Renewable Energy Global Innovations features: Hybrid photovoltaic-thermal solar systems for combined heating, cooling and power provision in urban environment

Significance Statement

The use of renewable energy resources offers a secure and sustainable solution to the energy problem, which encompasses complex and multifaceted aspects such as an increasing global energy demand notwithstanding stagnating oil production capacities and price volatility, concerns relating to energy independence and security, and the detrimental effects to human health and the environment that arise from the continued consumption of fossil fuels. Renewable energy resources currently supply only up to 14% of the world’s total energy, so there is considerable scope to develop and implement new renewable energy technologies.

Solar energy is a particularly promising renewable and sustainable source of energy, which can be tapped to address the energy problem simultaneously from environmental, health and economic perspectives. Nevertheless, the widespread delivery of affordable solar energy through suitable technologies remains an engineering grand challenge that continues to attract a strong interest from academia, industry, government, and beyond. In particular, solar energy systems based on hybrid photovoltaic-thermal (or, PV-T) collectors have been recently receiving an increased interest due to their higher overall efficiencies compared to conventional PV panels. These hybrid panels can reach overall efficiencies (electrical plus thermal) of over 70%, with electrical efficiencies reaching 15-20% and thermal efficiencies of over 50%.

In a PV-T panel, PV cells convert sunlight directly to electricity and thermal energy is removed from the cells via a contacting coolant fluid (liquid or gas); the heated fluid flow is then used downstream for hot water provision or space heating (and/or cooling if necessary), with the added benefit of actively cooling the PV cells and increasing their electrical efficiency. In most applications, the electrical output of a hybrid PV-T system is the main priority. Hence, the contacting fluid is kept at low temperature in order to maximize the system’s electrical performance. However, this imposes a limit on its posterior use and a design conflict arises between the electrical and thermal performance of hybrid PV-T systems.

When optimising the overall output of PV-T systems for combined electricity and heating/cooling provision, this solution can cover about 60% of the heating and between 50-100% (depending on the location) of the cooling demands of households in the urban environment, based on typical household demands and available roof space. To achieve this, PV-T systems can be coupled to vapour-compression heat pumps or absorption refrigeration units.

Researchers in the Clean Energy Processes (CEP) Laboratory at Imperial College London considered the techno-economic advantages and shortcomings of a range of such systems, while aiming at a low cost per kWh of combined energy generation (co- or tri-generation) in the housing sector. They studied the technical feasibility, performance and affordability of proposed systems in ten different geographical locations covering all European climates, with local weather profiles using monthly and annually averaged solar-irradiance and energy-demand data relating to houses with a 100-m² total floor area and 50-m²-rooftop area. The results of this research have been published in Energy Conversion and Management.

Amongst the locations studied, Seville, Rome, Bucharest and Madrid were the most promising for the proposed hybrid PV-T systems. The authors found that the most effective system arrangement entailed the coupling of PV-T panels to water-to-water heat pumps. The electrical output of the panels was used to run the heat pump or an air conditioning system, while the thermal output was used to maintain the source-side temperature of the heat pump at around 15 °C year round. This practice maximizes the heat pump and/or air-conditioning coefficient of performance (COP) and enables a reduction in their electricity consumption. The authors found that the temporal resolution of the simulations affects strongly the predicted system performance. Detailed high-resolution hourly simulations indicated that such PV-T systems are capable of covering 60% of the combined heating demands and almost 100% of the cooling demands of the examined households in middle and low European-latitude regions.

Moreover, the authors estimated the cost of solar thermal, PV and PV-T systems. For PV-T systems, the levelized cost of energy (LCOE), i.e., the total net present value of the system per unit total energy over the system’s lifetime, was found to be mainly influenced by the system size, which will be larger at higher latitudes (lower irradiance). Nevertheless, the calculated LCOE for the PV-T systems varied between 0.06 and 0.12 €/kW h, which is 30-40% lower than the LCOE of small-scale PV-only installations in Europe.

Finally, the authors identify important barriers for the market adoption of PV-T technology, which at present act to limit the PV-T market size, including high initial costs, and uncertainties caused by poor knowledge of the technology due to its limited penetration. They suggest that demonstration projects exploring the potential of PV-T co-generation or tri-generation systems should be encouraged, supported and advertised to the public, to increase the awareness of this technology and to accelerate the adoption rates of these much-promising systems.

