Comprehensive experimental design of perovskite solar cells based on interface design
[Objective]Perovskite solar cells(PSCs)have become a significant research topic in new-generation photovoltaic technology due to their unique photoelectronic properties and great application potential.Interfaces between the perovskite layer and charge transport layers are crucial regions for carrier separation and transport in PSCs.Defects and unpassivated dangling bonds at these interfaces can act as nonradiative recombination centers,which can lead to energy loss.In addition,interface defects can induce the permeation of moisture and oxygen,thereby accelerating the efficiency degradation of PSCs.Therefore,interface design is essential to improve the performance of PSCs.However,interface modification strategies with simple operation,good reproducibility,and obvious phenomena still deserve further research and development.The purpose of this study is to provide a simple and efficient method for interface modification to improve the performance of PSCs.[Methods]To realize the rational interface design for PSCs,the selection of interfacial materials is crucial.Notably,organic ammonium molecules with large sizes can not only passivate the interfacial defects but also form distinct heterostructures.Therefore,in this study,tetrabutylammonium iodide(TBAI)is used as an efficient interfacial modification material.Post-treatment of perovskite films with TBAI solution and subsequent annealing can form low-dimensional phase structures on the perovskite film surface.This strategy not only passivates the defects on the surface of the perovskite film but also effectively prevents erosion by water.[Results]Through a variety of characterization tests,this study found that TBAI can react with excess lead iodide(PbI2)on the surface of the perovskite film to form low-dimensional phase structures.The TBAI modification significantly reduces the residual PbI2 and increases the grain size of the perovskite film,leading to a reduction in grain boundaries and a decrease in defect-induced carrier nonradiative recombination losses.Moreover,the TBAI-treated perovskite film exhibits stronger light absorption in the 400-550 nm range compared to the pristine film.In addition,the photoluminescence intensity of the TBAI-treated perovskite film is significantly higher than that of the untreated film,confirming a reduction in nonradiative recombination.As a result,the efficiency of PSCs based on TBAI interface modification increased from 15.61%to 17.32%.In addition,water immersion tests also confirmed that the TBAI-modified perovskite film has better water resistance.[Conclusions]By modifying the interface of the perovskite film with TBAI,low-dimensional phase structures can be constructed on the perovskite film,thereby reducing the defect states of the perovskite film and ultimately improving the photovoltaic conversion efficiency of PSCs.In addition,the formation of the low-dimensional interface layer also enhances the tolerance to water,which is beneficial for improving device stability.These results confirm the key role of rational interface design in enhancing the performance of PSCs.This comprehensive experiment enables students to master important experimental skills,such as thin film preparation,device construction,and performance testing.At the same time,the interface engineering strategy also helps to guide students to keep up with the scientific breakthroughs in the field,stimulate their interest in learning,and cultivate their innovative consciousness and practical ability in the process of solving practical problems.
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