Samadpour Mahmoud
Department of Physics, K. N. Toosi University of Technology PO Box 15418-49611 Tehran Iran
RSC Adv. 2018 Jul 19;8(46):26056-26068. doi: 10.1039/c8ra04413a.
Here we investigate the effect of seed layer deposition on electron-transport parameters of chemical-bath-deposited (CBD) CdSe quantum dot sensitized solar cells (QDSCs). Fill factors were systematically improved to more than 0.6 through reduced recombination after seed layer deposition. Considering the beneficial effects of seed layer deposition, noticeably higher efficiency values were systematically obtained in cells with the seed layer (2-3.19%) in comparison to cells without a seed layer (0.03-0.46%) depending on the TiO photoanode particle size. Electron-transport parameters in cells, including chemical capacitance, recombination resistance, the diffusion coefficient, electron life time and small perturbation diffusion lengths of electrons were examined by modeling the experimental impedance spectroscopy data. We showed that a seed layer enhanced recombination resistance in cells, while the photoanode conduction band position was not affected. Higher diffusion lengths of electrons were obtained after seed layer deposition, correlated to the reduced electron recombination rate by redox electrolyte through seed layer deposition. As a general conclusion we report that while the seed layer generally is deposited to increase light absorption, at the same time this could be applied in order to systematically enhance charge-transport properties in cells and it has a clear application in the optimization of QDSC performance.
在此，我们研究了种子层沉积对化学浴沉积（CBD）CdSe量子点敏化太阳能电池（QDSC）电子传输参数的影响。通过种子层沉积后减少复合，填充因子系统地提高到了0.6以上。考虑到种子层沉积的有益效果，根据TiO光阳极粒径的不同，有种子层的电池（2 - 3.19%）相比于无种子层的电池（0.03 - 0.46%）系统地获得了明显更高的效率值。通过对实验阻抗谱数据进行建模，研究了电池中的电子传输参数，包括化学电容、复合电阻、扩散系数、电子寿命以及电子的小扰动扩散长度。我们表明，种子层提高了电池中的复合电阻，而光阳极导带位置不受影响。种子层沉积后获得了更高的电子扩散长度，这与通过种子层沉积使氧化还原电解质降低电子复合速率相关。作为一个总体结论，我们报告称，虽然种子层通常是为了增加光吸收而沉积的，但同时它也可用于系统地增强电池中的电荷传输特性，并且在QDSC性能优化方面有明确的应用。