Schematic diagram of the proposed PV-T system for solar heating and cooling provision.

Selected locations and global horizontal irradiation in Europe. (b) Space heating, DHW and cooling demands and global irradiance profiles for Seville and Vienna.

About The Author

Dr Alba Ramos Cabal is an Aeronautical Engineer who holds a Masters and a Doctorate degree in Photovoltaic Solar Energy from the Technical University of Madrid (Spain). Currently, she is a Postdoctoral Research Associate in the Clean Energy Processes (CEP) Laboratory at Imperial College London.

Her research involves the modelling, design, fabrication and testing of novel hybrid solar PV-thermal (PV-T) collector technology, as part of wider solar-energy heat, power and cooling (tri-generation) systems. Her previous experience includes the theoretical modelling of physical and chemical vapour deposition (CVD) processes, as well as experimental research with CVD reactor prototypes in the laboratory and at industrial scales. She was also involved in the modelling, design, fabrication and testing of a novel thermal energy storage (TES) system that utilizes high-temperature phase change materials (PCMs) and thermo-photovoltaic (TPV) cells. In addition, during her PhD she was involved with the Solar Energy Institute, a Spanish R&D centre, worked at the Institute for Energy Technology (IFE) in Norway, and undertook postdoctoral research stays at the Cyprus University of Technology (CUT) for the purpose of outdoor solar PV-T collector testing and characterization.

Contact: a.ramos-cabal@imperial.ac.uk 

About The Author

Ms Maria Anna Chatzopoulou is a PhD student in the Clean Energy Processes (CEP) Laboratory at the Department of Chemical Engineering of Imperial College London, working under the supervision of Dr Christos Markides. Her research focuses on the design of low-carbon cogeneration technologies with applications in buildings. She is interested in the design and optimization of novel technologies, such as the organic Rankine cycle (ORC) and absorption refrigeration systems, which are not currently widely adopted in the built environment.

Her research is co-funded by the Imperial College President’s PhD Scholarship scheme, and the Climate-KIC and European Institute of Innovation and Technology. She holds an MEng degree in Mechanical Engineering (Distinction) and an MSc in Environmental Engineering and Business Management (Distinction). Prior to her PhD, she worked as a design engineer in an international engineering consultancy in London. Her main responsibilities involved the design of HVAC systems for critical facilities, such as data centres, aiming to reduce their energy consumption and carbon emissions by considering novel cooling technologies.

Contact: maria-anna.chatzopoulou@imperial.ac.uk

About The Author

Dr Ilaria Guarracino holds a PhD in Chemical Engineering from Imperial College London. She completed her PhD at the Clean Energy Processes (CEP) Laboratory under the supervision of Dr Christos Markides and Dr Ned Ekins-Daukes who led the Quantum Photovoltaics group in the Blackett Laboratory at Imperial College. Her research focused on the design of hybrid solar PV-thermal (PV-T) systems for electricity, hot water and cooling, for which she developed a flexible computer tool for the evaluation of the performance of solar thermal and PV-T collectors and wider systems. The tool was validated against outdoor experimental data generated during a research visit to the Cyprus University of Technology (CUT) where she worked under the supervision of Professor Soteris Kalogirou.

Prior to the PhD, she completed a double Masters degree in Mechanical Engineering at the Royal Institute of Technology (KTH, Stockholm) and at the Universitat Politecnica de Catalunya (UPC, Barcelona) focusing on solar energy systems. She also worked as a summer intern at the Fraunhofer Institute for Solar Energy (ISE) working in a project conducting research into the thermodynamics of molten salts in steam generators for concentrated solar power systems.

Contact: ilaria.guarracino12@imperial.ac.uk

About The Author

Dr James Freeman is a Postdoctoral Research Associate in the Clean Energy Processes (CEP) Laboratory at the Department of Chemical Engineering, Imperial College London. He completed his PhD in solar thermal combined energy systems for distributed applications in 2017. His previous work has included the design, testing and modelling of a small-scale organic Rankine cycle (ORC) engine for use with non-concentrating solar collectors. He has also worked within the CEP Laboratory to develop methods for the testing and modelling of solar thermal and hybrid solar PV-thermal (PV-T) collectors and systems.

His current research focuses on a small-scale modular solar-cooling system for rural cold-chain applications based on a diffusion-absorption refrigeration cycle. He recently participated in an ongoing project to field-test the system in India, which runs until 2018.

