Quantitative Nanoscale Mapping of Photovoltaic Properties in Hybrid Organic/Inorganic Solar Cells*

Conductive atomic force microscopy (C-AFM) has been widely used to map local charge transport in functional materials and photovoltaic active layers. Recently, we have developed and employed C-AFM-based point-by-point current-voltage (PPIV) mapping to quantitatively investigate electrical properties such as local charge carrier mobility and to visualize local spatial variations in photovoltaic parameters such as open-circuit voltage, power conversion efficiency, and charge photogeneration rate. In this talk, we will present two examples in which PPIV mapping is employed to elucidate the influence of local morphology on photovoltaic properties in hybrid organic-inorganic systems. In the case of P3HT: ZnO nanorod active layers, photovoltaic properties are strongly dependent on the local P3HT hole transport layer thickness. Charge generation rate and charge collection probability maps reveal that photocurrent is mainly limited by charge collection. For inverted perovskite solar cells, PPIV photovoltaic characteristic maps exhibit an increased open-circuit voltage at crystal grain boundaries, indicating an important role played by these features.