Possible Mechanism of the 30–100 Picoseconds Fast and Efficient Photoluminescence From nc-Si/a-SiO2Doped with Transition Metals

1996 ◽  
Vol 452 ◽  
Author(s):  
S. Veprek ◽  
Th. Wirschem ◽  
J. Dian ◽  
S. Perná ◽  
R. Merica ◽  
...  
Keyword(s):  
Thin Films ◽  
Energy Transfer ◽  
Transition Metals ◽  
Comparative Study ◽  
Silicon Nanocrystals ◽  
Light Emission ◽  
Uv Light ◽  
Charge Carriers ◽  
Radiative Center ◽  
Insight Into

AbstractThe nc-Si/a-SiO2composite thin films doped with tungsten show very fast and efficient photoluminescence (PL). In order to obtain insight into the PL mechanism we have performed a comparative study with other metals. The results lend support to the suggested mechanism which includes the photogeneration of charge carriers due to efficient absorption of the excitation UV light in the silicon nanocrystals followed by energy transfer to the Wn+radiative center from which the light emission occurs.

scholarly journals Energy transfer-mediated white light emission from Nile red-doped 9,10-diphenylanthracene nanoaggregates upon excitation with near UV light

2019 ◽  
Vol 18 (11) ◽  
pp. 2748-2758 ◽  
Author(s):  
Biswajit Manna ◽  
Amitabha Nandi ◽  
Rajib Ghosh
Keyword(s):  
Energy Transfer ◽  
White Light ◽  
Light Emission ◽  
Uv Light ◽  
Nile Red ◽  
Blue Emission ◽  
Green Emission ◽  
White Light Emission ◽  
Bright White Light ◽  
Red Lead

The excitonic blue emission, excimeric green emission and energy transfer-mediated red emission of Nile red lead to bright white light emission upon the photoexcitation of Nile red-doped DPA nanoaggregates.

Temperature dependence of energy transfer in tunable white light-emitting phosphor BaY2Si3O10:Bi3+,Eu3+ for near UV LEDs

2015 ◽  
Vol 3 (42) ◽  
pp. 11151-11162 ◽  
Author(s):  
Hongpeng Zhou ◽  
Qingping Wang ◽  
Ye Jin
Keyword(s):  
Energy Transfer ◽  
Temperature Dependence ◽  
White Light ◽  
Light Emission ◽  
Uv Light ◽  
Energy Transfer Efficiency ◽  
White Light Emission ◽  
Transfer Efficiency ◽  
Light Emitting ◽  
Uv Leds

The white light emission of BaY2Si3O10:0.01 Bi3+, mEu3+ phosphor can be realized and utilizing the energy transfer under near UV light pumped. The energy transfer efficiency between Bi(i) and Bi(ii) change with the temperature increasing due to phonon-assisted process. It is rare in the experiment on directly proof with the phonon-assisted energy transfer.

Photoluminescence and Photocatalytic Properties of Nanocrystalline TiO2:Tb Thin Films

2012 ◽  
Vol 18-19 ◽  
pp. 187-193 ◽  
Author(s):  
Damian Wojcieszak ◽  
Jaroslaw Domaradzki ◽  
Danuta Kaczmarek ◽  
Eugeniusz Prociow ◽  
Antoni W. Morawski ◽  
...  
Keyword(s):  
Thin Films ◽  
Photocatalytic Activity ◽  
Light Emission ◽  
Uv Light ◽  
High Energy ◽  
Tio2 Thin Films ◽  
Rutile Structure ◽  
The Matrix ◽  
Phenol Decomposition ◽  
Crystallite Sizes

In this work photoluminescence together with photocatalytic activity of nanocrystalline TiO2 thin films doped with different amount of Tb are described. Thin films were manufactured by high energy reactive magnetron sputtering process. Structural investigation has shown that all as-deposited films had rutile structure. Doping of the matrix resulted in decrease of the average crystallite sizes from 8.7 nm to 6.6 nm for undoped and doped films, respectively. This testifies about densification of the matrix structure by Tb-doping. Photoluminescence measurements of TiO2:Tb films have revealed light emission in wide spectral range (from 350 up to 700 nm) with a strong green luminescence at 545 nm. In order to explain Tb3+ luminescence phenomenon in TiO2-rutile matrix possible energy transfer mechanisms are discussed. The photocatalytic activity of nanocrystalline films was determined based on phenol decomposition during UV-light irradiation. Results showed that all manufactured films were photocatalytically active and their activity was growing with increase of terbium amount. The highest decomposition rate was observed for the TiO2 thin films with Tb amount of 2.6 at. %.

scholarly journals Silicon Nanocrystals: Fundamental Theory and Implications for Stimulated Emission

