scholarly journals Light-emitting Ga-oxide nanocrystals in glass: a new paradigm for low-cost and robust UV-to-visible solar-blind converters and UV emitters

Nanoscale ◽  
2014 ◽  
Vol 6 (3) ◽  
pp. 1763-1774 ◽  
Author(s):  
Vladimir N. Sigaev ◽  
Nikita V. Golubev ◽  
Elena S. Ignat'eva ◽  
Alberto Paleari ◽  
Roberto Lorenzi
Keyword(s):  
Light Emission ◽  
Low Cost ◽  
New Paradigm ◽  
Light Emitting ◽  
Solar Blind ◽  
Donor Acceptor ◽  
Uv Emitters ◽  
Kinetics Of

We demonstrate that nano-confinement of donor–acceptor recombination can force a nanophase to follow efficient bimolecular kinetics of light-emission, allowing Ga2O3 nanocrystals to work in glass as unprecedented solar-blind UV-to-visible converters.

Ambipolar injection in a submicron channel light-emitting tetracene transistor with distinct source and drain contacts

2004 ◽  
Vol 846 ◽  
Author(s):  
J. Reynaert ◽  
D. Cheyns ◽  
D. Janssen ◽  
V. I. Arkhipov ◽  
G. Borghs ◽  
...  
Keyword(s):  
Integrated Circuits ◽  
Organic Semiconductor ◽  
Light Emission ◽  
Low Cost ◽  
Channel Length ◽  
Light Emitting ◽  
Organic Light ◽  
Optimal Injection ◽  
Distinct Source ◽  
Effect Transistor

ABSTRACTOver the last decade, organic semiconductor thin film transistors have been the focus of many research groups because of their potential application in low-cost integrated circuits. Recently, an organic light-emitting field-effect transistor (OLEFET) was reported. In an OLEFET structure, optimal injection of both holes and electrons into the light-emitting layer are required for maximum quantum efficiency, whereas the gate serves as a controlling electrode. In this work, we achieved an OLFET structure with interdigitated hole-injecting Au and electron-injecting Ca contacts within a submicrometer channel length. Both contacts are bottom contacts to the upper-lying tetracene organic semiconductor. The study of IV-characteristics and light emission from these devices shined light on the underlying physics of the OLEFETs.

Tuning optical properties of CsPbBr3 by mixing Nd3+trivalent lanthanide halide cations for blue light emitting devices.

2022 ◽  
Author(s):  
Muhammad Amin Padhiar ◽  
Minqiang Wang ◽  
Yongqiang Ji ◽  
Zhi Yang ◽  
Arshad Saleem Bhatti
Keyword(s):  
Optical Properties ◽  
Blue Light ◽  
Light Emission ◽  
Low Cost ◽  
Thermal Quenching ◽  
Visible Spectrum ◽  
Light Emitting ◽  
Light Emitting Devices ◽  
Lanthanide Halide ◽  
Trivalent Lanthanide

Abstract In recent years, significant progress has been made in the red and green perovskite quantum dots (PQDs) based light-emitting devices. However, a scarcity of blue-emitting devices that are extremely efficient precludes their research and development for optoelectronic applications. Taking advantage of tunable bandgaps of PQDs over the entire visible spectrum, herein we tune optical properties of CSPbBr3 by mixing Nd3+ trivalent lanthanide halide cations for blue light-emitting devices. The CsPbBr3 PQDs doped with Nd3+ trivalent lanthanide halide cations emitted strong photoemission from green into the blue region. By adjusting their doping concentration, a tunable wavelength from (515 nm) to (450 nm) was achieved with FWHM from (37.83 nm) to (16.6 nm). We simultaneously observed PL linewidth broadening thermal quenching of PL and the blue shift of the optical bandgap from temperature-dependent PL studies. The Nd3+ cations into CsPbBr3 PQDs more efficiently reduced non-radiative recombination. As a result of the efficient removal of defects from PQDs, the photoluminescence quantum yield (PLQY) has been significantly increased to 91% in the blue-emitting region. Significantly, Nd3+ PQDs exhibit excellent long-term stability against the external environment, including water, temperature, and ultraviolet light irradiation. Moreover, we successfully transformed Nd3+ doped PQDs into highly fluorescent nanocomposites. Incorporating these findings, we fabricate and test a stable blue light-emitting LED with EL emission at (462 nm), (475 nm), and successfully produce white light emission from Nd3+ doped nanocomposites with a CIE at (0.32, 0.34), respectively. The findings imply that low-cost Nd3+ doped perovskites may be attractive as light converters in LCDs with a broad color gamut.

