Personal Homepages

My main research interest in the development and application of atomistic simulation methods for real materials. My strategy is to combine the predictive capability of the quantum theory of real materials with the power of high-performance computing, in order to investigate the structural, electronic, and optical properties of third-generation solar cells and superconductors. My research group is currently active in the following areas:

• Photovoltaics
  • Solid-state dye-sensitised solar cells
  • Hybrid organic/inorganic solar cells
• Superconductors
  • Graphane
  • Diamond
  • Iron pnictides
  • Cuprates
• Electronic structure methods
  • Electron-phonon interaction
  • Many-body perturbation theory

Savini, G., Ferrari, A. C., Giustino, F. (2010) 'First-principles prediction of doped graphane as a high-temperature electron-phonon superconductor' Physical Review Letters 105 037002.

Schaffry, M., Filidou, V., Karlen, S. D., Gauger, E. M., Benjamin, S. C., Anderson, H. L., Ardavan, A., Briggs, G. A. D., Maeda, K., Henbest, K. B., Giustino, F., Morton, J. J. L., Lovett, B. W. (2010) 'Entangling remote nuclear spins linked by a chromophore' Physical Review Letters 104 200501.

Giustino, F., Cohen, M. L., Louie, S. G. (2010) 'GW method with the self-consistent Sternheimer equation' Physical Review B 81 115105.

Park, C.-H., Giustino, F., Spataru, C. D., Cohen, M. L., Louie, S. G. (2009) 'Angle-resolved photoemission spectra of graphene from first-principles calculations' Nano Letters 9 4234.

Noffsinger, J., Giustino, F., Louie, S.G. and Cohen, M.L. (2009). 'Role of fluorine in the iron pnictides: phonon softening and effective hole doping' Physical Review Letters 102 147003.

Noffsinger, J., Giustino, F., Louie, S.G. and Cohen, M.L. (2009). 'Origin of Superconductivity in boron-doped silicon carbide from first principles' Physical Review B 79 104511.

Park, C.-H., Giustino, F., Spataru, C.D., Cohen, M.L. and Louie, S.G. (2009). 'First-principles study of electron linewidths in graphene' Physical Review Letters 102 076803.

There is a more complete list of publications on my Personal Homepage.

 

*/**Computational modelling of biomimetic photovoltaics
Dr F Giustino

A PhD position is currently available within the group of Dr Feliciano Giustino in the Department of Materials at the University of Oxford (giustino.materials.ox.ac.uk), to work on the computational modelling of biomimetic photovoltaics. Dr Giustino is a Fellow of Wolfson College. The aim of this doctoral project is to study the mechanisms of light absorption in natural dyes and biopolymers using a combination of first-principles electronic structure methods (eg many-body perturbation theory) and semi-empirical approaches. The candidate is expected to hold a degree in Materials Science or Physics, and possess a strong background in quantum mechanics, solid state physics, and numerical analysis. Experience with programming languages and scripting environments is desirable. The successful candidate will join the Oxford Materials Modelling Laboratory, a thriving community of >20 researchers at the centre of one of the leading universities in the world. High-performance computing resources will be available through the Materials Modelling Laboratory and the Oxford Supercomputing Center.

Candidates are encouraged to apply as soon as possible and will be considered in the March gathered field which has an application deadline of 8 March. If the position is not been filled at this stage then applications will be considered on an as-received basis. This 3.5 year studentship is part of a broader five-year project led by Dr Giustino and is funded by the Leverhulme Trust. The studentship will cover all University and College fees as well as carrying an annual stipend of £15,590. Only UK or EU students will be considered for this position.

Applications for this post should be made via the online application system (http://www.ox.ac.uk/admissions/postgraduate_courses/apply/index.html), and will be reviewed until the position is filled. Any questions concerning the project can be addressed to Dr F Giustino (feliciano.giustino@materials.ox.ac.uk), and general inquiries on how to apply can be made to graduate.studies@materials.ox.ac.uk.

Also see homepages: Feliciano Giustino

Optical spectroscopy of nanomaterials
F Giustino

Many of today's most advanced solar cell concepts are based on the idea that sunlight can be harvested by using nanomaterials with high extinction coefficients, such as polymers, or nanomaterials with tunable optical absorption wavelengths, such as semiconductor quantum dots. For both categories a crucial feature is that the light harvesting takes place though the generation of bound electron-hole pairs called excitons, and is profoundly affected by the reduced dimensionality and by the nanoscale size of the light absorber. In this DPhil project we want to develop computational tools for investigating the mechanism of light harvesting in nanomaterials from an atomic-scale perspective. In particular we will develop methods for calculating excitonic properties such as exciton binding energies, exciton wavefunctions, and optical absorption spectra of nanomaterials. We are currently developing a technique for studying electronic excitations in large systems using quantum-mechanical methods based on density-functional theory. In this project we will extend that approach to the calculation of optical excitations in large systems, and we will investigate the excitonic properties of polymers and semiconductor quantum dots. This is a development-oriented project suitable for a student with a keen interest in condensed matter theory, programming, and high-performance scientific computing. [http://dx.doi.org/10.1103/PhysRevB.81.115105]

