Plastic solar cells: where the current begins: Ultrafast exciton-to-charge conversion in organic photovoltaics

Imagine a world with free energy everywhere. You don’t need to take a phone charger with you – your backpack generates energy. You don’t need to electrify your house – the energy is produced by the walls and windows. Even though this sounds like science fiction, this world is much closer to reality than you might think: our Sun provides more than enough energy to cover mankind’s needs.
Already now, people successfully use solar energy by converting it to electricity with silicon solar cells. However, these devices are quite heavy and bulky which essentially limits their application area. Alternatively, solar cells can be made of special plastics – and those solar cells can be foldable, semi-transparent, light-weight, shape-customizable, wearable – so that their potential application areas seem unlimited. However, to date the efficiencies of such solar cells are still twice as low as the efficiencies of their silicon analogues.
To promote the efficiency of plastic solar cells, we should understand all the photophysics behind light-to-electricity conversion. Many crucial processes occur faster than one billionth of a second but still have a great influence on overall device performance. In this Thesis, we use laser spectroscopy to reveal main processes which contribute to the photocurrent of the solar cells at such incredibly short timescales, along with possible losses which decrease the efficiency of the overall device. Armed with this understanding, we propose the pathways to maximize the efficiency of light-to-electricity conversion which we believe will make the Dream World a bit closer to us!