| 1. |
- Bauer, C., et al.
(författare)
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Ultrafast studies of electron injection in Ru dye sensitized SnO2 nanocrystalline thin film
- 2002
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Ingår i: International Journal of Photoenergy (Online). - 1110-662X .- 1687-529X. ; 4:1, s. 17-20
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Tidskriftsartikel (refereegranskat)abstract
- By using two-color femtosecond transient absorption spectroscopy, we have measured the electron injection rate for bis(tetrabutylammonium) cis di(thiocyanato) bis (2,2-bypiridine-4,4 carboxylic acid) Ruthenium (II) dye ( called N719) into SnO2 nanocrystalline thin films. The electron injection rate has been measured by monitoring the formation of the dye oxidized state and the arrival of electrons in the conduction band. Dynamics of electron injection are multiexponential (0.2, 4 and 130 ps) and are therefore slower than the N719-ZnO or N719-TiO2 systems. The photocurrent action spectrum of N719-SnO2 shows a quantum efficiency of 0.65 at 530 nm proving that efficient charge separation can take place despite of the relatively slow electron injection rate.
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| 2. |
- Edman Jönsson, Gustav, 1983, et al.
(författare)
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Nanostructures for Enhanced Light Absorption in Solar Energy Devices
- 2011
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Ingår i: International Journal of Photoenergy. - : Hindawi Limited. - 1687-529X .- 1110-662X. ; 2011
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Tidskriftsartikel (refereegranskat)abstract
- The fascinating optical properties of nanostructured materials find important applications in a number of solar energy utilization schemes and devices. Nanotechnology provides methods for fabrication and use of structures and systems with size corresponding to the wavelength of visible light. This opens a wealth of possibilities to explore the new, often of resonance character, phenomena observed when the object size and the electromagnetic field periodicity (light wavelength lambda) match. Here we briefly review the effects and concepts of enhanced light absorption in nanostructures and illustrate them with specific examples from recent literature and from our studies. These include enhanced optical absorption of composite photocatalytically active TiO(2)/graphitic carbon films, systems with enhanced surface plasmon resonance, field-enhanced absorption in nanofabricated carbon structures with geometrical optical resonances and excitation of waveguiding modes in supported nanoparticle assembles. The case of Ag particles plasmon-mediated chemistry of NO on graphite surface is highlighted to illustrate the principle of plasmon-electron coupling in adsorbate systems.
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| 3. |
- Göthelid, Mats, et al.
(författare)
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Structure-Dependent 4-Tert-Butyl Pyridine-Induced Band Bending at TiO2 Surfaces
- 2011
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Ingår i: International Journal of Photoenergy (Online). - : Hindawi Limited. - 1110-662X .- 1687-529X. ; 2011, s. 401356-
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Tidskriftsartikel (refereegranskat)abstract
- The role of 4-tert butyl pyridine (4TBP) adsorption on TiO2 surface band bending has been studied using photoelectron spectroscopy. Surface oxygen vacancies pin the Fermi level near the conduction band edge on rutile (110). 4TBP preferentially adsorbs in those vacancies and shift the Fermi level to lower binding energy in the band gap. This is done by transferring vacancy excess charge into the empty pi* orbital in the pyridine ring. The anatase (100) surface contains much less oxygen vacancies although the surface is much rougher than the rutile (110). 4TBP adsorption does not have any significant effect on the surface band bending. Thus the positive role associated with 4TBP addition to solar cell electrolytes is suggested to protection against adsorption of other electrolyte components such as Li and I.
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| 4. |
- Hansson, Henrik, et al.
(författare)
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Photo-Fenton and Fenton Oxidation of Recalcitrant Industrial Wastewater Using Nanoscale Zero-Valent Iron
- 2012
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Ingår i: International Journal of Photoenergy (Online). - : Hindawi Limited. - 1110-662X .- 1687-529X. ; 2012
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Tidskriftsartikel (refereegranskat)abstract
- There is a need for the development of on-site wastewater treatment technologies suitable for "dry-process industries," such as the wood-floor sector. Due to the nature of their activities, these industries generate lower volumes of highly polluted wastewaters after cleaning activities. Advanced oxidation processes such as Fenton and photo-Fenton, are potentially feasible options for treatment of these wastewaters. One of the disadvantages of the Fenton process is the formation of large amounts of ferrous iron sludge, a constraint that might be overcome with the use of nanoscale zero-valent iron (nZVI) powder. Wastewater from a wood-floor industry with initial COD of 4956 mg/L and TOC of 2730 mg/L was treated with dark-Fenton (nZVI/H2O2) and photo-Fenton (nZVI/H2O2/UV) applying a 2-level full-factorial experimental design. The highest removal of COD and TOC (80% and 60%, resp.) was achieved using photo-Fenton. The supply of the reactants in more than one dose during the reaction time had significant and positive effects on the treatment efficiency. According to the results, Fenton and mostly photo-Fenton are promising treatment options for these highly recalcitrant wastewaters. Future investigations should focus on optimizing treatment processes and assessing toxic effects that residual pollutants and the nZVI might have. The feasibility of combining advanced oxidation processes with biological treatment is also recommended.
