Study On Photovoltaic Performance Measurement Calibration And Device Modeling Of Mesoscopic Perovskite Solar Cells

In recent years,perovskite solar cells have developed rapidly,and their highest power conversion efficiency has reached 25.2%.As an emerging solar cell technology,accurately measuring the device performance is quite important.Previous research has found that the test area of perovskite solar cells has a great impact on the test results of device performance.We study the factors that influence this phenomenon and provide a method for calibrating the test results.The specific research contents are as follows:（1）Study the influence of test area on photovoltaic performance of devices.A printable mesoscopic perovskite solar cell based on TiO₂/ZrO₂/Carbon triple-mesoscopic layer structure was selected as the research object.For devices with an active area of 0.64 cm²,we applied masks with test area of 0.03～0.503 cm² to measure the J-V curves.The results show that when the test area gradually decreases,the measured short-circuit current density(J_SC)increases significantly and exceeds the theoretical values,while the open-circuit voltage(V_OC)decreases slightly.The overestimated J_SC test values are due to the diffuse light generated at the edge of the mask aperture.When the aperture area(A_ap)of the mask is reduced,the proportion of the ring-shaped diffuse light illuminated area to illumination area A_d/(A_ap+A_d)increases and results in an increase in J_SC values.The reason for the low V_OC test value is that the unilluminated area in the active area generates dark current.When the test area/active area ratio（X）decreases,the measured V_OC correspondingly decreases.（2）Calibration and analysis of photovoltaic performance measurements.The relationship between the test area and the J_SC test value is studied by establishing the diffuse model.Assuming that the width W_c and W_s are only affected by the uniformity of the light source and testing environment,and thus the width W_c and W_s are constant.The J_SC test value can be calculated as a quadratic correlation with reciprocal of the aperture of the mask.Correspondingly,a calibrating method for test value of the J_SC is proposed.At the same time,the measured V_OC values and the test area/active area ratio（X）are related to the Shockley diode equation and conform exponential function relationship.Through error analysis of J_SC,V_OC,fill factor（FF）,and power conversion efficiency（PCE）under different test areas,it is obtained that when the test area is small（0.018 and 0.031 cm2）,the J_SC,PCE is greatly overestimated.It is overestimated by 9.6～12.9%;when the test area is increased to 0.049～0.283 cm²,the test error is reduced to 0.06～3.5%.However,further increasing the test area cannot further reduce the PCE test error.（3）Application of electrochemical impedance spectroscopy.For the unique structure of hole-conductor-free mesoscopic perovskite solar cells,by referring the basic model of the equivalent circuit of traditional perovskite solar cells,CPE₂//R₂//L₂ composite element is applied for fitting the intermediate frequency region where the inductive loop may emerge.An improved equivalent circuit model is built.We provide several possible conjectures for induction loop emerging.By analyzing the capacitance and resistance from high frequency to low frequency,hole-conductor-free mesoscopic perovskite solar cells also obtained good dielectric properties but intermediate frequency inductive loop shown that the hole-free transport material structure may lead to more complex interface recombination,which may affect the increase of the open-circuit voltage.