Dear Abdul Azeez

The open-circuit voltage (VOC) in organic solar cells (OSCs) is still poorly understood. According to a widely held belief, VOCs are primarily determined by the energy level offset between donor and acceptor materials. VOC has recently been discovered to be blend composition dependent in ternary blend OSCs.

For further illustration: https://www.nature.com/articles/srep11363

Kind Regards

Qamar Ul Islam

Dear Abdul Azeez ,

The opencircuit voltage is basically depends on the difference between the lumolevel ELa and the EHd homolevel of the donor material.

The open circuit voltage is about 0.5 to 0.6 of the this energy difference because of the recombination of of mobile carriers at the intrefaces between the donors and acceptors.

So if there is ternary then the open circuit voltage will be dominated by the lower difference ELa- EHd,

For more information please follow the paper:Conference Paper Generic Analytical Models for Organic and Perovskite Solar Cells

In spite of its importance, there is little flow of researchers to this paper.

It discusses the how to make the open circuit voltage as high as possible and what are the factors affecting the opencircuit voltage.

Best wishes

Thank you Professor Abdelhalim abdelnaby Zekry for the suggestion.

I too find its very important and there are many variables (amount of each components in the blend, miscibility) involved.

Dear Abdul Azeez ,

Yes sure, you are right. What do you have? one donor and two acceptors or two donors and one acceptor.

In fact as the photocurrent both can be effective in collecting the photogenerated charge carriers. But they can differ in their energy lost during the collection process if the two donor materials have different have different homo levels EHd.

My opinion is that the two materials act as if two solar cells working in parallel.

The current will be summed but the open circuit voltage will be the smaller one.

This is just a basic idea.

Best wishes