Yellow-Emitting Carbon Nanodots and Their Flexible and Transparent Films for White LEDs

Kim, Tak H.; White, Alan; Sirdaarta, Joseph; Ji, Wenyu; Cock, Ian Edwin; John, James St; Boyd, Sue E.; Brown, Christopher L.; Q, Li

doi:10.1021/acsami.6b12113

Cited by 51 publications

(39 citation statements)

References 55 publications

(106 reference statements)

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“…The prime focus of solid-state lighting research, especially the fabrication of LEDs and displays, relies on the sustainability and environmental friendliness of luminescent nanomaterials, with extraordinary optical features in terms of QY, lifetime, photostability and other light-emitting parameters (such as colour chromaticity, colour rendering index (CRI) and correlated colour temperature (CCT)). 2,[132][133][134][135][136][137][138][139][140][141][142][143][144][145][146] The traditional approaches for the fabrication of LEDs are mostly based on the use of environmentally unfriendly materials and complicated fabrication procedures, which restrict their real-life application in indoor and outdoor lighting. 2,[132][133][134][135][136][137][138][139][140][141][142][143][144][145][146] This brings a new paradigm towards the fabrication of LEDs and displays using natural and biological sources, which are biocompatible in nature and have anticipated optical properties.…”

Section: Light-emitting Devices (White Leds)mentioning

confidence: 99%

Biomolecule-derived quantum dots for sustainable optoelectronics

et al. 2019

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Section: Light-emitting Devices (White Leds)mentioning

confidence: 99%

Biomolecule-derived quantum dots for sustainable optoelectronics

et al. 2019

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“…Carbon dots (CDs) have attracted significant research interest in the past decade owing to their excellent optical performance, low toxicity, chemical stability and flexibility and versatility in synthesis [2]. Their bright and tunable fluorescence has prompted development of CDs for a wide range of applications including biological imaging [3,4], sensing [5], solid state lighting [6,7], and drug delivery [8,9].…”

Section: Introductionmentioning

confidence: 99%

Selective toxicity of hydroxyl-rich carbon nanodots for cancer research

et al. 2018

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Authors are required to submit a graphic entry for the Table of Contents (TOC) in conjunction with the manuscript title. This graphic should capture the readers' attention and give readers a visual impression of the essence of the paper. Labels, formulae, or numbers within the graphic must be legible at publication size. Tables or spectra are not acceptable. Color graphics are highly encouraged. The resolution of the figure should be at least 600 dpi. The size should be at least 50 mm × 80 mm with a rectangular shape (ideally, the ratio of height to width should be less than 1 and larger than 5/8). One to two sentences should be written below the figure to summarize the paper. To create the TOC, please insert your image in the template box below. Fonts, size, and spaces should not be changed.Highly biocompatible carbon nanodots were synthesized, which are abundant in hydroxyl functional groups on particle surface. Interestingly, the nanoparticles display divergent antiproliferative activities against two ovarian choriocarcinoma cell lines, which may be further explored for cancer drug discovery. ABSTRACTThe toxicity of nanoparticles in a biological system is an integration of effects arising from surface functionality, particle size and ionic dissolution etc. Its complexity suggests that generalization on a material's toxicity may be inappropriate. Moreover, from medicinal point of view, toxicity can be used for treatment of malignant cells, such as cancer. In this study, highly biocompatible carbon nanodots (named gCDs) were synthesized by reacting citric acid and urea in glycerol, which resulted in abundant hydroxyl functional groups on particle surface. gCDs show excitation-dependent photoluminescence, but with brighter green to yellow emission. Importantly, a series of toxicity assessments showed that as-synthesized gCDs possess exceptional biocompatibilities to various biological entities including 18 bacteria species, Petunia axillaris seedlings and Artemia franciscana nauplii. Furthermore, the particles were shown to have low-to non-toxic effects on human embryonic kidney (HEK-293) cell lines, breast (MCF-7), oral squamous (CAL-27) carcinoma cell lines. Of particular interest, the gCDs display antiproliferative activities against ovarian choriocarcinoma cells (JAr / Jeg-3 cell lines), which may be further explored for cancer drug discovery.

