| The new perovskite materials has wide application prospects in the field of photovoltaics,because of its excellent photoelectric properties,such as bipolar transmission characteristics,large extinction coefficient,long carrier diffusion length,high carrier mobility,and low trap-state.In the past ten years,the power conversion efficiency(PCE)of perovskite solar cells(PSCs)has exceeded 23%,and was expected to exceed 30%of conventional silicon solar cells in the future.Although perovskite solar cells have excellent performance,simple and inexpensive preparation processes,and the ability to prepare shape-moldable devices,there are still some problems that need to be solved in the coumercial application,for example:how to improve the power conversion efficiency?how to improve device stability?how to find alternative materials for Pb?and how to prepare large area and flexible devices?In order to solve these problems,many researchers have done a lot of works in improving the quality of perovskite films,interfacial modification,developing new materials,and optimizing preparation processes.In this dissertation,we focused on the effect of an inexpensive additive on the power conversion efficiency and stability of perovskite solar cells,and the preparation of high PCE flexible perovskite solar cells.The main research contents are as follows:(1)We introduced amphiphilic hexadecyl trimethyl ammonium bromide(CTMAB)as additive into a CH3NH3PbI3 pervoskite precursor to adjust the morphology and crystallinity of perovskite layers during the film formation process.SEM and AFM images showed that the perovskite films with CTMAB present more uniform and better coverage compared with perovskite film without CTMAB.As a result,perovskite films with CTMAB exhibit favorable morphology and improved crystallinity and power conversion efficiency.The performance of CH3NH3PbI3 based on perovskite solar cell with optimized CTMAB content achieves a summit PCE of 18.03%under standard AM 1.5 solar light of 100 mW·cm-2 intensites,which was significantly higher than the traditional cell efficiency(17.05%).More importantly,the perovskite device with CTMAB into perovskite layer·showed good stability under humidity environment during 40 days.The efficiency still has 95%of the initial efficiency after 40 days under ambient environment with 40%humidity in the dark at room temperature,while the efficiency of the unadded device is only 70%of the initial efficiency.It can be seen that the addition of CTMAB can significantly improve the efficiency and stability of the perovskite soalr cells.(2)We proposed a new method for preparation of rigid and flexible perovskite solar cells,which SnO2 electron transport layer was treated by a low temperature thermal annealing and UV-ozone(UVO)assisted.It has been found that SnO2 layer treated by UVO-assisted annealing is more conducive to form tin oxide network structure than that of only treated by thermal annealing.After UVO-assisted annealing treatment,the results showed that the perovskite precursor solution can be easily spread on the surface of the SnO2 film,the perovskite crystal has better crystallinity and larger grain size,and the perovskite film is more uniform.Furthermore,the performance of the PSC is improved because of more sunlight absorbed and recombination efficiently reduced.A highly efficient rigid PSC with a PCE of 19.7%is obtained based on 120?sintered and UVO-treated SnO2 ETLs.Same method for SnO2 ETL treatment was used to prepare flexible PSC and high PCE of 18.88%was obtained,which was higher than the currently reported flexible device efficiency. |
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