Towards rare-earth-free white light-emitting diode devices based on the combination of dicyanomethylene and pyranine as organic dyes supported on zinc single-layered hydroxide

• Jeff L. Nyalosaso,
• Rachod Boonsin,
• Pierre Vialat,
• Damien Boyer,
• Geneviève Chadeyron,
• Rachid Mahiou and
• Fabrice Leroux

Beilstein J. Nanotechnol. 2019, 10, 760–770, doi:10.3762/bjnano.10.75

• occur. Photoluminescence properties of the integrated dyes Absolute quantum yield (QYab) is defined as the efficiency at which a given material re-emits by fluorescence a certain number of photons absorbed at a given wavelength. The parameters measured in a 3.3 inch integrating sphere provide

• information on the internal conversion (QYint) and the absorbance (Abs) of the studied material. QYint is defined as the ratio between photons emitted and photons absorbed by the material upon external excitation. The product of these two parameters gives the absolute quantum yield in percentage (QYab = QYint

• × Abs × 100%). Measuring the absolute quantum yield (through the scan mode of the software system) as a function of the excitation wavelength is used to plot the profile [QYab = f(λex)] from which one can determine at which excitation wavelength the maximum of QYab occurs. QYab has a direct impact on

Ultrasonication-assisted synthesis of CsPbBr₃ and Cs₄PbBr₆ perovskite nanocrystals and their reversible transformation

• Longshi Rao,
• Xinrui Ding,
• Xuewei Du,
• Guanwei Liang,
• Yong Tang,
• Kairui Tang and
• Jin Z. Zhang

Beilstein J. Nanotechnol. 2019, 10, 666–676, doi:10.3762/bjnano.10.66

• perovskite nanocrystals (PNCs) and their reversible transformation. The as-prepared CsPbBr3 PNCs and Cs4PbBr6 PNCs exhibit different optical properties that depend on their morphology, size, and structure. The photoluminescence (PL) emission and quantum yield (QY) of the CsPbBr3 PNCs can be tuned by changing

• demonstrate excellent properites, such as tunable photoluminescence (PL) throughout the visible spectrum, super high PL quantum yield (QY), low trap-state density, and narrow emission linewidth [6][7][8]. The crystal structure of CsPbX3 (X = Cl−, Br−, I−) PNCs consists of a 12-fold coordinated network created

Ceria/polymer nanocontainers for high-performance encapsulation of fluorophores

• Kartheek Katta,
• Dmitry Busko,
• Yuri Avlasevich,
• Katharina Landfester,
• Stanislav Baluschev and
• Rafael Muñoz-Espí

Beilstein J. Nanotechnol. 2019, 10, 522–530, doi:10.3762/bjnano.10.53

• quantum yield of the fluorophore are, the stronger is the sensitivity to the presence of oxygen quenching [13]. The solubility of oxygen in organic solvents is also an important factor in the quenching process of a florescent molecule. The solubility of oxygen in organic solvents decreases with increasing

• demonstrates an excellent fluorescence quantum yield (ca. 90%) [24], less affected by the presence of molecular oxygen. Using the example of TDI, we aim to demonstrate that in nanoconfined geometries, quenching of the fluorescence of a dye becomes an important issue that needs to be taken into account. To

Reduced graphene oxide supported C₃N₄ nanoflakes and quantum dots as metal-free catalysts for visible light assisted CO₂ reduction

• Md Rakibuddin and
• Haekyoung Kim

Beilstein J. Nanotechnol. 2019, 10, 448–458, doi:10.3762/bjnano.10.44

• GCN-5 towards the reduction of CO2 is found to be better than many other catalysts reported previously in the literature [41][42][43]. The CO2 photoreduction efficiency of the GCN-5 sample was also measured by apparent quantum yield (AQY) measurements, and was found to be 22.3%. The AQY value of GCN-5

• a standard calibration curve. The photoactivity usually depends on the quantity of catalyst and light intensity, therefore the CO2 photoreduction efficiency can also be measured by the apparent quantum yield (AQY), where AQY can be calculated according to Equation 1. The number of electrons required

Dumbbell gold nanoparticle dimer antennas with advanced optical properties

• Janning F. Herrmann and
• Christiane Höppener

Beilstein J. Nanotechnol. 2018, 9, 2188–2197, doi:10.3762/bjnano.9.205

• , and retracting the antenna by 50 nm from the surface. The high quantum yield dyes Alexa633 and Alexa680 respectively, are applied for these measurements, which provide suitable absorption and emission properties in regard to the LSPR of the applied monomer and dimer AuNP antennas. Dark-field

Multimodal noncontact atomic force microscopy and Kelvin probe force microscopy investigations of organolead tribromide perovskite single crystals

• Yann Almadori,
• David Moerman,
• Jaume Llacer Martinez,
• Philippe Leclère and
• Benjamin Grévin

Beilstein J. Nanotechnol. 2018, 9, 1695–1704, doi:10.3762/bjnano.9.161

• , including a direct band gap, high absorption coefficient, large and balanced carrier mobility, high diffusion length, long carrier lifetime and high photoluminescence quantum yield. Within a few years of their discovery, these materials were successfully used to develop photovoltaic cells [2] with power

Photoluminescence of CdSe/ZnS quantum dots in nematic liquid crystals in electric fields