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| 5. |
- Karabulut, Mehmet, et al.
(författare)
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Outdoor Performance Assessment of New and Old Photovoltaic Panel Technologies Using a Designed Multi-Photovoltaic Panel Power Measurement System
- 2020
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Ingår i: International Journal of Photoenergy (Online). - : Hindawi Publishing Corporation. - 1110-662X .- 1687-529X. ; 2020, s. 1-18
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Tidskriftsartikel (refereegranskat)abstract
- This paper presents a new multi-photovoltaic panel measurement and analysis system (PPMAS) developed for measurement of atmospheric parameters and generated power of photovoltaic (PV) panels. Designed system presented with an experimental study evaluates performance of four new and four 5-year-old PV panel technologies which are based on polycrystalline (Poly), monocrystalline (Mono), copper indium selenide (CIS), and cadmium telluride (CdTe) in real time, under same atmospheric conditions. The PPMAS system with the PV panels is installed in Yildirim Beyazit University, Ankara Province, in Turkey. The designed PPMAS consists of three different subsystems which are (1) photovoltaic panel measurement subsystem (PPMS), (2) meteorology measurement subsystem (MMS), and (3) data acquisition subsystem (DAS). PPMS is used to measure the power generation for PV panels. MMS involves different types of sensors, and it is designed to determine atmospheric conditions including wind speed, wind direction, outdoor temperature, humidity, ambient light, and panel temperatures. The measured values by PPMS and MMS are stored in a database using DAS subsystem. In order to improve the measurement accuracy, PPMS and MMS are calibrated. This study also focuses on outdoor testing performances of four new and four 5-year-old PV panels. Average monthly panel efficiencies are estimated as 8.46%, 8.11%, 5.65%, and 3.88% for new Mono, new Poly, new CIS, and new CdTe PV panels, respectively. Moreover, average monthly panel efficiencies of old panels are calculated as 8.22%, 7.85%, 5.35%, and 3.63% in the same order. Test results obtained from the experimental system are also statistically examined and discussed to analyze the performance of PV panels in terms of monthly panel efficiencie
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| 6. |
- Nonomura, Kazuteru, et al.
(författare)
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The effect of UV-irradiation (under short-circuit condition) on dye-sensitized solar cells sensitized with a Ru-complex dye functionalized with a (diphenylamino)styryl-thiophen group
- 2009
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Ingår i: International Journal of Photoenergy (Online). - : Hindawi Limited. - 1110-662X .- 1687-529X. ; :471828
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Tidskriftsartikel (refereegranskat)abstract
- A new ruthenium complex, cis-di(thiocyanato)(2,2'-bipyridine-4,4'-dicarboxylic acid)(4,4'-bis(2-(5-(2-(4-diphenylaminophenyl) ethenyl)-thiophen-2-yl)ethenyl)-2,2'-bipyridine)ruthenium(II) (named E322) has been synthesized for use in dye-sensitized solar cells (DSCs). Higher extinction coeff. and a broader absorption compared to the std. Ru-dye, N719, were aimed. DSCs were fabricated with E322, and the efficiency was 0.12% initially (4.06% for N719, as ref.). The efficiency was enhanced to 1.83% by exposing the cell under simulated sunlight contg. UV-irradn. at short-circuit condition. The reasons of this enhancement are (1) enhanceing electron injection from sensitizer to TiO2 following a shift toward pos. potentials of the conduction band of TiO2 by the adsorption of protons or cations from the sensitizer, or from the redox electrolyte and (2) improving the regeneration reaction of the oxidized dye by the redox electrolyte by the dissoln. of aggregated dye from the surface of TiO2 following the treatment.
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| 7. |
- Spasevska, H., et al.
(författare)
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Optimised In2S3 Thin Films Deposited by Spray Pyrolysis
- 2012
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Ingår i: International Journal of Photoenergy. - : Hindawi Limited. - 1687-529X .- 1110-662X. ; 2012
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Tidskriftsartikel (refereegranskat)abstract
- Indium sulphide has been extensively investigated as a component for different kind of photovoltaic devices (organic-inorganic hybrid devices, all inorganic, dye sensitized cells). In this paper, we have optimised the growth conditions of indium sulphide thin films by means of a low cost, versatile deposition technique, like spray pyrolysis. The quality of the deposited films has been characterised by micro-Raman, vis-UV spectroscopy, and atomic force microscopy. Substrate deposition temperature and different postdeposition annealing conditions have been investigated in order to obtain information about the quality of the obtained compound (which crystalline or amorphous phases are present) and the morphology of the deposited films. We have shown that the deposition temperature influences strongly the amount of amorphous phase and the roughness of the indium sulphide films. Optimised postdeposition annealing treatments can strongly improve the final amount of the beta phase almost independently from the percentage of the amorphous phase present in the as deposited films.
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