Enhanced Performance of PbS-quantum-dot-sensitized Solar Cells via Optimizing Precursor Solution and Electrolytes

• Published in: Scientific reports Vol. 6; no. 1; p. 23094
• Main Authors: Tian, Jianjun, Shen, Ting, Liu, Xiaoguang, Fei, Chengbin, Lv, Lili, Cao, Guozhong
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 15-03-2016; Nature Publishing Group
• Subjects: 639/301/299/946; 639/638/298/398; Adsorption; Crystal growth; Electrolytes; Humanities and Social Sciences; Interfaces; Limiting factors; Methanol; multidisciplinary; Permeability; Photovoltaic cells; Quantum dots; Recombination; Science; Solar cells; Titanium dioxide
• ISSN: 2045-2322; 2045-2322
• DOI: 10.1038/srep23094

This work reports a PbS-quantum-dot-sensitized solar cell (QDSC) with power conversion efficiency (PCE) of 4%. PbS quantum dots (QDs) were grown on mesoporous TiO
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film using a successive ion layer absorption and reaction (SILAR) method. The growth of QDs was found to be profoundly affected by the concentration of the precursor solution. At low concentrations, the rate-limiting factor of the crystal growth was the adsorption of the precursor ions and the surface growth of the crystal became the limiting factor in the high concentration solution. The optimal concentration of precursor solution with respect to the quantity and size of synthesized QDs was 0.06 M. To further increase the performance of QDSCs, the 30% deionized water of polysulfide electrolyte was replaced with methanol to improve the wettability and permeability of electrolytes in the TiO
2
film, which accelerated the redox couple diffusion in the electrolyte solution and improved charge transfer at the interfaces between photoanodes and electrolytes. The stability of PbS QDs in the electrolyte was also improved by methanol to reduce the charge recombination and prolong the electron lifetime. As a result, the PCE of QDSC was increased to 4.01%.