scholarly journals Effect of Laser Irradiation on Emissivity of Flame-Generated Nanooxides

Materials ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2303
Author(s):  
Silvana De Iuliis ◽  
Roberto Dondè ◽  
Igor Altman
Keyword(s):  
Laser Irradiation ◽  
Light Emission ◽  
Energy Gap ◽  
Particle Temperature ◽  
Electron Excitation ◽  
Flame Spray ◽  
Energy Bands ◽  
Light Emitting ◽  
Spectral Behavior ◽  
The Difference

The application of pyrometry to retrieve particle temperature in particulate-generating flames strictly requires the knowledge of the spectral behavior of emissivity of light-emitting particles. Normally, this spectral behavior is considered time-independent. The current paper challenges this assumption and explains why the emissivity of oxide nanoparticles formed in flame can change with time. The suggested phenomenon is related to transitions of electrons between the valence and conduction energy bands in oxides that are wide-gap dielectrics. The emissivity change is particularly crucial for the interpretation of fast processes occurring during laser-induced experiments. In the present work, we compare the response of titania particles produced by a flame spray to the laser irradiation at two different excitation wavelengths. The difference in the temporal behavior of the corresponding light emission intensities is attributed to the different mechanisms of electron excitation during the laser pulse. Interband transitions that are possible only in the case of the laser photon energy exceeding the titania energy gap led to the increase of the electron density in the conduction band. Relaxation of those electrons back to the valence band is the origin of the observed emissivity drop after the UV laser irradiation.

White-light-emitting magnetite nanoparticle–polymer composites: photonic reactions of magnetic multi-granule nanoclusters as photothermal agents

Nanoscale ◽  
2016 ◽  
Vol 8 (39) ◽  
pp. 17136-17140 ◽  
Author(s):  
Yu Jin Kim ◽  
Bum Chul Park ◽  
June Park ◽  
Hee-Dae Kim ◽  
Nam Hoon Kim ◽  
...  
Keyword(s):  
Polymer Composites ◽  
Laser Irradiation ◽  
White Light ◽  
Magnetite Nanoparticles ◽  
Light Emission ◽  
White Light Emission ◽  
Magnetite Nanoparticle ◽  
Light Emitting

Magnetite nanoparticles combined with polymers produce white-light emission under multiphoton laser irradiation.

A Novel Solid-State Light-Emitting Device Based on Ballistic Electron Excitation

2000 ◽  
Vol 638 ◽  
Author(s):  
Y. Nakajima ◽  
A. Kojima ◽  
N. Koshida
Keyword(s):  
Solid State ◽  
Light Emission ◽  
Nanocrystalline Silicon ◽  
Electron Excitation ◽  
Si Substrate ◽  
Light Emitting ◽  
Direct Excitation ◽  
Ballistic Electron ◽  
Visible Luminescence ◽  
Controlled Structure

AbstractThe concept of a novel solid-state light-emitting device is proposed on a basis of our previous report that the nanocrystalline porous silicon (PS) diode with a well-controlled structure operate as an efficient ballistic electron emitter. This device is composed of a semitransparent thin Au film, a fluorescent thin film, a PS layer, and n-type Si substrate. When a positive bias voltage is applied to the Au electrode, visible luminescence is emitted of which band corresponds to that of the deposited fluorescent material. The optoelectronic characteristics suggest that the light emission is based on direct excitation of fluorescent film by ballistic electrons generated in the PS layer. This result indicates another possibility of nanocrystalline silicon for photonic applications.

Heating, Laser Irradiation and Passivation Study on the Light-Emitting Porous Silicon

1991 ◽  
Vol 256 ◽  
Author(s):  
H. C. Chen ◽  
W. Wang ◽  
K. N. Manjularani ◽  
L. C. Snyder ◽  
X. L. Zheng
Keyword(s):  
Laser Irradiation ◽  
Light Emission ◽  
High Vacuum ◽  
Laser Wavelength ◽  
Ultra High Vacuum ◽  
Ambient Atmosphere ◽  
Severe Problem ◽  
Light Emitting ◽  
Ecr Plasma ◽  
Plasma Passivation

ABSTRACTFor light-emitting porous Si there has been a severe problem with instability and degradation of the light emission. We report that a stabilization of the emission intensity and the peak energy can be achieved in air by a proper laser irradiation, In-situ photoluminescence measurements were performed to monitor the degradation and stabilization process under different conditions and parameters, such as laser power, laser wavelength and environment (ambient atmosphere of certain gas or ultra high vacuum). We found oxygen is the major cause for the emission degradation in this laser enhanced adsorption process, and the laser heating effect can be excluded. For a comparison we study the reversible thermal heating and quenching process. We also discuss microwave and ECR plasma passivation results.

