Preparation And Research Of High-efficiency Carbon-based Perovskite Solar Cell Devices

The CsPbI₃ perovskite has gained extensive attention in recent years,and the phase stability issue is one of the research focuses.At present,the most effective strategy is to add DMAI to the CsPbI₃ perovskite,and the PCE of the CsPbI₃ battery device prepared by it has exceeded 19%.However,regarding the mechanism of action of DMAI,the conclusions of various research institutions are different.Someone proves that DMAI will completely volatilize as a volatile additive.Some have observed through experiments that DMA can form a hybrid perovskite structure with CsPbI₃ in the form of A-site ions.In this paper,the carbon-based CsPbI₃ perovskite material is used as the research object,and the CsPbI₃ perovskite stable at room temperature is prepared by adding DMAI as an auxiliary additive.And on this basis,by controlling the proportion of PbI₂ in the precursor solution,a more efficient perovskite solar cell is obtained,Finally,by adding hole-transporting material P3HT to the perovskite layer obtained in the previous research,a more excellent carbon-based perovskite solar cell was assembled.The main contents are as follows:（1）By adding DMAI to the CsPbI₃ perovskite precursor solution,the stability of CsPbI₃ perovskite at room temperature was achieved,and it was verified that the HI addition system actually played a stabilizing role for DMAI.The effects of DMAI purity,addition amount,annealing time,annealing temperature and thickness of perovskite layer were explored.In the end,the short-circuit current density can reach 16 mA/cm²,the open-circuit voltage is about 0.7V,and the fill factor reaches 60%of the carbon-based solar cell.Its PCE reaches 6±3%,and its maximum can reach 9%.The device thus prepared has good repeatability and stability.（2）On the basis of the first part,by changing the content of PbI₂ in the precursor solution,a highly dense large-grained CsPbI₃ perovskite thin film was obtained,The carbon-based perovskite solar cell assembled in this way has a Jsc of 17 m A/cm² and a Voc of about 1V.And the FF of the device reached 70%,and the PCE exceeded 12%.Compared with the CsPbI₃ device,the Voc can be improved by an average of 0.3V,the average FF can be increased by 9%,the average PCE can be increased by about 5%,and it has high repeatability and excellent stability.Assuming that the source of excellent performance is the Cs_1-xDMA_xPb I₃ hybrid structure,and verify this conjecture through different characterization tests,At the same time,it was found that during the volatilization process of DMAI,a trace of PbI₂ phase is generated,which assists in passivating the perovskite crystals,thereby significantly improving the performance of the perovskite device.（3）On the basis of the first two parts,by adding the hole transport material P3HT on the perovskite,the carrier transport in the solar cell device is effectively improved,.After adding P3HT,the device FF reached an unprecedented 75%,and the PCE increased to 13.6%.Based on this,this chapter explores the contact performance and charge transport performance of P3HT and perovskite layer in detail.Finally,in order to achieve the most efficient battery device,the P3HT hole transport layer is spin-coated while increasing the precursor concentration.The final device PCE reached14.17%,and has good repeatability.