Computer-aided design of zinc phosphide heterojunctions for efficient solar energy conversion
Lead Research Organisation:
CARDIFF UNIVERSITY
Department Name: Chemistry
Abstract
The growing need for energy by our society and the depletion of conventional energy sources demands the development and improvement of safe, renewable and low-cost clean energy technologies. Photovoltaic (PV) technology which makes use of the super-abundant and freely available Sun's energy to generate electricity has obvious economic, environmental and societal benefits. However, in order for PV technology to provide a significant fraction of the world's energy demands, devices must be composed of cheap and earth-abundant materials. Science and engineering are in a unique position to address the challenge to discover, design and develop inexpensive, non-toxic, and earth-abundant new materials that exhibit the ideal electronic properties for PV applications.
This proposal outlines the strategy for the rational design of zinc phosphide (Zn3P2) heterojunctions for the efficient conversion of solar energy into electricity. Zinc phosphide is ideally positioned as a next-generation PV material due to its direct band gap of 1.50 eV, which allows it to absorb a high percentage of the solar spectrum. Zn3P2 also has a high visible-light absorption coefficient, long minority-carrier diffusion length, a large range of potential doping concentrations, and both of its constituent elements are non-toxic, cheap and abundant, which makes Zn3P2 a promising material for cost-effective and scalable thin-film photovoltaic applications. Despite its germane electronic properties, to date, a Zn3P2 device of sufficient efficiency for commercial applications has not been demonstrated. The highest solar energy-conversion efficiencies of 6.0% for multi-crystalline and 4.3% for thin-film cells have been reported. The low efficiencies of the thin film and heterojunction-based Zn3P2 devices have been attributed to poor understanding of the interfaces and band-alignment between the emitter and the absorber layers, to high concentrations of interface trap states (Fermi-level pinning), and/or to inadequate interface passivation. Given their 2-dimensional nature and their typical location buried within bulk materials, interfaces are difficult to resolve or access by purely experimental means.
The goal of this cross-disciplinary project is, therefore, to develop and employ a combination of cutting-edge computational techniques and experiment to design and identify the key interfacial and electronic properties needed for the practical performance of zinc phosphide photovoltaics to achieve improved solar energy-conversion efficiencies. The use of a synergistic computational-experimental approach will help address key questions about the nature of atomic ordering (chemical and structural) and the electronic properties of the surface and interface of epitaxial Zn3P2 films grown on II-VI and III-V substrates, which will unlock a promising pathway towards the development and commercialization of low-cost, high-efficiency and earth-abundant Zn3P2 photovoltaic devices.
The innovation of the proposed project is based on the engineering and transformation of earth-abundant and non-toxic Zn3P2 into a cost-effective, highly efficient and scalable thin-film PV material that provides additional environmental, health and economic benefits to the UK and globally. The main deliverables and benefits of the proposed project include, but are not limited to (i) atomic-level understanding of the surface and interface properties of a Zn3P2 epilayer, which has important implications on device fabrication and performance; and (ii) the growth of high-quality epitaxial Zn3P2 films on II-VI and III-V substrates as proto-types for industrial-scale PV applications.
This proposal outlines the strategy for the rational design of zinc phosphide (Zn3P2) heterojunctions for the efficient conversion of solar energy into electricity. Zinc phosphide is ideally positioned as a next-generation PV material due to its direct band gap of 1.50 eV, which allows it to absorb a high percentage of the solar spectrum. Zn3P2 also has a high visible-light absorption coefficient, long minority-carrier diffusion length, a large range of potential doping concentrations, and both of its constituent elements are non-toxic, cheap and abundant, which makes Zn3P2 a promising material for cost-effective and scalable thin-film photovoltaic applications. Despite its germane electronic properties, to date, a Zn3P2 device of sufficient efficiency for commercial applications has not been demonstrated. The highest solar energy-conversion efficiencies of 6.0% for multi-crystalline and 4.3% for thin-film cells have been reported. The low efficiencies of the thin film and heterojunction-based Zn3P2 devices have been attributed to poor understanding of the interfaces and band-alignment between the emitter and the absorber layers, to high concentrations of interface trap states (Fermi-level pinning), and/or to inadequate interface passivation. Given their 2-dimensional nature and their typical location buried within bulk materials, interfaces are difficult to resolve or access by purely experimental means.
The goal of this cross-disciplinary project is, therefore, to develop and employ a combination of cutting-edge computational techniques and experiment to design and identify the key interfacial and electronic properties needed for the practical performance of zinc phosphide photovoltaics to achieve improved solar energy-conversion efficiencies. The use of a synergistic computational-experimental approach will help address key questions about the nature of atomic ordering (chemical and structural) and the electronic properties of the surface and interface of epitaxial Zn3P2 films grown on II-VI and III-V substrates, which will unlock a promising pathway towards the development and commercialization of low-cost, high-efficiency and earth-abundant Zn3P2 photovoltaic devices.
The innovation of the proposed project is based on the engineering and transformation of earth-abundant and non-toxic Zn3P2 into a cost-effective, highly efficient and scalable thin-film PV material that provides additional environmental, health and economic benefits to the UK and globally. The main deliverables and benefits of the proposed project include, but are not limited to (i) atomic-level understanding of the surface and interface properties of a Zn3P2 epilayer, which has important implications on device fabrication and performance; and (ii) the growth of high-quality epitaxial Zn3P2 films on II-VI and III-V substrates as proto-types for industrial-scale PV applications.
