About

Jean-Luc Brédas is a Regents Professor in the Department of Chemistry and Biochemistry at the University of Arizona. He holds a Ph.D. from the University of Namur, Belgium, obtained in 1979, and a B.Sc. from the same university in 1976. His specialties include Energy Science, Materials and Polymer Chemistry, Theory, Modeling, and Simulation. His research focuses on harnessing solar energy through organic and hybrid photovoltaic cells, addressing fundamental issues such as optical absorption, exciton formation, dissociation, charge separation, charge carrier mobility, and charge collection at electrodes. He is particularly interested in donor-acceptor polymers with low band gaps that are used in bulk-heterojunction solar cells due to their wider photon absorption window. Brédas's work aims to improve the photovoltaic response of organic solar cells by tackling these core challenges, contributing to advancements in sustainable energy technologies.

Research topics

• Materials science
• Chemistry
• Nanotechnology
• Optoelectronics
• Photochemistry
• Chemical physics
• Organic chemistry
• Physics
• Atomic physics
• Condensed matter physics
• Optics
• Physical chemistry
• Chemical engineering
• Composite material
• Electrical engineering
• Thermodynamics
• Computational chemistry
• Inorganic chemistry
• Quantum mechanics
• Molecular physics

Selected publications

• Cationic Diradicals Derived from Non-Aufbau Radicals toward Magnetoluminescence and Qubit Applications

  Journal of the American Chemical Society · 2026-05-15

  articleCorresponding

  Control over the spin and electronic structures of radicals and diradicals is essential for advancing magnetically responsive optoelectronics and quantum information technologies. Here, we elucidate an electronic structural distinction between cations derived from Aufbau- and non-Aufbau-type radicals through quantum chemical calculations. It shows that the oxidation of Aufbau-type radicals yields closed-shell singlet cations, whereas non-Aufbau-type radicals generate cationic diradicals with nearly degenerate singlet and triplet ground states (S0 and T0). Guided by molecular-orbital energetics, we establish a design principle for creating such cationic diradicals via oxidation of radicals consisting of strongly electron-donating donors and electron-withdrawing radical acceptors. We introduce the BM parameter to quantify the magnetic field required for S0–T0 resonance (magnetoluminescence suitability) and the η parameter to assess spin selectivity for qubit applications. These descriptors provide valuable guidance for future high-throughput screening of materials for magnetoluminescence and qubit applications.

  PublisherDOI

• Emergence of <i>g</i> -Wave Altermagnetism in Three-Dimensional Metal–Organic Frameworks

  Journal of the American Chemical Society · 2026-04-09

  articleSenior authorCorresponding

  Altermagnets integrate key characteristics of both antiferromagnets and ferromagnets, exhibiting a vanishing net magnetic moment while breaking time-reversal symmetry and displaying momentum-dependent spin splitting in the absence of an external field. Recognized as one of the top ten Science breakthroughs of 2024, altermagnetism has drawn increasing attention, particularly in inorganic systems. In this work, using density functional theory calculations, we identify a g-wave altermagnetic state in thermally stable three-dimensional (3D) metal–organic frameworks (MOFs) based on Co(pymo)2 and its halogen-substituted derivatives, thereby extending the scope of altermagnetism to organic-containing 3D frameworks. A range of magnetic configurations was systematically evaluated for these systems, with the altermagnetic state being consistently found as the most energetically favorable. This feature is consistent with the antiferromagnetic coupling experimentally observed between Co ions connected via ligand bridges. The momentum-dependent spin splitting in the electronic structure emerges independently of spin–orbit coupling and is not significantly enhanced through the inclusion of heavy halogen elements. Additional canted spin configurations were also explored, which confirmed the robustness of the spin splitting against fluctuations. These results not only establish a momentous presence of g-wave altermagnetism in these 3D MOFs but also highlight the potential of molecular framework design for realizing symmetry-driven spin phenomena in a class of 3D materials beyond conventional inorganic systems.