Contact: j.freeman12@imperial.ac.uk

About The Author

Dr Christos N. Markides is a Reader in Clean Energy Processes at the Department of Chemical Engineering, Imperial College London, where he heads the Clean Energy Processes (CEP) Laboratory, and leads the Department of Chemical Engineering Energy Research Theme and the cross-faculty Energy Efficiency Network. After graduating with a PhD in Energy Technologies from the University of Cambridge, he co-founded a Cambridge University spin-out company to develop and commercialize a novel thermally-powered device without moving parts capable of converting low-temperature waste heat or solar energy into fluid pumping. He acted as its Technical Director until his appointment at Imperial in 2008.

His research expertise lies in the application of fundamental aspects of thermodynamics, fluid flow, heat and mass transfer, both computationally and experimentally, to novel processes, components, technologies and systems for the recovery, utilization, conversion and storage of thermal energy. He has a particular interest in high-efficiency energy systems, renewable energy technologies, and the efficient utilization of solar and waste heat for cooling, heating and power. He has written over 200 scientific articles in these areas. He is an Executive Editor of Applied Thermal Engineering and is a Subject Editor of Renewable Energy, is on the Editorial Board of Energy (Elsevier) and Frontiers in Solar Energy (EPFL), and is also a member of the UK National Heat Transfer Committee and Scientific Board of the UK Energy Storage SUPERGEN Hub.

Contact: c.markides@imperial.ac.uk

The Clean Energy Processes (CEP) Laboratory, headed by Dr Christos Markides, is based in the Department of Chemical Engineering at Imperial College London. Currently, approximately 35 members (research fellows, postdoctoral and doctoral researchers, and postgraduate students) are at the core of this research laboratory. Its mission is to conduct high-impact research in applied thermodynamics, fluid flow, heat and mass transfer, as applied to technologies for high-performance power generation, heat and/or cooling provision. The CEP Laboratory fosters close interactions with industry and actively collaborates with international research centres and universities. The CEP solar-energy team focuses on innovation, research and development aimed at high-performance solar thermal and hybrid PV-thermal technologies for heating, cooling and power generation.

Reference

Alba Ramos, Maria Anna Chatzopoulou, Ilaria Guarracino, James Freeman, Christos N. Markides. Hybrid photovoltaic-thermal solar systems for combined heating, cooling and power provision in the urban environment. Energy Conversion and Management, Vol. 150, 838-850 (2017)

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Renewable Energy Global Innovations features: Optimization of A Three-Bed Adsorption Chiller by Genetic Algorithms and Neural Networks

Significance Statement

Recovery of waste heat is one of the main techniques of improving maximum energy efficiency utilization of a variety of processes with low parameters of heat generated as by-product. The use of waste heat driven pumps is slowly overtaking the predominantly applied mechanical coolers. Increased attention is currently being paid to adsorption chillers since they can be powered with low-temperature heat sources and yet allow to be integrated into cogenerative systems. Adsorption cycles of the applied systems have a distinctive advantage over other systems in that they can use low grade waste heat of near ambient temperature. A Tri-bed twin-evaporator adsorption chiller comprise of a ground-breaking design in cooling production which allows more efficient conversion and management of low grade sources of thermal energy due to more effective way of utilization adsorptive abilities of the beds during a single work. Although it is the most effective way in chilled water production, the intricacy of the Tri-bed twin evaporator adsorption chiller operation is still not sufficiently recognized and the enhancement in cooling capacity of the cooler is still a puzzling task.

A team of researchers led by professor Jaroslaw Krzywanski at the Jan Dlugosz University in Poland optimized a three-bed adsorption chiller by applying genetic algorithms and neural networks. They introduced an artificial intelligence approach for the optimization study of the Tri-bed twin evaporator adsorption chiller using low-temperature heat from cogeneration. Their research work is now published in the peer-reviewed journal, Energy Conversion and Management.

The research team began by developing genetic algorithms and artificial neural networks. The developed algorithm and network were then tested and validated before they were used to develop the model. The researchers then used the developed model to estimate the behavior of the adsorption heat pump by assessing the effects of: the time cycle, cooling and heating inlet water temperatures and that of temperatures in low-high pressure evaporators. The team also examined the cooling capacity as one of the major energy efficiency factors in cooling production during the study for various scenarios.

