Abstract
We have investigated effectiveness of electroluminescence (EL) measurement as an estimation method for organic-inorganic perovskite solar cells. EL images of CH3NH3PbI3-based solar cells under a constant voltage of 1 V were obtained. We evaluated a relationship between the current density-voltage (J-V) characteristics of the solar cells and these EL images. It was found that EL intensity from our solar cell has a distribution with respect to the position. Because EL intensity indicates correlation with the power conversion efficiency (PCE) of the solar cell, the distribution of EL intensity results from inhomogeneity of properties of material in the cell. These findings mean that an EL measurement is effective for estimation of perovskite solar cells. Moreover, we confirmed effects of applying a voltage during the EL measurement for the solar cell characteristics. By measuring EL for 15 min, decrease of EL intensity with time and decrease of PCE were observed. During the EL measurement with a constant voltage, the applied current density increased continuously. These findings suggest that the resistance of perovskite layer in the solar cell decreases by applying a voltage.