Planned Impact
The proposed project addresses questions in the UK's energy transition to a sustainable, low-carbon development path and it would have a combination of short- and long-term beneficiaries, and with continued effort, will offer long-term social and economic benefits.
Academic fields - computational and experimental
The most direct impact will be the personal and professional development that is appropriate for the extension of the Fellow's career beyond this fellowship and the training of the one PDRA and a Ph.D. candidate sponsored by Cardiff University. Using a synergistic computational-experimental approach, the knowledge generated on the design and identification of the key interfacial and electronic properties needed for the practical performance of zinc phosphide (Zn3P2) photovoltaics to achieve improved solar energy-conversion efficiencies will be of great interest and benefit to the academic community. The expected substantial Intellectual Property (IP) and know-how to be generated as a result of the research will revitalize the interest of the materials science community in zinc phosphide as well as to provide a template for the development of other new photovoltaic materials.
Industrial/users (medium to long-term)
In the medium term, this work will provide the data and computational tools applicable in many sectors, such as the electronic and solar cell manufacturing industries and it could underpin a new generation of energy materials companies exploiting the identified interface and electronic properties. In the longer term, the new knowledge will lead to the identification of new materials with enhanced properties for use in many current energy generation and storage devices and in future applications. Companies such as IQE plc, a leading global semiconductor company that manufactures advanced epitaxial wafers for a wide range of technology applications, will benefit from the outcomes of the proposed work.
Economy, society, and environment
The proposed research has the potential to contribute significantly in the long term, 10-20 years to solving economic, societal and environmental problems. By increasing the efficiency of zinc phosphide photovoltaics and opening up the opportunity of new advancements from a fundamental understanding of their material properties, the economy and society will benefit from more efficient, cheap, non-toxic and sustainable ways to generate and store energy. This increased efficiency will improve the security of supply and reduce the carbon footprint.
Academic fields - computational and experimental
The most direct impact will be the personal and professional development that is appropriate for the extension of the Fellow's career beyond this fellowship and the training of the one PDRA and a Ph.D. candidate sponsored by Cardiff University. Using a synergistic computational-experimental approach, the knowledge generated on the design and identification of the key interfacial and electronic properties needed for the practical performance of zinc phosphide (Zn3P2) photovoltaics to achieve improved solar energy-conversion efficiencies will be of great interest and benefit to the academic community. The expected substantial Intellectual Property (IP) and know-how to be generated as a result of the research will revitalize the interest of the materials science community in zinc phosphide as well as to provide a template for the development of other new photovoltaic materials.
Industrial/users (medium to long-term)
In the medium term, this work will provide the data and computational tools applicable in many sectors, such as the electronic and solar cell manufacturing industries and it could underpin a new generation of energy materials companies exploiting the identified interface and electronic properties. In the longer term, the new knowledge will lead to the identification of new materials with enhanced properties for use in many current energy generation and storage devices and in future applications. Companies such as IQE plc, a leading global semiconductor company that manufactures advanced epitaxial wafers for a wide range of technology applications, will benefit from the outcomes of the proposed work.
Economy, society, and environment
The proposed research has the potential to contribute significantly in the long term, 10-20 years to solving economic, societal and environmental problems. By increasing the efficiency of zinc phosphide photovoltaics and opening up the opportunity of new advancements from a fundamental understanding of their material properties, the economy and society will benefit from more efficient, cheap, non-toxic and sustainable ways to generate and store energy. This increased efficiency will improve the security of supply and reduce the carbon footprint.
Organisations
- CARDIFF UNIVERSITY (Fellow, Lead Research Organisation)
- University of Pune (Collaboration)
- Swiss Federal Institute of Technology in Lausanne (EPFL) (Collaboration)
- Eindhoven University of Technology (Collaboration, Project Partner)
- Swansea University (Project Partner)
- University College London (Project Partner)
- Syngaschem (Netherlands) (Project Partner)
Publications
Wu L
(2019)
The Origin of High Activity of Amorphous MoS2 in the Hydrogen Evolution Reaction.
in ChemSusChem
Bade B
(2019)
Investigation of growth mechanism for highly oriented TiO2 nanorods: the role of reaction time and annealing temperature
in SN Applied Sciences
Wu L
(2019)
Unraveling the Role of Lithium in Enhancing the Hydrogen Evolution Activity of MoS2: Intercalation versus Adsorption.
in ACS energy letters
Rondiya S.
