核壳型ZnO/三元氧化物基钙钛矿太阳能电池的制备及性能研究

In perovskite solar cells, high quality oxide electron transport layers and their interface with the organometal trihalides are key to achieve efficient and stable devices. the basic nature of the ZnO surface leads to proton-transfer reactions at the ZnO/CH3NH3PbI3 interface, which results in decomposition of the perovskite film. The decomposition process is accelerated by the presence of surface hydroxyl groups and/or residual acetate ligands. To overcome this issue, ZnO nanorods are passivated with ternary oxides interfacial layer (MTO). the core-shell electrodes of ZnO/ternary oxides (ZnO/MTO) will be developed, whose shell materials such as Zn2SnO4，SrTiO3，BaSnO3 et al show good resistance to strong acid and alkali. The core-shell electrodes of ZnO/MTO, with a buffer layer between ZnO surface and perovskite layer are beneficial to eliminate hydroxyl and acetic acid groups on ZnO surface, inhibit H2O and DMF molecules adsorbed on ZnO surface, avoid CH3NH3PbI3 contacting with ZnO, and enhance CH3NH3PbI3 crystallinity and stability. Further studies on ZnO/MTO electode will be studied and the interaction mechanism between modified ZnO and perovskite layers will be clarified. Furthermore, the effect law of the carrier collection efficiency, the band structure of photoanodes and the carrier lifetimes will be analyzed. This proposal will provide a valuable theoretical reference to design and construct core-shell structured ZnO/MTO based PSCs devices.

高质量的电极薄膜及界面是实现高效稳定钙钛矿太阳能电池的前提条件，ZnO/CH3NH3PbI3界面间容易发生质子转移反应会导致钙钛矿薄膜分解，而吸附在ZnO表面的羟基、醋酸根等基团会加速其进一步分解。针对这一问题，本项目拟引入三元半导体氧化物(MTO)钝化层开展核壳型ZnO/MTO的研制，利用MTO材料耐酸碱性强的特性，实现提高其稳定高效的目的。基于溶液自组装和原位生长技术，以Zn2SnO4，SrTiO3，BaSnO3等MTO材料为壳层制备核壳型ZnO/MTO复合电极，可有效消除ZnO表面羟基、醋酸根等离子的产生，抑制H2O、DMF等分子在ZnO表面的吸附，避免CH3NH3PbI3与ZnO表面直接接触，从而改善CH3NH3PbI3结晶性和稳定性。同时，解析ZnO/MTO材料与CH3NH3PbI3之间的最佳结合方式，揭示壳层材料MTO对能带结构、光电子注入效率、电荷传输与复合等微观参数的影响规

本项目开展有关高质量的ZnO电极薄膜及其界面以实现高效稳定钙钛矿太阳能电池的工作。首先研究了核壳层Zn2Ti3O8、H2Ti3O7等三元氧化物材料，表现出了较高的光电转化效率，优异的电子传输性能和长期器件稳定性；利用CeO2、ZrO、SnS2等二元氧化物材料和金属有机骨架ZIF-8材料作为钝化层，拓展了ZnO基钙钛矿太阳能电池电子传输层电荷分离结构的新思路，有效地提高了钙钛矿层的结晶度和晶粒尺寸，并显著改善了电池的光伏性能。虽然表面钝化技术在一定程度上缓解了这种不稳定性，但对于所有金属卤化物钙钛矿是否与氧化锌表现出这种不稳定性的研究尚待开展，因此，我们利用一种新型金属卤化物钙钛矿吸光材料(FAPbI3)83(MAPbBr3)17作为钙钛矿层，钙钛矿-氧化锌界面的效率和稳定性大幅度提高。因此，这项工作表明，在采用少含MA或者不含MA阳离子的情况下，具有良好透射率、较高导电性和合适带隙结构的ZnO材料是可行的电子传输层。