Effects of QD surface coverage in solid-state PbS quantum dot-sensitized solar cells
Effects of QD surface coverage in solid-state PbS quantum dot-sensitized solar cells
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DOI：
10.1109/pvsc.2013.6744328
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发表时间：
2013-06
期刊：
影响因子：
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通讯作者：
Katherine E. Roelofs;T. Brennan;O. Trejo;John Xu;F. Prinz;S. Bent
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文献类型：
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作者：
Katherine E. Roelofs;T. Brennan;O. Trejo;John Xu;F. Prinz;S. Bent
采用连续离子层吸附反应（SILAR）和原子层沉积（ALD）法在纳米多孔TiO2上原位生长硫化铅量子点（QD），制备固态量子点敏化太阳能电池（QDSSC）。以增加量子点表面覆盖率为最终目标，这项工作比较了这两种合成路线对器件光吸收和电学性能的影响。与ALD生长的QD器件相比，在反向偏压下在SILAR生长的QD器件中观察到更高的电流密度，这归因于SILAR生长的QD器件中存在的较低带隙QD的注入问题。为了理解QD表面覆盖对器件性能的影响，特别是界面复合，测量了不同QD沉积周期的电子寿命。发现电子寿命随着SILAR周期的增加而减少，这表明由于QD表面覆盖率的增加，TiO 2中的电子和空穴传输材料中的空穴之间的复合的预期减少并不是增加沉积周期的主导效应。
Lead sulfide quantum dots (QDs) were grown in situ on nanoporous TiO2 by successive ion layer adsorption and reaction (SILAR) and by atomic layer deposition (ALD), to fabricate solid-state quantum-dot sensitized solar cells (QDSSCs). With the ultimate goal of increasing QD surface coverage, this work compares the impact of these two synthetic routes on the light absorption and electrical properties of devices. A higher current density was observed in the SILAR-grown QD devices under reverse bias, as compared to ALD-grown QD devices, attributed to injection problems of the lower-band-gap QDs present in the SILAR-grown QD device. To understand the effects of QD surface coverage on device performance, particularly interfacial recombination, electron lifetimes were measured for varying QD deposition cycles. Electron lifetimes were found to decrease with increasing SILAR cycles, indicating that the expected decrease in recombination between electrons in the TiO2 and holes in the hole-transport material, due to increased QD surface coverage, is not the dominant effect of increased deposition cycles.