(2019)
Interface structure and band alignment of CZTS/CdS Heterojunction: An experimental and first-principles DFT investigation
in Materials
King HE
(2019)
Influence of Inorganic Solution Components on Lithium Carbonate Crystal Growth.
in Crystal growth & design
Živkovic A
(2019)
First-principles DFT insights into the structural, elastic, and optoelectronic properties of a and ß-ZnP2: implications for photovoltaic applications.
in Journal of physics. Condensed matter : an Institute of Physics journal
Bade B
(2019)
Correction to: Investigation of growth mechanism for highly oriented TiO2 nanorods: the role of reaction time and annealing temperature
in SN Applied Sciences
Jossou E
(2019)
DFT + U Study of the Adsorption and Dissociation of Water on Clean, Defective, and Oxygen-Covered U3Si2{001}, {110}, and {111} Surfaces.
in The journal of physical chemistry. C, Nanomaterials and interfaces
Rondiya S
(2019)
Interface Structure and Band Alignment of CZTS/CdS Heterojunction: An Experimental and First-Principles DFT Investigation.
in Materials (Basel, Switzerland)
Botchway C
(2020)
Influence of Topology and Brønsted Acid Site Presence on Methanol Diffusion in Zeolites Beta and MFI
in Catalysts
| Description | Zinc phosphide is an attractive earth-abundant solar absorber material for scalable thin-film photovoltaic applications. Despite its ideal optoelectronic properties, problems such as inadequate interface passivation, and low surface stability in the presence of moisture and oxygen remain major problems that severely limits the commercial fabrication of highly efficient Zn3P2-based photovoltaics. Zinc phosphide nanoparticles and thin films can easily get oxidized when in contact with water and oxygen owing to the higher specific surface area and higher reactivity relative to the bulk. By performing accurate first-principles density functional theory calculations, we are able to unravel the early oxidation mechanism of zinc phosphide surfaces by adsorbed oxygen and water, where we show that the adsorption of oxygen and water species is characterized by a significant charge transfer from the interacting surface species, causing them to be oxidized from Zn2+ to Zn3+ formal oxidation states. These results were published in the Journal of Physical Chemistry Chemical Physics (https://doi.org/10.1039/C9CP03902C). The study also highlighted the need for Zn3P2 nanoparticles to be protected against possible oxidation in the presence of oxygen and moisture via in situ functionalization, wherein the Zn3P2 nanoparticles are exposed to a vapor of organic functional molecules immediately after synthesis. In a follow follow-up study, the interface chemistry between the 4-amino thiophenol (4ATP) molecule and the (001), (101), and (110) surfaces of zinc phosphide (Zn3P2) has been investigated. It was demonstrated that the functionalization of the surfaces of Zn3P2 can be protected against oxidation a the electronic properties are essentially presented for device fabrication. This work is published in the ACS Omega journal (https://doi.org/10.1021/acsomega.9b02736). Recently, through a combined experimental and computation investigation, the ideal growth conditions of Zn3P2 are elucidated, and the nucleation of single-crystal nanopyramids that subsequently evolve towards coalesced thin films is demonstrated. The conditions for selective growth and the mechanism by which the material nucleates inside the nanoscale holes and grows into single crystals were elucidated. As the crystals develop, their surface is demonstrated to evolve from a mixture of (001), (112) and (101) facets, into nanopyramids enclosed solely by the most stable (101) facets. This work is published in Nanoscale Advances, 2021,3, 326-332 (https://doi.org/10.1039/D0NA00841A). A follow-up investigation looked at the formation mechanism and functionality of rotated domains in selective area epitaxy grown Zn3P, published also in Nanoscale, 2021,13, 18441-18450, https://doi.org/10.1039/D1NR06190A. |
| Exploitation Route | The outcome derived is helping in our experimental synthesis and characterization of zinc phosphide thin films for photovoltaic applications. The derived atomic-level insights should aid the rational design and engineering of heterojunctions (i.e. between the Zn3P2 absorber materials and buffer layer materials (eg, CdS, ZnS, ZnSe, etc) for efficient solar device fabrication. The successful demonstration of how to grow high-quality zinc phosphide nanostructures by selective area epitaxy constitutes a new, and transferrable, approach for the controlled and tunable growth of high-quality zinc phosphide, a step forward in the quest for earth-abundant photovoltaics. |
| Sectors | Education Electronics Energy |
| URL | https://sites.google.com/view/nelsondzade/home |
| Description | Computation and experimental approaches to catalytic PEC water splitting |
| Amount | € 6,000 (EUR) |
| Organisation | Ministry of Human Resource Development |
| Sector | Public |
| Country | India |
| Start | 01/2020 |
| End | 08/2020 |
| Title | Characteristics of K2Ca2(SO4)3:Eu TLD nanophosphor for its applications in electron and gamma rays dosimetry - data |