Organic Light Emitting Devices Fabricated from Semiconducting Nanospheres

2002 ◽  
Vol 738 ◽  
Author(s):  
Thomas Piok ◽  
Franz P. Wenzl ◽  
Stefan Gamerith ◽  
Christoph Gadermaier ◽  
Satish Patil ◽  
...  
Keyword(s):  
Light Emission ◽  
Energy Gap ◽  
Detailed Comparison ◽  
Homogeneous Layer ◽  
Semiconducting Polymer ◽  
Light Emitting ◽  
Light Emitting Devices ◽  
Surface Probe ◽  
Organic Light ◽  
Ladder Polymer

ABSTRACTOrganic light emitting diodes (OLEDs) have been fabricated from organic semiconducting polymer nanospheres (SPNs) which have been deposited from aqueous dispersions. The active layer of the devices consists of a single, homogeneous layer of light emitting SPNs, as verified by optical, interferometric and surface probe measurements. Different batches of SPNs with different SPN diameters have been tested (69nm, 95nm, 126nm and 150 nm). All SPN-based OLEDs exhibit a light emission onset corresponding to the SPN energy gap (ca. 2.7 eV for m-LPPP, a semiconducting para-phenylene ladder polymer). The low onset is attributed to field enhanced injection of charge carriers at the aluminum cathode due to the formation of stalactite-type nanostructures. A detailed comparison of the SPN-based and bulk semiconducting polymer films reveals no differences in the basic optoelectronic properties.

scholarly journals Recent advancements and perspectives on light management and high performance in perovskite light-emitting diodes

Nanophotonics ◽  
2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Shaoni Kar ◽  
Nur Fadilah Jamaludin ◽  
Natalia Yantara ◽  
Subodh G. Mhaisalkar ◽  
Wei Lin Leong
Keyword(s):  
High Performance ◽  
Light Propagation ◽  
Light Emission ◽  
Review Article ◽  
Rapid Progress ◽  
Light Emitting ◽  
Materials Engineering ◽  
Perovskite Materials ◽  
Light Management ◽  
Photon Recycling

Abstract Perovskite semiconductors have experienced meteoric rise in a variety of optoelectronic applications. With a strong foothold on photovoltaics, much focus now lies on their light emission applications. Rapid progress in materials engineering have led to the demonstration of external quantum efficiencies that surpass the previously established theoretical limits. However, there remains much scope to further optimize the light propagation inside the device stack through careful tailoring of the optical processes that take place at the bulk and interface levels. Photon recycling in the emitter material followed by efficient outcoupling can result in boosting external efficiencies up to 100%. In addition, the poor ambient and operational stability of these materials and devices restrict further commercialization efforts. With best operational lifetimes of only a few hours reported, there is a long way to go before perovskite LEDs can be perceived as reliable alternatives to more established technologies like organic or quantum dot-based LED devices. This review article starts with the discussions of the mechanism of luminescence in these perovskite materials and factors impacting it. It then looks at the possible routes to achieve efficient outcoupling through nanostructuring of the emitter and the substrate. Next, we analyse the instability issues of perovskite-based LEDs from a photophysical standpoint, taking into consideration the underlying phenomena pertaining to defects, and summarize recent advances in mitigating the same. Finally, we provide an outlook on the possible routes forward for the field and propose new avenues to maximally exploit the excellent light-emitting capabilities of this family of semiconductors.

Non-linear light emission of inorganic protonic diodes, H+LEDs

2021 ◽  
Vol 9 (9) ◽  
pp. 3052-3057
Author(s):  
Jerzy J. Langer ◽  
Ewelina Frąckowiak
Keyword(s):  
Light Emission ◽  
Stimulated Raman Scattering ◽  
Light Emitting ◽  
Light Emitting Devices ◽  
Light Pulses ◽  
Optical Effects ◽  
Non Linear ◽  
Intense Light ◽  
Light Beams ◽  
Intense Light Pulses

H+LEDs are light emitting devices based on a protonic p–n junction; now with no organic polymers. The unique are non-linear optical effects: collimated light beams and stimulated Raman scattering (SRS), observed while generating intense light pulses.

scholarly journals Universal Electroluminescence at Voltages below the Energy Gap in Organic Light‐Emitting Diodes

2021 ◽  
pp. 2101149
Author(s):  
Yungui Li ◽  
Oskar Sachnik ◽  
Bas Zee ◽  
Kalyani Thakur ◽  
Charusheela Ramanan ◽  
...  
Keyword(s):  
Light Emitting Diodes ◽  
Energy Gap ◽  
Organic Light Emitting Diodes ◽  
Light Emitting ◽  
Organic Light

White-light-emitting properties of SrTiO3:Pr3+ nanoparticles

RSC Advances ◽  
2015 ◽  
Vol 5 (35) ◽  
pp. 27491-27495 ◽  
Author(s):  
Wei Tang ◽  
Ye Sun ◽  
Miao Yu ◽  
Xiao Liu ◽  
Yongqi Yin ◽  
...  
Keyword(s):  
White Light ◽  
Light Emission ◽  
White Light Emission ◽  
Light Emitting

White-light emission from SrTiO3:Pr3+ nanoparticles has been achieved by tuning combination of the 3P0 and 1D2-related blue to red emissions.

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