Study On A Novel Two-Dimensional Organic-Inorganic Hybrid Perovskite And Its Photovoltaic Performance

ABX₃ type three-dimensional?3D?organic-inorganic metal halide perovskites have attracted extensive attention in the field of optoelectronics,especially in perovskite,due to their excellent photoelectric properties such as high extinction coefficient,low exciton binding energy,long carrier lifetime,and high defect tolerance.However,the intrinsic instability of 3D perovskites against moisture,light,and heat remains a major obstacle hindering the commercialization of perovskite solar cells?PSCs?.In recent years,two-dimensional?2D?perovskite with large cationic spacer has rapidly become a research hotspot due to its excellent stability.It is worth noting that in 2D perovskite,large cations increase the binding energy of excitons inside the perovskite and inhibit the transfer of charge,thus reducing the PCE of the PSCs.In this paper,aiming at the key problem that high stability and high PCE cannot be taken into account for the current 2D PSCs,the design of a new type of spacer cation and the photoelectric characteristics of 2D perovskite were carried out,and a new type of 2D PSCs device with high stability and high PCE was realized.The specific research content is as follows:In this paper,a novel asymmetric alkyl bisamine 3-?dimethylamino?-1-propylamine?DMAPA?is used as a spacer cation to prepare Dion-Jacobson?D-J?type2D perovskite thin film and device,the structural formula is?DMAPA?MA_n-1Pb_nI_3n+1?n is the number of inorganic layers?.First,in order to study the crystal structure of DMAPA-based 2D perovskite,?DMAPA?PbI₄?n=1?single crystal was prepared and analyzed.The results showed that the interlayer distance between adjacent inorganic layers became significantly smaller,which will be beneficial to the reduction of quantum well effect,the reduction of exciton binding energy,and the promotion of charge transport.The PCE of D-J type pure 2D PSCs based on?DMAPA?PbI₄?n=1?is 3.85%,which is the highest PCE of D-J type pure 2D PSCs.Second,the crystallization process of DMAPA-based 2D perovskite was studied,the influence of preheating and annealing temperatures on the crystallization was revealed,MACl and DMSO were determined as synergistic additives.Third,this paper systematically studied the crystallization kinetics of the perovskite layer with high n value?n=3,4,5?.The results show that the formation and decomposition of the intermediate phase determine the crystalline quality of the perovskite layer.Among them,?DMAPA?MA₃Pb₄I₁₃?n=4?perovskite exhibits optimal crystallinity and vertical substrate growth orientation.Its layered phase distribution and low trap density make the PSCs achieve a maximum PCE of 15.16%.Finally,the results of the device stability study confirmed that DMAPA-based 2D PSCs have excellent thermal,wet,and light stability.It is able to survive from 85?,1000 hours of high-temperature testing?maintaining 90%efficiency?in an unpackaged state,and 300 hours of continuous standard light test?maintaining 80%efficiency?,which is significantly better than traditional 3D perovskite devices.It can be seen that the D-J type DMAPA-based 2D perovskite allows PSCs to obtain high PCE and high stability simultaneously providing an effective reference for future industrial application of PSCs.