Highly Bright Research Articles

Highly Bright and Stable CsPbX3@Cs4PbX6 Hexagonal Nanoarchitectonics Created by Controlling Dissolution-Recrystallization of CsPbX3 Nanomaterials.

CsPbBr3@Cs4PbBr6 hexagonal NCs with a bright photoluminescence (PL) peak of 456nm are created through the dissolution-recrystallization of CsPbBr3 nanoplatelets. Small CsPbBr3 nanocrystals are encapsulated in hexagonal Cs4PbBr6 during recrystallization to form a core-shell structure and keep high brightness and stability. The recrystallization kinetics is systematically investigated to explore the roles of methyl acetate, oleylamine, and n-hexane. Result further indicates that core/shell NCs remained high PL under a variety of harsh conditions (e.g., light irradiation and heat treatment) because of Cs4PbX6 shell and the controlling of recrystallization. Their initial PL intensity is remained after 4 months of storage under ambient conditions and continuous exposure to UV lamp for 180min. The bright PL is also maintained even treatment at 120°C. To indicate the universality of this synthesis method, CsPbX3@Cs4PbX6 hexagonal NCs with different emission colors are fabricated by changing temperature, solvent viscosity, and precursors (e,g, oleylamine and halogens). These core-shell samples reveal bright and stable green, orange, and red PL. Because of its high stability, the core/shell NCs are dispersed in flexible films to create diverse patterns. The films also exhibit high brightness and excellent stability. This strategy opens a novel avenue for the application of perovskite nanomaterials in the display field.

Water sensitized and highly bright multicolor Ni-doped carbon dots nanoarchitectonics in polar solvents towards stable flexible films

To address the issues of low photoluminescence quantum yields (PLQYs), broad PL spectra, and poor stability, multicolor carbon dots (CDs) were synthesized by using different precursors. Blue-emitting CDs were created via a solvothermal synthesis by using citric acid and ethylenediamine while green-emitting CDs were fabricated using O-phenylenediamine. Ni doping further increased the PLQYs and stability of CDs. Ni-doped CDs (Ni-CDs) with blue- and green-emitting were synthesized through a one-step solvothermal method. The PL peak wavelengths of Ni-doped blue CDs (Ni-BCDs) and Ni-doped green CDs (Ni-GCDs) were located at 450 and 540 nm, respectively. After Ni-doping, the average particle size of green-emitting CDs was increased from 2.35 to 2.65 nm. Compared with undoped CDs, Ni-CDs exhibited narrow PL spectra, high PLQYs, and long fluorescent lifetime. The PLQYs of Ni-BCDs and Ni-GCDs were increased to 83.92 and 35.60 %, respectively. Interestingly, the PL peak wavelengths of Ni-doped CDs revealed a red-shift with increasing the solvent polarity (e.g. acetone, acetonitrile, N, N-dimethylformamide, tetrahydrofuran, dimethyl sulfoxide, ethanol, methanol, and H2O). In addition, the PL peaks of green-emitting Ni-CDs generated a large red-shift with increase the ratio of water in organic solvents compared with blue one. Namely, solid Ni-GCDs powders also revealed water dependent PL. After incorporating the CDs in flexible films, Ni-GCDs still revealed high brightness and stability. These results supplied important possibility for the application of multicolor CDs.

Synthesis-Kinetics of Violet- and Blue-Emitting Perovskite Nanocrystals with High Brightness and Superior Stability toward Flexible Conversion Layer.

The low photoluminescence (PL) efficiency and unstable features of small blue-emitting CsPbX3 nanocrystals (NCs) greatly limit their applications in optoelectronics field. Herein, the synergistic and post-treatment kinetics are studied to create highly bright and anomalous stable violet (peak position of ≈408nm) and blue (peak position of ∼ 466nm) emitting perovskite NCs. Ligand and ion exchange mechanism are systematic studied by the evolution of absorption, PL, and fluorescence lifetime to evaluate ligand bonding, defect engineering, and non-radiative recombination. Didodecyl dimethyl mmonium chloride (DDAC) and CuX2 post-synergistictreatment created DDAC-CsPbCl3-CuCl2 and DDAC-CsPbCl3-CuBr2 NCs that remained the phase composition, morphology, and size of CsPbCl3 NCs. The PL efficiencies are drastically increased to 42 and 85% for violet- and blue-emitting NCs, respectively. The stability test indicated that the NCs enable against various harsh conditions (e.g., ultraviolet light irradiation and heat-treatment). The NCs retained their initial PL efficiency after 2 months under ambient conditions and UV light irradiation. These NCs also exhibited high stability after heat-treatment at 120°C. The emitting NCs embedded in flexible films still revealed bright PL and high stability, suggesting current results provide a new avenue for the application in the field of optoelectronics.