  PublisherDOI

• The Aromatic-to-Quinonoid Transformation in π-Conjugated Polymer Chains Is Not Necessarily Related to a Topological Phase Transition

  Chemistry of Materials · 2025-08-12

  articleSenior authorCorresponding

  A topological aromatic-to-quinonoid (AQ) phase transition has recently been reported in several one-dimensional π-conjugated polymers that display low bandgaps. An intriguing question then arises: Does the AQ transformation universally indicate a topological phase transition in such systems, specifically in those with wide bandgaps? To address this issue, poly(para-phenylene) (PPP) is considered here as a representative model system. Using first-principles calculations and tight-binding models, its intra- and inter-ring electronic interactions, topological invariant characteristics, bandgap evolution during the AQ transformation, and emergence of topological boundary states are systematically evaluated. Our results demonstrate that PPP exhibits intraring interactions that are stronger than inter-ring interactions in both its aromatic and quinonoid configurations. Also, the topological invariant remains unchanged between the two configurations, and no bandgap closure and reopening are observed during the AQ transformation. Additionally, the conditions governing the emergence of topological end modes in finite chains are identical for both configurations, indicating their topological equivalence. Overall, these findings firmly establish that in PPP, the aromatic and quinonoid configurations belong to the same topological class. What this means is that the AQ transformation in π-conjugated polymers does not universally correspond to a topological phase transition, which points out the importance of a comprehensive approach in evaluating the topological properties of low-dimensional organic materials.

  PublisherDOI

• The Role of Chalcogen Substitution and Helical Frameworks in Designing Efficient Chiral Multi‐Resonant TADF Emitters

  Advanced Optical Materials · 2025-03-07 · 7 citations

  articleOpen accessCorresponding

  Abstract Multi‐resonance thermally activated delayed fluorescence (MR‐TADF) emitters that display efficient reverse intersystem crossing (RISC) rates and circularly polarized luminescence (CPL) are of great interest for next‐generation organic light‐emitting diode (OLED) applications, owing to their narrowband emission, high efficiency, and remarkable color purity. Here, the photophysical and chiroptical properties of three series of molecules derived from boron/nitrogen‐embedded MR cores by systematically introducing chalcogen atoms (O, S, Se) and/or incorporating ortho‐fused benzo or naphtho groups are investigated. Highly correlated quantum‐chemical calculations reveal that steric repulsions resulting from the ortho‐fused positions induce molecular distortions and twist the molecular backbone into helical structures, which enhances the chiral properties; the incorporation of heavier chalcogens increases spin–orbit coupling (SOC), leading to enhanced RISC rates. These findings demonstrate that several of the molecules that are considered exhibit high radiative decay rates (≈10 8 s − ¹), substantial RISC rates (≈10 4 –10 8 s − ¹), and values of the dissymmetry factor g of the order of 10 −3 , which makes them potential candidates for CPL applications. Overall, this study highlights the complex interplay among chalcogen substitution, structural modifications, and electronic structure in governing the photophysical and chiroptical properties of MR‐TADF emitters, and offers valuable insight for the rational design of next‐generation CPL‐enabled OLEDs.

  PublisherOA PDFDOI

• Non-Covalent Interactions and Helical Packing in Thiophene-Phenylene Copolymers: Tuning Solid-State Ordering and Charge Transport for Organic Field-Effect Transistors

