The effect of built-in field on the interface exciton recombination and dissociation in NN type organic solarcells

The free carrier generation processes at the interface formed by fullerene (C60) and perfluorinated hexadecafluorophthalo-cyaninatozinc (F16ZnPc) are investigated in detail. It is found that the exciton dissociation and recombination across the interface can happen at the same C60/F16ZnPc interface. And it is demonstrated in this study that both processes can be the dominant process for photocurrent generation by simply changing the direction of the built-in electric field. The observed superlinear dependence between photocurrent and light intensity confirms that the photocurrent indeed is the second order to the incident light intensity. Thus the photocurrent can be generated from the exciton recombination across the C60/F16ZnPc interface.

► Exciton recombination for photocurrent generation has been confirmed. ► The superlinear dependence of photocurrent to light intensity was firstly observed. ► Photocurrent was adjusted by changing the direction of built-in electricfield.