Slow Relaxation of Photogenerated Charge Carriers Boosts Open-Circuit Voltage of Organic Solar Cells.

ABSTRACT: Among the parameters determining the efficiency of an organic solar cell, the open-circuit voltage (V_OC) is the one with most room for improvement. Existing models for the description of V_OC assume that photogenerated charge carriers are thermalized. Here, we demonstrate that quasi-equilibrium concepts cannot fully describe V_OC of disordered organic devices. For two representative donor:acceptor blends, it is shown that V_OC is actually 0.1-0.2 V higher than it would be if the system was in thermodynamic equilibrium. Extensive numerical modeling reveals that the excess energy is mainly due to incomplete relaxation in the disorder-broadened density of states. These findings indicate that organic solar cells work as noneq

SUBMITTER: Upreti T 

PROVIDER: S-EPMC8521526 | biostudies-literature | 2021 Oct

REPOSITORIES: biostudies-literature