Photoinduced chemical potential gradient

The fundamentals and the various factors affecting the physics of bulk heterojunction solar cells have already been studied and modeled in several original research papers [1-3, 28, 30, 57-59]. However, diffusion processes driven by photoinduced chemical potential gradients appear to play a very important role in D-A solar cells, a fact that, at least from a molecular point of view, must be taken into account when designing intrinsic D-A ambipolar materials. As discussed below, this impUes that a too intimate, overly homogenous D-A distribution is counterproductive for the operation of bulk heterojunction solar cells. 

Therefore, no photoinduced chemical-potential energy gradient Vght) (represented by arrows) is established. For the cell functioning, an electric field is required, in D-A cells electrons are photogenerated In one phase while holes are generated in the other via interfacial exciton dissociation Vgto drives... 

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