Keith Butler

Mr
Keith
Butler
Job Title
Office Phone Number
(01235) 446541
Yes
Email
keith.butler@stfc.ac.uk
No
Office Location
RAL R116,FirstFloor
Yes
Mobile Phone Number
No

​Contact

keith.butler@stfc.ac.uk

Biography

My background is in computational and data driven materials science. I have been a staff scientist/senior scientist at the Rutherford Appleton Laboratory (RAL) since 2018. During this time I have been part of the Laboratory’s Scientific Machine Learning group (SciML) where I lead projects related to developing and using Machine Learning (ML) methods for analysing and understanding measurements performed at the facilities based at RAL (in particular ISIS Neutron and Muon Source and Diamond Light Source), and also for developing and applying new ML methods for simulation and modelling of solid state materials. Previously I was research co-investigator on an EPSRC grant on multi-scale modelling of hybrid perovskite materials, and worked in the group of Prof. Aron Walsh at the University of Bath. I recieved my PhD in Computational Chemistry from UCL, working on modelling of nucleation and growth of Zeolites. My undergraduate Bachelors is in Medicinal Chemistry from Trinity College Dublin.

Research interests

I use machine learning (ML) and simulation to accelerate materials design _and_ characterisation. My ultimate vision is to work in an environment with colleagues involved in synthesis and characterisation to build integrated, ‘Smart’ laboratories with ML methods at the core. My basic science research focus is developing statistical methods for accelerated energy materials discovery - concentrating on various aspects of the discovery process; new materials design – through virtual high-throughput screening and generative models – and automated characterisation.

My research interestes centre on the application of machine learning to solve problems in materials science.

  • Surrogate models to speed up simulations and materials design
  • Explainable machine learning models to understand the resutls of data-driven models
  • Uncertainty quantification and active learning for materials science
  • Unsupervised learning and clustering to classify experimental and numerical data

Publications

2021


[1] *J. Allotey, K.T. Butler, J Thiyagalingam “Entropy-based Active Learning of Graph Neural Network
Surrogate Models for Materials Properties”, J. Chem. Phys. , vol. 155, pp. 174116, 2021.
[2] *N. Artrith, K.T. Butler, F.X. Coudert, S. Han, O. Isayev, A. Jain, A. Walsh “Best practices in machine
learning for chemistry”, Nat. Chem. , vol. 13, pp. 505–508, 2021.
[3] *S.D. Midgley, S. Hamad, K.T. Butler, R. Grau-Crespo “Bandgap engineering in the configurational
space of solid solutions via machine learning:(Mg, Zn) O case study”, J. Phys. Chem. Lett. , vol. 12,
pp. 5163–5168, 2021.
[4] *K. Li, Z.-G. Li, J. Xu, Y. Qin, W. Li, A. Stroppa, K.T. Butler, C.J. Howard, M.T. Dove, A.K.
Cheetham, X.-H. Bu “Origin of Ferroelectricity in Two Prototypical Hybrid Organic–Inorganic Perovskites”,
J. Am. Chem. Soc., vol. 144, pp. 816–823, 2022.
[5] B. Moss, Q. Wang, K. T. Butler, R. Grau-Crespo, S. Selim, A. Regoutz, T. Hisatomi, R. Godin,
D. J. Payne, A. Kafizas, K. Domen, L. Steier, J. R. Durrant “Linking in situ charge accumulation
to electronic structure in doped SrTiO 3 reveals design principles for hydrogen-evolving photocatalysts”,
Nat. Mater., pp. 1–7, 2021.
[6] *K. T. Butler, M. Duc Le, J. Thiyagalingam, T. G. Perring, “Interpretable, calibrated neural networks
for analysis and understanding of inelastic neutron scattering data”, J. Phys. Condens. Mat,,vol. 33,
pp. 194006, 2021.
[7] A. Vamvakeros, D. Matras, T.E. Ashton, A.A. Coelho, H. Dong, D. Bauer, Y. Odarchenko, S.W.T.
Price, K.T. Butler, O. Gutowski, A.-C. Dippel, M. von Zimmerman, J.A. Darr, S.D.M. Jacques, A.M.
Beale “Cycling Rate-Induced Spatially-Resolved Heterogeneities in Commercial Cylindrical Li-Ion Batteries”,
Small Methods , vol. 5, pp. 2100512, 2021.
[8] S. Burger, S. Grover, K. T. Butler, H. Boström, R. Grau-Crespo, G. Kieslich “Tilt and shift polymorphism
in molecular perovskites”, Mater. Horiz., vol. 8, pp. 2444–2450, 2021.
[9] H. Dong, K. T. Butler, D. Matras, S. W. T. Price, Y. Odarchenko, R. Khatry, A. Thompson,
V. Middelkoop, S. D. M. Jacques, A. M. Beale, A. Vamvakeros “A deep convolutional neural network
for real-time full profile analysis of big powder diffraction data”, npj Comp. Mater. Sci., vol. 7, pp. 1–9,
2021.
[10] C. N. Singh, B. A. Crafton, M. P. West, A. S. Weidenbach, K. T. Butler, A. H. MacDonald,
A. Raychowdury, E. M. Vogel, W. .A. Doolittle, L. F.J. Piper, W. C. Lee “Quantum Statistical Transport
Phenomena in Memristive Computing Architectures”, Phys. Rev. Appl. vol. 054030, pp. 054030,
2021.
[11] L. Wang, Y. Bao, S. Wang, F. Wang, C. Xie, K. T. Butler, X. Fan “Revealing the Potential Crystal
Structures of Earth-Abundant Nontoxic Photovoltaic CuBiI4”,J. Cryst. Growth Des., vol.21, pp. 2850–
2855, 2021

