Geminate electron-hole recombination in organic solids in the presence of a donor-acceptor heterojunction

2010 ◽  
Vol 96 (16) ◽  
pp. 162102 ◽  
Author(s):  
Mariusz Wojcik ◽  
Przemyslaw Michalak ◽  
M. Tachiya
Keyword(s):  
Electron Hole ◽  
Organic Solids ◽  
Donor Acceptor ◽  
Hole Recombination

Photoluminescence Investigation of Pb(Zr,Ti)O3 Thin Films

1991 ◽  
Vol 243 ◽  
Author(s):  
Peter Zurcher ◽  
Raymond P. Jones ◽  
Yongchen Sun ◽  
R.L. Cone
Keyword(s):  
Thin Films ◽  
Deep Trap ◽  
Electrical Performance ◽  
Electron Hole ◽  
Pzt Thin Films ◽  
Pzt Films ◽  
Donor Acceptor ◽  
Defect Densities ◽  
La Doped ◽  
Hole Recombination

AbstractPhotoluminescence (PL) excited at 1.7K with a N2-Laser (3.679eV) was used to investigate defect related electron-hole recombination transitions in ferroelectric PZT thin films. The interaction of doping, heat treatment, and hydrogen with the defect related PL spectrum has been studied. Donor/acceptor related transitions between 3.0 and 3.5eV and deep trap transitions between 2.0 and 2.6eV have been found. Certain heat treatments produce high densities of deep trap transitions in Pb(Zr0.48Ti0.52)03 thin films but not in 6% La doped PZT; different treatments are neccessary to produce similar deep trap transitions in the doped films. Hydrogen anneals eliminate the strongest deep trap transition at 2.15eV in both undoped and La-doped PZT films; however the donor/acceptor transitions are affected differently. Correlation with electrical properties seems to indicate the expected result: smaller defect densities are associated with better electrical performance.

Optically Detected Magnetic Resonance and Double Beam Photoluminescence of CdS/HgS/CdS Nanoparticles

1998 ◽  
Vol 536 ◽  
Author(s):  
H. Porteanu ◽  
A. Glozman ◽  
E. Lifshitz ◽  
A. Eychmüller ◽  
H. Weller
Keyword(s):  
Optical Properties ◽  
Magnetic Resonance ◽  
Cds Nanoparticles ◽  
Electron Hole ◽  
Cladding Layer ◽  
Double Beam ◽  
Optically Detected Magnetic Resonance ◽  
Optically Detected ◽  
Cladding Layers ◽  
Hole Recombination

AbstractCdS/HgS/CdS nanoparticles consist of a CdS core, epitaxially covered by one or two monolayers of HgS and additional cladding layers of CdS. The present paper describes our efforts to identify the influence of CdS/HgS/CdS interfaces on the localization of the photogenerated carriers deduced from the magneto-optical properties of the materials. These were investigated by the utilization of optically detected magnetic resonance (ODMR) and double-beam photoluminescence spectroscopy. A photoluminescence (PL) spectrum of the studied material, consists of a dominant exciton located at the HgS layer, and additional non-excitonic band, presumably corresponding to the recombination of trapped carriers at the interface. The latter band can be attenuated using an additional red excitation. The ODMR measurements show the existence of two kinds of electron-hole recombination. These electron-hole pairs maybe trapped either at a twin packing of a CdS/HgS interface, or at an edge dislocation of an epitaxial HgS or a CdS cladding layer.

Pre-Industrial Experience in Solar Photocatalytic Mineralization of Real Wastewaters. Application to Pesticide Container Recycling

1999 ◽  
Vol 40 (4-5) ◽  
pp. 123-130 ◽  
Author(s):  
S. Malato ◽  
J. Blanco ◽  
C. Richter ◽  
B. Milow ◽  
M. I. Maldonado
Keyword(s):  
Organic Contaminants ◽  
Toxic Waste ◽  
Experimental Plant ◽  
Electron Hole ◽  
Particulate Suspensions ◽  
Photocatalytic System ◽  
Commercial Pesticide ◽  
Pesticide Container ◽  
By Products ◽  
Hole Recombination

Particulate suspensions of TiO2 irradiated with natural solar tight in a large experimental plant catalyse the oxidation of organic contaminants. The problem in using TiO2 as a photocatalyst is electron/hole recombination. One strategy for inhibiting e−/h+ recombination is to add other (irreversible) electron acceptors to the reaction. In many highly toxic waste waters where degradation of organic pollutants is the major concern, the addition of an inorganic anion to enhance the organic degradation rate may be justified. For better results, these additives should fulfil the following criteria: dissociate into harmless by-products and lead to the formation of ·OH or other oxidising agents. In this paper, we attempt to demonstrate the optimum conditions for the treatment of commercial pesticide rinsates found in the wastewater produced by a pesticide container recycling plant. The experiments were performed in one of the pilot plants of the largest solar photocatalytic system in Europe, the Detoxification Plants of the Plataforma Solar de Almería (PSA), in Spain. After testing ten different commercial pesticides, results show that peroxydisulphate enhances the photocatalytic miniralization of all of them. This study is part of an extensive project focused on the design of a solar photocatalytic plant for decontamination of agricultural rinsates in Almería (Spain).

Tuning the electronic and structural properties of WO3 nanocrystals by varying transition metal tungstate precursors

RSC Advances ◽  
2014 ◽  
Vol 4 (107) ◽  
pp. 62423-62429 ◽  
Author(s):  
Sara Rahimnejad ◽  
Jing Hui He ◽  
Wei Chen ◽  
Kai Wu ◽  
Guo Qin Xu
Keyword(s):  
Methylene Blue ◽  
Transition Metal ◽  
Oxygen Vacancy ◽  
Band Gap ◽  
Azo Dye ◽  
Electron Hole ◽  
Recombination Time ◽  
Metal Tungstate ◽  
Electronic And Structural Properties ◽  
Hole Recombination

WO3 nanoplates derived from NiWO4 were found to have the highest concentration of oxygen vacancy, narrowest band gap, longest electron–hole recombination time, and in turn the highest rate of photodegradation of azo dye methylene blue.

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