Maximizing TADF via Conformational Optimization

2021 ◽  
Author(s):  
Changhae Andrew Kim ◽  
Troy Van Voorhis
Keyword(s):  
Density Functional ◽  
Minimum Energy ◽  
Delayed Fluorescence ◽  
New Paradigm ◽  
Light Emitting ◽  
Td Dft ◽  
New Strategy ◽  
Donor Acceptor ◽  
The Right ◽  
Geometric Changes

We investigate a new strategy to enhance thermally activated delayed fluorescence (TADF) in organic light-emitting diodes (OLEDs). Given that the TADF rate of a molecule depends on its conformation, we hypothesize that there exists a conformation that maximizes the TADF rate. In order to test this idea, we use time-dependent density functional theory (TD-DFT) to simulate the TADF rates of several TADF emitters, while shifting their geometries towards higher TADF rates in a select subspace of internal coordinates. We find that geometric changes in this subspace can increase the TADF rate up to three orders of magnitude with respect to the minimum energy conformation, and the simulated TADF rate can even be brought into the submicrosecond timescales under the right conditions. Furthermore, the rate enhancement can be maintained with a conformational energy that are within the reach of modern synthetic chemistry. Analyzing the maximum TADF conformation, we extract a number of structural motifs that might provide a useful handle on the TADF rate of a donor-acceptor (DA) system. The incorporation of conformational engineering into the TADF technology could usher in a new paradigm of OLEDs.

scholarly journals Low Cost Fabrication of Si NWs/CuI Heterostructures

Nanomaterials ◽  
2018 ◽  
Vol 8 (8) ◽  
pp. 569 ◽  
Author(s):  
Maria Lo Faro ◽  
Antonio Leonardi ◽  
Dario Morganti ◽  
Barbara Fazio ◽  
Ciro Vasi ◽  
...  
Keyword(s):  
Silicon Nanowires ◽  
Light Emission ◽  
Low Cost ◽  
Dye Sensitized Solar Cells ◽  
Copper Iodide ◽  
Light Emitting ◽  
Junction Device ◽  
Type Semiconductor ◽  
P Type ◽  
Sensitized Solar Cells

In this paper, we present the realization by a low cost approach compatible with silicon technology of new nanostructures, characterized by the presence of different materials, such as copper iodide (CuI) and silicon nanowires (Si NWs). Silicon is the principal material of the microelectronics field for its low cost, easy manufacturing and market stability. In particular, Si NWs emerged in the literature as the key materials for modern nanodevices. Copper iodide is a direct wide bandgap p-type semiconductor used for several applications as a transparent hole conducting layers for dye-sensitized solar cells, light emitting diodes and for environmental purification. We demonstrated the preparation of a solid system in which Si NWs are embedded in CuI material and the structural, electrical and optical characterization is presented. These new combined Si NWs/CuI systems have strong potentiality to obtain new nanostructures characterized by different doping, that is strategic for the possibility to realize p-n junction device. Moreover, the combination of these different materials opens the route to obtain multifunction devices characterized by promising absorption, light emission, and electrical conduction.

Light-emitting properties of donor–acceptor and donor–acceptor–donor dyes in solution, solid, and aggregated states: structure–property relationship of emission behavior

RSC Advances ◽  
2015 ◽  
Vol 5 (108) ◽  
pp. 89171-89187 ◽  
Author(s):  
Tsutomu Ishi-i ◽  
Kei Ikeda ◽  
Michiaki Ogawa ◽  
Yutarou Kusakaki
Keyword(s):  
Light Emission ◽  
Aqueous Environment ◽  
Structure Property ◽  
Light Emitting ◽  
Property Relationship ◽  
Structure Property Relationship ◽  
Donor Acceptor ◽  
Emission Behavior ◽  
Relationship Of

In a polar aqueous environment, a series of triphenylamine-based donor–acceptor-type dyes showed efficient light emission upon the formation of aggregates.

Near sunlight continuous broadband white-light emission by single-phase Zn(ii)-1,3,5-benzenetricarboxylate MOFs

2019 ◽  
Vol 48 (40) ◽  
pp. 14966-14970 ◽  
Author(s):  
Ce Wang ◽  
Zheng Yin ◽  
Wei-Min Ma ◽  
Xi-Yao Li ◽  
Li-Hui Cao ◽  
...  
Keyword(s):  
White Light ◽  
Single Phase ◽  
Light Emitting Diodes ◽  
Light Emission ◽  
Low Cost ◽  
White Light Emission ◽  
Light Emitting ◽  
White Light Emitting Diodes

A white light MOF was constructed from low-cost 1,3,5-benzenetricarboxylate and nontoxic Zinc(ii) ions, which exhibited near sunlight continuous white-light emission under a wide radiation range of 300 to 390 nm and was used for white-light emitting diodes.

