Quantum Dot-Based Light Emitting Diodes (QDLEDs): New Progress

Heydari, Neda; Ghorashi, Seyed Mohammad Bagher; Han, Wooje; Park, Hyung Ho

doi:10.5772/intechopen.69014

Cited by 9 publications

(6 citation statements)

References 86 publications

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“…One of the striking applications of C-NCs is in the field of biological imaging of cells, where quantum dots are used owing to their excellent fluorescent properties and also they do not photo-chemically bleach out like organic dyes [20]. Recently, quantum dots are being used commercially in LED displays also known as QLED-displays [21]. In addition, C-NCs-based photo/ electro-catalysts for ECO 2 RR and EH 2 ER are being developed to solve the energy crisis and global warming.…”

Section: Colloidal Synthesis Of Ncsmentioning

confidence: 99%

Colloidal Nanocrystal-Based Electrocatalysts for Combating Environmental Problems and Energy Crisis

Nazır¹,

Prasad²,

Parihar³

et al. 2021

Colloids - Types, Preparation and Applications

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The serious threat that human beings face in near future will be shortage of fossil fuel reserves and abrupt changes in global climate. To prepare for these serious concerns, raised due to climate change and shortage of fuels, conversion of excessive atmospheric CO2 into valuable chemicals and fuels and production of hydrogen from water splitting is seen most promising solutions to combat the rising CO2 levels and energy crises. Amoung the various techniques that have been employed electrocatalytic conversion of CO2 into fuels and hydrogen production from water has gained tremendous interest. Hydrogen is a zero carbon-emitting fuel, can be an alternative to traditional fossil fuels. Therefore, researchers working in these areas are constantly trying to find new electrocatalysts that can be applied on a real scale to deal with environmental issues. Recently, colloidal nanocrystals (C-NCs)-based electrocatalysts have gained tremendous attention due to their superior catalytic selectivity/activity and durability compared to existing bulk electrodes. In this chapter, the authors discuss the colloidal synthesis of NCs and the effect of their physiochemical properties such as shape, size and chemical composition on the electrocatalytic performance and durability towards electrocatalytic H2 evolution reaction (EH2ER) and electrocatalytic CO2 reduction reactions (ECO2RR). The last portion of this chapter presents a brief perspective of the challenges ahead.

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Section: Colloidal Synthesis Of Ncsmentioning

confidence: 99%

Colloidal Nanocrystal-Based Electrocatalysts for Combating Environmental Problems and Energy Crisis

Nazır¹,

Prasad²,

Parihar³

et al. 2021

Colloids - Types, Preparation and Applications

View full text Add to dashboard Cite

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“…Owing to the tiny size of these semiconducting QDs, they can produce high photoluminescence quantum yield when compared to their bulk materials [3]. Moreover, they can resist photobleaching for long time, and hence can be included in the design of optical biosensors [4][5][6], photovoltaic [7,8], bioimaging [9] and light emitting diode [10]. The most commonly utilized types of QDs are composed of semiconductors of periodic group II-VI (CdTe, CdSe, CdS, ZnSe, ZnS, PbS, PbSe, PbTe, SnTe) [11].…”

Section: Introductionmentioning

confidence: 99%

Glutathione-Capped ZnS Quantum Dots-Urease Conjugate as a Highly Sensitive Urea Probe

