Research On Stability And Large Area Module’s Preparation Of Planar Perovskite Solar Cells

Perovskite solar cell is a new type of solar cell with great development potential.Its photoelectric conversion efficiency has been rapidly increased from 3.8%to 24.2%within ten years,which is comparable to the performance of crystalline silicon solar cells.However,perovskite solar cells are extremely sensitive to humidity,temperature and light,which cannot work long-term under environmental conditions.Besides,it is difficult to control the uniformity of films during large-area module’s preparation,which hinders the commercialization of perovskite solar cells.Improving the stability of perovskite devices mainly depends on the material properties and the preparation process.In this paper,the perovskite solar cells with planar formal structure are prepared by solution method,and the influence of electron transport layer and perovskite light absorption layer on the stability of the devices were systematically analyzed.Finally,we applied the optimized process to the large area modules.This provides reference for the commercialization of perovskite solar cells.The main research results are summarized as follows:（1）The effects of various electron transport layers on the photoelectric properties of perovskite solar cells were investigated,including TiO₂ prepared by high temperature spray pyrolysis,SnO₂ prepared by spin-coating tin oxide colloidal solution,and n-type layers prepared by combining both of them（TiO₂/SnO₂）.The results show that the TiO₂/SnO₂ stacked electron transport layer has better performance than the single electron transport layer,and thus prepared no hysteresis perovskite device with the photoelectric conversion efficiency of 18.03%.By testing the influence of devices fabricated by different electron transport layers on the humidity,temperature and illumination stability,it is obviously that the devices with TiO₂/SnO₂ stacked electron transport layers have better stability under different conditions compared to the single electron transport layer.（2）The SnO₂ electron transport layer was prepared by hydrolysis of SnCl₂·2H₂O by chemical bath deposition method,and then we optimized the preparation process of SnO₂ films.The thickness of SnO₂ films was controlled by adjusting the number of deposition cycles,and the interface of SnO₂ films was optimized with different concentrations of（6,6）-phenyl-c61 methyl butyrate（PCBM）.As a result,we obtained high-efficiency small-area perovskite device with the photoelectric conversion efficiency of more than 19%and large-area series modules with the photoelectric conversion efficiency of 15.88%（having a size of 6.5 cm×6.5 cm and an active area of20.56 cm²）.Long-term stability test results show that the modules encapsulated with PIB can maintain about 80%of the initial efficiency after being stored in the atmosphere for 720 h.（3）By introducing tert-Butylammonium iodide（t-BAI）into methylamine lead iodine perovskite（MAPbI₃）system,the influence of large tert-Butylamine cation（t-BA⁺）with different doping contents on the quality of perovskite crystal and device performance were investigated.The XRD test proves that t-BA cation can substitute unstable MA ions in the perovskite crystal structure,so as to increase the grain size and crystal quality of perovskite.We could fabricate perovskite devices with excellent performance in the atmospheric environment with high humidity.Compared to the MAPbI₃ devices,the efficiency of doped device was significantly increased from 17%to 19.3%.In addition,the degradation of perovskite devices in this system is obviously decreased under high temperature or high humidity environment.