2020


[12] A. Vamvakeros, A. A. Coelho, D. Matras, H. Dong, Y. Odarchenko, S. W. T. Price, K. T. Butler,
O. Gutowski, A. C. Dippel, M. Zimmermann, I. Martens, J. Drnec, A. M Beale, S. D. M. Jacques,
“DLSR: a solution to the parallax artefact in X-ray diffraction computed tomography data”, J. Appl.
Cryst., vol. 53, pp. 1531-1541, 2020.
[13] *J. A. Armstrong, M. R. Ryder, K. T. Butler, “Computers in Neutron Science”, J. Phys. Comm., vol. 4,
pp. 110401, 2020.
[14] *J. A. Armstrong, A. J. O’Malley, M. R. Ryder, K. T. Butler, “Understanding dynamic properties of
materials using neutron spectroscopy and atomistic simulation”, J. Phys. Comm., vol. 4, pp. 072001,
2020.
[15] * K. Morita, D. W. Davies, K. T. Butler, A. Walsh “Modeling the dielectric constants of crystals using
machine learning”, J. Chem. Phys., vol. 153, pp. 024503, 2020.

2019


[16] * D. Bodesheim, G. Kieslich, K. T. Butler “Understanding the Balance of Entropy and Enthalpy in
Hydrogen–Halide Noncovalent Bonding”, J. Phys. Chem. Lett., vol. 3495–3500, pp 3495–3500, 2020.
[17] H. Wang and J. Jia and L. Wang, K. T. Butler, R. Song, G. Casillas,L. He, N. P. Kherani,
D. D. Perovic,L. Jing, Liqiang, G. A. Ozin, “Heterostructure Engineering of a Reverse Water Gas Shift
Photocatalyst”, Advanced Science, vol. 6, pp.1902170, 2019.
[18] D. W. Davies, K. T. Butler, and A. Walsh, “Data-driven discovery of photoactive quaternary oxides
using first-principles machine learning,” Chemistry of Materials, vol. 31, no. 18, pp. 7221–7230, 2019.
[19] C. Schneider, D. Bodesheim, M. G. Ehrenreich, V. Crocella, J. Mink, R. A. Fischer, K. T. Butler, and
G. Kieslich, “Tuning the negative thermal expansion behavior of the metal–organic framework cu3btc2
by retrofitting,” Journal of the American Chemical Society, vol. 141, no. 26, pp. 10504–10509, 2019.
[20] D. Davies, K. Butler, A. J. Jackson, J. Skelton, K. Morita, and A. Walsh, “Smact: Semiconducting
materials by analogy and chemical theory,” The Journal of Open Source Software, vol. 4, 2019.
[21] * T. W. Kasel, Z. Deng, A. M. Mroz, C. H. Hendon, K. T. Butler, and P. Canepa, “Metal-free
perovskites for non linear optical materials,” Chemical Science, vol. 10, no. 35, pp. 8187–8194, 2019.
[22] S. M. Collins, D. M. Kepaptsoglou, K. Butler, L. Longley, J. Hou, T. D. Bennett, Q. Ramasse, and
P. Midgley, “Local coordination in metal-organic frameworks probed in the vibrational and optical
regime by eels,” Microscopy and Microanalysis, vol. 25, no. S2, pp. 606–607, 2019.
[23] R. Pandey, G. Vats, J. Yun, C. R. Bowen, A. W. Ho-Baillie, J. Seidel, K. T. Butler, and S. I. Seok,
“Mutual insight on ferroelectrics and hybrid halide perovskites: a platform for future multifunctional
energy conversion,” Advanced Materials, p. 1807376, 2019.
[24] * C. N. Singh, K. T. Butler, A. H. MacDonald, L. F. Piper, and W.-C. Lee, “Dynamic disorder induced
memristance in amorphous solids,” arXiv preprint arXiv:1908.08070, 2019.
[25] * K. T. Butler, P. Vervoorts, M. G. Ehrenreich, J. Armstrong, J. M. Skelton, and G. Kieslich, “Experimental
evidence for vibrational entropy as driving parameter of flexibility in the metal–organic framework
zif-4 (zn),” Chemistry of Materials, vol. 31, no. 20, pp. 8366–8372, 2019.
[26] D. Rusu, L. D. Filip, L. Pintilie, K. T. Butler, and N. Plugaru, “Designing functional ferroelectric
interfaces from first-principles: Dipoles and band bending at oxide heterojunctions,” New Journal of
Physics, 2019.
[27] T. Hey, K. Butler, S. Jackson, and J. Thiyagalingam, “Machine learning and big scientific data,” Phil.
Trans.Royal Soc. A, vol. 378, pp. 20190054, 2019.

[28] * A. Nearchou, J. Armstrong, K. T. Butler, P. R. Raithby, and A. Sartbaeva, “Differentiating the role
of organic additives to assemble open framework aluminosilicate zeolites using ins spectroscopy,” Phys.
Chem. Chem. Phys., vol. 22, pp. 14177–14186, 2019.
[29] * K. T. Butler, G. S. Gautam, and P. Canepa, “Designing interfaces in energy materials applications
with first-principles calculations,” npj Comp. Mater., vol. 5, no. 1, p. 19, 2019.
[30] * M. J. Wahila, Z. W. Lebens-Higgins, K. T. Butler, D. Fritsch, R. E. Treharne, R. G. Palgrave, J. C.
Woicik, B. J. Morgan, A. Walsh, and L. F. Piper, “Accelerated optimization of transparent, amorphous
zinc-tin-oxide thin films for optoelectronic applications,” APL Mater., vol. 7, no. 2, p. 022509, 2019.
[31] S. K. Wallace, K. T. Butler, Y. Hinuma, and A. Walsh, “Finding a junction partner for candidate
solar cell absorbers enargite and bournonite from electronic band and lattice matching,” J. Appl. Phys.,
vol. 125, no. 5, p. 055703, 2019.

