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Visible light switchable bR/TiO2 nanostructured photoanodes for bio-inspired solar energy conversion
, Article RSC Advances ; Volume 5, Issue 24 , Jan , 2015 , Pages 18642-18646 ; 20462069 (ISSN) ; Janfaza, S ; Irani, R ; Sharif University of Technology
Royal Society of Chemistry
2015
Abstract
Today, regarding the limitation and environmental side effects of fossil fuel resources, solar hydrogen production is one of the main interests in the energy research area. The development of visible light sensitized semiconductors based on non-toxic components, low cost and available bio-species is an ongoing approach for H2 generation based on water splitting reactions. Here, two different morphologies of TiO2 photoanodes, nanoparticulated and nanotubular, have been modified with simply extracted bacteriorhodopsin (bR) without any linker. Achieving a significant enhancement in photoconversion efficiency of TiO2 photoanodes, η% was increased from 2.9 to 16.5 by bR addition to the TiO2...
TiO 2 fibers enhance film integrity and photovoltaic performance for electrophoretically deposited dye solar cell photoanodes
, Article ACS Applied Materials and Interfaces ; Volume 3, Issue 3 , February , 2011 , Pages 638-641 ; 19448244 (ISSN) ; Rahman, M ; Tajabadi, F ; Taghavinia, N ; Sharif University of Technology
2011
Abstract
Nanoparticulated TiO 2 fibers as one-dimensional long structures were introduced into TiO 2 P25 nanoparticle films using coelectrophoretic deposition. This prevented the usual crack formation occurring in wet coatings, and resulted in less porosity and higher roughness factor of the films that provided more favorable conditions for electron transport. The films used as the photoanode of a dye solar cell (DSC) produced 65% higher photovoltaic efficiency. TiO 2 fibers can be excellent binders in single-step, organic-free electrophoretic deposition of TiO 2 for DSC photoanode
Thermo-economic analysis and multi-objective optimization of a solar dish Stirling engine
, Article Energy Sources, Part A: Recovery, Utilization and Environmental Effects ; 2020 ; Assareh, E ; Moltames, R ; Jafarinejad, T ; Sharif University of Technology
Bellwether Publishing, Ltd
2020
Abstract
Stirling engines operate in a variety of temperatures and the electric power production via dish Stirling systems could be considered as an appropriate alternative for high-temperature solar concentrator energy harvesting systems. To this end, by performing various studies and analyses on the engine, Stirling cycle, and heat exchangers while utilizing the solar energy as the input thermal energy of the Stirling engine, parameters with the highest effect on the output power and engine stability are detected and considered as optimization variables. In this case, output power, thermal efficiency, and economic evaluation are taken to be the three suitable objective functions for multi-objective...
Thermo-economic analysis and multi-objective optimization of a solar dish Stirling engine
, Article Energy Sources, Part A: Recovery, Utilization and Environmental Effects ; Volume 43, Issue 22 , 2021 , Pages 2861-2877 ; 15567036 (ISSN) ; Assareh, E ; Moltames, R ; Jafarinejad, T ; Sharif University of Technology
Taylor and Francis Ltd
2021
Abstract
Stirling engines operate in a variety of temperatures and the electric power production via dish Stirling systems could be considered as an appropriate alternative for high-temperature solar concentrator energy harvesting systems. To this end, by performing various studies and analyses on the engine, Stirling cycle, and heat exchangers while utilizing the solar energy as the input thermal energy of the Stirling engine, parameters with the highest effect on the output power and engine stability are detected and considered as optimization variables. In this case, output power, thermal efficiency, and economic evaluation are taken to be the three suitable objective functions for multi-objective...
Thermal residual stresses in silicon thin film solar cells under operational cyclic thermal loading: A finite element analysis
, Article Solar Energy ; Volume 135 , 2016 , Pages 366-373 ; 0038092X (ISSN) ; Dehghany, M ; Sohrabpour, S ; Naghdabadi, R ; Sharif University of Technology
Elsevier Ltd
2016
Abstract
In manufacturing amorphous silicon solar cells, thin films are deposited at high temperatures (200-400 °C) on a thick substrate using sputtering and plasma enhanced chemical vapor deposition (PECVD) methods. Since the thin films and substrate have different thermal expansion coefficients, cooling the system from deposition temperature to room temperature induces thermal residual stresses in both the films and substrate. In addition, these stresses, especially those having been induced in the amorphous silicon layer can change the carrier mobility and band gap energy of the silicon and consequently affect the solar cell efficiency. In this paper, a 2D finite element model is proposed to...
