Study On The Preparation And Performance Of Perovskite Solar Cells Based On Ionized Organic Interface Materials

Organic-inorganic hybrid perovskite solar cells have attracted considerable attention due to their excellent photoelectric performance,low preparation costs and solution processing.At present,the certificated power conversion efficiency(PCE)has reached 25.2%,which is close to the PCE of commercialized silicon-based solar cells.It is expected to replace silicon-based solar cells as the third-generation solar cells in the future.Furthermore,the inverted perovskite solar cells exhibit many advantages compared with conventional counterpart,such as negligible hysteresis and low temperature processing.However,how to simultaneously realize high PCE and stability is still a bottleneck issue due to the enormous interface layer defects.Based on that,this thesis systematically studied the effects of interface modification materials between perovskite and electron transport layer(ETL)on defects,interface energy level structure,PCE and stability.The specific research is as follows:1.We used an iodide ionized benzimidazole salt DMBI-Ph as the interface modification layer between perovskite and ETL.The resulted device PCE is increased to 20.45% accompanying with significantly improved stability.Because the ammonium iodide salt DMBI-Ph can passivate the defects in perovskite,reduce non-radiative recombination,enhance carrier transport.Moreover,the hydrophobic alkyl and aryl groups on DMBI-Ph and the defect passivation effect of DMBI-Ph were demonstrated to effectively maintain device performance when storing in a relative humidity 50%-60%.2.Based on the excellent properties of ionized materials,we further designed and synthesized the iodine ionized organic amine salt fullerene derivative PCBB-3N-3I with high dipole moment as the interface modification layer between perovskite and ETL.And we compared it with non-ionized PCBB-3N.Among them,the PCE of the device modified by iodine-ionized PCBB-3N-3I has been greatly improved,reaching 21.10%.We also revealed that the iodine ion at the end of molecule is very important,which can not only passivate the perovskite defects,but also provide a driving force to enhance the PCBB-3N-3I molecular ordering on top of perovskite film,and forms the interface dipole layer.The interface energy level was reconfigured,showing a well band alignment in the device,which was demonstrated by in-situ scanning Kelvin probe microscopy.Morevoer,the carrier transport and collection capabilities are also enhanced,thus the device performance was overall improved.