2018


[32] * K. T. Butler, D. W. Davies, H. Cartwright, O. Isayev, and A. Walsh, “Machine learning for molecular
and materials science,” Nature, vol. 559, no. 7715, p. 547, 2018.
[33] S. M. Collins, D. M. Kepaptsoglou, K. T. Butler, L. Longley, T. D. Bennett, Q. M. Ramasse, and P. A.
Midgley, “Subwavelength spatially resolved coordination chemistry of metal–organic framework glass
blends,” J. Am. Chem. Soc., vol. 140, no. 51, pp. 17862–17866, 2018.
[34] G. Kieslich, J. M. Skelton, J. Armstrong, Y. Wu, F. Wei, K. L. Svane, A. Walsh, and K. T. Butler,
“Hydrogen bonding versus entropy: Revealing the underlying thermodynamics of the hybrid organic–
inorganic perovskite [ch3nh3] pbbr3,” Chem. Mater., vol. 30, no. 24, pp. 8782–8788, 2018.
[35] K. T. Butler, “The chemical forces underlying octahedral tilting in halide perovskites,” J. Mater. Chem.
C, vol. 6, no. 44, pp. 12045–12051, 2018.
[36] D. W. Davies, K. T. Butler, J. M. Skelton, C. Xie, A. R. Oganov, and A. Walsh, “Computer-aided
design of metal chalcohalide semiconductors: from chemical composition to crystal structure,” Chem.
Sci., vol. 9, no. 4, pp. 1022–1030, 2018.
[37] D. W. Davies, K. T. Butler, O. Isayev, and A. Walsh, “Materials discovery by chemical analogy: role
of oxidation states in structure prediction,” Faraday Dissc., vol. 211, pp. 553–568, 2018.
[38] M. Makaremi, S. Grixti, K. T. Butler, G. A. Ozin, and C. V. Singh, “Band engineering of carbon nitride
monolayers by n-type, p-type, and isoelectronic doping for photocatalytic applications,” ACS Appl.
Mater. Inter., vol. 10, no. 13, pp. 11143–11151, 2018.
[39] W. Wei, W. Li, K. T. Butler, G. Feng, C. J. Howard, M. A. Carpenter, P. Lu, A. Walsh, and A. K.
Cheetham, “An unusual phase transition driven by vibrational entropy changes in a hybrid organic–
inorganic perovskite,” Angew. Chem., vol. 130, no. 29, pp. 9070–9074, 2018.
[40] J.-S. Park, Y.-K. Jung, K. T. Butler, and A. Walsh, “Quick-start guide for first-principles modelling of
semiconductor interfaces,” J. Phys.: Energy, vol. 1, no. 1, p. 016001, 2018.