The impact of climate condition on the optimal size of direct coupled photovoltaic-electrolyzer systems
, Article Simulation Series, 26 July 2015 through 29 July 2015 ; Volume 47, Issue 10 , July , 2015 , Pages 224-229 ; 07359276 (ISSN) ; Maroufmashat, A ; Sattari khavas S ; Elkamel, A ; Aladwani, S ; Sharif University of Technology
The Society for Modeling and Simulation International
2015
Abstract
Solar energy exists extensively in all parts of the world. However the intermittency of solar energy presents critical challenges to PV system. The intermittency can be covered by storing solar energy in chemical bonds such as hydrogen. This process can be performed by photovoltaic powered electrolysis of water. The energy transfer efficiency between PV and electrolyzer is subject to the distance between maximum power points (MPP) of PV module and operating points. The operating points can be adjusted by optimizing the design parameters of the electrolyzer but the maximum power points are function of PV module characteristics, solar radiation and ambient temperature. Therefore the weather...
The effect of lithium doping in solution-processed nickel oxide films for perovskite solar cells
, Article ChemPhysChem ; Volume 20, Issue 24 , 2019 , Pages 3322-3327 ; 14394235 (ISSN) ; Sveinbjornsson, K ; Boschloo, G ; Taghavinia, N ; Sharif University of Technology
Wiley-VCH Verlag
2019
Abstract
The effect of substitutional Li doping into NiOx hole transporting layer (HTL) for use in inverted perovskite solar cells was systematically studied. Li doped NiOx thin films with preferential crystal growth along the (111) plane were deposited using a simple solution-based process. Mott-Schottky analysis showed that hole carrier concentration (NA) is doubled by Li doping. Utilizing 4 % Li in NiOx improved the power conversion efficiency (PCE) of solar devices from 9.0 % to 12.6 %. Photoluminescence quenching investigations demonstrate better hole capturing properties of Li:NiOx compared to that of NiOx, leading to higher current densities by Li doping. The electrical conductivity of NiOx is...
Techno-economic comparative study on hydrogen and electricity cogeneration systems with CO2 capture
, Article ASME 2016 10th International Conference on Energy Sustainability, ES 2016, collocated with the ASME 2016 Power Conference and the ASME 2016 14th International Conference on Fuel Cell Science, Engineering and Technology, 26 June 2016 through 30 June 2016 ; Volume 1 , 2016 ; 9780791850220 (ISBN) ; Soltanieh, M ; Mansouri Majoumerd, M ; Arild, Ø ; Sharif University of Technology
American Society of Mechanical Engineers
2016
Abstract
In order to achieve the international climate goals and to keep the global temperature increase below 2 °C, carbon capture and storage in large point sources of CO2 emissions has received considerable attention. In recent years, mitigation of CO2 emissions from the power sector has been studied extensively whereas other industrial point source emitters such as hydrogen industry have also great potential for CO2 abatement. This study aims to draw an updated comparison between different hydrogen and power cogeneration systems using natural gas and coal as feedstock. The goal is to show the relative advantage of cogeneration systems with respect to CO2 emission reduction costs. Accordingly, the...
Techno-economic and environmental analysis of an integrated standalone hybrid solar hydrogen system to supply CCHP loads of a greenhouse in Iran
, Article International Journal of Green Energy ; Volume 14, Issue 3 , 2017 , Pages 295-309 ; 15435075 (ISSN) ; Roshandel, R ; Hamidi, A. A ; Sharif University of Technology
Abstract
The techno-economic and environmental performance of hybrid solar hydrogen energy systems was investigated to provide combined cooling, heating and power (CCHP) demands of a standalone greenhouse in Iran to achieve sustainable agriculture based on an optimization procedure. From the environmental point of view, by deploying hybrid energy systems, 83%, to 100% of emissions can be avoided. Also a sensitivity analysis was performed on the hybrid energy systems in order to study the effect of major parameter variation on the systems justification. It was concluded that hybrid solar systems are economically competitive with conventional systems, for high solar intensity locations with high diesel...
Techno-economic analysis of a modified concentrating photovoltaic/organic Rankine cycle system
, Article International Journal of Ambient Energy ; 17 February , 2020 ; Roshandel, R ; Sharif University of Technology
Taylor and Francis Ltd
2020
Abstract
The combination of concentrating photovoltaic (CPV) and organic Rankine cycle (ORC) systems not only leads to a reduction of photovoltaic (PV) operating temperature, but also leads to an additional electric power production. Increase in the temperature of the PV decreases its operating efficiency, while increases the ORC efficiency. Therefore, there is an optimum temperature in which the total electricity produced by the combined system will be maximum. In this study, a modified CPV/ORC system is simulated and the optimum operating temperature of the PV panel is determined for different PV efficiencies. The most striking result is that increase in the PV nominal efficiency will result in the...
