Efficient light-emitting diodes from organic radicals with doublet emission
John M. Hudson, Timothy J. H. Hele and Emrys W. Evans
Journal of Applied Physics 129 180901 (2021), DOI 10.1063/5.0047636
J. Appl. Phys.PDF (accepted manuscript)
In this article Emrys Evans, John Hudson and I review recent progress in organic radical light-emitting diodes, including the breakthroughs in our Nature and Nature Materials papers, and identify future challenges.
Understanding the luminescent nature of organic radicals for efficient doublet emitters and pure-red light-emitting diodes
Alim Abdurahman, Timothy J. H. Hele, Qinying Gu, Jiangbin Zhang, Qiming Peng, Ming Zhang, Richard H. Friend, Feng Li & Emrys W. Evans
Nature Materials 19, 1224-1229 (2020), https://doi.org/10.1038/s41563-020-0705-9 Nature MaterialsCambridge Repository
This article explains why the vast majority of organic radicals do not emit, and gives a simple design rule for creating those that do. My theory also explains how to blue-shift emission from the infra red (in the Nature article below) to the visible using aza-substitution. Using this we make the most efficient known radical OLEDs with emission in the visible, and this article paves the way for the design of many other radical OLEDs in the future.
Environmental Control of Triplet Emission in Donor-Bridge-Acceptor Organometallics
J. Feng, L. Yang, A. S. Romanov, J. Ratanapreechachai, S.T. E. Jones, A. M. Reponen, M. Linnolahti, T.J.H. Hele, A. Köhler, H. Bässler, M. Bochmann and D. Credgington
Advanced Functional Materials (2020), 30, 1908715 Adv. Funct. Mater.arxiv preprintPDF
This article shows (somewhat surprisingly) that the colour of light-emitting diodes (LEDs) made from carbene-metal-amides can be changed substantially without actually changing the carbene-metal-amide itself, but by changing the host material around it.
Switching between coherent and incoherent singlet fission via solvent-induced symmetry-breaking
Antonios M Alvertis, Steven Lukman, Timothy J. H. Hele, Eric G Fuemmeler, Jiaqi Feng, Jishan Wu, Neil C. Greenham, Alex W Chin and Andrew J. Musser The Journal of the American Chemical Society (2019) 141 17558-17570 DOI: 10.1021/jacs.9b05561 JACS
Anticipating acene-based chromophore spectra with molecular orbital arguments
T. J. H. Hele, E. G. Fuemmeler, S. N. Sanders, E. Kumarasamy, M. Y. Sfeir, L. M. Campos and N. Ananth The Journal of Physical Chemistry A, 123 (2019) 2527-2536 Arxiv preprintJPCA
This article solves problem in the spectra (colour) of molecules known as acene dimers which puzzled scientists since 1948. It also develops a design rule for highly absorbent acene dimers which can be used in photovoltaic applications due to their ability to undergo singlet fission.
Efficient radical-based light-emitting diodes with doublet emission
X. Ai, E. W. Evans, S. Dong, A. J. Gillett, H. Guo, Y. Chen, T. J. H. Hele, R. H. Friend & F. Li Nature563, (2018) 536–540 Nature
The discovery of the world's most efficient deep-red organic light-emitting diode (OLED), with 27% external quantum efficiency. My theory explained the unusual orbital structure which was relevant to the intense, and efficient, emission.
Vibrationally Assisted Intersystem Crossing in Benchmark Thermally Activated Delayed Fluorescence Molecules
E. W. Evans, Y. Olivier, Y. Puttisong, W. K. Myers, T. J. H. Hele, S. M. Menke, T. H. Thomas, D. Credgington, D. Beljonne, R. H. Friend and N. C. Greenham J. Phys. Chem. Lett.9 (2018) 4053-4058 PDFJPCL
Nonadiabatic semiclassical dynamics in the mixed quantum-classical initial
M. S. Church, T. J. H. Hele, G. S. Ezra and N. Ananth J. Chem. Phys.,148 (2018), 102326 JCParxivPDF
This article presents the MInt algorithm, the only known symplectic (energy-conserving) algorithm for computing non-adiabatic dynamics with the commonly-used Meyer-Miller Hamiltonian
A Mapping Variable Ring Polymer Molecular Dynamics Study of Condensed Phase Proton-Coupled Electron Transfer
S. Pierre, J. R. Duke, T. J. H. Hele and N. Ananth J. Chem. Phys.,147 (2017), 234103, DOI: 10.1063/1.4986517 JCPPDF
Tuning Singlet Fission in Pi-Bridge-Pi Chromophores
E. Kumarasamy, S. N. Sanders, M. J. Y. Tayebjee, A. Asadpoordarvish, T. J. H. Hele, E. G. Fuemmeler, A. B. Pun, L. M. Yablon, J. Z. Low, D. W. Paley, J. C. Dean, B. Choi, G. D. Scholes, M. L. Steigerwald, N. Ananth, D. R. McCamey, M. Y. Sfeir, and L. M. Campos J. Am. Chem. Soc.,139 (2017), 12488–12494, DOI: 10.1021/jacs.7b05204 JACS
Thermal quantum time-correlation functions from classical-like dynamics
T. J. H. Hele Molecular Physics13 (2017) 1435-1462, DOI 10.1080/00268976.2017.1303548
Invited New View article Mol. Phys.arxivPDF
Published alongside an Author Profile
Competing quantum effects in the free energy profiles and diffusion rates of hydrogen and deuterium molecules through clathrate hydrates
J. R. Cendagorta, A. Powers, T. J. H. Hele, O. Marsalek, Z. Bačić and M. E. Tuckerman Phys. Chem. Chem. Phys.18 (2016) 32169-32177 PCCParxivPDF
Fundamentals: general discussion
S. C. Althorpe, V. Beniwal, P. G. Bolhuis, J. Brandao, D. C. Clary, J. Ellis, W. Fang, D. R. Glowacki, T. J. H. Hele, H. Jonsson, J. Kastner, N. Makri, D. E. Manolopoulos, L. K. McKemmish, G. Menzl, T. F. Miller III, W. H. Miller, E. Pollak, S. Rampino, J. O. Richardson, M. Richter, P. R. Chowdhury, D. Shalashilin, J. Tennyson and R. Welsch Faraday Discussions195 (2016) 139-169. Faraday Discuss.