  Chemistry of Materials · 2025-05-23 · 5 citations

  articleOpen access

  In this study, we introduce two thiophene-phenylene-thiophene (TPT) polymers designed to leverage noncovalent intramolecular interactions to regulate main-chain conformation and enhance solid-state ordering. By incorporating unsubstituted thiophene (T) or bithiophene (2T) units, we reveal striking divergence in the thermal, morphological, and optoelectronic properties of the resulting films, facilitated by these noncovalent interactions. Using a combination of computational and experimental approaches, we show that annealing yields remarkably different polymer conformations and, consequently, charge transport properties. TPT-T undergoes a significant structural transformation, adopting a more planar backbone conformation and a highly crystalline, edge-on molecular orientation. In contrast, the introduction of a single additional thiophene unit in TPT-2T leads to a more isotropic molecular orientation with a slight preference for face-on alignment, resulting in a heterogeneous film structure that hinders charge transport despite achieving tighter molecular packing. Remarkably, despite being composed of achiral components, TPT-2T develops chirality upon annealing, indicating the formation of a helical conformation. Organic field-effect transistor measurements reveal that the well-ordered alignment in annealed TPT-T films results in higher charge carrier mobility and a narrower distribution of mobility values than in TPT-2T. These findings provide critical insights into the structure-property relationships of conjugated polymers, offering guidance for optimizing molecular design and processing strategies for high-performance organic electronic materials.

  PublisherDOI

• Atomic‐Scale Mechanistic Insights into the Ring‐Opening Polymerization of Elemental Sulfur

  Angewandte Chemie International Edition · 2025-09-07 · 1 citations

  articleCorresponding

  A detailed understanding of the composition and polymerization mechanism of elemental sulfur remains a decades long unresolved question for modern chemistry. However, the dynamic nature of molten sulfur significantly complicates its accurate characterization. To overcome this challenge, we performed the first comprehensive molecular dynamics (MD) simulations using a ReaxFF reactive force field specifically parameterized to capture the complex ring-opening polymerization dynamics of elemental sulfur. Rigorous development of the force field parameters, trained against extensive quantum mechanical datasets, was key to enabling these large-scale (>10 000 atoms) reactive MD simulations at polymerization-relevant temperatures. This study provides the first detailed atomic-level description of liquid sulfur, elucidating temperature-dependent molecular composition and offering unprecedented insights into sulfur polymerization mechanisms. These are the first simulations to reveal the formation of remarkably large macrocyclic sulfur rings at the onset of polymerization-a discovery that challenges longstanding mechanistic misconceptions, thus reshaping our understanding of sulfur polymerization. Our findings highlight the power of molecular dynamics in exploring complex polymerization processes, with broad impact in dynamic covalent chemistry and covalent adaptable polymers.

  PublisherDOI

• Optical Properties of Macrocyclic Chiral Molecules: The Limitations of Ring Size Increase

  The Journal of Physical Chemistry Letters · 2025-04-04 · 6 citations

  articleCorresponding

  Chiral macrocyclic molecules are extensively investigated as potential candidates to develop organic emitters exhibiting circularly polarized luminescence (CPL) with large dissymmetry factors (g). Here, based on time-dependent density functional theory calculations, we investigate the relationship between macrocycle size and chiral properties. Our results underline that the rotatory strength (R) of the transition to the first excited state (S0 → S1) increases linearly with the macrocycle loop area. While this evolution could promote high g values in the case of very large rings, it is found that the increase in system size can lead to energetic quasi-degeneracy of several low-lying transitions. In large macrocycles, among those transitions, it is the slightly higher-energy transitions possessing large oscillator strengths but small g values that come to dominate over the S0 → S1 transition. Also, the corresponding decrease in energy spacing among these lowest excited states can trigger a broken symmetry of the S1-state geometry via a pseudo Jahn–Teller effect. Overall, our results highlight that in large macrocycles the CPL can gain in intensity but this occurs at the expense of the g value. Thus, it is critical that the interaction of the S0 → S1 transition with higher-energy states be carefully considered when designing large-size CPL emitters.

  PublisherDOI

• Hierarchical incremental learning deciphers multi-component materials

  ChemRxiv · 2025-03-21

  preprintOpen access

  Identifying meaningful patterns of atomic and molecular arrangements from molecular simulations is crucial for revealing microscopic mechanisms in materials. Unraveling these patterns is challenging for the multi-component systems frequently encountered in advanced materials, energy and environmental applications. This limits the understanding of the microscopic mechanisms that ultimately govern the performance of devices based on these systems. Here, we propose a hierarchical incremental learning research protocol named HiDiscover to systematically expedite the mechanistic exploration in multi-component materials. As illustrations, we study Li-ion transport and gas adsorption in nanoporous framework materials, as well as molecular packing in organic active layers for photovoltaics. The HiDiscover protocol enables the detailed differentiation and facile extraction of ionic and molecular arrangements, and reveals quantitative microscopic features that are difficult to discern through conventional molecular simulations, thereby informing materials design. Our approach is seen to improve the reliability of mechanistic descriptions for three different processes in three different classes of materials. More broadly, this report highlights the potential of incremental learning to provide atomistic insight into complex materials and processes.