Techno-economic analysis of a modified concentrating photovoltaic/organic Rankine cycle system
, Article International Journal of Ambient Energy ; Volume 43, Issue 1 , 2022 , Pages 2026-2038 ; 01430750 (ISSN) ; Roshandel, R ; Sharif University of Technology
Taylor and Francis Ltd
2022
Abstract
The combination of concentrating photovoltaic (CPV) and organic Rankine cycle (ORC) systems not only leads to a reduction of photovoltaic (PV) operating temperature, but also leads to an additional electric power production. Increase in the temperature of the PV decreases its operating efficiency, while increases the ORC efficiency. Therefore, there is an optimum temperature in which the total electricity produced by the combined system will be maximum. In this study, a modified CPV/ORC system is simulated and the optimum operating temperature of the PV panel is determined for different PV efficiencies. The most striking result is that increase in the PV nominal efficiency will result in the...
Sustainable starfish like cobalt electrocatalyst grown on optimized CNT-graphene hybrid host for efficient water oxidation
, Article Applied Surface Science ; Volume 524 , 15 September , 2020 ; Ghasemi, S ; Pourreza, M ; Moshfegh, A. Z ; Sharif University of Technology
Elsevier B.V
2020
Abstract
Solar energy generation is one of the most efficient approach to solve emerging environment and energy challenges. In this context, solar assisted dissociation of water into oxygen and hydrogen utilizing scalable and high performance electrocatalysts plays key role since the produced hydrogen is a clean energy carrier. Here, cobalt based nanoflakes with metallic core and oxidized surface were grown on the designed carbonaceous layer for anodic oxygen evolution reaction (OER) using an electrochemical approach. Carbonaceous layers containing proper amount of carbon nanotubes (CNT) and reduced graphene oxide (rGO) species were used to optimize the system. Although higher weight percent of rGO...
Surface passivation of titanium dioxide via an electropolymerization method to improve the performance of dye-sensitized solar cells
, Article RSC Advances ; Volume 6, Issue 15 , 2016 , Pages 12537-12543 ; 20462069 (ISSN) ; Khoshroo, A ; Taghavinia, N ; Hosseinzadeh, L ; Sharif University of Technology
Royal Society of Chemistry
2016
Abstract
In dye-sensitized solar cells recombination reactions at the TiO2 photoanode with the electrolyte interface plays a critical role in cell efficiency. Recombination of injected electrons in the TiO2 with acceptors in the electrolyte usually occurs on uncovered areas of TiO2 surfaces. In this work, we report electropolymerization of polymer films on nanoporous TiO2 electrode surfaces using an ionic liquid as the growth medium. The choice of ionic liquid as the growth medium for this study is based on the insolubility of dye N719 in this electrolyte, thus avoiding dye molecule detachment from the TiO2 photoanode surface over the entire potential range investigated during the...
Suppressing recombination in perovskite solar cells via surface engineering of TiO2 ETL
, Article Solar Energy ; Volume 197 , 2020 , Pages 50-57 ; Tavakoli, M. M ; Wolska Pietkiewicz, M ; Jędrzejewska, M ; Trivedi, S ; Kumar, M ; Zakeeruddin, S. M ; Lewiński, J ; Graetzel, M ; Yadav, P ; Sharif University of Technology
Elsevier Ltd
2020
Abstract
Hybrid perovskite solar cells (PSCs) have gained significant attention owing to their excellent physicochemical and photovoltaic properties. PSCs typically consist of a perovskite light absorber sandwiched between two carrier selective layers optimized with respect to optimal band alignment and low interfacial recombination. The quality of the perovskite layer and interfaces play major roles in the fabrication of high-performance PSCs. In the present work, we systematically investigate the planar structure PSCs based on TiO2 and TiO2/ZnO electron transport layers (ETLs), which provide deeper insight into the charge recombination and accumulation mechanisms. We show that the double-layer...
Supercritical synthesis and in situ deposition of PbS nanocrystals with oleic acid passivation for quantum dot solar cells
, Article Materials Chemistry and Physics ; Volume 156 , 2015 , Pages 163-169 ; 02540584 (ISSN) ; Simchi, A ; Aashuri, H ; Sharif University of Technology
Elsevier Ltd
2015
Abstract
Colloidal quantum dot solar cells have recently attracted significant attention due to their low-processing cost and surging photovoltaic performance. In this paper, a novel, reproducible, and simple solution-based process based on supercritical fluid toluene is presented for in situ growth and deposition PbS nanocrystals with oleic-acid passivation. A lead precursor containing sulfur was mixed with oleic acid in toluene and processed in a supercritical fluid condition at different temperatures of 140, 270 and 330 °C for 20 min. The quantum dots were deposited on a fluorine-doped tin oxide glass substrate inside the supercritical reactor. Transmission electron microscopy, X-ray diffraction,...