The authors also observed that the highest value which could be obtained for the considered range of input operational parameters was equal to 93 kW. It was also noted that such a value was only attainable where specific: cycle time, cooling water temperature, heating water temperature, high pressure inlet temperature and low pressure inlet temperatures as specified in this paper were used.

Results of their study showed the cooling capacity evaluated using the model, is in good agreement with the experimental data. The maximum relative error between the measured and calculated results is lower than ±10%. Therefore, the developed model in Krzywanski  and colleagues is an easy to use and powerful optimization tool which allows to estimate the cooling capacity of the Tri-bed twin evaporator adsorption chiller, integrated into multi-generative systems.

The structure of the [5-2-2-1] type of neural network for optimization of a Tri-bed twin evaporator adsorption chiller

About The Author

Jaroslaw Krzywanski is an Associate Professor the head the Division of Advanced Computational Methods at the Faculty of Mathematics and Natural Science of Jan Dlugosz University in Czestochowa, Poland.

He received the M.Sc. degree from Czestochowa University of Technology, Department of Mechanical Engineering and Computer Sciences, Institute of Thermal Machinery, Poland and Ph.D. degree from Silesian University of Technology, Faculty of Energy and Environmental Engineering, Poland.

He has published more than 120 refereed works, including papers, a monograph, conference proceedings and serves as an editorial board member of several international journals. He has participated in the scientific committee of several conferences and serves as a reviewer in a wide range of international journals.

He is interested in modeling of energy devices and processes, including solid fuels combustion, waste driven adsorption chillers as well as gas emissions and hydrogen production from biomass combustion and gasification, respectively.

Reference

Krzywanski, K. Grabowska, F. Herman, P. Pyrka, M. Sosnowski, T. Prauzner, W. Nowak. Optimization of a three-bed adsorption chiller by genetic algorithms and neural networks. Energy Conversion and Management, volume 153 (2017) pages 313–322.

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Renewable Energy Global Innovations features: Optimal Arrangement of Photovoltaic Panels Coupled with Electrochemical Storages

Significance Statement

Maximizing power generation using photovoltaic panels can be achieved by combining the perfect azimuth and tilt angle for a given site and climate throughout the year. Nonetheless, in many contemporary projects of sustainable buildings, the surface occupied by the photovoltaic cells is composed of subsurface of varying alignments and gradients. In already existing buildings, exploitation of all the available roof surface is necessary since there is little or no choice left at all. However, in new buildings the photovoltaic panels maybe hosted in different azimuth and tilt angles in order to maximize electricity generation with continuity during the day, by talking optimum advantage of surfaces inclined towards the sun in different periods of the day, with greater match with the demand time profile. In the latter scenario, the utmost purpose would be to maximize the building’s autarchy, even if at the cost of larger photovoltaic panel surface and hence a higher installation cost. However, the relevant decline in photovoltaic system costs and their consequent rapid spread are moving the attention from the achievement of the maximum areal electricity generation to a photovoltaic generation profile in agreement with building energy needs.

Italian researchers Antonio Carbonari and Massimiliano Scarpa from the University IUAV of Venice investigated various configurations of photovoltaic systems supported by electrochemical storages, aiming at the increment of electricity self-consumption, considering climates in two different cities: Venice and Trapani. They compared various configurations of the photovoltaic system by means of computer simulations. Their research work is now published in Energy Procedia.

Carbonari and Scarpa began by defining the ideal photovoltaic panel configuration for the two localities. The consequent photovoltaic generation was then compared with the ones characterizing other configurations, derived from actual projects. The research team then considered a case study consisting of a residential building typical of the Italian suburbs. Eventually, two possible orientations of the building’s main axis and consequent possible photovoltaic panel arrangements were considered and compared from various points of view: electricity generation and life cycle assessment of primary energy.

They observed that for buildings having greater surface exposed according to the ideal arrangement provide a higher yearly electricity yield thus, in the case study, the East-West of the building’s main axis is slightly more convenient than the North-South orientation in terms of annual electric generation and consequent payback time of the plant.

The study successfully presented a comprehensive analysis of various configurations of photovoltaic systems supported by electrochemical storages, aiming at increase of electricity self-consumption in two Italian climates. From this analysis, it is possible to deduce that the use of storage system allows to increase significantly the degree of self-consumption of the building, therefore its self-sufficiency.