| Description | In the present report, nanorods (~25 nm × 200 nm) of K2Ca2(SO4)3:Eu phosphor (powder) were synthesized by chemical coprecipitation method followed by annealing at 700 °C. Dimensions of nanorods were confirmed by TEM and XRD. The material (pellets) was irradiated by 60Co gamma-rays for various doses over the range of 0.1 Gy-100 kGy and also by 6 MeV electrons at different fluences varying from 2.5 × 1011 e/cm2 to 5 × 1013 e/cm2 at room temperature. Thermoluminescence (TL) and photoluminescence (PL) of the gamma and electron irradiated phosphors were also studied. TL glow curve apparently exhibited a peak at around 152 °C with a small hump around 258 °C. The exact number of peaks in a glow curve were determined by thermal cleaning method and glow curves were further deconvoluted by CGCD method to determine trapping parameters. PL emission spectrum consisted of a single emission band at 388 nm (Eu2+ emission) on excitation by 320 nm. The intensity of this peak increased with the electron fluence up to 5 × 1012 e/cm2 and decreases thereafter. The TL response is linear in the dose range from 0.1 Gy to 1 kGy of gamma radiation and electron fluence range from 2.5 × 1011 e/cm2 to 2.5 × 1012 e/cm2 . The electronic structures of the pristine and Eu doped K2Ca2(SO4)3 materials were analyzed by means of first-principles density functional theory (DFT) calculations. The dosimetric characteristics suggest that the K2Ca2(SO4)3:Eu nanophosphor can be useful for its application in radiation dosimetry, especially, for measurement of high-doses of gamma and electrons. The data underpinning the results are available in the .xlsx format (can be viewed either by MS Office or Libre Office) comprising 12 datasheets named after the Figure numbers in the published manuscript in the Journal of Optical Materials. The data comprises of XRD, thermoluminescence (TL) and optically stimulated luminescence (OSL) response data. All data can be plotted using any plotting software, e.g., xmgrace, excel or other plotting software of choice. |
| Type Of Material | Database/Collection of data |
| Year Produced | 2020 |
| Provided To Others? | Yes |
| URL | https://research.cardiff.ac.uk/converis/portal/detail/Dataset/114040390?auxfun=&lang=en_GB |
| Title | Enhanced Field Emission Properties of Au/SnSe Nano-heterostructure: A Combined Experimental and Theoretical Investigation - dataset |
| Description | Tin selenide (SnSe), an inorganic layered metal chalcogenide material with direct and indirect bandgap of 0.9 eV and 1.3 eV, respectively, is a promising material for field emission applications. In the related publication, we present a simple and yet very effective method for synthesizing the SnSe NSs and Au/SnSe NHS with superior field emission performance. Surface modification of the SnSe NSs via Au nanoparticles decoration is demonstrated to significantly enhance the field emission characteristics of the resulting Au/SnSe NHS. Ultra-low turn-on field and reliable high emission current density was obtained through the Au/SnSe nanocomposite formation. Through first-principles Density Functional Theory (DFT) calculations, we have provided atomic-level insights into the structure of the Au/SnSe NHS and the corresponding work function tuning. The experimental and Density functional theory (DFT) theoretical simulation datasets are available in the .xlsx format (can be viewed either by MS Office or Libre Office) comprising 8 datasheets named by their contents. The experimental data comprises of X-ray diffraction patterns of SnSe NSs and Au/SnSe NHS, the field emission current versus applied field (J-E) characteristic, the Fowler-Nordheim (F-N) data, and the emission current versus time (I-t) data. Data for the DFT optimized structures for the bulk SnSe is available in the CONTCAR format of the VASP simulation program The CONTCAR files consist of lattice parameter and atomic positions and can be viewed either by MS Office or WordPad. The density of states (DOS) data are in 2 columns: the first column is the Energy (eV) and the second column is the intensity of the DOS (arb. units). The electrostatic potential data for the naked and Au-covered SnSe surface are provided. All data can be plotted using any plotting software, e.g., xmgrace, excel. |
| Type Of Material | Database/Collection of data |
| Year Produced | 2020 |
| Provided To Others? | Yes |
| URL | https://research.cardiff.ac.uk/converis/portal/detail/Dataset/98900038?auxfun=&lang=en_GB |
| Title | Enhanced photocatalytic activity of N, P, co-doped carbon quantum dots: an insight from experimental and computational approach - data |
| Description | Herein, we demonstrate the single-step microwave radiation assisted approach to develop nitrogen (N) and phosphorous (P) co-doped carbon quantum dots (NP-CQD). The developed NP-CQD showed enhancement in visible light photocatalytic activity towards methylene blue dye degradation than that of N-CQD and P-CQD due to creation of energy states thereby decrease in its work function which is corroborated by Ultraviolet photoelectron spectroscopy as determined experimentally as well as first principles Density Functional Theory (DFT) calculations as determined theoretically. The experimental and Density functional theory (DFT) theoretical simulation datasets are available in the .xlsx format (can be viewed either by MS Office or Libre Office) comprising 11 datasheets. The experimental data consist of UV-Visible absorption spectrum; XRD patterns; high-resolution XPS; Ultraviolet photoelectron spectrum; UV-Visible spectrum of MB degradation. The DFT data is comprised of optimized structures for the pure, nitrogen (N) and phosphorous (P) co-doped carbon quantum dots (NP-CQD). The CONTCAR files consist of lattice parameter and atomic positions and can be viewed either by VESTA program, MS Office or WordPad. |
| Type Of Material | Database/Collection of data |
| Year Produced | 2020 |
| Provided To Others? | Yes |
| URL | https://research.cardiff.ac.uk/converis/portal/detail/Dataset/112140691?auxfun=&lang=en_GB |