  PublisherOA PDFDOI

• Cyclo‐Octasulfur Crystals as Light‐Controlled Molecular Muscles

  Angewandte Chemie · 2025-06-24

  articleOpen access

  Abstract Here, we describe the synthesis and photo‐responsive properties of 2D cyclo‐octasulfur microcrystals (α‐ S8 MCs), produced using a quick, simple, cost‐effective, and environmentally friendly hydrothermal method. Controlled 385‐nm irradiation of these crystals induces an immediate, reversible, and sustained bending effect. The time required for the crystals to return to their initial shape is significantly reduced when exposed to 475‐nm light, completing the entire excitation‐relaxation cycle in less than 2 s. Moreover, this process can be repeated up to 50 times as long as the crystals remain in water. The dependence of recovery time on light wavelength is rationalized qualitatively via highly correlated quantum‐chemical calculations of the absorption spectra of S8 chains. The underlying mechanism involves a combination of ring‐to‐chain and chain‐to‐ring transformations: the breaking of α‐ S8 rings by 385‐nm radiation induces bending in the α‐ S8 MCs, while the excitation of the chains with 475‐nm light facilitates an accelerated recovery process, allowing the S8 molecules to swiftly regain their ring shape. Thus, our study demonstrates that α‐ S8 MCs represent intelligent actuators as light‐controlled molecular muscles with the simplest inorganic composition reported to date.

  PublisherDOI

• Luminescent Radicals Based on the Tris(trichlorophenyl)methyl acceptor: How to Choose the Donor Component

  ACS Materials Letters · 2025-03-27 · 7 citations

  articleCorresponding

  The donor–acceptor (D-A•) radicals containing the tris(2,4,6-trichlorophenyl)methyl (TTM•) acceptor have recently received much attention in view of their efficient luminescence. Since TTM• is structurally alternant, based on the orbital-pairing features described for alternant hydrocarbons, it was proposed that the D-A• molecule could exhibit emissive properties only when the donor component is nonalternant. This hypothesis seemed to be validated by the synthesis of the alternant TTM•-tetracene system, which was measured to be nonemissive. While some experimental findings have deviated from the alternant rule, the underlying mechanism remains unclear. Here, we investigate quantum mechanically the excited-state properties of a series of TTM•-acene radicals. The results of our high-level calculations highlight that alternant hydrocarbons should not be disregarded in the design of radical emitters, rationalize the absence of emission in TTM•-tetracene, and lead to a set of simple rules to obtain highly luminescent TTM-D emitters.

  PublisherDOI

Frequent coauthors

• Seth R. Marder

  501 shared

• Veaceslav Coropceanu

  University of Arizona

  478 shared

• Jérôme Cornil

  University of Mons

  341 shared

• Stephen Barlow

  University of Colorado Boulder

  303 shared

• Chad Risko

  259 shared

• Egbert Zojer

  Graz University of Technology

  239 shared

• Roberto Lazzaroni

  University of Mons

  237 shared

• David Beljonne

  178 shared

Education

• Agregation de L'Enseignesement Superieur ("Habilitation)

  Universite Catholique de Louvain Ecole de Chimie

  1986

• Postdoctoral Fellowship, Chemistry

  Massachusetts Institute of Technology

  1981

• Ph.D., Theoretical Chemistry

  Universite de Namur Département de Chimie

  1979

• B.Sc., Chemistry

  Universite de Namur Département de Chimie

  1976