Ultrathin ALD coating on TiO₂ photoanodes with enhanced quantum dot loading and charge collection in quantum dots sensitized solar cells

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• 作者：Ting Shen 沈婷 ; Jianjun Tian 田建军 ; Bo Li 李波 ; Guozhong Cao 曹国忠
• 关键词：CdS/CdSe ; atomic layer deposition ; quantum dots solar cells ; charge recombination ; electron collection
• 刊名：Science China Materials
• 出版年：2016
• 出版时间：October 2016
• 年：2016
• 卷：59
• 期：10
• 页码：833-841
• 全文大小：2,312 KB
• 刊物类别：Materials Science, general; Chemistry/Food Science, general;
• 刊物主题：Materials Science, general; Chemistry/Food Science, general;
• 出版者：Science China Press
• ISSN：2199-4501
• 卷排序：59

文摘

TiO₂ nanocrystals are widely used in photoanodes for quantum dot solar cells (QDSCs) owing to their chemical stability and suitable energy band structure. However, surface defects and grain boundaries of TiO₂ nanocrystals photoanodes allow high surface charge recombination, which limits the performance of QDSCs. In this work, an ultrathin TiO₂ layer is introduced to the surface of TiO₂ photoanodes by atomic layer deposition (ALD). The ultrathin layer not only reduces the surface defects of TiO₂ nanoparticles and strengthens the connection between adjacent nanoparticles to suppress the charge recombination for improving the electron collection efficiency (η_cc), but also increases the surface energy of photoanodes to load more quantum dots (QDs) for enhancing the light harvesting efficiency (LHE). As a result, the solar cell based on CdS/CdSe QDs with ALD treatment exhibits an efficiency of 5.07% that is much higher than that of the cells without modification (4.03%).