New solar cell model challenges 80-year-old equation

Physicists from Swansea University and Åbo Akademi University have developed an analytical model that enhances the understanding and efficiency of thin-film photovoltaic (PV) devices and how such flexible, low-cost solar cells can achieve higher efficiency, challenging the 80-year-old understanding of how solar cells work.

This new model challenges the Shockley diode equation, which has long explained how electrical current flows through solar cells, reports SciTechDaily.

Thin-film solar cells, made from flexible and affordable materials, have often struggled with efficiency. The existing analytical models could not fully explain why these cells did not perform as well as traditional silicon-based cells.

The new research sheds light on this mystery, showing that achieving higher efficiency in these cells involves a careful balance between collecting electricity and minimising a process called recombination.

What is recombination?

Recombination happens when electrical charges cancel each other out, reducing the amount of electricity that can be collected.

In simple terms, it is like having water leaking out of a pipe — we lose some of what we are trying to save. The new model helps scientists understand how to minimise this loss, especially in next-gen thin-film solar cells, which are more prone to recombination due to their structure.

Capturing the missing piece

The key to the new model's success lies in addressing "injected carriers," or charges that enter the solar cell from its electrical contacts.

Dr Oskar Sandberg, a lead researcher from Åbo Akademi University, explained that their findings offer new insights into what drives or limits the efficiency of low-cost, flexible solar cells.

Associate Professor Ardalan Armin of Swansea University added that by introducing a new version of the diode equation, the team has captured a more complete picture of how these solar cells operate.

Impact on future solar cell development

This new understanding is expected to have a significant impact on the development of next-generation solar cells. The model offers a new way to design more efficient thin-film solar cells and improve existing ones.

It also helps in training machines that are used to optimise these devices, marking a big step forward in solar energy technology.

This advancement could lead to more affordable and efficient solar panels, making solar energy a more viable option for widespread use in the future.