Improved organic solar cells through quantum simulation

A new collaboration between HQS Quantum Simulations GmbH and RMIT University’s Jared Cole aims to use quantum computers to improve the efficiency of organic solar cells.

Karlsruhe, 26.10.22. The resonant transfer model is a mathematical model that is difficult to solve, but can provide important information about of the movement and lifetime of excitation energy in molecules. HQS has developed software to solve the resonant transfer model using quantum computers, while Prof. Cole - a Chief Investigator with the Australian Research Council Centre of Excellence in Exciton Science - has extensive experience with modeling electron transfer in molecular and semiconductor devices. Together, HQS and the RMIT team are aiming to bridge the gap from material development for improved organic solar cells to the quantum mechanical solution of the resonant transfer model.

Photovoltaic (solar) cells made from organic molecules can be flexible and light weight, offering an exciting potential impact on a sector that has made rapid progress amid lower manufacturing costs in recent decades. “One of the most exciting aspects of solar cells based on organic semiconductors is that they can be flexible and tunable for a range of applications. Solar power generation on buildings, on cars, on street signs. These are just not possible with existing photovoltaic cells.” said Prof. Cole. “But organic solar cells would be a game changer.”

To create more efficient solar cells, it is vital to understand the fundamental effects that allow the conversion of light into energy. In an organic photovoltaic cell, a photon excites the electron structure of a molecule. The energy stored in this excited electron structure then moves through a chain of molecules until it can convert into electrical current. In organic solar cells, the movement of excitation energy can be engineered by choosing particular organic molecules. The overall efficiency of this process is determined by the electronic structure and by the effect of the vibrational modes of the molecules.

To understand the effect of the motion of electronic excitations, resonant transfer model can be used. It describes the probability for an excitation to hop from one molecule to the next and the coupling of each excitation on a molecule to the local vibrational modes. But this type of simulation is very difficult for current computers, which is where quantum computers come in.
“Using the current generation of noisy intermediate scale quantum computers is extremely difficult. Solving problems that can be described by the resonant transfer model, seems like one of the most promising areas,” HQS CEO Michael Marthaler said. “However, what is critical is that these model systems are connected to important properties that we can use to improve actual material development cycles.”

In addition to generating clean energy using cheaper and more flexible materials, the software developed by HQS can be used for simulating quantum mechanical processes in a range of industries.