基于量子点敏化剂的表面重构及其对太阳电池内部电荷传输机制影响的研究

The development of a new-type solar cell technology with low-cost and high-efficiency represented by quantum dot sensitized solar cells (QDSCs) is an effective way to solve the current energy and environment problems. Currently, the photovoltaic performance and stability of QDSCs are limited by the unsolved scientific problems between surface defect passivation and electron-hole fast separation transmission simultaneously. Based on structure-function design concept of nanomaterials, a novel and efficient regulation technical route of two-step surface reconstruction for quantum dots is developed in this project，and the surface passivation control and electron-hole separation transmission will be integrated appropriately. The essential issues, that is, the kinetics of the transportation and recombination of photo-generated electrons at the surface and interface will be investigated systematically. Meanwhile, the intrinsic relationship between surface reconstruction of quantum dots and charge transmission will be clarified, and the electron-hole separation regulating mechanism based on the surface reconstruction will be also revealed. It is expected that high photoecectric conversion efficiency and excellent stability can be realized by virtue of the above effective strategies. The results of this project not only offer theoretical basis and technical support for the final industrial application of QDSCs, but also provide inspiration and reference for improving the performance of other types of solar cells.

开发以量子点敏化太阳电池（QDSCs）为代表的低成本、高效率潜质的新型太阳电池技术是解决目前能源与环境等问题的一种有效途径。目前，QDSCs普遍存在的表面缺陷态钝化与电子-空穴分离传输之间顾此失彼的矛盾仍没有得到有效解决，严重制约其光伏性能及稳定性的进一步提升。本项目采用纳米材料构效关系设计理念，拟发展一条新颖高效的量子点二次表面重构的调控技术路线，达到量子点表面钝化调控与电子-空穴快速分离传输的双重效果。系统研究电池内部电荷表界面传输及复合动力学机制，厘清量子点表面重构与电荷迁移传输之间的内在联系，揭示表面重构对光生电子-空穴分离传输的可控调节机制，籍以实现更高光电转换效率和优良器件稳定性的新突破。本研究结果将为QDSCs最终工业化应用提供理论基础和技术支撑，同时对其他类型太阳能电池性能提升提供启示和借鉴意义。

开发高效率、低成本太阳能电池是解决目前能源危机和环境污染等影响社会经济可持续发展问题的一种有效途径。本项目主要基于I-III-VI族环境友好型量子点敏化太阳能电池，设计构筑出高效量子点表面重构的调控技术路线，研究电池内部电荷表界面传输及复合动力学机制，厘清量子点表面重构与电荷迁移传输之间的内在联系，揭示表面重构对光生电子-空穴分离传输的可控调节机制，最终显著增强量子点敏化太阳电池器件的器件性能和稳定性。同时，从光阳极、电解质及对电极等部件出发，多途径优化策略提升量子点敏化太阳电池的光电转换效率。本项目主要内容简要概述如下：首先，选取具有自钝化效应的铝金属离子对I-III-VI族Zn-Cu-In-Se量子点进行表面掺杂，铝离子遇到空气能够自动发生自动氧化，形成氧化铝薄膜，既提高了量子点溶液本身的稳定性，又能起到表面钝化层作用，抑制电荷复合，最终提高电池性能。其次，通过β-丙氨酸和对氨基苯甲酸等氨基类空穴离域配体对水相量子点进行表面修饰，适量空穴离域配体引入能够改善量子点的空穴提取能力，提升器件的光电转换效率。第三，利用金纳米棒强的等离子体共振增强效应，将金纳米棒包覆TiO2纳米结构添加到TiO2光阳极中，此结构不仅能够有效提高量子点的光捕获能力，而且金纳米棒/TiO2形成的界面层抑制电荷复合，加快TiO2光阳极内部的电荷转移。第四，将TiO2溶胶互联修饰的光阳极与海藻酸盐水凝胶辅助电解质膜协同作用，制备了高效、稳定的准固态QDSCs器件。此外，以Cu-MOF和卡拉胶凝胶自组装杂化制备出Cu-MOF衍生CuxS纳米球自组装双面修饰碳纳米片作为对电极，此对电极表现出优秀的导电性和催化活性，提升了聚硫电解质还原反应速率，最终提升了器件性能。本项目所开发的量子点表面重构策略为后续化研究工作提供了新的思路，也为量子点在其他类型光伏器件及光催化等方面的应用提供了指导和借鉴。

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