Perovskite Solar Cells Preparation And Its State Monitoring System Study

Solar photovoltaic power generation occupies an important position in the field of new energy,and the key is solar cells.Perovskite solar cells(PSCs)have the advantages of easy material availability,low cost and low temperature preparation,and have attracted the attention of many researchers.At present,although the photoelectric conversion efficiency(PCE)of PSCs is comparable to that of silicon-based solar cells,there are still some problems such as stability and durability,which seriously restrict their practical application in the photovoltaic field.Electrochemical AC impedance spectroscopy(EIS)is an important tool to analyze the electrical process of PSCs,which can effectively diagnose the working state of PSCs by online monitoring the EIS of PSCs.Based on this,this paper prepared PSCs,designed the AC impedance spectrum detection system and carried out state monitoring research,which provided a reference for in-depth exploration of the internal coupling mechanism between the electrical process of PSCs and EIS.Firstly,MAPb I3 thin films were prepared by a two-step spinning coating method,and the prepared films were compact and reproducible.In the process of preparing the thin film,the effect of adding different contents of dimethyl sulfoxide(DMSO)solution to the precursor solution on the quality of the thin film growth and the photoelectric performance of the device was studied.For dimethylformamide(DMF): DMSO ratio of four different concentration gradients,through the material characterization and photoelectric performance test,determined the optimal ratio of DMF: DMSO,so that the film has the best growth quality and crystallinity,and the photoelectric performance index also greatly improved,PCE reached 9.087 %.Secondly,the principle of EIS was explored and its equivalent circuit was analyzed.Based on the characteristics of PSCs,the online detection system of AC impedance spectrum was designed,and the hardware circuit to realize the online monitoring of impedance spectrum was designed,including the AC signal generation circuit of sweep frequency(0.01 Hz ～100 k Hz),voltage and current acquisition circuit,digital-to-analog conversion circuit,data communication circuit and power management circuit,etc.Thirdly,the system software for online monitoring of PSCs was researched and developed,and the overall structure of the system software was determined.Mainly completed the frequency conversion AC signal generation function,voltage and current signal acquisition function,human-computer interaction function and network communication function,and focus on the design and implementation of voltage and current data to EIS data and then to the equivalent circuit model parameters of the processing algorithm.The processing method of EIS data was proposed,including the K-K transformation algorithm of EIS data inspection and correction and the nonlinear least square method of EIS data curve fitting.Finally,the whole system hardware and software are debugged and tested to meet the design of performance indicators and functional requirements.Four common equivalent circuit models of PSCs were used for curve fitting to EIS data respectively,and the PSCs equivalent circuit model was determined according to the fitting results.The equivalent circuit model parameters of PSCs under different light intensities and before and after decomposition were analyzed.The test results show that the online monitoring system can effectively diagnose the status of PSCs.