Preparation And Study Of Three-Dimensional Perovskite Solar Cells And Resistive Random Access Memory

MHPs have aroused great interest in the scientific and industrial circles due to their good photoelectric properties,such as high optical absorption coefficient,adjustable band gap,long diffusion length,and high carrier mobility.In addition,the MHPs also has the advantages of low cost,easy preparation,large area and so on.Therefore,MHPs is widely used in Solar cells,Photodiode,Field-effect transistor,Resistive random access memory and LEDs field.Perovskite solar cells have developed rapidly in the last decade,with their highest efficiencies already exceeding 25%.The preparation of high efficiency solar cells requires continuous optimization of process parameters and corresponding theoretical support.How to prepare high-performance perovskite solar cell and how to analyze the influence of various parameters on the performance of perovskites have become problems that need to be solved urgently.Therefore,this paper attempts to optimize the performance of perovskite solar cells using a combination of SCAPS simulation and experiment.In addition,the rapid development of Big Data and Internet of Things has stimulated the exploration of next-generation data storage devices.Perovskite-based RRAM has unique resistive advantages due to its inherent ion migration and ferroelectric effect.Therefore,this paper also investigates the effect of device structure on the resistive mechanism of perovskite based resistive memory.The specific research work is as follows.（1）Numerical analysis of perovskite solar cells was carried out using SCAPS simulation software to investigate the effects of absorbing layer thickness,defect density and defect energy level location,light intensity and electrode selection on performance.Simulation results show that device performance is significantly affected by absorber thickness and absorber layer defects,their optimum values were obtained to be 500 nm and 1×10¹⁴ cm^-3 or less.Moreover,deep energy level defects have a significant impact on the device performance compared to shallow.In addition,the devices exhibit recombination mechanism transitions and significant space charge limiting effects at high light intensities.The high series resistance of perovskite causes a decrease in FF and PCE at high light intensities.Finally,the results show that electrode metal work functions of less than 4.5 e V lead to higher performance devices.（2）By dynamically dropping 300μL of chlorobenzene solution,photovoltaic devices with almost no hysteresis and high photovoltaic conversion efficiency were obtained.Further,the addition of chlorobenzene as an antisolvent to the perovskite precursor solution increased the open circuit voltage by approximately 150 m V compared to the dropping device,but the short circuit current density and hysteresis were the shortcomings of the performance.In addition,a comparative study of the effect of precursor concentration on device performance showed that an increase in concentration enhanced light absorption and thus short-circuit current.Finally,the analysis focused on the effect of spin coating speed on the performance of the film as well as the device,and the results showed that at a spin-coating speed of 4000 rpm,the films are grown with fast nucleation without the solution curing too quickly,which will result in sharp grain boundaries and more pinholes,thus achieving a uniform and flat film with a low concentration of defects.And Three-dimensional MAPb I₃ perovskite solar cells with high power conversion efficiency and long-term stability was produced by an optimal process.（3）Two common hole-only device structures were investigated using SCLC method The results show that the mobility of the device without the PTAA layer is two orders of magnitude higher than that of the device with the PTAA layer.While fitting the J-V curves to multiple forward and reverse scans of the device with the PTAA layer,a mobility close to the former was obtained.By analysing the J-V curves and the energy level arrangement of the two devices,the reason may be that the space charge effect is enhanced by the space electric field formed by anions and cations from the perovskite.At the same time,the PTAA layer-free device has a smaller electron barrier,the mobility is thus a superposition of holes and electrons,and the I^-ions from the perovskite also migrate easily to the Ag electrode interface to bond with Ag⁺to form Ag I_x thus attenuating the enhanced space effect produced by the anions.（4）By comparing and analysing the multiple J-V curves of devices containing PTAA layers and devices without PTAA layers,it was found that the two show different resistance mechanisms.The former is mainly unipolar in behaviour,manifesting itself as TCM.The latter is mainly bipolar in behaviour,is characterised by ECM.Finally,based on the formation and breakage characteristics of the conductive filaments in devices with and without PTAA layers,devices with PTAA layers are expected to be prepared as high-performance unipolar resistive memories due to their high switching ratio and low operating voltage,while devices without PTAA layers are expected to be prepared as bipolar resistive memories.Finally,the effect of current limiting on the resistance performance of the PTAA-free layer is investigated.The results show that a"relaxed"current limiting prevents the conductive filaments from breaking completely,resulting in a low switching ratio,but when the current limiting is made"strict",the device shows a high switching ratio and a long retention time.