钙钛矿太阳能电池空穴传输层的优化研究

	钙钛矿太阳能电池空穴传输层的优化研究
其他题名	Optimization of the Hole Transport Layer ofPerovskite Solar Cell
	侯福华
学位类型	硕士
导师	苏子生
	2015-10
学位授予单位	中国科学院大学
学位专业	光学工程
关键词	钙钛矿太阳能电池空穴传输层稳定性
摘要	钙钛矿材料及电池因其结构简单，可低温制备，优良的双极性载流子性质，消光系数高且带隙合适，开路电压高，可制备柔性器件等优点吸引了众多研究者的目光。钙钛矿太阳能电池的效率从3.8%提升至20%仅仅用了5 年时间，但器件的稳定性有待进一步提升。为了实现钙钛矿太阳能电池的商业应用，必须在获得高效率器件的前提下，提高器件在空气中的稳定性。本论文通过对钙钛矿太阳能电池空穴传输层的优化研究，提高了器件的能量转换效率和在空气中的稳定性，主要研究集中在以下几个方面： 1、构筑了MoO3/PEDOT:PSS 双层空穴传输层的钙钛矿太阳能电池。将 MoO3 层插入ITO 导电玻璃和PEDOT:PSS 之间，制备了器件结构为 ITO/MoO3/PEDOT:PSS(40 nm)/CH3NH3PbI3(350 nm)/C60(40 nm)/Bphen(5 nm)/Ag(100 nm)的钙钛矿太阳能电池。MoO3 的引入不仅不影响PEDOT:PSS 层的形貌，而且极大的提高了器件转换效率和稳定性。优化器件获得了12.78%的能量转换效率，与单层PEDOT:PSS 器件相比提高了30%左右。效率的提升归因于MoO3 的引入增加了器件的空穴收集效率。而且，优化器件在空气中遮光放置一段时间后器件效率提升至14.87%，这是当时倒置平面异质节钙钛矿太阳能电池最高效率之一。更重要的是，放置10 天后，器件效率仅下降初始效率的 7%，而此时PEDOT:PSS 器件已经完全衰减为零。相关工作提供了一种可同时增加器件的能量转换效率和稳定性的方案。 2、采用热蒸发工艺将钙钛矿层直接沉积在导电玻璃上，制备了高效稳定的无空穴传输层钙钛矿太阳能电池。优化器件结构为ITO/CH3NH3PbI3-xClx (35nm)/C60(40 nm)/Bphen(5 nm)/Al(100 nm)。所制备的钙钛矿薄膜无需退火就可获得平整致密的形貌。相关器件具有高的空穴提取效率和低的载流子复合率，相应地，器件具有高的短路电流和填充因子。虽然钙钛矿薄膜厚度只有35 nm，但是器件的最高能量转换效率达到了8.37%。相关工作提供了一种制备高效半透明钙钛矿太阳能电池的可能途径。 3、设计并制备了CuI/PbPc 作为空穴传输层的钙钛矿太阳能电池。采用真空沉积法制备CuI/PbPc 层，溶液旋涂法制备钙钛矿薄膜，优化器件结构为 ITO/CuI(2 nm)/PbPc(20 nm)/CH3NH3PbI3(350 nm)/C60(40 nm)/Bphen(5 nm)/Ag(100 nm)。使用CuI/PbPc 代替PEDOT:PSS 作为空穴传输层不仅可以获得和PEDOT:PSS 器件相近的效率，还可极大的提高器件在潮湿环境下的稳定性。优化器件在空气中遮光放置6 天后可达到9.61%的高转换效率，更重要的是，器件遮光放置21 天后仍能保持最高效率的73%，而PEDOT:PSS 参考器件放置6 天后效率完全衰减为零。相关实验证明了采用CuI/PbPc 空穴传输层可明显提高器件在周围大气环境中的稳定性。
其他摘要	Organic inorganic halide perovskite, possessing the desirable properties of high absorption coefficient, very low material costs, long charge diffusion length, appropriate bad gap, and solution processability, shows great potential for photovoltaic applications. Within just five years, the power conversion efficiency (PCE) of the perovskite solar cell (PSC) has risen from 3.8% to 20%. The issues of the degradation of perovskite should be urgently addressed to achieve good reproducibility and long lifetimes for PSC. Without studies on stability, exciting achievements cannot be transferred from the laboratory to industry and outdoor applications. In this thesis, we aim to improve the power conversion efficiency and stability of the PSC by optimizing the hole transport layer. 1. Designing MoO3/PEDOT:PSS hole transport bilayer in PSC. MoO3 is inserted between ITO conductive glass and PEDOT:PSS layer to prepare hole transport bilayers, the optimized device structure is ITO/MoO3/PEDOT:PSS(40 nm)/CH3NH3PbI3(350 nm)/C60(40 nm)/Bphen(5 nm)/Ag(100 nm). The incorporation of an MoO3 layer does not affect the growth of PEDOT:PSS, but dramatically improves the PCE and stability of the device. The as-prepared optimized device shows a PCE of 12.78%, which is increased by about 30% as compared