Great news! After several rounds of review, which included a change of the title, our study on the effect of slow carrier relaxation on the open-circuit voltage of organic solar cells (see previous entry) has now finally been published in the Journal of Physical Chemistry Letters.

In the article we argue that the open-circuit voltage (Voc) of disordered organic solar cells is higher than what is expected according to equilibrium thermodynamics. The reason is that photogenerated charge carriers are not fully thermalized in their density of states when they are extracted – and that even at Voc, where is by definition no net current flow, there is a significant exchange of charge carriers with the contacts (that act as thermic reservoirs).

Schematic charge carrier kinetics in an organic solar cell at Voc with the (nonthermalized) photocurrent and the (thermalized) injected currents.

T. Upreti, S. Wilken, H. Zhang, M. Kemerink, Slow Relaxation of Photogenerated Charge Carriers Boosts Open-Circuit Voltage of Organic Solar Cells, J. Phys. Chem. Lett. 12, 9874–9881 (2021)