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Stefan Bernhard - Carnegie Mellon University. Pittsburgh, PA, US

Stefan Bernhard

Professor | Carnegie Mellon University


Stefan Bernhard is interested in interconverting radiative and electrochemical energy through the use of transition metal complexes.


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.

Areas of Expertise (6)


Organic Light Emitting Devices

Luminescent Materials

Solar Fuels

Organic Photovoltaics

Circular Polarized Luminescence

Media Appearances (2)

Designer catalyst with enzyme-like cavity splits water almost as fast as plants

Chemistry World  online


‘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.’

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Bernhard Designs Materials for Energy, Electronics of the Future

Carnegie Mellon University Mellon College of Science  online


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.

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Industry Expertise (3)




Accomplishments (3)

Graduate Mentoring Award (professional)

2006 Princeton University

National Science Foundation CAREER Award (professional)


Dreyfus New Faculty Award (professional)


Education (3)

Université de Fribourg, Switzerland: Ph.D., Chemistry 1996

School of Engineering, Burgdorf, Switzerland: Diploma, Chemical Engineering 1988

University of Fribourg, Switzerland: Diploma, Chemistry 1993

Articles (5)

Synthesis and Structure of an Ion-Exchanged SrTiO3 Photocatalyst with Improved Reactivity for Hydrogen Evolution

Advanced Materials Interfaces

2023 BaTiO3 heated in an excess of SrCl2 at 1150 °C converts to SrTiO3 through an ion exchange reaction. The SrTiO3 synthesized by ion exchange produces hydrogen from pH 7 water at a rate more than twice that of conventional SrTiO3 treated identically. The apparent quantum yield for hydrogen production in pure water of the ion exchanged SrTiO3 is 11.4% under 380 nm illumination.

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Photogeneration of Hydrogen from Glycerol and Other Oxygenates Using Molecular Photocatalysts and In Situ Produced Nanoparticulate Cocatalysts

ACS Sustainable Chemistry & Engineering

2022 This work describes a photocatalytic process using the oxidation of biorenewable alcohols as the electron/proton source for the photogeneration of hydrogen. The approach utilizes a molecular iridium photosensitizer (PS), an in situ synthesized Pd-containing colloid catalyst, and a redox shuttle (RS). By virtue of the high-throughput photoreactor utilized in this work, rapid reaction parameter screening for five donor species (oxalic acid, benzyl alcohol, isopropanol, ethanol, and glycerol) was undertaken, resulting in the identification of reaction conditions conducive to the formation of hydrogen from all species.

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Identifying limitations in screening high-throughput photocatalytic bimetallic nanoparticles with machine-learned hydrogen adsorptions

Applied Catalysis B: Environmental

2023 The Sabatier principle is of fundamental importance to computational catalyst discovery, saving researchers time and expense by predicting catalytic activity in silico at scale. However, as polycrystalline and nanoscale catalysts increasingly dominate industry, computational screening tools must be adapted to these uses. In this work, we demonstrate the effectiveness of computational adsorption energy screening in nanocatalysis by comparing a multisite adsorption energy prediction workflow against a large experimental dataset of hydrogen evolution activities over bimetallic nanoparticles.

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Reinterpreting the Fate of Iridium(III) Photocatalysts─Screening a Combinatorial Library to Explore Light-Driven Side-Reactions

Journal of the American Chemical Society

2022 Photoredox catalysts are primarily selected based on ground and excited state properties, but their activity is also intrinsically tied to the nature of their reduced (or oxidized) intermediates. Catalyst reactivity often necessitates an inherent instability, thus these intermediates represent a mechanistic turning point that affords either product formation or side-reactions. In this work, we explore the scope of a previously demonstrated side-reaction that partially saturates one pyridine ring of the ancillary ligand in heteroleptic iridium(III) complexes.

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Ligand Enhanced Activity of In Situ Formed Nanoparticles for Photocatalytic Hydrogen Evolution


2021 Hundreds of metal combinations and concentrations can be and have already been tested to determine promising hydrogen evolution catalysts. However, variables such as the formation of nanoparticles and the stability of those nanoparticles complicate interpretation of successful metal stoichiometries. Here, we report the addition of nanoparticle ligands is necessary to sustain hydrogen evolution in nanoparticle catalysts.

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