Stable fluorescent CdS:Cu QDs and their hybridization with carbon polymer dots for white light emission

2016 ◽  
Vol 4 (8) ◽  
pp. 1665-1674 ◽  
Author(s):  
Manish Kr Mishra ◽  
Sangita Kundu ◽  
Goutam De
Keyword(s):  
White Light ◽  
Colloidal Solution ◽  
Light Emission ◽  
White Light Emission ◽  
Facile Synthesis ◽  
Acceptor Pair ◽  
Light Emitting ◽  
Polymer Dots ◽  
Donor Acceptor ◽  
Donor Acceptor Pair

Facile synthesis of a white light emitting colloidal solution and ORMOSIL film, by hybridizing the orange emission of CdS:Cu and the cyan emission of CPD, as a donor–acceptor pair.

FIREFLY FLASHING IS CONTROLLED BY GATING OXYGEN TO LIGHT-EMITTING CELLS

2001 ◽  
Vol 204 (16) ◽  
pp. 2795-2801 ◽  
Author(s):  
GRAHAM S. TIMMINS ◽  
FRASER J. ROBB ◽  
CARMEN M. WILMOT ◽  
SIMON K. JACKSON ◽  
HAROLD M. SWARTZ
Keyword(s):  
Gas Phase ◽  
Oxygen Diffusion ◽  
Control Mechanism ◽  
Light Emission ◽  
Dark State ◽  
Normobaric Hyperoxia ◽  
Light Emitting ◽  
Gas Phases ◽  
Firefly Bioluminescence ◽  
Kinetics Of

SUMMARY Although many aspects of firefly bioluminescence are understood, the mechanism by which adult fireflies produce light as discrete rapid flashes is not. Here we examine the most postulated theory, that flashing is controlled by gating oxygen access to the light-emitting cells (photocytes). According to this theory, the dark state represents repression of bioluminescence by limiting oxygen, which is required for bioluminescence; relief from this repression by transiently allowing oxygen access to the photocytes allows the flash. We show that normobaric hyperoxia releases the repression of light emission in the dark state of both spontaneously flashing and non-flashing fireflies, causing continual glowing, and we measure the kinetics of this process. Secondly, we determine the length of the barriers to oxygen diffusion to the photocytes in the aqueous and gas phases. Thirdly, we provide constraints upon the distance between any gas-phase gating structure(s) and the photocytes. We conclude from these data that the flash of the adult firefly is controlled by gating of oxygen to the photocytes, and demonstrate that this control mechanism is likely to act by modulating the levels of fluid in the tracheoles supplying photocytes, providing a variable barrier to oxygen diffusion.

scholarly journals Maximizing TADF via Conformational Optimization

2021 ◽  
Author(s):  
Changhae Andrew Kim ◽  
Troy Van Voorhis
Keyword(s):  
Density Functional ◽  
Minimum Energy ◽  
Delayed Fluorescence ◽  
New Paradigm ◽  
Light Emitting ◽  
Td Dft ◽  
New Strategy ◽  
Donor Acceptor ◽  
The Right ◽  
Geometric Changes

We investigate a new strategy to enhance thermally activated delayed fluorescence (TADF) in organic light-emitting diodes (OLEDs). Given that the TADF rate of a molecule depends on its conformation, we hypothesize that there exists a conformation that maximizes the TADF rate. In order to test this idea, we use time-dependent density functional theory (TD-DFT) to simulate the TADF rates of several TADF emitters, while shifting their geometries towards higher TADF rates in a select subspace of internal coordinates. We find that geometric changes in this subspace can increase the TADF rate up to three orders of magnitude with respect to the minimum energy conformation, and the simulated TADF rate can even be brought into the submicrosecond timescales under the right conditions. Furthermore, the rate enhancement can be maintained with a conformational energy that are within the reach of modern synthetic chemistry. Analyzing the maximum TADF conformation, we extract a number of structural motifs that might provide a useful handle on the TADF rate of a donor-acceptor (DA) system. The incorporation of conformational engineering into the TADF technology could usher in a new paradigm of OLEDs.

Study of the Cu(II) removal from aqueous solutions by adsorption on titania

2013 ◽  
Vol 12 (3) ◽  
pp. 239-247
Keyword(s):  
Heavy Metals ◽  
Ionic Strength ◽  
Toxic Metals ◽  
Low Cost ◽  
Lateral Interaction ◽  
Tio2 Surface ◽  
High Toxicity ◽  
Removal Of Heavy Metals ◽  
Solution Parameters ◽  
Kinetics Of

The removal of heavy metals from wastewaters is a matter of paramount importance due to the fact that their high toxicity causes major environmental pollution problems. One of the most efficient, applicable and low cost methods for the removal of toxic metals from aqueous solutions is that of their adsorption on an inorganic adsorbent. In order to achieve high efficiency, it is important to understand the influence of the solution parameters on the extent of the adsorption, as well as the kinetics of the adsorption. In the present work, the adsorption of Cu(II) species onto TiO2 surface was studied. It was found that the adsorption is a rapid process and it is not affected by the value of ionic strength. In addition, it was found that by increasing the pH, the adsorbed amount of Cu2+ ions and the value of the adsorption constant increase, whereas the value of the lateral interaction energy decreases.

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