Brighten strontium aluminate long-persistence materials via optimizing defect energy level distribution

Afterglow brightness of inorganic persistent luminescent (PersL) materials upon ceasing light excitation represents an important parameter for various glow-in-the-dark applications. Although the emission wavelength of PersL materials is developed to cover over the whole spectral range from ultraviolet to near infrared light, and light emission is sufficiently long-lasting with a fractional number of rare-earth doped PersL materials commercially available, PersL materials with high initial afterglow brightness at room-temperature condition remain rarely reported. Employing trap-controlled temperature dependency of persistent luminescence mechanism, defect energy level distribution, and microwave-assisted solid-state reaction, here a highly bright green-emitting strontium aluminate phosphor is reported. Higher initial afterglow brightness (a photometric luminance of 99.8 cd/m2, enhanced 1.7 times than that of the commercial one) is achieved due to the massive aggregation of charge carriers at shallow-trap energy levels. The relation between initial afterglow brightness and trap energy level distribution is investigated. The glowing-in-the-dark composite panel composed of Sr4Al14O25:Eu2+, Dy3+ and Polydimethylsiloxane can light up the safety sign and the map of fire evacuation route. These findings may provide a major step forward to developing high-brightness PersL materials and are expected to further benefit a wide range of PersL material systems for practical glow-in-the-dark applications.

Highly Bright Near-Infrared Chemiluminescent Probes for Cancer Imaging and Laparotomy.

Near-infrared (NIR) chemiluminescence imaging holds potential for sensitive imaging of cancer due to its low background; however, few NIR chemiluminophores are available, which share the drawback of low chemiluminescence quantum yields (ΦCL ). Herein, we report the synthesis of NIR chemiluminophores for cancer imaging and laparotomy. Molecular engineering of the electron-withdrawing group at the para-position of the phenol-dioxetane leads to a highly bright NIR chemiluminophore (DPT), showing the ΦCL (4.6×10-2 Einstein mol-1 ) that is 3 to 5-fold higher than existing NIR chemiluminophores. By caging the phenol group of DPT with a cathepsin B (CatB) responsive moiety, an activatable chemiluminescence probe (DPTCB ) is developed for real-time turn-on detection of deeply buried tumor tissues in living mice. Due to its high brightness, DPTCB permits accurate chemiluminescence-guided laparotomy.

Highly Bright Near‐Infrared Chemiluminescent Probes for Cancer Imaging and Laparotomy

AbstractNear‐infrared (NIR) chemiluminescence imaging holds potential for sensitive imaging of cancer due to its low background; however, few NIR chemiluminophores are available, which share the drawback of low chemiluminescence quantum yields (ΦCL). Herein, we report the synthesis of NIR chemiluminophores for cancer imaging and laparotomy. Molecular engineering of the electron‐withdrawing group at the para‐position of the phenol‐dioxetane leads to a highly bright NIR chemiluminophore (DPT), showing the ΦCL(4.6×10−2 Einstein mol−1) that is 3 to 5‐fold higher than existing NIR chemiluminophores. By caging the phenol group of DPT with a cathepsin B (CatB) responsive moiety, an activatable chemiluminescence probe (DPTCB) is developed for real‐time turn‐on detection of deeply buried tumor tissues in living mice. Due to its high brightness, DPTCBpermits accurate chemiluminescence‐guided laparotomy.

High-Resolution Imaging of the Ocular Vasculature of Conjunctivitis in Mice Using Highly Bright Polymer Dots.