Fig. 7. Venice E-W orientation, uses of generated electricity and imports during the year [kWh/month], without storage (a) and with storage (b).

About The Author

Antonio Carbonari he graduated in architecture from 1983 at the University IUAV of Venice, is Assistant Professor in the field “Building’s Physics” from 1997 at the same University in the Department of Design and Planning in Complex Environments

Research interests: analysis of urban energy demand, buildings energy balance and solar radiation: energy and luminous aspects, acoustic of interiors.

Reference

Antonio Carbonari, Massimiliano Scarpa. Optimal arrangement of photovoltaic panels coupled with electrochemical storages. Energy Procedia, volume 113(2017) pages 35-42.

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Renewable Energy Global Innovations features: Solution processed Cu2CdSnS4 as a low-cost inorganic hole transport material for polymer solar cells

Significance Statement

Polymer solar cells have a wide range of advantages, and their bulk heterojunction formations, especially the solution-processed type, contribute to improved power conversion efficiency. Traditionally, PEDOT:PSS is used as a hole transport layer in an polymer solar cells (PSCs) owing to its potential advantages such as ease in processability, smooth surface topography, and matching work function with HOMO of many donor-type organic semiconductors. But the acidity and hygroscopic nature of the PEDOT:PSS makes it inefficient electron-blocking performance, and thus negatively contribute to the performance and stability of PSCs under ambient conditions. The transparent metal oxides (TMOs) are being used to replace PEDOT:PSS requires expensive and complicated vacuum based processes, the toxicity and scarcity of some materials such as NiOx and VOx makes it immaterial for PSCs application. So it is essential to focus on materials that are based on earth abundant elements, low-cost, nontoxic and environmentally stable HTMs for highly efficient OSCs.

Professor Sudip Batabyal and colleagues at Amrita University in India demonstrated the capability of applying solution-processed copper cadmium tin sulfide nanoparticles as low-cost inorganic hole transporting materials in polymer solar cells, and studied the effect of particles structure on the functioning of the cells. Their research is published in Solar Energy Materials and Solar Cells

The authors prepared 4 different samples by spin coating a cernyite solution on an indium tin oxide substrate and varied the number of layers in the samples from 1 to 4. A reference cell was fabricated using poly(3,4-ethylenedioxythiophene): polystyrenesulfonate as the hole transporting layer.

Structural features of the particles showed that they had a size of about 7-12nm, and a tetragonal structure. The band gap values for the as-deposited thin films were 1.65eV for 1 layer, 1.60eV for 2 layers, and 1.35eV for both 3 and 4 layers. This shows that the band gap values decrease with an increase in thickness for the as deposited thin films, which confirms that particles agglomerate and their sizes increase with an increase in layer thickness. Further, the absorption spectrum of the as-deposited thin films was observed to cover the entire visible spectrum and increases with an increase in thickness, which shows the nanoparticles have an additional contribution in photocurrent.

The authors calculated the surface roughness values for the samples which were 23.54 nm for 1 layer, 13.11 nm for 2 layers, 11.07 nm for 3 layers, and 21.00 nm for 4 layers. The as-deposited thin film having 3 layers had the minimum surface roughness which implies a more uniform coating over its surface.Although increasing the number of layers improves the compactness in the thin films, it reaches a point where particles aggregate which in effect deters transportation of charge carriers and thus reduces the device’s overall performance. Therefore, the 3 layers were observed to be the optimum number for use of the nanoparticles as a hole transporting layer.

The research team also noted that the solar cell power conversion efficiency improves with an increase in thickness of the as developed thin film and then it decreases significantly. This power conversion efficiency is comparable to that of the poly(3,4-ethylenedioxythiophene): polystyrenesulfonate hole transporting layer. Furthermore, the sample having 3 layers of the nanoparticles had the highest power conversion efficiency as compared with the other samples.This is as a result of the uniform thickness of the film and its compactness, which generates an optimum interface as well as improves the dynamics of the charge transfer.

Comments from Authors:

Metal sulfide nanomaterials have drawn drastic attention because of their exotic electronic properties and high specific surface areas that are potentially useful in photovoltaic applications. For the first time, the compound chalcogenides were used as a hole transport layer in a polymer solar cells. In addition to the transporting property of the p-type buffer layer it is also expected in generation of excitons resulting in increased photo generated currents. The inorganic materials are known for its stability than the organic materials and in future it is interested to work in this direction.

