Jain Kalpna, Kaniyankandy Sreejith, Kishor Shyam, Josefsson Ida, Ghosh Hirendra N, Singh Khundrakpam S, Mookerjee Sumit, Odelius Michael, Ramaniah Lavanya M
Department of Physics, D. J. College, Baraut, Uttar Pradesh 250611, India.
Chemistry Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400085, India.
Phys Chem Chem Phys. 2015 Nov 21;17(43):28683-96. doi: 10.1039/c5cp03816b.
Dye-sensitized quantum dots (QDs) are promising candidates for dye-sensitized solar cells (DSSCs). Here, we report steady state (absorption and photoluminescence) optical measurements on several sizes of CdS QDs ligated with Coumarin 343 dye (C-343) and two different solvents, viz., chloroform and toluene. We further report detailed first principles density functional theory and time-dependent density functional theory studies of the geometric, electronic and optical (absorption and emission) properties of three different sized capped QDs, ligated with C-343 dye. The absorption spectrum shows a QD-size-independent peak, and another peak which shifts to blue with decrease in QD size. The first peak is found to arise from the dye molecule and the second one from the QD. Charge transfer using natural transition orbitals (NTOs) is found to occur from dye-to-QDs and is solvent-dependent. In the emission spectra, the luminescence intensity of the dye is quenched by the addition of the QD indicating a strong interaction between the QD and the dye.
染料敏化量子点（QD）是染料敏化太阳能电池（DSSC）的有前途的候选材料。在此，我们报告了对几种尺寸的与香豆素343染料（C-343）连接并使用两种不同溶剂（即氯仿和甲苯）的硫化镉量子点进行的稳态（吸收和光致发光）光学测量。我们还进一步报告了对三种不同尺寸的与C-343染料连接的封端量子点的几何、电子和光学（吸收和发射）性质进行的详细第一性原理密度泛函理论和含时密度泛函理论研究。吸收光谱显示出一个与量子点尺寸无关的峰，以及另一个随着量子点尺寸减小而向蓝光方向移动的峰。发现第一个峰源于染料分子，第二个峰源于量子点。利用自然跃迁轨道（NTO）发现电荷转移发生在从染料到量子点的过程中，并且与溶剂有关。在发射光谱中，通过添加量子点使染料的发光强度猝灭，这表明量子点与染料之间存在强相互作用。