Ocular diseases are mainly caused by vascular aberrations in the eye, and accurate imaging and analysis of the ocular vascular structure is crucial. In this study, poly(9,9-dioctylfluorene-alt-benzothiadiazole) (PFBT) polymer dots (Pdots), with the advantages of easy synthesis, high brightness, and low toxicity, are used as nanoprobes to perform high-resolution imaging of the vasculature of the eyeball and optic nerve. Moreover, rapid imaging of the choroidal microvessels is carried out by stereoscopic fluorescence microscopy with a resolution of up to 1.6µm. The comprehensive 3D vascular information of retinal aorta and optic nerve microvessels is obtained by combining tissue clearing and multiphoton microscopy. In addition, the vascular density of Schlemm's canal and iris blood vessels is compared between the conjunctivitis mice and the normal mice. These results suggest that PFBT Pdots have great application potential in the fast and accurate imaging of ocular diseases.

The Design and Bioimaging Applications of NIR Fluorescent Organic Dyes with High Brightness

AbstractDue to the merits of decreased photon attenuation, autofluorescence, and scattering, the near‐infrared (NIR, 700–1700 nm) region is an important window in the field of biomedicine, such as in vivo fluorescence imaging, in which both the optical detection depth and the resolution/contrast have been significantly improved. In particular, for second NIR (NIR‐II, 1000–1700 nm) dyes, biological tissues have almost no background interference. Typical fluorophores have excellent spectral performance and rich functional modification sites and can be optimized into NIR dyes for bioimaging. However, as the absorption/emission wavelength of fluorophores redshift to NIR, it is challenging to keep fluorophores with satisfying brightness. Therefore, for the purpose of increasing the absorption/emission wavelength of dye while promoting its brightness, it is necessary to study the structure–property relationship of the dyes. This review introduces the influences of fluorophores’ structure on their photophysical properties, summarizes the strategies for maintaining high fluorescence brightness along with redshifted absorption/emission wavelengths, and the latest advances of highly fluorescent brightness dyes. Finally, the opportunities and challenges in this emerging field are also provided. The authors aim to provide insightful design guidelines and clear overview of highly bright NIR fluorescent dyes, which might trigger new ideas and applications.

Achieving High Afterglow Brightness in Organic Dopant‐Matrix Systems

AbstractAfterglow brightness upon ceasing excitation represents an important parameter for afterglow material applications, while purely‐organic room‐temperature afterglow materials with high quantum yields, long emission lifetimes, and strong absorption capability, which are necessary to realize high afterglow brightness, remain rarely reported. Using dopant‐matrix collaboration, thermally activated delayed fluorescence mechanism, and spiro molecular design, here a highly bright afterglow system is reported, that possesses persistent luminescence quantum yields as high as 30% and emission lifetimes up to 0.6 s at ambient conditions by doping spiro‐shaped difluoroboron β‐diketonate (spiroBF2, ε = 6.5 × 104 M−1cm−1) luminogens into benzophenone (BP) matrices. After being processed into desired shapes and large‐area panels by melt casting, the spiroBF2‐BP material exhibits intense green afterglow that is much brighter than a typical SrAl2O4:Eu2+, Dy3+ inorganic afterglow material and can last for more than 5 s under room light, which is among the brightest afterglow in purely‐organic systems.

Silafluorene as a promising core for cell-permeant, highly bright and two-photon excitable fluorescent probes for live-cell imaging

In this study, we report the synthesis, linear and non-linear photophysical studies and live-cell imaging of two two-photon activatable probes based on a silafluorene core: SiFluo-V and SiFluo-L. Thanks to their quadrupolar (A-π-D-π-A) design, these probes exhibit respectively good to impressive two-photon cross-sections (from 210 GM to 2150 GM). TD-DFT calculations support the experimental evidence that SiFluo-L displays far better two-photon absorption properties than SiFluo-V. Moreover, SiFluo-L possesses all requirements for bioimaging as it is water soluble, cell-permeant and presents a low cytotoxicity (IC80 ≥ 10 μM). It labels mitochondria in live-cell imaging at low laser power with high brightness, contrast and photostability. This study demonstrates that silafluorene is a promising core to develop new two-photon fluorophores for live-cell imaging.

Planar and Twisted Molecular Structure Leads to the High Brightness of Semiconducting Polymer Nanoparticles for NIR-IIa Fluorescence Imaging.

