Enhancement of band-edge luminescence and photo-stability in colloidal CdSe quantum dots by various surface passivation technologies

Xu, Ling; Chen, Kunji; El-Khair, Hatim Mohamed; Li, Minghai; Huang, Xinfan

doi:10.1016/s0169-4332(00)00834-5

Cited by 49 publications

(24 citation statements)

References 8 publications

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“…The use of fluorescence to quantify the QD distribution in tissues was deemed problematic, owing to the high and variable background fluorescence from native blood and tissue. Moreover, the fluorescence of the QDs is susceptible to environmental factors-the quantum yield (unit brightness) has been demonstrated to change drastically with surface chemistry, [21] rearrangement of surface ligands, [22,23] photoenhanced oxidization, [24] and solvent effects. [25] Any of these would give rise to large error deviations in fluorescence measurements.…”

Section: Resultsmentioning

confidence: 99%

Pharmacokinetics of Nanoscale Quantum Dots: In Vivo Distribution, Sequestration, and Clearance in the Rat

et al. 2006

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Section: Resultsmentioning

confidence: 99%

Pharmacokinetics of Nanoscale Quantum Dots: In Vivo Distribution, Sequestration, and Clearance in the Rat

et al. 2006

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“…This material has been widely used for photoelectronic devices [2]. In the past decade, a great deal of research has been done on controlling the size, shape and crystal structure of CdSe nanocrystals because their electrical and optical properties are strongly related to their morphology.…”

Section: Introductionmentioning

confidence: 99%

Synthesis and characterization of CdSe nanorods using a novel microemulsion method at moderate temperature

Lam

2007

Journal of Colloid and Interface Science

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“…Although better performing blue (singlet) emitting conjugated polymers exist for the moment, PVK has energy levels excellently situated to host a blue triplet emitter. Furthermore a large amount of experimental information exists on this commercially available polymer and its photophysics [15][16][17][18][19][20][21][22][23][24][25].…”

Section: Introductionmentioning

confidence: 99%

“…After the synthesis the QDs are further encapsulated with a desired ligand. The ligands bound to the surface of quantum dots largely dictate their solution properties, and their miscibility in a particular medium including organic solvents and polymer films [2][3][25][26]. It has been reported that most of the commonly used ligands are insulating, due to a wide optical bandgap (σ-σ* or wide π-π*), which could prevent the transfer of charges and/or excitons when the QDs are incorporated in a polymer.…”

Section: Introductionmentioning

confidence: 99%

Blue light-emitting-diodes from poly (N-vinylcarbazole) doped with colloidal quantum dots encapsulated with carbazole terminated ligand: spectroscopic studies and devices

et al. 2012

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Blue emitting CdSe/ZnS quantum dots (QDs) were encapsulated with the ligand 11-(N-carbazolyl) undecanoic acid (C11). Steady-state photoluminescence (PL) experiments show an enhancement of the QD emission upon the excitation of the carbazole ligand in solution compared to the situation where a solution with the same concentration of QDs capped with oleic acid (OA) were excited at the same wavelength. This suggests energy transfer from the carbazole moiety to the QD cores. When incorporating the QDs in a poly (N-vinylcarbazole) (PVK) matrix, a significant enhancement of the QD emission upon the excitation of PVK was also observed indicating an efficient energy transfer from PVK to the QDs in the case of C11 capped ligands. Confocal microscopy images of the doped PVK films show clearly better miscibility of PVK and QDs capped with C11 compared with those capped with OA. Nanosecond time-resolved PL experiment shows evidence of singlet transfer with Förster resonance energy transfer (FRET) efficiency of 39% for the QDs in solution, while the efficiency of this process amounted to 15.6% for a PVK film doped with 30 wt% of the QDs. The smaller efficiency of the singlet transfer compared to the overall efficiency of energy transfer, suggested by the stationary PL spectra suggests an important role for triplet energy transfer. Electroluminescent devices were prepared with the structure; ITO/PEDOT:PSS/doped PVK with C11 capped QDs/Butyl PBD/Aluminum. Upon applying voltage, the devices show pure blue electroluminescence at low concentration of QDs (10 wt%) with a turn on voltage close to 6V.Keywords: Colloidal quantum dots, organic light emitting diodes, electroluminescence, blue OLEDs, energy transfer, triplet transfer, organic electronics, PVK INTRODUCTIONColloidal semiconductor quantum dots (QDs) are a relatively a new class of materials for optoelectronics. Due to their unique properties, e.g., tunable emission wavelength, they are attractive for many applications such as light emitting diodes, solar cells, and lasers [1-2]. Among them, cadmium selenide (CdSe) QDs have become a bench mark material for research on colloidal nanomaterials for (electro)luminesncence applications due to the tunability of their emission over the visible range between 475 and 670 nm upon increasing QD size [3]. To use QDs as a light source however requires also a the absence of (photo)chemical degradation and a high luminescence quantum yield (QY). These can be fulfilled by surface passivation with inorganic compounds which have broader band gap that encompasses the bandgap of the QD core, so-called core/shell nanostructure (type I) [2,[4][5].

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Enhancement of band-edge luminescence and photo-stability in colloidal CdSe quantum dots by various surface passivation technologies

Cited by 49 publications

References 8 publications

Pharmacokinetics of Nanoscale Quantum Dots: In Vivo Distribution, Sequestration, and Clearance in the Rat

Pharmacokinetics of Nanoscale Quantum Dots: In Vivo Distribution, Sequestration, and Clearance in the Rat

Synthesis and characterization of CdSe nanorods using a novel microemulsion method at moderate temperature

Blue light-emitting-diodes from poly (N-vinylcarbazole) doped with colloidal quantum dots encapsulated with carbazole terminated ligand: spectroscopic studies and devices

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