基于碳纳米管空穴传输层和电极的反式钙钛矿太阳电池的研究

The efficiency of solar cells based on organic-inorganic hybrid perovskite materials has a rapid growth from 3.8% in 2009 to 19.3%. The perovskite material (CH3NH3PbX3) exhibits advantages of high absorbing coefficient, low cost, and easily synthesised, which achieved extremely rapid development in recent years and gain great concern from the academic circle. Carbon nanotubes (CNTs), with their excellent electrical conductivity, chemical stability, and unique nanostructure, have been applied as electrodes in CdTe, dye sensitized solar cells, and organic solar cells. Not only did the CNT electrode show comparable performance to conventional architectures, it also provided the solar cell with more features such as flexibility and semi-transparency for tandem solar cells. The recent development of silicon/CNTs solar cells revealed the advantages of CNTs over metallic grids, due to the better local charge collection of the nanometer-scale networks and tunable electrical properties with chemical doping. Here we introduce a facile perovskite solar cell fabrication technique by directly transferring CNT films, exempting the energy-consuming metal deposition process. Herein, Carbon nanotubes is first introduced into the inverted heterojunction perovskite solar cell as a hole conductor and electrode，employing CH3NH3PbX3 as absorber. The charge transfer between CNTs and the perovskite, morphology and crystallization of the perovskite film grown on CNTs are also investigated. The addition of the hole transporter grapheme oxide (GO) will improved the efficiency of cells of PET/CNT/CH3NH3PbX3/PCBM/Al, for the synergistic action of CNTs and GO. Thus, the organic-inorganic hybrid perovskite materials which have a stable conductors, lower cost and high efficiency should be obtained.

基于杂化钙钛矿太阳电池效率自2009年从3.8%增长到19.6%, 因其较高的光吸收系数，较低的成本及易于制备等优势获得了广泛关注。碳纳米管具有高迁移率的“直线”空穴传输通道、可作透明导电电极等特性。本项目拟采用CNT为空穴传输及电极材料，CH3NH3PbX3作为吸收材料，碳60衍生物(PCBM)作为电子传输材料，建立CNT/CH3NH3PbX3/PCBM/Al反式钙钛矿太阳电池模型，进行系统研究。利用氧化石墨烯特殊的结构及优异的空穴传输性能，还将建立CNT-GO/CH3NH3PbX3/PCBM/Al电池模型， CNT与GO复合，对电子-空穴对的分离及空穴快速传输将起协同加速效应。研究电池的结构与光电性能的关系，电池环境稳定性和光稳定性，光电转换机理和载流子输运机理。通过对电池的系统研究、工艺优化，有望获得寿命稳定、高效低廉的太阳能电池，为钙钛矿太阳电池的应用开发提供理论和实验基础。

2009年，有机无机杂化钙钛矿太阳能电池首次被提出。研究者发现有机无机杂化钙钛矿材料几乎拥有完美光吸收材料的所有条件：合适的直接带隙、高的吸收系数、优异的载流子输运性能以及高的缺陷容忍度。近年来，钙钛矿太阳电池研究发展迅速，但仍有若干关键因素可能制约钙钛矿太阳电池的发展: 1)有机无机钙钛矿材料的稳定性问题, 由于其为离子型化合物，紫外光、空气中的水气等都会引起钙钛矿材料的分解，导致太阳电池在大气中效率衰减严重；2)虽然钙钛矿材料相对便宜，但用其制造太阳能电池还需要用到一种名为spiro-OMeTAD 的有机空穴导电聚合物，其市场价格是黄金的10 倍以上，而且空穴迁移率较低，对空气很敏感，是引起电池不稳定，寿命短的原因之一。本项目以铅卤钙钛矿为吸光材料，碳基材料为空穴传输材料和对电极，制备了高效低廉稳定性优良的太阳能电池。研究了几种配体添加剂(包括聚醚酰亚胺、聚苯胺以及质子化氮化碳、三聚氰胺、L-半胱氨酸、油酸油胺等)对卤化物钙钛矿薄膜或纳米晶体进行生长控制和表面钝化对稳定性和光电性能的影响。研究了太阳电池对电极碳基材料(包括导电碳浆、石墨烯/碳纳米管、石墨烯/氮化碳、Ni3S2/三维石墨烯自支撑，Ni3S2/氮掺杂碳纳米管)的制备、表征、生长机理。探讨碳基材料和钙钛矿材料的结构、组成、形貌、尺寸、界面结构等对太阳电池光伏性能的影响。探讨太阳能电池的载流子的产生、分离及传输等光电转换和传导机理。获得的太阳能电池具有优良的环境稳定性，在湿度为60%的空气环境中不需要封装，电池光电转换效率20天基本保持不变，且转化效率达到10%。这项研究结果表明我们可以采取一种简单而有效的方法来制造高效和稳定的低成本钙钛矿太阳电池。