| Title | First-Principles Mechanistic Insights into the Hydrogen Evolution Reaction on Ni2P Electrocatalyst in Alkaline Medium |
| Description | Nickel phosphide (Ni2P) is a promising material for the electrocatalytic generation of hydrogen from water. Here, we present a chemical picture of the fundamental mechanism of Volmer-Tafel steps in hydrogen evolution reaction (HER) activity under alkaline conditions at the (0001) and (10-10) surfaces of Ni2P using dispersion-corrected density functional theory calculations. Two terminations of each surface (Ni3P2- and Ni3P-terminated (0001); and Ni2P- and NiP-terminated (10-10)), which have been shown to coexist in Ni2P samples depending on the experimental conditions, were studied. Water adsorption on the different terminations of the Ni2P (0001) and (10-10) surfaces is shown to be exothermic (binding energy in the range of 0.33-0.68 eV) and characterized by negligible charge transfer to/from the catalyst surface (0.01-0.04 e-). The activation energy barriers for the dissociation of water on each termination of the Ni2P (0001) and (10-10) surfaces are determined. The Gibbs free energy of hydrogen adsorption (?GH*) at different surface sites is also predicted. The density functional theory (DFT) theoretical simulation datasets are available in the .xlsx format (can be viewed either by MS Office or Libre Office) comprising 8 datasheets which gives information about the bulk-Ni2P structure; DOS of Ni2P; H2O molecular and dissociative adsorption structures adsorption (0001) and (10-10) surfaces; and the transition state structures for H2O dissociation. Data for the optimized structures are available in CONTCAR format of the VASP simulation program. The CONTCAR files consist of lattice parameter and atomic positions and can be viewed either by MS Office or WordPad. The density of states (DOS) data are in 2 columns: first column been the Energy (eV) and second column been the intensity of the DOS (arb. units). This DOS data can be plotted using any plotting software, e.g., xmgrace, excel. |
| Type Of Material | Database/Collection of data |
| Year Produced | 2020 |
| Provided To Others? | Yes |
| URL | https://research.cardiff.ac.uk/converis/portal/detail/Dataset/102983129?auxfun=<=en_GB |
| Title | First-principles DFT Insights into the Adsorption of Hydrazine on Bimetallic ß1-NiZn Catalyst: Implications for Direct Hydrazine Fuel Cells - data |
| Description | We present a systematic first-principles density functional theory study with dispersion corrections (DFT-D3) of hydrazine adsorption on the experimentally observed (111), (110) and (100) surfaces of the binary ß1-NiZn alloy. A direct comparison has been drawn between the bimetallic and monometallic Ni and Zn counterparts to understand the synergistic effect of alloy formation. The hydrazine adsorption mechanism has been characterised through adsorption energies, Bader charges, the d-band centre model, and the coordination number of the active site - which is found to dictate the strength of the adsorbate-surface interaction. The bimetallic ß1-NiZn nanocatalyst is found to exhibit higher activity towards adsorption and activation of hydrazine compared to the monometallic Ni and Zn counterparts. The Ni-sites of the bimetallic NiZn surfaces are found to be generally more reactive than Zn sites, which is suggested to be due to the higher d-band centre of -0.13 eV (closer to the Fermi level), forming higher energy anti-bonding states through Ni-N interactions. The observed synergistic effects derived from surface composition and electronic structure modification from Ni and Zn alloying should provide new possibilities for the rational design and development of low-cost bimetallic Ni-Zn alloy catalysts for direct hydrazine fuel cell (DHFC) applications. The data underpinning the research are available in the .xlsx format (can be viewed either by MS Office or Libre Office) comprising 7 datasheets which gives information about the bulk structure of monometallic Ni and Zn and bimetallic NiZn; hydrazine (N2H4) adsorption structures adsorption Ni(111), Zn(001), NiZn(111), NiZn(110) and NiZn(100) surfaces. Data for the optimized structures are available in CONTCAR format of the VASP simulation program. The CONTCAR files consist of lattice parameter and atomic positions and can be viewed either by MS Office or WordPad and displayed using VESTA software. |
| Type Of Material | Database/Collection of data |
| Year Produced | 2020 |
| Provided To Others? | Yes |
| URL | https://research.cardiff.ac.uk/converis/portal/detail/Dataset/115779666?auxfun=&lang=en_GB |
| Title | First-principles Investigation of the Structural, Elastic, Electronic, and Optical Properties of a- and ß-SrZrS3: Implications for Photovoltaic Applications |