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“…The electroluminescence (EL) spectrum of the WLED shown in Figure 5c displays three emission bands centered individually at 452, 520, and 611 nm. The as‐synthesized WLED also showed color coordinates of 0.366 and 0.366 with a correlated color temperature (CCT) of 4333 K. It was remarkable to see that that the CRI of the WLED could reach a maximum of 93.5, performing better than most of CD‐based WLEDs and commercial lights (Table S3, Supporting Information) . As shown in Figure 5d, the WLED maintains great color rendering ability, with true picture colors under ambient light vividly reflected.…”

Section: Resultsmentioning

confidence: 99%

Scalable Synthesis of Green Fluorescent Carbon Dot Powders with Unprecedented Efficiency

Wei

Lou

Zang

et al. 2020

Advanced Optical Materials

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quantum yield (PL QY) of 93.3%; the highest yield to date among the blue-emitting CDs. [21] Sun and co-workers developed a CD synthesis technique using multicolored emission through controlled graphitization and surface functionalization. [1] They found the CD emission band to be tunable from 430 nm to 630 nm, which covers the blue and red region.Despite such large progress achieved for CD synthesis, plenty of barriers still exist to CD commercialization. Typically, CDs with great performance are primarily prepared through solvothermal routes, meaning at least several hours are needed to prepare CDs at milligram levels. [1,3,4,6,[19][20][21][22][23] Nevertheless, expensive precursors and complex purification processes will no doubt enlarge the construction costs and increase the preparation time. [3][4][5][6] In another way, CDs suffer from aggregation-causedquenching (ACQ) due to π-π stacking in the solid state, which has shown to greatly hinder the application of CDs in light-emitting fields. [24][25][26][27][28] To overcome this deficiency, efforts have been targeted to develop solid CDs with efficient fluorescence by way of CD monomer separation from direct contact, including CD implantation inside polymer matrices and combining them with inorganic salts as composites. [29][30][31][32][33][34][35][36][37][38] Although this effectively prevents the ACQ of CDs in solid state by the dispersal of CDs into various matrices, only CDs at lower loading fractions (i.e., <0.2 wt%) have the ability to achieve high PL QY. [39] While most white LEDs (WLEDs) are created using the one-step synthesis of white light-emitting CDs, the down-conversion fluorescent powders usually suffer from low luminous efficiency or color instability. [40][41][42] Therefore, it is paramount to develop solid CDs with high fluorescence efficiency and stability in facile, low cost, and high-output ways in order to satisfy scale-up industrial production and application.In this study, we report a facile one-step microwave-assisted heating method to prepare solid CDs with strong green emissions. Here, citric acid, urea, and sodium hydroxide (NaOH) have been used as precursors. The CDs were also made to be resistant to self-quenching by in situ embedding the CD into the crystal matrix of NaOH, so that the PL QY could reach 75.9% in the solid state. To the best of our knowledge, this is the highest value attained for solid CDs having green emission. [8,32,[35][36][37][38] Moreover, powdered CD (CDPs) would also have the potential to be prepared on a much larger scale in several minutes It still remains a challenge to synthesize solid-state carbon dots (CDs) with high emission efficiency; a hurdle that has hindered the application of CDs in many fields. In this work, efficient fluorescent CDs have been prepared through a one-step microwave-assisted heating method. Experimental data show strong green emissions produced from the CD powders (CDPs), carrying an unprecedented 75.9% quantum yield due to both spatial confinement and defect reduction with the ...

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Yellow-Emitting Carbon Nanodots and Their Flexible and Transparent Films for White LEDs

Cited by 51 publications

References 55 publications

Biomolecule-derived quantum dots for sustainable optoelectronics

Biomolecule-derived quantum dots for sustainable optoelectronics

Selective toxicity of hydroxyl-rich carbon nanodots for cancer research

Scalable Synthesis of Green Fluorescent Carbon Dot Powders with Unprecedented Efficiency

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