The U.S. Department of Energy has selected Robert Jacobberger, an assistant professor of electrical and computer engineering at the University of Wisconsin-Madison, to receive a 2025 DOE Office of Science Early Career Research Program award.
The award provides $875,000 in support over five years for promising early-stage investigators at U.S. academic institutions, DOE national laboratories, and Office of Science user facilities. The goal of the award is to allow researchers to pursue new ideas and harness the resources of the DOE—including access to supercomputers, powerful x-ray light sources, and specialized nanoscience tools—to increase the potential for breakthrough new discoveries.
Jacobberger will investigate techniques for harnessing “singlet fission” to efficiently produce electricity and chemical fuels and to enable photocatalysis, near-infrared light emission and quantum-coherent states important in quantum information science.
When particles of light, known as photons, strike semiconducting materials, electron-hole pairs, known as excitons, are generated. These excitons determine how light is absorbed, emitted, and converted into electricity and underly the operation of a variety of electronic devices ranging from solar cells to photodetectors to light-emitting diodes. In conventional semiconductors, one absorbed photon produces one exciton.
Recently, however, researchers have discovered a select subset of carbon-based organic semiconductors that undergo a process called singlet fission that can do even more. When photons strike these unique materials, singlet fission transforms each photon into two excitons instead of one. If the excitons can be transferred to another semiconductor, like silicon, singlet fission can significantly boost the efficiency with which energy is generated from light. In effect, in singlet fission, each photon produces two electrons, doubling the energy harvested in the form of electricity.
Thin films of these singlet fission molecules, which are essentially dyes and pigments, can be painted or coated onto conventional electronics based on semiconductors like silicon. Therefore, singlet fission films can be manufactured over large areas and at low cost.
One problem is that organic singlet fission films and conventional inorganic electronics, like those based on silicon, don’t interface in a way that allows energy produced via singlet fission to be harnessed. Jacobberger and his students, however, plan to develop new approaches to interfacing singlet fission films with silicon that will overcome this longstanding challenge, bringing the technology a major step closer to commercial development.
“Our hope is that this technology will significantly increase the efficiency with which light is converted into useable energy and will enable the development of next-gen electronic and quantum technologies, such as high-efficiency solar cells and scalable quantum computers with new functionalities,” says Jacobberger.
The team will use cutting-edge materials discovery and state-of-the-art spectroscopy to figure out how to produce singlet fission films on silicon substrates with new types of structures that are ideal for light harvesting. They will engineer the organic-inorganic interface with atomic-scale precision to learn how to efficiently transfer excitons between the two materials. Overall, their work will establish fundamental molecular design rules for efficiently harvesting energy using singlet fission.
The researchers’ work could have a variety of applications. For instance, it’s estimated that integrating singlet fission films could improve the efficiency of current silicon solar cells by 35% without introducing significant manufacturing costs or complexity. This is important because the performance of silicon solar cells—which account for roughly 95% of the solar cell market—is approaching the theoretical limit that can be achieved without taking advantage of singlet fission.
These films could also be used to generate qubits—the fundamental units used in quantum computing—on demand and at precisely controlled locations using light, which is not currently possible using conventional materials. In fact, these new qubits could offer a whole new level of performance and functionality in quantum computers, increasing information density and allowing the processing to happen at room temperature instead of the near absolute zero temperatures many quantum qubits now require.