石墨烯量子点/CdS/CdSe共敏化太阳能电池

摘要

以三维锐钛矿TiO2微球为上层光散射层材料,以商业纳米TiO2为下层连接材料,采用刮刀法制备了一种新颖的双层TiO2薄膜,并应用于量子点敏化太阳能电池(QDSSC).其中,石墨烯量子点(GQDs)采用滴液法引入,CdS/CdSe量子点采用连续离子层吸附法(SILAR)制备.采用场发射扫描电镜、透射电镜、X射线衍射、紫外-可见漫反射光谱及荧光光谱对样品进行表征.实验还制备了CdS/CdSe量子点敏化及石墨烯量子点/CdS/CdSe共敏化太阳能电池,并研究了石墨烯量子点及CdS不同敏化周期及对电池性能影响.研究结果表明,石墨烯量子点及CdS不同敏化周期对薄膜的光学性质、电子传输及载流子复合均有较大影响.优选条件下,TiO2/QGDs/CdS(4)/CdSe电池的光电转换效率为1.24%,光电流密度为9.47mA/cm2,显著高于TiO2/CdS(4)/CdSe电池的这些参数(0.59%与6.22mA/cm2).这主要是由于TiO2表层吸附石墨烯量子点后增强了电子的传输,减少了载流子的复合.%Using three-dimensional anatase TiO2microspheres as light scattering overlayer and commercial TiO2na-nocrystalline as connecting underlayer, novel double-layered TiO2films were prepared by a doctor blade method for quantum dots sensitized solar cell (QDSSC) application. The graphene quantum dots (GQDs) were introduced by dripping, and the CdS/CdSe quantum dots were deposited by continuous ion-layer adsorption (SILAR) method, re-spectively. The prepared quantum dots sensitized thin films were characterized by field emission scanning electron microscopy, transmission electron miscroscopy, X-ray diffraction, Uv-vis diffuse reflectance spectra, and fluorescence spectra. CdS/CdSe quantum dots sensitized and GQDs/CdS/CdSe co-sensitized solar cells were fabricated, respec-tively. And the effects of GQDs and CdS quantum dots with different deposition cycles on the microstructures and the photovoltaic performance of the double-layered TiO2QDSSCs were investigated and discussed. The results revealed that the introduced GQDs and the CdS deposition cycle obviously influenced the optical properties of the dou-ble-layered TiO2film. The electron transfer and charge-recombination process are also affected by the CdS deposition cycle and the introduced GQDs. Optimally, the conversion efficiency and photocurrent density of the TiO2/QGDs/CdS(4)/CdSe solar cell is 1.24% and 9.47 mA/cm2, respectively, which are higher than those (0.59% and 6.22 mA/cm2, respectively) of the TiO2/CdS(4)/CdSe cell. This is due to the effective electrons transport and reduced charge recombination within the co-sensitized cell.