【作者】 郭莹；

【导师】 郝策； 史彦涛；

【作者基本信息】 大连理工大学 ， 化学工程（专业学位）， 2015， 硕士

【摘要】 在常规钙钛矿太阳能电池(Perovskite solar cells, PSCs)中,通常使用有机P型半导体提取空穴,并使用蒸镀法制备的Au或Ag薄膜电极进行收集。目前,PSCs普遍使用的有机空穴传输层spiro-MeOTAD不仅价格昂贵而且稳定性较差,Au或Ag作为PSCs的背电极需要高真空设备进行制备,不适合商业化大规模生产。因此,选择优异的背电极材料不仅可以保证电池的性能,还可以提高电池稳定性,从而有利于PSCs未来的大规模生产。本论文围绕降低钙钛矿太阳能电池成本及提高器件的稳定性进行了一系列探索性研究,主要内容是制备适合碳基钙钛矿太阳能电池的背电极,并研究背电极材料、结构、制备方法及热处理对电池性能的影响规律,对其中有关重要发现进行了分析,具体内容如下：(1)使用商业导电炭黑和有机添加剂来制备适合印刷的碳浆,发现制备出的碳背电极具有非常差的导电性,不适合做钙钛矿太阳能电池背电极。研究在导电炭黑中加入大尺寸的针状焦从而提高碳背电极的导电性,光电转换效率为0.53%,并对光电性能进行了分析,发现难以控制的碳背电极较差的界面接触是导致电池性能低下的原因。(2)使用喷涂替代刮涂,电池最高光电转化效率达到3.9%。针对炭黑粒子间接触不良这一问题,使用机械加压增加碳背电极导电性和提高电池性能。研究了复合碳材料制备背电极对电池性能的影响,发现碳纳米管制备成钙钛矿太阳能电池背电极后导电性较差,但将碳纳米管与炭黑复合后,电池的光电转换效率可达到6.57%。(3)研究了用针状焦制备钙钛矿太阳能电池背电极,优化了样品热处理温度,发现1500℃下碳化的针状焦的电阻最小,适合作为钙钛矿太阳能电池的背电极。发现由于水分的存在,在空气中喷涂针状焦容易对钙钛矿层造成破坏。对以针状焦背电极为基础的碳基钙钛矿电池进行了稳定性研究,连续8天的测试表明电池光电转化效率并未下降。(4)研究了热处理对以针状焦背电极为基础的碳基钙钛矿电池性能的影响,发现热处理后电池的光电转换效率可达到8.57%。通过对电池进行一系列的表征,得出的结论是：热处理过程中针状焦可以有效保护钙钛矿层不受外界不良气氛的侵蚀,同时,钙钛矿层在这种保护下自身的结晶性也得到了改善,这也解释了器件热处理后光吸收增强以及电池光电转化效率的提高。这项研究为提高碳基钙钛矿电池的性能提供了新的思路。更多还原

【Abstract】 In conventional Perovskite solar cells (PSCs), organic p-type semiconductors are usually used to extract holes, then being collected by Au or Ag thin film cathode that can be fabricated by thermal evaporation deposition. Presently, the widely used organic material for hole-transport layer is spiro-MeOTAD, which is not only expensive but also shows inferior stability. On the other hand, high-vacuum techniques are usually needed for fabrication of Au or Ag cathode for PSCs, also unsuitable for commercial and large-scale manufacture. Hence, it is ungently desired to seek suitable cathode materials to ensure both photovoltaic performance and enhancement in PSCs stability, enabling them for future large-scale production.In this thesis, with the aim at reducing the production cost of PSCs and enhancing their stability, we focus our researches on developing carbon back electrodes for PSCs, for example, research on the influence of material type, structure and fabrication method on the photovoltaic performance of PSCs. Meanwhile, we give analysis to some important findings, details are listed as follows:(1) We researched on fabrication of carbon paste that was suitable for printing. Results showed that the as-obtained carbon paste had very poor conductivity, unsuitable for serving as back electrode for PSCs. We carried our research that showed that, when adding large-sized needle-coke, the conductivity of the carbon back electrode could be enhanced and the power conversion efficiency (PCE) is 0.53%. After analysis, we found that the difficulty in film thickness control, as well as the poor interfacial contact finally resulted in inferior photovoltaic performance of PSCs.(2) We researched on replacing doctor-balding with spray for fabrication of carbon back electrode for PSCs, by which the photovoltaic performance was enhanced obviously and the highest efficiency is 3.9%. To improve the contact between carbon black nanoparticles, we used mechanic pressure treatment to enhance the conductivity and the cell performance. Besides, we researched the fabrication of composite as carbon back electrode for PSCs. Results showed that using CNTs alone as back electrode gave poor performance. When composited with carbon black, the cell performance was enhanced obviously and the PCE is 6.57%.(3)We researched on using needle-coke as source for fabrication of carbon back electrode for PSCs. Temperatures of thermal treating needle-coke samples were optimized, we found that the one treated at 1500℃ had the smallest resistance, suitable for fabrication of carbon back electrode for PSCs. In addition, we found that, due to moisture, perovskite could be easily damaged when using spray in air. The stability test to PSCs was conducted, after 8 days, no decrease on cell PCE was found.(4) We researched the effect of thermal treating of PSCs on the device stability and found that the highest PCE can reach 8.57% after thermal treating. By some characterizations, we conclude that the needle-coke-based electrode might protect perovskite from being etched by external unfriendly atmosphere, meanwhile, by which the crystallinity of perovskite could be improved. Our analysis could be used to interpret why the absorption property and the cell performance were improved after thermal treating. Our research offers new strategy for improving the photovoltaic performance of PSCs.更多还原