Research On Electronic Collection Interface Of Perovskite Solar Cells

Organic-inorganic hybrid perovskite solar cell has been an hot research field because of its high efficiency, low cost and simple process and was considered as one of the top 10 scientific breakthroughs of 2013 by Science. Perovskite solar cell is considered to be the hope of photovoltaic field. Perovskite solar cells was reported for the first time in 2009.The efficiency has exceeded 20% only after a few years of development and there is hope to further increase to the level of monocrystalline silicon cells.Although the structure of perovskite solar cell is simple but it is particularly sensitive to various conditions during the preparation. Firstly, the thesis has optimized the preparation of the battery systematically and then has studied the influence of the interface of electron collector and the atmosphere of experiment on the battery performance. This thesis includes the following three parts:1. Optimization of the perovskite solar cell was done. This thesis has optimized the influence of the ratio Pb I2 and CH3NH3 I, mixed with a little additive, different solvent extraction, the thickness of active layer, the annealing time of the active layer and annealing with different atmosphere on the battery performance systematically and ultimately has got the optimal parameter.2. The effect of the electron collector interface on perovskite solar cell performance was studied. There were mainly three aspects : studying the influence of PCBM thickness and the annealing parameter on the battery performance and the mechanism; Studying the effect of inserting BCP or Bphen buffer layer between PCBM and Al and comparing the influence of spin-coating and vacuum thermal evaporation process of preparing cell on the device. The results showed that: PCBM thin layer is unstable and deteriorates when heated, so the performance of the cell is the best without heating. To get good performance, the thickness of PCBM must be over 40 nm in order to prevent the diffusion of aluminum electrode into perovskite thin film and resulting in carrier recombination. The cell performance won't change with increasing thickness of PCBM because the electron mobility of PCBM is high and the effect on series resistance is small. The effect of BCP and Bphen is similar that a certain thickness of the film can significantly improve cell performance but cell performance will decrease when the film exceeds a certain thickness. This indicates the electron mobility of BCP and Bphen is small and the series resistance will increase significantly with increasing the thickness. Moreover, This thesis shows that perovskite doped with PCBM and PCBM doped with BCP or Bphen can't improve battery performance bu will make it drop.3. The effect of the experimental atmosphere of the battery preparation on perovskite solar cells performance was studied. There were mainly two aspects which affected the battery performance: the species of solvent atmosphere and the concentration of corresponding solvent atmosphere. The results showed that: 1200 ul solvent atmosphere can markedly improve cell performance but less has no effect or more becomes worse. Qualitative experiment atmosphere can not only improve battery performance but also greatly improve the control of preparation.