Semiconducting polymer nanoparticles (SPNs) emitting in the second near-infrared window (NIR-II, 1000-1700 nm) are promising materials for deep-tissue optical imaging in mammals, but the brightness is far from satisfactory. Herein, we developed a molecular design strategy to boost the brightness of NIR-II SPNs: structure planarization and twisting. By integration of the strong absorption coefficient inherited from planar π-conjugated units and high solid-state quantum yield (ΦPL) from twisted motifs into one polymer, a rise in brightness was obtained. The resulting pNIR-4 with both twisted and planar structure displayed improved ΦPL and absorption when compared to the planar polymer pNIR-1 and the twisted polymer pNIR-2. Given the emission tail extending into the NIR-IIa region (1300-1400 nm) of the pNIR-4 nanoparticles, NIR-IIa fluorescence imaging of blood vessels with enhanced clarity was observed. Moreover, a pH-responsive poly(β-amino ester) made pNIR-4 specifically accumulate at tumor sites, allowing NIR-IIa fluorescence image-guided cancer precision resection. This study provides a molecular design strategy for developing highly bright fluorophores.

Dragonfly-shaped near-infrared AIEgen with optimal fluorescence brightness for precise image-guided cancer surgery

Organic near-infrared (NIR) emitters with simultaneously high absorption coefficient and photoluminescence quantum yield (PLQY) are highly desirable for biomedical imaging yet seldom reported because these two aspects are usually contradictory. The conjugated planar structures exhibit strong absorption but the emission is seriously quenched in aggregate state, whereas the twisted unplanar molecules display opposite phenomena. Herein, we report a kind of dragonfly-shaped NIR aggregation-induced emission luminogen (AIEgen) with both high absorption coefficient (6.24 × 104 M−1 cm−1) and superior PLQY (51.2%) for precise image-guided cancer surgery. The compound possessing a conjugated structure with vibrational substitutes has been synthesized, in which the good conjugation enables strong absorption, and the molecular vibration affords AIE signature. Moreover, the nonfluorescent processes are significantly suppressed, making every effort to boost fluorescence. The highly bright and stable AIE nanoparticles warrant efficient in vitro cellular imaging and in vivo tumor imaging. Moreover, the fluorescence imaging-guided cancer surgery helps to precisely delineate tiny tumor nodules, significantly improving the cancer surgery outcome. This work will inspire more insights into the development of organic NIR emitters with high brightness for biomedical applications.

Deep-red fluorescence from isolated dimers: a highly bright excimer and imaging in vivo.

Restricted by the energy-gap law, the development of bright near-infrared (near-IR) fluorescent luminophors in the solid state remains a challenge. Herein, we report a new design strategy for realizing high brightness and deep-red/near-IR-emissive organic molecules based on the incorporation of a hybridized local and charge-transfer (HLCT) state and separated dimeric stacks into one aggregate. Experimental and theoretical analyses show that this combination not only contributes to high photoluminescent quantum yields (PLQYs) but also significantly lessens the energy gap. The fluorophore BTA-TPA exhibits excellent fluorescence performance, achieving a PLQY of 54.8% for the fluorescence peak at 690 nm, which is among the highest reported for near-IR fluorescent excimers. In addition, because of its bioimaging performance, the designed luminophor has potential for use as a deep-red fluorescent probe for biomedical applications. This research opens the door for developing deep-red/near-IR emissive materials with high PLQYs.

ATP-Independent Bioluminescent Reporter Variants To Improve in Vivo Imaging.

Coelenterazine (CTZ)-utilizing marine luciferases and their derivatives have attracted significant attention because of their ATP-independency, fast enzymatic turnover, and high bioluminescence brightness. However, marine luciferases typically emit blue photons and their substrates, including CTZ and the recently developed diphenylterazine (DTZ), have poor water solubility, hindering their in vivo applications. Herein, we report a family of pyridyl CTZ and DTZ analogs that exhibit spectrally shifted emission and improved water solubility. Through directed evolution, we engineered a LumiLuc luciferase with broad substrate specificity. In the presence of corresponding pyridyl substrates (i.e., pyCTZ, 6pyDTZ, or 8pyDTZ), LumiLuc generates highly bright blue, teal, or yellow bioluminescence. We compared our LumiLuc-8pyDTZ pair with several benchmark reporters in a tumor xenograft mouse model. Our new pair, which does not need organic cosolvents for in vivo administration, surpasses other reporters by detecting early tumors. We further fused LumiLuc to a red fluorescent protein, resulting in a LumiScarlet reporter with further red-shifted emission and enhanced tissue penetration. LumiScarlet-8pyDTZ was comparable to Akaluc-AkaLumine, the brightest ATP-dependent luciferase-luciferin pair, for detecting cells in deep tissues of mice. In summary, we have engineered a new family of ATP-independent bioluminescent reporters, which will have broad applications because of their ATP-independency, excellent biocompatibility, and superior in vivo sensitivity.