Also see homepages: Feliciano Giustino

Excitonic solar cells
F Giustino

The ability to manufacture low-cost and high-efficiency solar cells is a strategic asset to meet the increasing global energy demand. In view of conjugating cost-effective materials processing with adequate energy conversion efficiency, significant efforts are currently being devoted to developing excitonic solar cells, including dye-sensitized solar cells and hybrid organic/inorganic solar cells. In such devices the interface between the semiconductor nanocrystals and the dye or polymer plays a crucial role in the separation of the excitons into electrons and holes, and influences both the energy-conversion efficiency and the open-circuit voltage of the solar cell. Despite the key role of the photovoltaic interface in excitonic solar cells, its morphology at the nanoscale is not well understood. A detailed modelling of the interface at the atomistic level would represent the first step towards a rational approach to device optimization. The aim of this DPhil project is to investigate the electronic and optical properties of these interfaces using atomic-scale quantum-mechanical simulations. We will first construct atomistic computer models of the interfaces between semiconductors and dyes or polymers, and then we will investigate their electronic and optical properties, including the ideal open circuit voltage and light absorption, using advanced electronic-structure techniques based on density-functional theory. The project will involve the extensive use of parallel high-performance computers.

Also see homepages: Feliciano Giustino

Electronic and optical properties of quantum-dot sensitizers for nanostructured solar cells
F Giustino

The solid-state semiconductor-sensitized solar cell is an evolution of the concepts of dye-sensitized solar cells and hybrid nanocrystal/polymer solar cells, whereby the molecular sensitizers are replaced by semiconductor quantum dots and the liquid electrolyte is replaced by a solid-state hole-transporter. These new solar cells are very promising because the semiconductor sensitizer can be obtained by inexpensive colloidal synthesis and the harvesting of sunlight can be tuned via quantum size effects by changing the size of the quantum dots. As this research field is very young, there exists a large number of semiconductor nanoparticles which could act potentially as quantum-dot sensitizers. The goal of this DPhil project is to investigate, using first-principles computational modelling, the electronic and optical properties of the most promising sensitizers, in order to identify candidate materials for high-efficiency solar cells. Computational techniques include highly accurate many-body perturbation theory methods such as the GW and the Bethe-Salpeter approach. Our group has a strong background in these computational methodologies and is currently developing high-performance algorithms for GW/BSE calculations. This DPhil project will involve the extensive use of high-performance parallel computers. Interactions with experimental groups both in Oxford and overseas are anticipated. [http://dx.doi.org/10.1002/adfm.201101103]

Also see homepages: Feliciano Giustino

Atomistic modelling of semiconductor/polymer interfaces for excitonic solar cells
F Giustino

Hybrid excitonic solar cells based on blends of semiconductor nanocrystals and polymers have emerged as a potential alternative to dye-sensitized and all-organic solar cells. In hybrid solar cells the polymer enables the deposition of the active layer onto flexible substrates, and the semiconductor offers high carrier mobilities. During the past five years hybrid solar cells based on ZnO and the polymer poly(3-hexylthiophene) have received considerable attention, and solar cells using ZnO quantum dots or nanowires have successfully been demonstrated. The power conversion efficiencies of these devices, however, have not exceeded 2% due to low short-circuit currents and open-circuit voltages. In this DPhil project we want to clarify, using first-principles computational modelling, the atomic-scale mechanisms underlying the operation of semiconductor/polymer excitonic cells. Particular emphasis will be given to the alignment of the quantum-mechanical energy levels at the photovoltaic interface and to the generation of charge carriers. Computational techniques include hybrid-functional approaches and many-body perturbation theory methods. This DPhil project will involve the extensive use of high-performance parallel computers. Interactions with experimental groups in Oxford are anticipated.

Also see homepages: Feliciano Giustino

Reverse-engineering the atomic-scale structure of dye-sensitized solar cells
F Giustino

Among the many innovative photovoltaic concepts currently under consideration, dye-sensitized solar cells based on mesoporous TiO2 films sensitized with molecular dyes have gained prominence due to their relatively high energy conversion efficiencies in excess of 10%. In these devices the photocurrent is generated via ultrafast electron transfer from the photoexcited dye to the nanostructured semiconductor. Since the electron injection takes place within a sub-nanometer length scale, the atomistic nature of the dye/semiconductor interface plays a critical role in the performance of dye-cells. Determining the atomic-scale structure of TiO2/dye interfaces is a formidable task, because there exists a very large number of possible geometries and bonding configurations. In this DPhil project we will determine the atomistic structures of dye-cell interfaces by reverse-engineering measured X-ray photoemission spectra and measured infrared absorption spectra using first-principles calculations. Since these spectra are very sensitive to the local bonding environment, they carry the signature of the interface structure at the atomic scale. This project will focus on the most advanced dye-cell configurations, including organic dyes and alternative metal-oxide substrates. Computational techniques include density-functional theory, core-level spectroscopy, vibrational spectroscopy, and molecular dynamics. This DPhil project will involve the extensive use of high-performance parallel computers. Interactions with experimental groups both in Oxford and overseas are anticipated. [http://dx.doi.org/10.1103/PhysRevB.84.085330]

Also see homepages: Feliciano Giustino

Also see a full listing of New projects available within the Department of Materials.