2017


[41] K. L. Svane, A. C. Forse, C. P. Grey, G. Kieslich, A. K. Cheetham, A. Walsh, and K. T. Butler, “How
strong is the hydrogen bond in hybrid perovskites?,” J. Phys. Chem. Lett., vol. 8, no. 24, pp. 6154–6159,
2017.
[42] J. Jia, C. Qian, Y. Dong, Y. F. Li, H. Wang, M. Ghoussoub, K. T. Butler, A. Walsh, and G. A.
Ozin, “Heterogeneous catalytic hydrogenation of co 2 by metal oxides: defect engineering–perfecting
imperfection,” Chem. Soc. Rev., vol. 46, no. 15, pp. 4631–4644, 2017.
[43] K. T. Butler, C. H. Hendon, and A. Walsh, “Designing porous electronic thin-film devices: band offsets
and heteroepitaxy,” Faraday disc., vol. 201, pp. 207–219, 2017.
[44] Y.-K. Jung, K. T. Butler, and A. Walsh, “Halide perovskite heteroepitaxy: Bond formation and carrier
confinement at the pbs–cspbbr3 interface,” The J. Phys. Chem. C, vol. 121, no. 49, pp. 27351–27356,
2017.
[45] * K. T. Butler, S. D. Worrall, C. D. Molloy, C. H. Hendon, M. P. Attfield, R. A. W. Dryfe and A. Walsh,
“Electronic structure design for nanoporous, electrically conductive zeolitic imidazolate frameworks” J.
Mater. Chem. C, vol. 5,pp. 7726, 2017
[46] C. H. Hendon, K. T. Butler, A. M. Ganose, Y. Roman-Leshkov, D. O. Scanlon, G. A. Ozin, and A.
Walsh, “Electroactive Nanoporous Metal Oxides and Chalcogenides by Chemical Design” Chem. Mater.,
vol. 29,pp. 3663, 2017
[47] Y. Kumagai, K. T. Butler, A. Walsh, and F. Oba, “Theory of ionization potentials of nonmetallic solids”
Phys. Rev. B, vol. 95,pp. 125309, 2017
[48] N. Plugaru, G. A. Nemnes, L. Filip, I. Pintille, L. Pintille, K. T. Butler, A. Manolescu “Atomistic
simulations of methylammonium lead halide layers on PbTiO3 (001) Surfaces” J. Phys. Chem. C
vol. 121, pp. 9096, 2017
[49] H. Sepehri-Amin, H. Iwama, G. Hrkac, K. T. Butler, T. Shima, K. Hono “Pt surface segregation in
L10-FePt nano-grains” Scr. Mater. vol. 135, pp. 88, 2017
[50] J. K. Bristow, K. T. Butler, K. L. Svane, J. D. Gale and A. Walsh, “Chemical bonding at the metalorganic
framework / metal oxide interface: simulated epitaxial growth of MOF-5 on rutile TiO2” J.
Mater. Chem. A, vol. 5,pp. 6226, 2017.
[51] * K. T. Butler, C. H. Hendon, and A. Walsh, “Designing porous electronic thin-film devices: Band
offsets and heteroepitaxy,” Faraday Diss., In press, 2017.

2016


[52] A. Walsh, K. T. Butler, and C. H. Hendon, “Chemical principles for electroactive metal–organic frameworks,”
MRS Bull., vol. 41, no. 11, pp. 870–876, 2016.
[53] * K. T. Butler, B. J. Dringoli, L. Zhou, P. M. Rao, A. Walsh, and L. Titova, “Ultrafast carrier
dynamics in BiVO4 thin film photoanode material: interplay between free carriers, trapped carriers and
low-frequency lattice vibrations,” J. Mater. Chem. A vol. 4, no. 47, pp. 18516-18523, 2016.