with the reference device based on pristine PEDOT:PSS. The improvement is attributed to the increased hole collection efficiency with an MoO3 layer. A maximum PCE of 14.87% is obtained for the device after a short storage under ambient conditions in the dark, which is one of the highest PCE reported for inverted planar heterojunction (PHJ) PSC. More importantly, only 7% degradation in PCE is observed for the optimal device and almost complete failure of the reference device for storage under ambient conditions for 10 days. This work has provided a simple strategy to simultaneously improve the PCE and stability of PHJ PSC. 2. High efficiency and stable hole transporting material-free (HTM-free) PHJ PSC is constructed by directly thermal evaporating perovskite materials onto indium tin oxide substrate. The optimized device structure is ITO/CH3NH3PbI3-xClx(35 nm)/C60(40 nm)/Bphen(5 nm)/Al(100 nm). A condense and homogeneous morphology is found for this perovskite film even without any annealing process. The optimized HTM-free CH3NH3PbI3-xClx/C60 PHJ device with a 35 nm ultra-thin CH3NH3PbI3-xClx layer presents a high hole extraction efficiency and a low charge carrier recombination probability, which results in a high short circuit current and fill factor. The HTM-free device shows a high power conversion efficiency of 8.37%, which is one of the highest efficiency among reported inverted HTM-free PSCs even that a thinner perovskite film is used. More importantly, the device also exhibits a superior stability in ambient condition. The related experiment provides a simple and efficient perovskite structure. 3. Design and apply CuI/PbPc as HTL in PSC. The CuI/PbPc layer is prepared by vacuum deposition method and the perovskite thin film by solution spin coated. The optimized device structure is ITO/CuI(2 nm)/PbPc(20 nm) /CH3NH3PbI3(350 nm)/C60(40 nm)/Bphen(5 nm)/Ag(100 nm). We found that the CuI/PbPc as HTL perform a comparable efficiency to PEDOT:PSS, and largely enhance the stability of PSC in high humidity. The as-prepared optimized device reach the maximum PCE of 9.61% after storage in ambient conditions in dark for 6 days. More importantly, the optimized device retains 73% of its best PCE when they were stored in ambient conditions for 21 days, compared to an almost full failure for the reference device after 6 days, and interestingly, Voc remains unchangeable even in nearly two months test. Experiments show that the CuI/PbPc HTL can significantly improve device stability in the surrounding atmosphere.
语种	中文
文献类型	学位论文
条目标识符	http://ir.ciomp.ac.cn/handle/181722/49321
专题	中科院长春光机所知识产出
推荐引用方式 GB/T 7714	侯福华. 钙钛矿太阳能电池空穴传输层的优化研究[D]. 中国科学院大学,2015.

条目包含的文件
文件名称/大小	文献类型	版本类型	开放类型	使用许可
侯福华.pdf（3477KB）	学位论文		开放获取	CC BY-NC-SA	请求全文