Expertise

Topics:  Energy, Organic Light Emitting Devices, Luminescent Materials, Solar Fuels, Organic Photovoltaics, Circular Polarized Luminescence

Industries: Research, Education/Learning, Chemicals

Stefan Bernhard started his chemistry career as a laboratory technician with Chocolat Tobler, which was followed by a degree in chemical engineering from the Ingenieurschule Burgdorf. Further endeavors were rewarded with a diploma and a Ph.D. in chemistry. These studies were complemented by a laser spectroscopy project at Los Angeles National Laboratory and time in the Abruña Group at Cornell University focused on electrochemistry. His first faculty appointment at Princeton University explored luminescent metal complexes for optoelectronic and solar conversion applications. In 2014, he was promoted to the rank of Professor at Carnegie Mellon University where he founded the Bernhard Research Group. The Bernhard Group's research includes luminescent materials, solar fuels, organic photovoltaics, organic light emitting devices, and circular polarized luminescence.

The Bernhard lab is interested in interconverting radiative and electrochemical energy through the use of transition metal complexes with electronically tunable architectures. That is, they study both the absorption of light to generate electrochemical potential (organic photovoltaics and artificial photosynthesis) as well as the emanation of light using electrical current (organic light emitting devices). The Bernhard lab is also deeply involved in the exploration of chiral luminophores (and chiral ensembles) that emit circularly polarized light. Their work in this area has produced cutting-edge tools for both the characterization and prediction of polarized luminescence. In each of the above areas, it is our aspiration to precisely understand and administer the interactions that control ensemble properties by establishing clear structure-activity relationships.

Media Experience

Reports Summarize Science Study Results from Carnegie Mellon University (Accelerated Turn-On and High Performance in Light-Emitting Electrochemical Cells Using Highly Charged Iridium Complexes)  — Chemicals & Chemistry Daily
2026 MAR 11-- By a News Reporter-Staff News Editor at Chemicals& Chemistry Daily Daily-- A new study on Science is now available. According to news reporting originating from Pittsburgh, Pennsylvania, by NewsRx correspondents, research stated,“ Light-emitting electrochemical cells based on ionic transition metal complexes are attractive as efficient. 2026 MAR 11 (NewsRx) -- By a News Reporter-Staff News Editor at Chemicals & Chemistry Daily Daily -- A new study on Science is now available. According to news reporting originating from Pittsburgh, Pennsylvania, by NewsRx correspondents, research stated, “Light-emitting electrochemical cells based on ionic transition metal complexes are attractive as efficient electroluminescent devices due to their simple, single-layer solution-processed architecture. One challenge for their operation is improving the response times of iridium iTMC LECs, which are highly efficient but slow in their pristine form due to the low ionic conductivity of the singly cationic iridium complexes.” Our news editors obtained a quote from the research from Carnegie Mellon University, “To address this challenge, we synthesized a series of triply cationic iridium complexes that produced solid-state films with higher conductivity and wider-bandgap emission than conventional [Ir] complexes. These [Ir] complexes featured alkylated (ethyl (EPP) or propyl (PPP)) 2.3’-bipyridine ligands serving as the cyclometalating units, CN, and an ancillary 2,2’-bipyridine ligand, N N, which is either unmodified (bpy) or substituted with dimethoxy (meoxy) moieties. These complexes exhibited sky-blue photoluminescence and electroluminescence. LECs from simple pristine films of these [Ir] complexes yielded 100-1000-fold faster electroluminescence than a pristine [Ir] control, but also suffered from correlating 100-1000-fold lower luminance half-lives and lower luminance maxima. Blending the singly and triply cationic complexes enabled enhanced performance by leveraging the benefits of each. In particular, an exemplary 10% EPP bpy [Ir] device turns on in 4 s while retaining the luminance and stability characteristics of the [Ir] control complex.” According to the news editors, the research concluded: “This illustrates a strategy for enhancing the DC response of iTMC LECs without foreign dopants, and further refinement of these ionically conductive [Ir] emitters could yield even greater gains.” This research has been peer-reviewed.

Designer catalyst with enzyme-like cavity splits water almost as fast as plants  — Chemistry World
‘It is very hard to oxidise water,’ explains Stefan Bernhard, a renewable energy chemist at Carnegie Mellon University, US. ‘The process requires the transfer of four electrons and so needs a lot of electrochemical or photochemical energy. One of the particularly tricky aspects is ensuring that the catalyst isn’t just “burnt up” by these demanding conditions.’

Bernhard Designs Materials for Energy, Electronics of the Future  — Carnegie Mellon University Mellon College of Science
Stefan Bernhard, Scott Institute Energy fellow and Carnegie Mellon University chemistry professor, conducts research on converting sunlight into fuel, which has been the driving force of his work since his undergraduate career.