Key Laboratory for Advanced Materials, School of Chemistry and Molecular Engineering, East China University of Science and Technology , Shanghai 200237, China.
College of Materials and Energy, South China Agricultural University , 483 Wushan Road, Guangzhou 510642, China.
ACS Appl Mater Interfaces. 2017 Jun 7;9(22):18936-18944. doi: 10.1021/acsami.7b03715. Epub 2017 May 24.
The insulating nature of organic ligands containing long hydrocarbon tails brings forward serious limitations for presynthesized quantum dots (QDs) in photovoltaic applications. Replacing the initial organic hydrocarbon chain ligands with simple, cheap, and small inorganic ligands is regarded as an efficient strategy for improving the performance of the resulting photovoltaic devices. Herein, thiosulfate (SO), and sulfide (S) were employed as ligand-exchange reagents to get access to the inorganic ligand SO- and S-capped CdSe QDs. The obtained inorganic ligand-capped QDs, together with the initial oleylamine-capped QDs, were used as light-absorbing materials in the construction of quantum dot sensitized solar cells (QDSCs). Photovoltaic results indicate that thiosulfate-capped QDs give excellent power conversion efficiency (PCE) of 6.11% under the illumination of full one sun, which is remarkably higher than those of sulfide- (3.36%) and OAm-capped QDs (0.84%) and is comparable to the state-of-the-art value based on mercaptocarboxylic acid capped QDs. Photoluminescence (PL) decay characterization demonstrates that thiosulfate-based QDSCs have a much-faster electron injection rate from QD to TiO substrate in comparison with those of sulfide- and OAm-based QDSCs. Electrochemical impedance spectroscopy (EIS) results indicate that higher charge-recombination resistance between potoanode and eletrolyte interfaces were observed in the thiosulfate-based cells. To the best of our knowledge, this is the first application of thiosulfate-capped QDs in the fabrication of efficient QDSCs. This will lend a new perspective to boosting the performance of QDSCs furthermore.
有机配体的绝缘性质含有长烃尾带来了严重的限制对于预合成量子点（QDs）在光伏应用中。用简单、廉价、小的无机配体取代初始有机碳氢链配体被认为是提高光伏器件性能的有效策略。在这里，硫代硫酸盐（SO）和硫化物（S）被用作配体交换试剂，得到无机配体 SO-和 S 封端的 CdSe QDs。所得的无机配体封端的 QDs，连同初始的油胺封端的 QDs，被用作量子点敏化太阳能电池（QDSCs）的光吸收材料。光伏结果表明，硫代硫酸盐封端的 QDs 在全一太阳照射下表现出优异的功率转换效率（PCE）为 6.11%，明显高于硫化物（3.36%）和 OAm 封端的 QDs（0.84%），与基于巯基羧酸封端的 QDs 的最新值相当。光致发光（PL）衰减特性表明，与基于硫化物和 OAm 的 QDSCs 相比，硫代硫酸盐基 QDSCs 中 QD 到 TiO 衬底的电子注入速率更快。电化学阻抗谱（EIS）结果表明，在硫代硫酸盐基电池中观察到更咼的光电阳极和电解质界面之间的电荷复合电阻。据我们所知，这是首次将硫代硫酸盐封端的 QDs 应用于高效 QDSCs 的制备。这将为进一步提高 QDSCs 的性能提供新的视角。