Stable and efficient CuO based photocathode through oxygen-rich composition and Au-Pd nanostructure incorporation for solar-hydrogen production
, Article ACS Applied Materials and Interfaces ; Volume 9, Issue 33 , 2017 , Pages 27596-27606 ; 19448244 (ISSN) ; Siavash Moakhar, R ; Chua, C. S ; Kushwaha, A ; Dalapati, G. K ; Sharif University of Technology
Abstract
Enhancing stability against photocorrosion and improving photocurrent response are the main challenges toward the development of cupric oxide (CuO) based photocathodes for solar-driven hydrogen production. In this paper, stable and efficient CuO-photocathodes have been developed using in situ materials engineering and through gold-palladium (Au-Pd) nanoparticles deposition on the CuO surface. The CuO photocathode exhibits a photocurrent generation of ∼3 mA/cm2 at 0 V v/s RHE. Time-of-flight secondary ion mass spectrometry (TOF-SIMS) analysis and X-ray spectroscopy (XPS) confirm the formation of oxygen-rich (O-rich) CuO film which demonstrates a highly stable photocathode with retained...
Stability and performance analysis of a single-stage grid-connected photovoltaic system using describing function theory
, Article International Transactions on Electrical Energy Systems ; Volume 26, Issue 9 , 2016 , Pages 1898-1916 ; 20507038 (ISSN) ; Mokhtari, H ; Karimi, S ; Azizian, M. R ; Sharif University of Technology
John Wiley and Sons Ltd
Abstract
Challenging problems in the design and analysis of photovoltaic (PV) systems stem from the nonlinear current–voltage (I–V) characteristics of solar cells. This paper presents an analytical analysis based on a describing function method to investigate the transient and steady-state characteristics of a three-phase single-stage grid-connected PV system. In this study, the nonlinear I–V characteristic of the PV array is linearized around the operating point. The nonlinear dynamic of the maximum power point tracking controller is divided into two parts of continuous and discrete. For the continuous part, the common small-signal linearization is applied, while for the discontinuous part, a...
Solar-hydrogen renewable supply system optimisation based on demand side management
, Article International Journal of Ambient Energy ; 2019 ; 01430750 (ISSN) ; Jafarinejad, T ; Badpar, F ; Sharif University of Technology
Taylor and Francis Ltd
2019
Abstract
Stand-alone hybrid power systems are an alternative to main electricity grids, where the grid extension is costly or the trifling local consumption would not justify its expansion. However, lack of consistency and uniformity in renewable energy sources, and the restrictions of energy storage systems make system sizing a challenging task. Optimum size of a stand-alone system depends on several factors including energy demand function. In this paper, different types of demand functions are addressed for optimising a solar-hydrogen supply system. Different parameters are defined to investigate the impact of household population on the power generation cost, and also to determine the optimum...
Solar-hydrogen renewable supply system optimisation based on demand side management
, Article International Journal of Ambient Energy ; 2019 ; 01430750 (ISSN) ; Jafarinejad, T ; Badpar, F ; Sharif University of Technology
Taylor and Francis Ltd
2019
Abstract
Stand-alone hybrid power systems are an alternative to main electricity grids, where the grid extension is costly or the trifling local consumption would not justify its expansion. However, lack of consistency and uniformity in renewable energy sources, and the restrictions of energy storage systems make system sizing a challenging task. Optimum size of a stand-alone system depends on several factors including energy demand function. In this paper, different types of demand functions are addressed for optimising a solar-hydrogen supply system. Different parameters are defined to investigate the impact of household population on the power generation cost, and also to determine the optimum...
Solar-hydrogen renewable supply system optimisation based on demand side management
, Article International Journal of Ambient Energy ; Volume 43, Issue 1 , 2022 , Pages 754-763 ; 01430750 (ISSN) ; Jafarinejad, T ; Badpar, F ; Sharif University of Technology
Taylor and Francis Ltd
2022
Abstract
Stand-alone hybrid power systems are an alternative to main electricity grids, where the grid extension is costly or the trifling local consumption would not justify its expansion. However, lack of consistency and uniformity in renewable energy sources, and the restrictions of energy storage systems make system sizing a challenging task. Optimum size of a stand-alone system depends on several factors including energy demand function. In this paper, different types of demand functions are addressed for optimising a solar-hydrogen supply system. Different parameters are defined to investigate the impact of household population on the power generation cost, and also to determine the optimum...