[54] * D. W. Davies, K. T. Butler, A. J. Jackson, A. Morris, J. M. Frost, J. M. Skelton, and A. Walsh,
“Computational screening of all stoichiometric inorganic materials” Chem vol. 1 pp. 617–627, 2016
[55] C. H. Hendon, S. T. Hunt, M. Milina, K. T. Butler, A. Walsh, and Y. Roman-Leshkov, “Realistic
surface descriptions of heterometallic interfaces: The case of TiWC coated in noble metals,” J. Phys.
Chem. Lett. vol. 7, no. 22, pp. 4475-4482, 2016.
[56] * K. T. Butler, K. Svane, G. Kieslich, A. K. Cheetham, and A. Walsh, “Microscopic origin of entropydriven
polymorphism in hybrid organic-inorganic perovskite materials,” Phys. Rev. B, vol. 94, no. 18,
p. 180103, 2016.
[57] * K. T. Butler, A. Walsh, A. K. Cheetham, and G. Kieslich, “Organised chaos: entropy in hybrid
inorganic–organic systems and other materials,” Chem. Sci., vol. 7, no. 10, pp. 6316–6324, 2016.
[58] * M. J. Wahila, K. T. Butler, Z. W. Lebens-Higgins, C. H. Hendon, A. S. Nandur, R. E. Treharne, N. F.
Quackenbush, S. Sallis, K. Mason, H. Paik, et al., “Lone-pair stabilization in transparent amorphous tin
oxides: A potential route to p-type conduction pathways,” Chem. Mater. vol. 28, no. 13, pp. 4706-4713,
2016.
[59] E. Uman, M. Colonna-Dashwood, L. Colonna-Dashwood, M. Perger, C. Klatt, S. Leighton, B. Miller,
K. T. Butler, B. C. Melot, R. W. Speirs, et al., “The effect of bean origin and temperature on grinding
roasted coffee,” Sci. Rep., vol. 6, p. 24483, 2016.
[60] C. Caetano, K. T. Butler, and A. Walsh, “Analysis of electrostatic stability and ordering in quaternary
perovskite solid solutions,” Phys. Rev. B, vol. 93, no. 14, p. 144205, 2016.
[61] * K. T. Butler, J. M. Frost, J. M. Skelton, K. L. Svane, and A. Walsh, “Computational materials design
of crystalline solids,” Chem. Soc. Rev., 2016.
[62] * K. T. Butler, S. McKechnie, P. Azarhoosh, M. Van Schilfgaarde, D. O. Scanlon, and A. Walsh,
“Quasi-particle electronic band structure and alignment of the V-VI-VII semiconductors SbSI, SbSBr,
and SbSeI for solar cells,” Appl. Phys. Lett., vol. 108, no. 11, p. 112103, 2016.
[63] A. M. Ganose, M. Cuff, K. T. Butler, A. Walsh, and D. O. Scanlon, “Interplay of orbital and relativistic
effects in bismuth oxyhalides: BiOF, BiOCl, BiOBr, and BiOI,” Chem. Mater., vol. 28, no. 7, pp. 1980–
1984, 2016.
[64] A. M. Ganose, K. T. Butler, A. Walsh, and D. O. Scanlon, “Relativistic electronic structure and band
alignment of BiSI and BiSeI: candidate photovoltaic materials,” J. Mater. Chem. A, vol. 4, no. 6,
pp. 2060–2068, 2016.
[65] * K. T. Butler, Y. Kumagai, F. Oba, and A. Walsh, “Screening procedure for structurally and electronically
matched contact layers for high-performance solar cells: hybrid perovskites,” J. Mater. Chem. C,
vol. 4, no. 6, pp. 1149–1158, 2016.

