The Research Of The Effect Of Interface Modification On The Performance Of Perovskite Solar Cell Devices

In recent years,hybrid perovskite solar cells?PSC?have developed rapidly.The surface properties of the substrates will greatly affect the quality of the perovskite film and thus affect the device performance.At the same time,there are interfacial layers in the perovskite solar cells.The interface layers also participate in the collection and transfer of carriers.In addition to the nature of each layer,the properties of the interface layer also affect the performance of the device.This thesis mainly focuses on two methods of interface modification,doping and self-assembled monolayers,which is divided into the following three works:?1?By doping polymer PFO or F8BT into the PCBM as electron transport layer?ETL?to improve the PSC performance.PFO and F8BT are polymers commonly used in organic optoelectronic devices,and both have excellent film-forming properties.F8BT and PFO were doped into PCBM at different mass ratios of 5 wt%and 10 wt%,respectively,as electron transport layers to investigate the effects of ETL film-forming properties and charge carrier transport properties on PSC performance.The experimental results show that the addition of F8BT effectively improves the film-forming quality of PCBM,the surface roughness of ETL is also reduced,and the film uniformity is improved which is beneficial to the separation of electron-hole pairs.PCBM was best treated with 5 wt%F8BT,the PCE of the device was increased from 12.6±0.24%to 15±0.26%.?2?Improve the performance of PSC by adding a self-assembled monolayer?SAM?to the interface between the hole transport layer and the light absorbing layer.The effects as SAMs of three materials with different intermediate functional groups,bromoacetic acid,p-bromobenzoic acid,and 5-bromo-2 carboxypyridine,were studied by Ultroviolet Photoelectron Spectrometer?UPS?and other characterization methods.The experimental results show that bromoacetic acid has the best effect in suppressing defect formation,optimizing energy level matching,and improving surface morphology.The PCE of the device was increased from 14.86%of the original device to17.15%,the V_OC was increased from 1.02 V to 1.08 V,and the J_SC is 21.38 m A/cm².At the same time,the stability of the bromoacetic acid modified device also improved slightly.This work confirms the feasibility of self-assembled monolayers for improving the performance of perovskite solar cells and provides a fast method for finding suitable monolayers.?3?In order to find the optimal concentration of the bromoacetic acid solution as the monolayer to modifiy Ni O_X hole transport layer,six different concentrations,0.5 mg/m L,0.75mg/m L,1 mg/m L,1.5 mg/m L,2 mg/m L and 3 mg/m L were chosen.The surface morphology,crystallinity,and light absorption spectrum of the perovskite films prepared on Ni O_X modified with different concentrations of SAM were tested.The result shows that the bromoacetic acid solution with the concentration of 1 mg/m L improved the film best.Then,the devices based on different concentrations of bromoacetic acid were prepared and tested.Finally,the consequence was that 1mg/m L is the optimal concentration as SAM,which was consistent with the film test.