Alternating-current driven quantum-dot light-emitting diodes with high brightness.

Highly bright alternating-current (AC) driven quantum-dot light-emitting diodes (QLEDs) are demonstrated based on a single dielectric layer structure. The use of a single dielectric layer P(VDF-TrFE-CFE) enables the injection of electrons under AC driving, whereas holes are generated inside the devices by using MoO3/TFB hole generating layers. The brightness of the device is greatly affected by the capacitance of the dielectric layer, the hole generating capability of MoO3/TFB and the driving frequency of the bias. By optimizing the thicknesses of P(VDF-TrFE-CFE) and MoO3 and the driving frequency, an AC-driven QLED with a luminance of 65 760 cd m-2 is demonstrated, which is the highest value ever reported. To improve the efficiency, a tandem AC-driven QLED is further developed, which alternately emits light in the positive and the negative driving cycles. As a result, the tandem AC-driven QLED exhibits a higher luminance and a current efficiency of 50 750 cd m-2 and 5.1 cd A-1, which are 1.3-fold higher than those (39 200 cd m-2, 3.9 cd A-1) of a single AC-driven QLED at the same current density. The demonstrated highly bright QLEDs that are directly driven by AC electricity could therefore eliminate the use of a direct-current (DC) power converter and could provide a potential alternative to conventional DC-driven devices for displays and lighting application.

Green Light-Emitting Devices Based on Perovskite CsPbBr3 Quantum Dots.

In this paper, high quality green-emitting CsPbBr3 quantum dots (QDs) are successfully synthesized by hot-injection method. Different injection temperatures are tested to optimize the synthesis conditions. High brightness with the photoluminescence (PL) quantum yields (QYs) up to 90% and narrow size-distribution with the full width at half-maximum (FWHM) of 18.5 nm are obtained under the optimized conditions. Green light emitting diodes (LEDs) based on the CsPbBr3 QDs are successfully demonstrated by combining solution method with vapor deposition method. Composite films of poly[9,9-dioctylfluorene-co- N-[4-(3-methylpropyl)]-diphenylamine] (TFB) and bathocuproine (BCP) layers are chosen as the hole-transporting and the electron-transporting layers, respectively. The highly bright green QD-based light-emitting devices (QLEDs) showing maximum luminance up to 46,000 cd/m2 with a low turn on voltage of 2.3 V, and peak external quantum efficiency (EQE) of 5.7%, corresponding to 19.9 cd/A in luminance efficiency. These devices also show high color purity for electroluminescence (EL) with FWHM <20 nm, and no redshift and broadening with increasing voltage as well as a spectral match between PL and EL.

One‐pot preparation of multicolor polymeric nanoparticles with high brightness by single wavelength excitation

ABSTRACTFluorescent nanoparticles with multiplex distinct emission signatures and high brightness by a single wavelength excitation are substantially needed in multiplex bioassays and imaging. In this study, we synthesized fluorescent polymeric nanoparticles incorporated with three polymerizable organic dyes via a one‐pot miniemulsion. By altering the doping ratio of three tandem dyes, the nanoparticles display abundant multiple fluorescence such as blue, cyan, green, orange, pink, red etc., together with distinguishable emission signatures under a single wavelength excitation, which were arising from the effective fluorescence resonance energy transfer (FRET) between the three energy‐matched dyes. Meanwhile, a large Stokes shift (up to 250 nm) can be generated by taking place multiple FRET cascade mechanism between donor and acceptor fluorophores in nanoparticles, which also suggests broad applications in biological labeling and imaging. Moreover, these nanoparticles are uniform in size, highly bright, excellently photostable, and shown prominent longterm stability. Overall, the novel multicolor fluorescent polymeric nanoparticles augur well for their potential applications in multiplexed bioanalysis and emitting displays. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41492.