2015


[66] * K. T. Butler, J. M. Frost, and A. Walsh, “Band alignment of the hybrid halide perovskites
CH3NH3PbSl3, CH3NH3PbBr3 and CH3NH3PbI3,” Materials Horizons, vol. 2, no. 2, pp. 228–231,
2015.
[67] R. X. Yang, K. T. Butler, and A. Walsh, “Assessment of hybrid organic–inorganic antimony sulfides for
earth-abundant photovoltaic applications,” J. Phys. Chem. Lett., vol. 6, no. 24, pp. 5009–5014, 2015.
[68] * G. Kieslich, S. Kumagai, K. T. Butler, T. Okamura, C. H. Hendon, S. Sun, M. Yamashita, A. Walsh,
and A. K. Cheetham, “Role of entropic effects in controlling the polymorphism in formate ABX3 metal–
organic frameworks,” Chem. Comm., vol. 51, no. 85, pp. 15538–15541, 2015.
[69] G. Hrkac, P. S. Keatley, M. T. Bryan, and K. Butler, “Magnetic vortex oscillators,” J. Phys. D: Appl.
Phys., vol. 48, no. 45, p. 453001, 2015.
[70] A. J. Jackson, J. M. Skelton, C. H. Hendon, K. T. Butler, and A. Walsh, “Crystal structure optimisation
using an auxiliary equation of state,” J. Chem. Phys., vol. 143, no. 18, p. 184101, 2015.
[71] * P. J. Isherwood, K. T. Butler, A. Walsh, and J. M. Walls, “A tunable amorphous p-type ternary oxide
system: The highly mismatched alloy of copper tin oxide,” J. Appl. Phys., vol. 118, no. 10, p. 105702,
2015.
[72] J. Buckeridge, K. T. Butler, C. R. A. Catlow, A. J. Logsdail, D. O. Scanlon, S. A. Shevlin, S. M.
Woodley, A. A. Sokol, and A. Walsh, “Polymorph engineering of TiO2: Demonstrating how absolute
reference potentials are determined by local coordination,” Chem. Mater., vol. 27, no. 11, pp. 3844–
3851, 2015.
[73] * K. T. Butler, “Morphological control of band offsets for transparent bipolar heterojunctions: The
Bädeker diode,” Phys. Stat. Sol. (a), vol. 212, no. 7, pp. 1461–1465, 2015.
[74] C. H. Hendon, K. E. Wittering, T.-H. Chen, W. Kaveevivitchai, I. Popov, K. T. Butler, C. C. Wilson,
D. L. Cruickshank, O. S. Miljanic, and A. Walsh, “Absorbate-induced piezochromism in a porous
molecular crystal,” Nano Lett., vol. 15, no. 3, pp. 2149–2154, 2015.
[75] C.-E. Kim, Y.-J. Tak, K. T. Butler, A. Walsh, and A. Soon, “Lattice-mismatched heteroepitaxy of iv-vi
thin films on PbTe (001): An ab initio study,” Phys. Rev. B, vol. 91, no. 8, p. 085307, 2015.
[76] * K. T. Butler, J. M. Frost, and A. Walsh, “Ferroelectric materials for solar energy conversion: photoferroics
revisited,” Energy & Environmental Science, vol. 8, no. 3, pp. 838–848, 2015.

