A methodology for improving laser beam induced current images of dye sensitized solar cells

Using the laser beam induced current (LBIC) technique for the study of solar cells and photovoltaic devices, it is possible to obtain images representing the different degrees of quantum efficiency observed on the surface of these elements. Dye sensitized solar cells (DSSCs) or photoelectrochemical solar cells, in contrast to those based on solid-solid interfaces, show a slow response to irradiance variations--up to tens of seconds. This is basically due to both viscous matter transport processes and load transfer. This response is inappreciable when the device is functioning continuously but when a LBIC scan is performed, in which the laser moves quickly from one point to another, the slow response produces a memory effect and the signal generated at one given point depends on the conversion efficiency coefficients of the previously excited positions, resulting in diffuse images and a lack of sharpness. This work presents a methodology to correct high-resolution LBIC mappings of DSSCs using an algorithm based on the kinetics of the discharge process of the irradiated zone. The validity of the proposed method has been evaluated by carrying out experiments where the algorithm has been applied to LBIC mappings.