2008 ◽  
Vol 2008 ◽  
pp. 1-32 ◽  
Author(s):  
V. A. Belyakov ◽  
V. A. Burdov ◽  
R. Lockwood ◽  
A. Meldrum
Keyword(s):  
Energy Transfer ◽  
Silicon Nanocrystals ◽  
Light Emission ◽  
Theoretical Calculations ◽  
Energy Levels ◽  
Optical Gain ◽  
Stimulated Emission ◽  
Recombination Rates ◽  
Physical Mechanisms ◽  
Gain Profile

Silicon nanocrystals (NCs) represent one of the most promising material systems for light emission applications in microphotonics. In recent years, several groups have reported on the observation of optical gain or stimulated emission in silicon NCs or in porous silicon (PSi). These results suggest that silicon-NC-based waveguide amplifiers or silicon lasers are achievable. However, in order to obtain clear and reproducible evidence of stimulated emission, it is necessary to understand the physical mechanisms at work in the light emission process. In this paper, we report on the detailed theoretical aspects of the energy levels and recombination rates in doped and undoped Si NCs, and we discuss the effects of energy transfer mechanisms. The theoretical calculations are extended toward computational simulations of ensembles of interacting nanocrystals. We will show that inhomogeneous broadening and energy transfer remain significant problems that must be overcome in order to improve the gain profile and to minimize nonradiative effects. Finally, we suggest means by which these objectives may be achieved.

Trapping and Luminescence Mechanism Studies in SrS:Eu2+, Sm3+ Thin Films at Various Temperatures

1992 ◽  
Vol 281 ◽  
Author(s):  
Susan Z. Hua ◽  
L. Salamanca-Riba ◽  
M. Wuttig ◽  
P. K. Soltani
Keyword(s):  
Thin Films ◽  
Energy Transfer ◽  
Excitation Energy ◽  
Uv Light ◽  
Electronic Transitions ◽  
Energy Bands ◽  
Excitation Energies ◽  
Light Excitation ◽  
Direct Inter ◽  
Transfer Mechanisms

ABSTRACTThe temperature dependence of photoluminescence in SrS singly and doubly doped with Eu2+, Sm3+ was studied with different excitation energies. Different energy transfer mechanisms, namely, phonon-assisted energy transfer and electron transfer through energy bands, depending on the excitation energy, are proposed to take place in SrS:Eu2+, Sm3+ thin films. We estimate that under UV light excitation 10% of Eu2+ emission originates from electronic transitions between Eu2+ and Sm3+ through the conduction and valance bands. In contrast, direct inter-ionic transitions take place for 2.84 eV excitation energy via a phonon assistance mechanism.

scholarly journals A Comparative Study of the Photodegradation of Two Series of Cyclic Olefin Copolymers

2017 ◽  
Vol 2017 ◽  
pp. 1-10 ◽  
Author(s):  
Mario H. Gutiérrez-Villarreal ◽  
Sara A. Zavala-Betancourt
Keyword(s):  
Thin Films ◽  
Comparative Study ◽  
Tensile Properties ◽  
Uv Light ◽  
Extrusion Process ◽  
Accelerated Weathering ◽  
Carbonyl Index ◽  
Cyclic Olefin ◽  
Cyclic Olefin Copolymers ◽  
Higher Sensitivity

A series of commercial cyclic olefin copolymers (COC), namely, ethylene-norbornene (E-NB) and ethylene-tetracyclododecene (E-TD), were processed as thin films with thicknesses of 25 μm by an extrusion process. The photodegradation of neat and formulated films with different metal stearates (Fe, Co, and Mn) was investigated using an ultraviolet (UV) light lamp (340 nm) for a period of 30 days in an accelerated weathering tester model QUV from Q-LAB according to the ASTM D 5208-01 standard practice. Changes in carbonyl index (CI) and tensile properties were used to evaluate the photodegradation of the films and other properties, such as Tg variation by DSC, were also analyzed. The present study reveals that (E-NB) copolymers show higher sensitivity to photodegradation than (E-TD) resins, in the absence and presence of metal stearates. We also find that the Fe salt shows the highest oxidative activity.

Luminescence Properties and energy transfer mechanism of Eu3+ and Tm3+ Co-doped AlN Thin Films

2021 ◽  
pp. 118082
Author(s):  
Hai Ma ◽  
Xiaodan Wang ◽  
Feifei Chen ◽  
Jiafan Chen ◽  
Xionghui Zeng ◽  
...  
Keyword(s):  
Thin Films ◽  
Energy Transfer ◽  
Transfer Mechanism ◽  
Luminescence Properties ◽  
Energy Transfer Mechanism ◽  
Co Doped
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