Highly Efficient Blue–Green Quantum Dot Light-Emitting Diodes Using Stable Low-Cadmium Quaternary-Alloy ZnCdSSe/ZnS Core/Shell Nanocrystals

High-quality blue-green emitting ZnxCd(1-x)S(1-y)Se(y)/ZnS core/shell quantum dots (QDs) have been synthesized by a phosphine-free method. The quantum yields of as-synthesized ZnxCd(1-x)S(1-y)Se(y)/ZnS core/shell QDs can reach 50-75% with emissions between 450 and 550 nm. The emissions of such core/shell QDs are not susceptible to ligand loss through the photostability test. Blue-green light-emitting diodes (LEDs) based on the low-cadmium ZnxCd(1-x)S(1-y)Se(y)/ZnS core/shell QDs have been successfully demonstrated. Composite films of poly[9,9-dioctylfluorene-co-N-[4-(3-methylpropyl)]-diphenylamine] (TFB) and ZnO nanoparticle layers were chosen as the hole-transporting and the electron-transporting layers, respectively. Highly bright blue-green QD-based light-emitting devices (QD-LEDs) showing maximum luminance up to 10000 cd/m(2), in particular, the blue QD-LEDs show an unprecedentedly high brightness over 4700 cd/m(2) and peak external quantum efficiency (EQE) of 0.8%, which is the highest value ever reported. These results signify a remarkable progress in QD-LEDs and offer a practicable platform for the realization of QD-based blue-green display and lighting.

Multicolor Fluorescent Semiconducting Polymer Dots with Narrow Emissions and High Brightness

Fluorescent semiconducting polymer dots (Pdots) have attracted great interest because of their superior characteristics as fluorescent probes, such as high fluorescence brightness, fast radiative rates, and excellent photostability. However, currently available Pdots generally exhibit broad emission spectra, which significantly limit their usefulness in many biological applications involving multiplex detections. Here, we describe the design and development of multicolor narrow emissive Pdots based on different boron dipyrromethene (BODIPY) units. BODIPY-containing semiconducting polymers emitting at multiple wavelengths were synthesized and used as precursors for preparing the Pdots, where intraparticle energy transfer led to highly bright, narrow emissions. The emission full width at half-maximum of the resulting Pdots varies from 40 to 55 nm, which is 1.5-2 times narrower than those of conventional semiconducting polymer dots. BODIPY 520 Pdots were about an order of magnitude brighter than commercial Qdot 525 under identical laser excitation conditions. Fluorescence imaging and flow cytometry experiments indicate that the narrow emissions from these bright Pdots are promising for multiplexed biological detections.

Highly bright multicolor tunable ultrasmall β-Na(Y,Gd)F4:Ce,Tb,Eu/β-NaYF4 core/shell nanocrystals

Herein, we report highly bright multicolor-emitting β-Na(Y,Gd)F₄:Ce,Tb,Eu/β-NaYF₄ nanoparticles (NPs) with precise color tunability. First, highly bright sub-20 nm β-Na(Y,Gd)F₄:Ce,Tb,Eu NPs were synthesized via a heating-up method. By controlling the ratio of Eu(3+) to Tb(3+), we generated green, yellow-green, greenish yellow, yellow, orange, reddish orange, and red emissions from the NP solutions via energy transfer of Ce(3+)→ Gd(3+)→ Tb(3+) (green) and Ce(3+)→ Gd(3+)→ Tb(3+)→ Eu(3+) (red) ions under ultraviolet light illumination (254 nm). Because of Ce(3+) and Gd(3+) sensitization, Tb(3+) ions exhibited strong green emission. The decay time of Tb(3+) emission decreased from 4.0 to 1.4 ms as the Eu(3+) concentration was increased, suggesting that energy was transferred from Tb(3+) to Eu(3+). As a result, Eu(3+) emission peaks were generated and the emission color was transformed from green to red. Monodisperse sub-6 nm β-Na(Y,Gd)F₄:Ce,Tb,Eu NPs were synthesized through a simple reduction of the reaction temperature. Although fine color tunability was retained, their brightness was considerably decreased owing to an increase in the surface-to-volume ratio. The formation of a β-NaYF₄ shell on top of the sub-6 nm NP core to produce β-Na(Y,Gd)F₄:Ce,Tb,Eu/β-NaYF₄ significantly increased the emission intensity, while maintaining the sub-10 nm sizes (8.7-9.5 nm). Quantum yields of the ultrasmall NPs increased from 1.1-6.9% for the core NPs to 6.7-44.4% for the core/shell NPs. Moreover, highly transparent core/shell NP-polydimethylsiloxane (PDMS) composites featuring a variety of colors, excellent color tunability, and high brightness were also prepared.