Metwly

Fadl

Soliman

et al. 2023

J Inorg Organomet Polym

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Quantum dots (QDs) possess characteristic chemical and optical features. In this light, ZnS QDs capped with glutathione (GSH) were synthesized via an easy aqueous co-precipitation technique. Fabricated QDs were characterized in terms of X-ray diffraction (XRD), high resolution transmission electron microscope (HRTEM), Fourier transform infrared (FTIR) and Zeta potential analyses. Optical properties were examined using photoluminescence (PL) and ultraviolet–visible (UV–visible) spectroscopies. Moreover, GSH-capped ZnS QDs were evaluated as an optical probe for non-enzymatic detection of urea depending on the quenching of PL intensity of ZnS QDs in the presence of urea from concentration range of 0.5–5 mM with a correlation coefficient (R2) of 0.995, sensitivity of 0.0875 mM−1 and LOD of 0.426 mM. Furthermore, GSH-capped ZnS QDs-urease conjugate was utilized as an optical probe for enzymatic detection of urea in the range from 1.0 µM to 5.0 mM. Interestingly, it was observed that urea has a good affinity towards ZnS QDs-urease conjugate with a linear relationship between the change of PL intensity and urea concentration. It was found that R2 is 0.997 with a sensitivity of 0.042 mM−1 for mM concentration (0.5–5 mM) and LOD of 0.401 mM. In case of µM concentration range (1–100 µM), R2 was 0.971 with a sensitivity of 0.0024 µM−1 and LOD of 0.687 µM. These data suggest that enzyme conjugation to capped QDs might improve their sensitivity and applicability. Graphical Abstract

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“…CdSe/ZnS colloidal QDs possess a high quantum yield and good photostability at room temperature. This makes them an excellent choice for the lighting industry, and they have been extensively studied [20][21][22]. In many optoelectronic devices, quantum dots (QDs) are used as phosphors to absorb light in order to convert it into low-energy light in long wavelengths, since they exhibit excellent optical properties.…”

Section: Introductionmentioning

confidence: 99%

Quantum Dot-Based White Organic Light-Emitting Diodes Excited by a Blue OLED

et al. 2022

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In this study, white organic light-emitting diodes (OLEDs) consisting of red quantum dots (RQD) and green quantum dots (GQD) were investigated. These are the most exciting new lighting technologies that have grown rapidly in recent years. The white OLED development processes used consisted of the following methods: (a) fabrication of a blue single-emitting layer OLED, (b) nanoimprinting into QD photoresists, and (c) green and red QD photoresists as color conversion layers (CCL) excited by blue OLEDs. To fabricate the blue OLED, the HATCN/TAPC pair was selected for the hole injection/transport layer on ITO and TPBi for the electron transport layer. For blue-emitting material, we used a novel polycyclic framework of thermally activated delayed fluorescence (TADF) material, ν-DABNA, which does not utilize any heavy metals and has a sharp and narrow (FWHM 28 nm) electroluminescence spectrum. The device structure was ITO/HATCN (20 nm)/TAPC (30 nm)/MADN: ν-DABNA (40 nm)/TPBi (30 nm)/LiF (0.8 nm)/Al (150 nm) with an emitting area of 1 cm × 1 cm. The current density, luminance, and efficiency of blue OLEDs at 8 V are 87.68 mA/cm2, 963.9 cd/m2, and 1.10 cd/A, respectively. Next, the bottom emission side of the blue OLED was attached to nanoimprinted RQD and GQD photoresists, which were excited by the blue OLED in order to generate an orange and a green color, respectively, and combined with blue light to achieve a nearly white light. In this study, two different excitation architectures were tested: BOLED➔GQD➔RQD and BOLED➔RQD➔GQD. The EL spectra showed that the BOLED➔GQD➔RQD architecture had stronger green emissions than BOLED➔RQD➔GQD because the blue OLED excited the GQD PR first then RQD PR. Due to the energy gap architectures in BOLED-GQD-RQD, the green QD absorbed part of the blue light emitted from the BOLED, and the remaining blue light penetrated the GQD to reach the RQD. These excited spectra were very close to the white light, which resulted in three peaks emitting at 460, 530, and 620 nm. The original blue CIE coordinates were (0.15, 0.07). After the excitation combination, the CIE coordinates were (0.42, 0.33), which was close to the white light position.

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Quantum Dot-Based Light Emitting Diodes (QDLEDs): New Progress

Cited by 9 publications

References 86 publications

Colloidal Nanocrystal-Based Electrocatalysts for Combating Environmental Problems and Energy Crisis

Colloidal Nanocrystal-Based Electrocatalysts for Combating Environmental Problems and Energy Crisis

Glutathione-Capped ZnS Quantum Dots-Urease Conjugate as a Highly Sensitive Urea Probe

Quantum Dot-Based White Organic Light-Emitting Diodes Excited by a Blue OLED

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