| Description | Transition metal perovskite chalcogenides are attractive solar absorber materials for renewable energy applications. Herein, we present the first-principles screened hybrid density functional theory analyses of the structural, elastic, electronic and optical properties of the two structure modi?cations of strontium zirconium sulfide (needle-like a-SrZrS3 and distorted ß-SrZrS3 phases). Through the analysis of the predicted electronic structures, we show that both a- and ß-SrZrS3 materials are direct band gaps absorbers, with calculated band gaps of 1.38, and 1.95 eV, respectively, in close agreement with estimates from diffuse-reflectance measurements. Strong light absorption in the visible region is predicted for the a- and ß-SrZrS3, as reflected in their high optical absorbance (in the order of 105 cm-1), with the ß-SrZrS3 phase showing stronger absorption than the a-SrZrS3 phase. We also report the first theoretical prediction of effective masses of photo-generated charge carriers in a- and ß-SrZrS3 materials. Predicted small effective masses of holes and electrons at the valence, and conduction bands, respectively, point to high mobility (high conductivity) and low recombination rate of photo-generated charge carriers in a- and ß-SrZrS3 materials, which are necessary for efficient photovoltaic conversion. Density functional theory (DFT) theoretical simulation datasets are available in the .xlsx format (can be viewed either by MS Office or Libre Office) comprising 7 datasheets named according to their contents. Data for the optimized structures for the bulk alpha and beta SrZrS3 materials are available in CONTCAR format of the VASP simulation program. Volume vs Energy is provided for both phases; the band structure data (1st column is KPOINTS and the 2nd is Energy); the density of states (DOS) data are in 2 columns: first column been the Energy (eV) and the second column being the intensity of the DOS (arb. units). The optical absorbance, reflectivity, and refractive index data are also provided. All data can be plotted using any plotting software, e.g., xmgrace, excel. |
| Type Of Material | Database/Collection of data |
| Year Produced | 2020 |
| Provided To Others? | Yes |
| URL | https://research.cardiff.ac.uk/converis/portal/detail/Dataset/99250231?auxfun=&lang=en_GB |
| Title | Interface chemistry between 4-aminothiophenol (4ATP) molecule and Zn3P2 surfaces - dataset |
| Description | |
| Type Of Material | Database/Collection of data |
| Year Produced | 2020 |
| Provided To Others? | Yes |
| URL | https://research.cardiff.ac.uk/converis/portal/detail/Dataset/86503638?auxfun=&lang=en_GB |
| Title | Thermoluminescence, Photoluminescence and Optically Stimulated Luminescence Characteristics of CaSO4:Eu Phosphor: An Experimental and Density Functional Theory (DFT) Investigation - dataset |
| Description | In the present report, CaSO4:Eu in the nanocrystalline form have been synthesized by chemical method and studied its luminescence properties. The thermoluminescence (TL) and optically stimulated luminescence (OSL) response of the CaSO4:Eu nanophosphor have been investigated up to 100 Gy and theoretical fitting of the OSL decay curve is done. First-principles Density Functional Theory (DFT) calculations have also been performed to gain atomistic insights into the luminescence properties of the pure CaSO4 and CaSO4:Eu materials, by predicting the electronic band structures and partial density of states (PDOS). The experimental and Density functional theory (DFT) theoretical simulation datasets are available in the .xlsx format (can be viewed either by MS Office or Libre Office) comprising 13 datasheets named after the Figure numbers in the published manuscript in the Journal of Luminescence. The experimental data comprises, XRD data, thermoluminescence (TL) and optically stimulated luminescence (OSL) response data. Data for the optimized structures for the bulk CaSO4 and CaSO4:Eu in the hexagonal and orthorhombic phases are available in the CONTCAR format of the VASP simulation program (datasheet 11). The CONTCAR files consist of lattice parameter and atomic positions and can be viewed either by MS Office or WordPad. The CONTCAR files for the lowest-energy configurations predicted on the (001), (101) and (110) surface of Zn3P2 are provided. The density of states (DOS) data are in 2 columns: the first column is the Energy (eV) and the second column is the intensity of the DOS (arb. units). All data can be plotted using any plotting software, e.g., xmgrace, excel. |
| Type Of Material | Database/Collection of data |
| Year Produced | 2020 |
| Provided To Others? | Yes |
| URL | https://research.cardiff.ac.uk/converis/portal/detail/Dataset/98315425?auxfun=&lang=en_GB |
| Title | Uncovering the origin of enhanced field emission properties of rGO-MnO2 heterostructures: a synergistic experimental and computational investigation - data |
| Description | Herein, we report the synthesis of MnO2 nanorods and rGO/MnO2 nano-heterostructure using low-cost hydrothermal and modified Hummer's methods, respectively. Detailed characterization and confirmation of the structural and morphological properties are done via X-Ray Diffraction (XRD), Field Emission Scanning Electron Microscope (FESEM) and Transmission Electron Microscopy (TEM). Compared to the isolated MnO2 nanorods, the rGO/MnO2 nano-heterostructure exhibits impressive field emission (FE) performance in the terms of the low turn-on field of 1.4 V/µm for an emission current density of 10 µA/cm2 and high current density of 600 µA/cm2 at relatively very low applied electric field of 3.1 V/µm. The isolated MnO2 nanorods display a high turn-on field of 7.1 for emission current density of 10 µA/cm2 and low current density 221 µA/cm2 at an applied field of 8.1 V/µm. Besides the superior FE characteristics of the rGO/MnO2 nano-heterostructure, the emission current remains quite stable over the continuous 2h period of measurement. The improvement of the FE characteristics of the rGO/MnO2 heterostructure can be ascribed to the nanometric features and the lower work function (6.01 and 6.12 eV for the rGO with 8% and 16% oxygen contents) compared to the isolated a-MnO2(100) surface (F =7.22 eV) as predicted from complementary first-principles electronic structure calculations based on density functional theory (DFT) methods. These results suggest that an appropriate coupling of rGO with