Research On Perovskite Solar Cell With CuSCN Hole Transport Layer

Perovskite solar cells（PSCs）have developed rapidly in recent years,and their laboratory photoelectric conversion efficiency has reached 23.7%,which has caught up with the efficiency of commercial solar cells modeules.Compared with the first-generation solar cells with high energy consumption,the second-generation solar cells with limited reserves of raw material,and other third-generation solar cells with low efficiency,PSCs have strong photoelectric conversion ability,aboundant raw materials reserves,flexibility,and simple preparation processes.Perovskite solar cell is expected to become a new generation of photovoltaic devices.However,there are still some problems to be solved in large scale commercialization of PSCs,and the stability of PSCs is the most critical issue.In this paper,the optimization of the hole-transporting layer of traditional PSCs is carried out to improve the stability of the device in the atmospheric enviroment and reduce the cost of the device.The research mainly focuses on the following aspects:（1）Abandoning the traditional organic hole transport material spiro-MeOTAD+Li-TFSI+TBP,using a simple one-step method to prepare a non-hole transport layer device with FTO/c-TiO₂/mp-TiO₂/CH₃NH₃PbI₃/Au structure.By regulating the preheating temperature and time during annealing of the perovskite layer,found that the device performance is optimal at 9%with preheating at 50°C for6 minutes and annealing at 110°C for 10 minutes,and retains 85%of the initial efficiency after placed in the N₂ atmosphere for two months.At atmospheric temperature of 25°C and humidity of 30 RH%,the device decays significantly,but the stability is better than that of perovskite solar cell with spiro-MeOTAD+Li-TFSI+TBP hole transport layer.（2）Using the inorganic material CuSCN as the hole transpor layer,PSCs with FTO/c-TiO₂/m-TiO₂/CH₃NH₃PbI₃/CuSCN/Au structure were prepared,and the influence of the CuSCN hole transport layer on PSCs performance with different preparation methods was found.When spin coating at 3000rpm and annealing at room temperature,the perovskite solar cells are the best performance and the efficiency reached 13.8%.Moreover,too fast spin coating speed and high annealing temperature lead to reduce PSCs effficiency when preparing the CuSCN film.The device still has a photoelectric conversion efficiency of 10.8%when it is placed in an atmospheric enviroment with a temperature of25°C and a humidity of 30 RH%for two months,and the decay rate is less than 30%.Compared with the perovskite solar cell without a hole-transporting layer,solar cells efficiency and stability have great improvement,and lower costs and simpler processes are required.With the fabrication process further be improved,perovskite solar cells with CuSCN as a hole transport layer will enter people’s daily life just around the corner.（3）A CuSCN diethyl ether solution was used to replace the pure diethyl ether as antisolvent to prepare perovskite solar cells with FTO/c-TiO₂/m-TiO₂/CH₃NH₃PbI₃/CuSCN/Au structure.It was found that the efficiency and stability of the solar cells were optimized and the photoelectric conversion efficiency reached 14.9%,and PSCs still retained 82%of the original efficiency after kept at an environment of 25°C and 30%humidity for two months.The reason for the increase in efficiency is that a mesoporous CuSCN layer is well formed and combined with upper perovskite layer,and the mesoscopic structure enhances CuSCN’s hole extraction ability.Although there is still a gap in efficiency with perovskite solar cells with the traditional spiro-MeOTAD+Li-TFSI+TBP hole transport layer,the lower cost and better stability have revealed the dawn of perovskite solar cell in practical use.