About The Author

Dr. Sudip Kumar Batabyal is the Senior Research Scientist in ACIRI. Prior to joining ACIRI in 2015, Sudip has over 8 years of research experience in nanomaterials fabrication and application in renewable energy sector. His areas of expertise and research interests include semiconducting nanomaterials for energy harvesting and storage, perovskite materials, printed electronics, and energy storage. Sudip received his M.Sc in Physics from Vinoba Bhave University and Ph.D from Indian Association for the Cultivation of Science ( Jadavpur University). Sudip worked in National University of Singapore and Energy Research Institute @ Nanyang Technological University (ERI@N) on the project of solution processed Cu2InGa(S/Se)2 (CIGS) and Cu2SnZn(S/Se)4 solar cell. He developed the CIGS and CZTS absorber layer deposition on Mo substrate by spray pyrolysis method. He successfully fabricated the solution processed CIGS device with more than 10% efficiency. Sudip developed some CNT based perovskite device with more than 10% efficiency. He developed some metal chalcogenide based holetransporting materials for OPV.

 In his research career, he has focused on a wide variety of novel materials (metal chalcogenide, metal oxide, organic semiconductors, carbon nanotubes and graphene) synthesised by a range of fabrication procedures. His main emphasis was on the electronic and optical properties of these materials and direct application of these nanostructures in practical devices. His primary research interests are photovoltaics, photoelectrochemical systems and energy storage. His research work has been published (90 publications) in many high impact factor journals such as Nature Communication, Advanced Materials, ACS Nano and Advanced Energy Materials etc.

Reference

Suresh Kumar, KallolMohanta, Sudip K. Batabyal. Solution processed Cu₂CdSnS₄ as a low-cost inorganic hole transport material for polymer solar cells. Solar Energy Materials and Solar Cells, 161 (2017) 157-161.

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Renewable Energy Global Innovations features: Generation of excited electronic states at nonmetal surface by hydrogen atoms beam

Significance Statement

Long-lived vibrationally excited states are formed by the interaction of hydrogen atoms of thermal energy and their isotopes with nonmetallic surfaces. Heterogeneous chemo-luminescence regarded as the final stage of conversion of energy released during the interaction of hydrogen with the surface into light. Spectral measurements upon excitation of heterogeneous chemo-luminescence are useful for obtaining information on changes in the electronic states of the luminescence centers on the surface.

The researchers, led by professors Yuri Tyurin and Nikolai Nikitenkov at Tomsk Polytechnic University studied the luminescence of zinc sulfide activated by thulium, which excited by free hydrogen atoms. The electronic states of the impurity centers of the thulium ion on the zinc sulfide surface and the interaction of hydrogen with the phosphor surface were studied. Their research work now published in the peer review journal, International Journal of Hydrogen Energy.

The authors carried out research in an automated high-vacuum installation. The free hydrogen atoms were obtained by dissociation of molecular hydrogen in a high-frequency electrodeless plasma discharge. The luminescence spectra of a crystalline phosphor of zinc sulfide activated with thulium were recorded using an optical spectrometer, a multichannel photomultiplier, and a charge-coupled device. The methods of nonstationary luminescence were used to study elementary acts of interaction of hydrogen atoms with the surface.

The research team found that when hydrogen atoms interact with the phosphor surface, a weak luminescence in the thulium ion band of 480 nm is observed at the beginning, which was followed by aa monotonic increase in the luminescence intensity. They noted that the luminescence spectrum of zinc sulfide activated by thulium has peaks at 480 nm, 481.5 nm and at 807.5 nm, which are characteristic for the thulium ion 3⁺. It was also noted that the peak at 480 nm was significantly brighter compared to the peak at 807.5 nm. The spectra of photoluminescence and luminescence upon excitation by hydrogen atoms practically coincided. This shows that the valences of the thulium ion are the same in the volume and on the surface of the zinc sulfide, since hydrogen atoms that have thermal energy interact only with the first atomic layer of the phosphor.  The authors also noted that the appearance and accumulation of vibrationally excited hydrogen molecules on the surface of zinc sulphide generates a transition to nonstationary periodic regimes in fluorescent kinetic curves. Explanation and simulation of such regimes seems relevant for heterogeneous catalytic processes, and for the problems of increasing the stability of the hydrogen maser, managing the growth of crystals and films by layering molecular-beam epitaxy, increase the service life of protective coatings reentry spacecraft and in the formation of structures of the thin film solid oxide fuel elements and others.