MnO2 nanorods would have a synergistic effect of lowering the electronic work function, resulting in a beneficial tuning of the FE characteristics. The experimental and Density functional theory (DFT) theoretical simulation datasets are available in the .xlsx format (can be viewed either by MS Office or Libre Office) comprising 6 datasheets named by their contents. The experimental data comprises of X-ray diffraction, Field Emission (FE), and XPS data of MnO2 and rGO/MnO2 heterostructure. Data for the DFT optimized structures for the bulk MnO2, rGO with 8 and 16 % oxygen contents, and the rGO/MnO2 heterostructures available in the CONTCAR format of the VASP simulation program. The CONTCAR files consist of lattice parameter and atomic positions and can be viewed either by MS Office or WordPad. The electrostatic potential data for the rGO with 8 and 16 % oxygen contents and the rGO/MnO2 heterostructures are provided. All data can be plotted using any plotting software, e.g., xmgrace, excel. |
| Type Of Material | Database/Collection of data |
| Year Produced | 2020 |
| Provided To Others? | Yes |
| URL | https://research.cardiff.ac.uk/converis/portal/detail/Dataset/111099343?auxfun=&lang=en_GB |
| Title | Unravelling the early oxidation mechanism of zinc phosphide (Zn3P2) surfaces by adsorbed oxygen and water: a first-principles DFT-D3 investigation |
| Description | Zinc phosphide (Zn3P2) is a novel earth-abundant photovoltaic material with a direct bandgap of 1.5 eV. Herein, the incipient oxidation mechanism of the (001), (101), and (110) Zn3P2 surfaces in the presence of oxygen and water, which severely limits the fabrication of efficient Zn3P2-based photovoltaics has been investigated in detail by means of dispersion-corrected density functional theory (DFT-D3) calculations. The fundamental aspects of the oxygen and water adsorption, including the initial adsorption geometries, adsorption energies, structural parameters, and electronic properties are presented and discussed. A chemical picture and origin of the initial steps of Zn3P2 are proposed through Bader population analyses. Density functional theory (DFT) theoretical simulation datasets are available in the .xlsx format (can be viewed either by MS Office or Libre Office) comprising 10 datasheets namely: Bulk-Zn3P2-strucure; DOS-bulk-Zn3P2-data; Adsorption-energies; Bader-charge-analyses; O2-ads-Zn3P2(001); O2-ads-Zn3P2(101); O2-ads-Zn3P2(110); H2O-ads-Zn3P2(001); H2O-ads-Zn3P2(101); and H2O-ads-Zn3P2(110), which provides information on the structural, binding energies, charge analyses, and optimized adsorption geometries of O2 and H2O molecules on the (001), (101), and (110) Zn3P2 surfaces. Data for the optimized structures for the bulk Zn3P2 and the surface+O2/H2O systems are available in CONTCAR format of the VASP simulation program. The CONTCAR files consist of lattice parameter and atomic positions and can be viewed using VESTA, and P4VASP software. The density of states (DOS) data for the bulk-Zn3P2are in 2 columns: the first column been the Energy (eV) and the second column been the intensity of the DOS (arb. units). This DOS data can be plotted using any plotting software, e.g., xmgrace, excel. |
| Type Of Material | Database/Collection of data |
| Year Produced | 2020 |
| Provided To Others? | Yes |
| URL | https://research.cardiff.ac.uk/converis/portal/detail/Dataset/88117956?auxfun=&lang=en_GB |
| Title | Unravelling the early oxidation mechanism of zinc phosphide (Zn3P2) surfaces by adsorbed oxygen and water: a first-principles DFT-D3 investigation |
| Description | Zinc phosphide (Zn3P2) is a novel earth-abundant photovoltaic material with a direct bandgap of 1.5 eV. Herein, the incipient oxidation mechanism of the (001), (101), and (110) Zn3P2 surfaces in the presence of oxygen and water, which severely limits the fabrication of efficient Zn3P2-based photovoltaics has been investigated in detail by means of dispersion-corrected density functional theory (DFT-D3) calculations. The fundamental aspects of the oxygen and water adsorption, including the initial adsorption geometries, adsorption energies, structural parameters, and electronic properties are presented and discussed. A chemical picture and origin of the initial steps of Zn3P2 are proposed through Bader population analyses. Density functional theory (DFT) theoretical simulation datasets are available in the .xlsx format (can be viewed either by MS Office or Libre Office) comprising 10 datasheets namely: Bulk-Zn3P2-strucure; DOS-bulk-Zn3P2-data; Adsorption-energies; Bader-charge-analyses; O2-ads-Zn3P2(001); O2-ads-Zn3P2(101); O2-ads-Zn3P2(110); H2O-ads-Zn3P2(001); H2O-ads-Zn3P2(101); and H2O-ads-Zn3P2(110), which provides information on the structural, binding energies, charge analyses, and optimized adsorption geometries of O2 and H2O molecules on the (001), (101), and (110) Zn3P2 surfaces. Data for the optimized structures for the bulk Zn3P2 and the surface+O2/H2O systems are available in CONTCAR format of the VASP simulation program. The CONTCAR files consist of lattice parameter and atomic positions and can be viewed using VESTA, and P4VASP software. The density of states (DOS) data for the bulk-Zn3P2are in 2 columns: the first column been the Energy (eV) and the second column been the intensity of the DOS (arb. units). This DOS data can be plotted using any plotting software, e.g., xmgrace, excel. |
| Type Of Material | Database/Collection of data |
| Year Produced | 2020 |
| Provided To Others? | Yes |
| URL | https://research.cardiff.ac.uk/converis/portal/detail/Dataset/88117956?auxfun=&lang=en_GB |
