Light emission driven by magnetic and electric toroidal dipole resonances in a silicon metasurface

Over the past decade, interest about metal halide perovskites has rapidly increased, as they can find wide application in optoelectronic devices. Nevertheless, although thermal evaporation is crucial for the development and engineering of such devices based on multilayer structures, the optical properties of thermally deposited perovskite layers (spontaneous and amplified spontaneous emission) have been poorly investigated. This paper is a study from a nano- to micro- and macro-scale about the role of light-emitting species (namely free carriers and excitons) and trap states in the spontaneous emission of thermally evaporated thin layers of CH3NH3PbBr3 perovskite after wet air UV light trap passivation. The map of light emission from grains, carried out by SNOM at the nanoscale and by micro-PL techniques, clearly indicates that free and localized excitons (EXs) are the dominant light-emitting species, the localized excitons being the dominant ones in the presence of crystallites. These species also have a key role in the amplified spontaneous emission (ASE) process: for higher excitation densities, the relative contribution of localized EXs basically remains constant, while a clear competition between ASE and free EXs spontaneous emission is present, which suggests that ASE is due to stimulated emission from the free EXs.

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Effect of Laser Irradiation on Emissivity of Flame-Generated Nanooxides

Materials ◽

10.3390/ma14092303 ◽

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.

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

Nanophotonics ◽

10.1515/nanoph-2021-0033 ◽

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.

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Tunable Light‐Emission Properties of Solution‐Processable N‐Heterocyclic Carbene Cyclometalated Gold(III) Complexes for Organic Light‐Emitting Diodes

Chemistry - A European Journal ◽

10.1002/chem.202100499 ◽

2021 ◽

Author(s):

Robert Malmberg ◽

Tobias Arx ◽

Monirul Hasan ◽

Olivier Blacque ◽

Atul Shukla ◽

...

Keyword(s):

Light Emitting Diodes ◽

Light Emission ◽

Organic Light Emitting Diodes ◽

Light Emitting ◽

Emission Properties ◽

Organic Light ◽

Solution Processable

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

Journal of Materials Chemistry C ◽

10.1039/d0tc05935h ◽

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.

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

RSC Advances ◽

10.1039/c4ra16757k ◽

2015 ◽

Vol 5 (35) ◽

pp. 27491-27495 ◽

Cited By ~ 18

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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White light emission from a blue polymer light emitting diode combined with YAG:Ce3+ nanoparticles

physica status solidi (a) ◽

10.1002/pssa.201330346 ◽

2013 ◽

Vol 211 (3) ◽

pp. 651-655 ◽

Cited By ~ 5

Author(s):

Jorge Oliva ◽

Elder De la Rosa ◽

Luis Diaz-Torres ◽

Anvar Zakhidov

Keyword(s):

White Light ◽

Light Emission ◽

Light Emitting Diode ◽

White Light Emission ◽

Light Emitting ◽

Polymer Light Emitting Diode

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Visible Light Emission from Erbium Doped Yttria Stabilized Zirconia

MRS Proceedings ◽

10.1557/proc-789-n11.8 ◽

2003 ◽

Vol 789 ◽

Cited By ~ 3

Author(s):

Michael Cross ◽

Walter Varhue

Keyword(s):

Band Gap ◽

Light Emission ◽

Green Light ◽

Yttria Stabilized Zirconia ◽

Stabilized Zirconia ◽

Rare Earth Ion ◽

Device Structure ◽

Insulating Layer ◽

Light Emitting ◽

Erbium Doped

ABSTRACT: One of the major shortcomings of silicon (Si) as a semiconductor material is its inability to yield efficient light emission. There has been a continued interest in adding rare earth ion impurities such as erbium (Er) to the Si lattice to act as light emitting centers. The low band gap of Si however has complicated this practice by quenching and absorbing this possible emission. Increasing the band gap of the host has been successfully tried in the case of gallium nitride (GaN) [1] and Si-rich oxide (SRO) [2] alloys. A similar approach has been tried here, where Er oxide (ErOx) nanocrystals have been formed in a yttria stabilized zirconia (YSZ) host deposited on a Si (100) substrate. The YSZ is deposited as a heteroepitaxial, insulating layer on the Si substrate by a reactive sputtering technique. The Er is also incorporated by a sputtering process from a metallic target and its placement in the YSZ host can be easily controlled. The device structure formed is a simple metal contact/insulator/phosphor sandwich. The device has been found to emit visible green light at low bias voltages. The advantage of this material is that it is much more structured than SiO2 which can theoretically lead to higher emission intensity.

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