Deriving the exact nonadiabatic quantum propagator in the mapping variable representation
T. J. H. Hele and N. Ananth Faraday Discussions195 (2016) 269-289, DOI: 10.1039/C6FD00106H
Selected for presentation at the Reaction Rate Theory Faraday discussion held in Cambridge, UK, September 2016. Faraday Discuss.arxivPDF
Non-adiabatic reactions: general discussion
S. C. Althorpe, N. Ananth, G. Angulo, R. D. Astumian, V. Beniwal, J. Blumberger, P. G. Bolhuis, B. Ensing, D. R. Glowacki, S. Habershon, S. Hammes-Schiffer, T. J. H. Hele, N. Makri, D. E. Manolopoulos, L. K. McKemmish, T. F. Miller III, W. H. Miller, A. J. Mulholland, T. Nekipelova, E. Pollak, J. O. Richardson, M. Richter, P. R. Chowdhury, D. Shalashilin and R. Szabla Faraday Discussions195 (2016) 311-344. Faraday Discuss.
Application to large systems: general discussion
S. Althorpe, G. Angulo, R. D. Astumian, V. Beniwal, P. G. Bolhuis, J. Brandao, J. Ellis, W. Fang, D. R. Glowacki, S. Hammes-Schiffer, T. J. H. Hele, H. Jonsson, T. Lelievre, N. Makri, D. Manolopoulos, A. M. Mebel, G. Menzl, T. F. Miller III, M. Parrinello, P. M. Piaggi, E. Pollak, P. Roy, Chowdhury, E. Sanz, D. Shalashilin, E. Skulason, R. Spezia and S. Taraphder Faraday Discussions195 (2016) 671-698. Faraday Discuss.
An alternative derivation of ring-polymer molecular dynamics transition-state theory
T. J. H. Hele and S. C. Althorpe J. Chem. Phys.144 (2016) 174107 JCParxivPDF This article featured as an Editor's Pick on the JCP homepage, and as a 2016 Editors' Choice article
On the relation between thermostatted ring polymer molecular dynamics and exact quantum dynamics
T. J. H. Hele Mol. Phys.1149 (2016) 1461-1471, DOI: 10.1080/00268976.2015.1136003 Mol. Phys. (published version)
arxiv (submitted version)
PDF (accepted version)
This article won the Longuet-Higgins prize from Molecular Physics,who published an accompanying Winner Profile.
Should Thermostatted Ring Polymer Molecular Dynamics be used to calculate
thermal reaction rates?
T. J. H. Hele and Y. V. Suleimanov J. Chem. Phys.143 (2015) 074107. JCParxivPDF
Communication: Relation of centroid
molecular dynamics and ring-polymer molecular dynamics to exact quantum dynamics
T. J. H. Hele, M. J. Willatt, A. Muolo and S. C. Althorpe J. Chem. Phys142 (2015) 191101. JCParxivPDF This article was showcased by J. Chem. Phys. as one of the most read papers of 2015
Boltzmann-conserving classical dynamics in quantum time-correlation functions: ‘Matsubara dynamics’
T. J. H. Hele, M. J. Willatt, A. Muolo and S. C. Althorpe J. Chem. Phys142 (2015) 134103. JCParxivPDF
Quantum Transition-State Theory
T. J. H. Hele
Dissertation submitted for the degree of Doctor of Philosophy, University of Cambridge arxivPDF
On the uniqueness of t → 0 + quantum transition-state theory
T. J. H. Hele and S. C. Althorpe J. Chem. Phys139 (2013) 084116. JCParxivPDF
Derivation of a true (t → 0 + ) quantum transition-state theory. II.
Recovery of the exact quantum rate in the absence of recrossing
S. C. Althorpe and T. J. H. Hele J. Chem. Phys139 (2013) 084115. JCParxivPDF
Derivation of a true (t → 0 + ) quantum transition-state theory. I.
Uniqueness and equivalence to ring-polymer molecular dynamics transition-state theory.
T. J. H. Hele and S. C. Althorpe J. Chem. Phys138 (2013) 084108. JCParxivPDF
An Electronically Non-Adiabatic Generalization of Ring Polymer Molecular Dynamics
T. J. H. Hele
Dissertation submitted for the degree of Master of Chemistry, University of Oxford arxivPDF