It has been experimentally established that the “shutdown” of hydrogen atoms at relatively low temperatures and high fluxes leads to a sharp decrease in the intensity of heterogeneous chemo- luminescence by approximately 10 times. This makes it possible to study the luminescent method of adsorption, desorption, recombination, and dissociation of hydrogen on the surface. The authors noted that the concentration of adsorbed atoms at the stage of the dark pause varied nonmonotonically. The decrease in the intensity of heterogeneous chemiluminescence during the dark pause is associated with the diffusion recombination of hydrogen atoms on the surface

The authors noted that the luminescence centers are excited by nonequilibrium vibrational quanta of the hydrogen bond.  The higher the energy of the vibrational quantum and the smaller the energy of the electronic transition, the greater the transition rate. The transition rate increases with increasing dipole moment of the vibrationally excited bond.

  Luminescent methods provide a sensitive tool for studying the chemical composition of the surface, the processes of electron energy transfer on the surface, mechanisms of surface degradation. It becomes possible to study elementary acts of gas-solid interaction; the electronic state the centers of luminescence, adsorption and catalysis on the surface, and the dynamic properties of the surface.

About The Author

Nikitenkov Nikolay Nikolaevich

Professor of the Tomsk Polytechnic University, General Physics Department, Russia. Graduated the Physical Department of the Moscow State University in 1980.  Has protected the candidate’s thesis (1987) and doctor’s thesis (2007) on physical and mathematical sciences in the Moscow State University.

The expert in areas:

• Development, making, operation high-vacuum technique for research of the solid surfaces; in particular, installation and procedures for measurement of energy and mass spectra of the secondary ions at sputtering of solid surfaces by the ion beams with energy 1–10 keV are created;
• The physical processes at ion-surface and atom-surface interactions; in particular, designed pattern interaction of secondary atoms with the surface plasmons at the ion sputtering and pattern of atom excitation in stages of atom collisions in a solid;
• Physics of metal-hydrogen systems;
• Modern technologies for creating of the thin-film systems and coatings;
• Modern research methods of the solid surfaces and thin films.

Presented numerous reports at the international conferences to Germany, USA, Austria, Turkey, Spain, et.al. Trained in Berkeley’s University (USA), Vienna University of Technology (Austria).
Have more than 180 published scientific articles and manuals. More then 10 master’s and candidate’s dissertations are protected under the guidance of Nikolay. He is the winner of the prize of the Tomsk region governor in the field of science, education and health

About The Author

Tyurin Yurij Ivanovich, Professor of the Tomsk Polytechnic University, Russia. Graduated in 1973. Tomsk State University, specializing in physics, mathematics

In 1989, Yurij Tyurin presented doctoral thesis in the Institute of Chemical Physics, Moscow. He has academic honors and is an Honored worker of higher education of Russia, full member of the international academy of Sciences of the Higher.

Yurij I. Tyurin is a known expert in physics of radiation and atomic interaction with matter, problems of technique and technology of radiation and atomic treatment of solid-state materials, low energy plasma deposition methods for surface modification. Prof. Yuri I. Tyurin is an author of more than 360 printed works including 7 monographs, 22 patents.

Areas of research activity: developed the original experimental methods for analysis of physical and chemical properties of solid surfaces, studied nonequilibrium gas – solid systems, discovered and gave a theoretical explanation of the electronic subsystem excitation of solids with free atoms of ultralow energies, hydrogen storage properties in metals and semiconductors, nonequilibrium yields of atomic hydrogen from solids under the influence of radiation. New scientific field, hemoelectronics of heterogeneous systems, was developed.

Yurij I. Tyurin devotes a lot of time to young scientists, graduate students, PhD students. Six employees under his guidance presented their PhD dissertations, 2 – doctoral theses. The scientific activity of prof. Tyurin has a significant impact on the development priorities of the University, which are related to the creation of new radiation and plasma technologies for processing materials.

Reference

Yu. I. Tyurin, N. N. Nikitenkov, T. I. Sigfusson, A. Hashhash, Yaomin Van, N. D. Tolmacheva. Generation of excited electronic states at the nonmetal surface by the hydrogen atoms beam. International Journal of Hydrogen Energy, 42 (2017) 12448-12457.

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