Photovoltaic Properties and Mechanism Analysis of a Dye/Al2O3 Alternating Assembly Structure by Electrochemical Impedance Spectroscopy

N3 dye and Al2O3 were used to form an alternating assembly structure. The current density-voltage (J-V) characterization showed that this structure improved the performance of dye-sensitized solar cells (DSCs). Electrochemical impedance spectroscopy (EIS) was used to study the internal resistance of this alternating assembly structured DSCs. The results showed that the resistance at the sensitized TiO2/electrolyte interface decreased as the number of (dye/Al2O3) units increased, and the device's conversion efficiency improved significantly. Based on the EIS results, a series of equivalent circuit models were well established to investigate the dye/Al2O3 alternating assembly structure theoretically.