| Title | ZnO/CuSCN Nano-Heterostructure as a Highly Efficient Field Emitter: a Combined Experimental and Theoretical Investigation - dataset |
| Description | ZnO-based heterojunctions are also attractive for field emission (FE) applications, where electrons are extracted from the surface of a metal/semiconductor by an electrostatic ?eld through quantum mechanical tunneling. In this study, we report a simple and yet very effective low-temperature method for fabricating the ZnO/CuSCN nano heterostructures for field emission applications. By decorating the porous ZnO nanosheets with CuSCN nanocoins, significant improvements in field emission characteristics were observed (ultra-low turn-on field of 0.7 V/µm for an emission current density 10 µA/cm2). Our results were corroborated through first-principles DFT analyses, which predict lower work functions for the ZnO/CuSCN heterostructure compared to the isolated ZnO and CuSCN as the primary origin for improved field emission. These findings demonstrate that the rational design of nanoscale heterostructures can be used as an effective strategy to drastically enhance the field emission characteristics, such as the turn-on and threshold electric fields and emission current density. The experimental and Density functional theory (DFT) theoretical simulation datasets are available in the .xlsx format (can be viewed either by MS Office or Libre Office) comprising 10 datasheets named by their contents. The experimental data comprises of X-ray diffraction pattern of ZnO, CuSCN and ZnO/CuSCN heterostructure films; Raman spectra of ZnO, CuSCN and ZnO/CuSCN heterostructure films; the field emission current versus applied field (J-E) characteristic, the Fowler-Nordheim (F-N) data, and the emission current versus time (I-t) data. Data for the DFT optimized structures for the bulk ZnO and CuSCN and the ZnO/CuSCN heterostructure available in the CONTCAR format of the VASP simulation program. The CONTCAR files consist of lattice parameter and atomic positions and can be viewed either by MS Office or WordPad. The density of states (DOS) data are in 2 columns: the first column is the Energy (eV) and the second column is the intensity of the DOS (arb. units). The electrostatic potential data for the naked ZnO and CuSCN surfaces and that of the and ZnO/CuSCN heterostructure are provided. All data can be plotted using any plotting software, e.g., xmgrace, excel. |
| Type Of Material | Database/Collection of data |
| Year Produced | 2020 |
| Provided To Others? | Yes |
| URL | https://research.cardiff.ac.uk/converis/portal/detail/Dataset/102985077?auxfun=&lang=en_GB |
| Description | |
| Type Of Material | Database/Collection of data |
| Year Produced | 2020 |
| Provided To Others? | Yes |
| URL | https://research.cardiff.ac.uk/converis/portal/detail/Dataset/89432082?auxfun=&lang=en_GB |
| Description | Quaternary semiconductors for photovoltaic applications |
| Organisation | Savitribai Phule Pune University |
| Country | India |
| Sector | Academic/University |
| PI Contribution | My research group has provided intellectual inputs and theoretical insights into puzzling experimental preservation through first-principles electronic structure calculations. |
| Collaborator Contribution | Our experimental collaborators provided expertise and intellectual inputs in the synthesis and characterization of materials of interest. They have also provided access to data and equipment/facilities. |
| Impact | This collaboration has generated the following publication with DOI numbers below: https://doi.org/10.1680/jnaen.19.00041 https://doi.org/10.3390/ma12244040 https://doi.org/10.1007/s42452-019-0978-2) |
| Start Year | 2019 |
| Description | Transition metal chalcogenidefor hydrogen generation |
| Organisation | Eindhoven University of Technology |
| Country | Netherlands |
| Sector | Academic/University |
| PI Contribution | My research group has provided theoretical insights into puzzling experimental preservation through first-principles electronic structure calculations to collaborators |
| Collaborator Contribution | Our experimental collaborators provided expertise and intellectual inputs in the synthesis and characterization of materials of interest. They have also provided access to data and equipment/facilities. |
| Impact | This collaboration has lead to a number of publications. The DOI of these publications are provided as follows: https://doi.org/10.1021/acsenergylett.9b00945 https://doi.org/10.1002/cssc.201901811 https://doi.org/10.1039/C9CP00722A) |
| Start Year | 2018 |
| Description | Zn3P2 Photovoltaics |
| Organisation | Swiss Federal Institute of Technology in Lausanne (EPFL) |
| Country | Switzerland |
| Sector | Public |
| PI Contribution | My research team provided a computational characterization of the structures, composition, and relative stabilities of the various low-Miller index surfaces of Zn3P2. |
| Collaborator Contribution | The project partners carry out the synthesis of high-quality zinc phosphide nanostructures by selective area epitaxy and elucidated the conditions for selective growth and the mechanism by which the material nucleates inside the nanoscale holes and grows into single crystals. |
| Impact | Publication: Towards Defect-Free Thin Films of the Earth-Abundant Absorber Zinc Phosphide by Nano-patterning Authors: S. E. Steinvall, E. Stutz, R. Paul, M. Zamani, N. Y. Dzade, V. Piazza, M. Friedl, V. de Mestral, J.B. Leran, R. R. Zamani, A. F. i Morral. Journal: Nanoscale Advances, 3, 326-332 (2020). Link: https://doi.org/10.1039/D0NA00841A |
| Start Year | 2020 |