An analytical model for bulk heterojunction organic solar cells using a new empirical expression of space dependent photocarrier generation

We present an analytical model for bulk heterojunction organic solar cells on the basis of an empirical expression of space dependent carrier generation rate. By developing the empirical formula of the carrier generation rate and successfully incorporating that in the transport equations, we bring in the spatial distribution effect of generation rate into the current-voltage (J-V) characteristic of this solar cell. The proposed empirical expression helps us to derive a J-V curve expression, especially for the cases where carrier generation rate cannot be described by any physics-based closed form analytical expression and/or where the spatial distribution of the generation rate profile is to be extracted and used directly from published/available data. We justify the model by comparing with numerical simulations and published data.