Morphology dependent short circuit current in bulk heterojunction solar cell

Polymer based bulk heterostructure (BH) solar cell offers a relatively inexpensive option for the future solar cell technology, provided its efficiency increases beyond the current limit of 4-6%. In this paper we propose a novel theoretical/computational process/device simulation model of organic solar cell and thereby quantitatively and explicitly relate (possibly for the first time) the process conditions to the solar cell performance. We find that the maximum limit of short-circuit current (J_SC) follows a simple power law with the anneal time (J_SC ∝ t_a^-n) for t_a ≥ t_a,opt, and we determine the optimum anneal time (t_a,opt) considering exciton dissociation (t_hj) and percolating pathway formation for charge carriers (t_prc). Our results anticipate experimentally observed trends and have obvious and significant implications for the determination of performance limit and the optimization of the BH solar cell.