶MoO3混合薄膜 原子力显微镜 X射线衍射分析 光学性质和电学性质 

分 类 号：TN304.055[电子电信—物理电子学]