2009 - 2015


[77] * K. T. Butler, C. H. Hendon, and A. Walsh, “Electronic chemical potentials of porous metal–organic
frameworks,” J. Am. Chem. Soc., vol. 136, no. 7, pp. 2703–2706, 2014.
[78] S.-H. Yoo, K. T. Butler, A. Soon, A. Abbas, J. M. Walls, and A. Walsh, “Identification of critical
stacking faults in thin-film CdTe solar cells,” Appl. Phys. Lett., vol. 105, no. 6, p. 062104, 2014.
[79] * S. Sallis, K. Butler, N. Quackenbush, D. Williams, M. Junda, D. Fischer, J. Woicik, N. Podraza,
B. White Jr, A. Walsh, et al., “Origin of deep subgap states in amorphous indium gallium zinc oxide:
Chemically disordered coordination of oxygen,” Appl. Phys. Lett., vol. 104, no. 23, p. 232108, 2014.
[80] G. Hrkac, K. Butler, T. Woodcock, L. Saharan, T. Schrefl, and O. Gutfleisch, “Modeling of Nd-oxide
grain boundary phases in Nd-Fe-B sintered magnets,” JOM, vol. 66, no. 7, pp. 1138–1143, 2014.
[81] J. M. Frost, K. T. Butler, and A. Walsh, “Molecular ferroelectric contributions to anomalous hysteresis
in hybrid perovskite solar cells,” Apl Materials, vol. 2, no. 8, p. 081506, 2014.
[82] A. M. Svensson, S. Olibet, D. Rudolph, E. Cabrera, J. Friis, K. Butler, and J. Harding, “Contact
resistance of screen printed Ag-contacts to Si emitters: Mathematical modeling and microstructural
characterization,” Journal of The Electrochemical Society, vol. 161, no. 8, pp. E3180–E3187, 2014.
[83] * K. T. Butler, J. Buckeridge, C. R. A. Catlow, and A. Walsh, “Crystal electron binding energy and
surface work function control of tin dioxide,” Phys. Rev. B, vol. 89, no. 11, p. 115320, 2014.
[84] J. M. Frost, K. T. Butler, F. Brivio, C. H. Hendon, M. Van Schilfgaarde, and A. Walsh, “Atomistic
origins of high-performance in hybrid halide perovskite solar cells,” Nano Lett., vol. 14, no. 5, pp. 2584–
2590, 2014.
[85] F. Brivio, K. T. Butler, A. Walsh, and M. Van Schilfgaarde, “Relativistic quasiparticle self-consistent
electronic structure of hybrid halide perovskite photovoltaic absorbers,” Phys. Rev. B, vol. 89, no. 15,
p. 155204, 2014.
[86] M. Lamers, L. E. Hintzsche, K. T. Butler, P. E. Vullum, C.-M. Fang, M. Marsman, G. Jordan, J. H.
Harding, G. Kresse, and A. Weeber, “The interface of a-SiN x: H and Si: Linking the nano-scale
structure to passivation quality,” Sol. Ene. Mater. Solar Cells, vol. 120, pp. 311–316, 2014.
[87] * K. T. Butler and A. Walsh, “Ultra-thin oxide films for band engineering: design principles and
numerical experiments,” Thin Solid Films, vol. 559, pp. 64–68, 2014.
[88] A. Walsh and K. T. Butler, “Prediction of electron energies in metal oxides,” Accounts of chemical
