Nondestructive Three-Dimensional Observation of the Electrolyte in a Dye-Sensitised Solar Cell Combined with the Local Photocurrent Dynamics

The three-dimensional (3D) visualisation of the photovoltaic active layer in a dye-sensitised solar cell (DSSC) was newly achieved by employing an optical interference measurement system. The technique was used to measure with high precision the active layer thickness of a complete cell to evaluate the diffusion resistance of the electrode layer made of titania and the electrolyte layer containing tetracyanoborate ionic liquid. Additionally, the visualised image was compared with the local photovoltaic characteristics in a region with diameter 100 µm studied using an AC impedance technique as well as by transient photocurrent and photovoltage decay measurements to elucidate the charge transport properties of the ionic-liquid-based electrolyte.