research, vol. 47, no. 2, pp. 364–372, 2013.
[89] G. Hrkac, T. Woodcock, K. Butler, L. Saharan, M. Bryan, T. Schrefl, and O. Gutfleisch, “Impact
of different Nd-rich crystal-phases on the coercivity of Nd–Fe–B grain ensembles,” Scripta Materialia,
vol. 70, pp. 35–38, 2014.
[90] * K. T. Butler and J. Harding, “A computational investigation of nickel (silicides) as potential contact
layers for silicon photovoltaic cells,” Journal of Physics: Condensed Matter, vol. 25, pp. 395003–395012,
2013.
[91] * K. Butler, B. Slater, and D. W. Lewis, “29 Si NMR chemical shifts from density functional theory
incorporating solvent effects,” Studies in Surface Science and Catalysis, vol. 174, pp. 725–728, 2008.
[92] * M. Lamers, K. Butler, P. E. Vullum, J. Harding, and A. Weeber, “Characterization of a-SiNx: H
layer: Bulk properties, interface with Si and solar cell efficiency,” Phys. Stat. Sol. (a), vol. 210, no. 4,
pp. 658–668, 2013.
[93] A. P. Green, K. T. Butler, and A. R. Buckley, “Tuning of the emission energy of fluorophores using
solid state solvation for efficient luminescent solar concentrators,” Appl. Phys. Lett., vol. 102, no. 13,
p. 133501, 2013.
[94] * K. T. Butler and D. W. Lewis, “Calculation of the 29Si NMR chemical shifts of aqueous silicate
species,” The Journal of Physical Chemistry A, vol. 116, no. 34, pp. 8786–8791, 2012.
[95] * K. T. Butler and J. H. Harding, “Atomistic simulation of doping effects on growth and charge
transport in Si/Ag interfaces in high-performance solar cells,” Phys. Rev. B, vol. 86, no. 24, p. 245319,
2012.
[96] * K. T. Butler, J. H. Harding, M. P. Lamers, and A. W. Weeber, “Stoichiometrically graded SiNx for
improved surface passivation in high performance solar cells,” J. Appl. Phys., vol. 112, no. 9, p. 094303,
2012.
[97] * M. W. Lamers, K. T. Butler, J. H. Harding, and A. Weeber, “Interface properties of a-SiNx: H/Si
to improve surface passivation,” Sol. Ene. Mater. Solar Cells, vol. 106, pp. 17–21, 2012.
[98] * K. T. Butler, M. P. Lamers, A. W. Weeber, and J. H. Harding, “Molecular dynamics studies of the
bonding properties of amorphous silicon nitride coatings on crystalline silicon,” J. Appl. Phys., vol. 110,
no. 12, p. 124905, 2011.
[99] * K. T. Butler, P. E. Vullum, A. M. Muggerud, E. Cabrera, and J. H. Harding, “Structural and electronic
properties of silver/silicon interfaces and implications for solar cell performance,” Phys. Rev. B, vol. 83,
no. 23, p. 235307, 2011.
[100] * K. T. Butler, F. J. Luque, and X. Barril, “Toward accurate relative energy predictions of the bioactive
conformation of drugs,” J. Comp. Chem., vol. 30, no. 4, pp. 601–610, 2009.