• Margarita A. Kurochkina,
• Elena A. Konshina and
• Daria Khmelevskaia

Beilstein J. Nanotechnol. 2018, 9, 1544–1549, doi:10.3762/bjnano.9.145

• demonstrate unique properties such as high quantum yield, narrow symmetric luminescence peak and high photostability, which are used in optical molecular sensor systems [1], bioanalysis [2], solar cells [3][4], and light-emitting devices [5]. The application of external electric fields to semiconductor NPs

• LC monomers and dimers [21]. The peak of the maximum luminescence intensity of QDs with 5 nm core diameter is at the wavelength of 630 nm. The quantum yield of the semiconductor NPs luminescence strongly depends on the polarity of the surrounding molecules, the electrostatic properties, the

Absence of free carriers in silicon nanocrystals grown from phosphorus- and boron-doped silicon-rich oxide and oxynitride

• Daniel Hiller,
• Julian López-Vidrier,
• Keita Nomoto,
• Michael Wahl,
• Wolfgang Bock,
• Tomáš Chlouba,
• František Trojánek,
• Sebastian Gutsch,
• Margit Zacharias,
• Dirk König,
• Petr Malý and
• Michael Kopnarski

Beilstein J. Nanotechnol. 2018, 9, 1501–1511, doi:10.3762/bjnano.9.141

• probabilities, allowing the luminescence quantum yield to reach ≈30% [36][37], or even ≈60% for organically-capped NCs [38]. In the presence of a third charge carrier (a free electron from an ionized P-donor or a hole from an ionized B-acceptor) radiative recombination is very unlikely, since ultra-fast non

Cr(VI) remediation from aqueous environment through modified-TiO₂-mediated photocatalytic reduction

• Rashmi Acharya,
• Brundabana Naik and
• Kulamani Parida

Beilstein J. Nanotechnol. 2018, 9, 1448–1470, doi:10.3762/bjnano.9.137

• behavior in photocatalytic Cr(VI) reduction. Gherbi et al. reported the visible-light-driven photoreduction of Cr(VI) over CuAl2O4/TiO2 [181] with 95% reduction after 3 h irradiation at pH 2. The photoreduction follows first order kinetics with a half-life of ≈1 h and a quantum yield of 0.11

Electro-optical interfacial effects on a graphene/π-conjugated organic semiconductor hybrid system

• Karolline A. S. Araujo,
• Luiz A. Cury,
• Matheus J. S. Matos,
• Thales F. D. Fernandes,
• Luiz G. Cançado and
• Bernardo R. A. Neves

Beilstein J. Nanotechnol. 2018, 9, 963–974, doi:10.3762/bjnano.9.90

• packing and/or ordering [7]. Previous works have demonstrated that intermolecular interactions can dramatically reduce the luminescence quantum yield in solid-state devices [8][9][10][11][12][13]. In this context, it is important to control the ordering of π-conjugated organic molecules to make their use

Synthesis and characterization of two new TiO₂-containing benzothiazole-based imine composites for organic device applications

• Anna Różycka,
• Agnieszka Iwan,
• Krzysztof Artur Bogdanowicz,
• Michal Filapek,
• Natalia Górska,
• Damian Pociecha,
• Marek Malinowski,
• Patryk Fryń,
• Agnieszka Hreniak,
• Jakub Rysz,
• Paweł Dąbczyński and
• Monika Marzec

Beilstein J. Nanotechnol. 2018, 9, 721–739, doi:10.3762/bjnano.9.67

• conversion efficiency, lifetime) and luminescence parameters (e.g., quantum yield, lifetime) [7][8][9][10][11][12][13][14]. In recent years, the efficiency of bulk heterojunction organic solar cells has shown great improvement, from 2.5 to 13%. Such rapid progress brings us closer to actual commercialization

Green synthesis of fluorescent carbon dots from spices for in vitro imaging and tumour cell growth inhibition

• Nagamalai Vasimalai,
• Vânia Vilas-Boas,
• Juan Gallo,
• María de Fátima Cerqueira,
• Mario Menéndez-Miranda,
• José Manuel Costa-Fernández,
• Lorena Diéguez,
• Begoña Espiña and
• María Teresa Fernández-Argüelles

Beilstein J. Nanotechnol. 2018, 9, 530–544, doi:10.3762/bjnano.9.51

• , respectively. The relative intensities of D band and G band (ID/IG) for cinnamon, red chilli, turmeric and black pepper C-dots were 1.1, 1.2, 1.4 and 1.1, respectively, and reveal the existence of vacant lattice sites of sp3 carbon [27][49][50]. Quantum yield measurements The fluorescent quantum yield of each

• type of spice C-dots was calculated by using the comparative William’s method [51]. For this purpose, quinine sulphate was employed as a reference and the quantum yield was calculated according to Equation 1: where, Fs is the integrated fluorescence emission of the sample, Fr is the integrated

• fluorescence emission of the reference (quinine sulfate), As is the absorbance at the excitation wavelength of the sample, Ar is the absorbance at the excitation wavelength of the reference, QYs is the quantum yield of the sample, and QYr is the quantum yield of the reference fluorophore (quinine sulfate QY

Influence of the preparation method on the photocatalytic activity of Nd-modified TiO₂

• Patrycja Parnicka,
• Paweł Mazierski,
• Tomasz Grzyb,
• Wojciech Lisowski,
• Ewa Kowalska,
• Bunsho Ohtani,
• Adriana Zaleska-Medynska and
• Joanna Nadolna

Beilstein J. Nanotechnol. 2018, 9, 447–459, doi:10.3762/bjnano.9.43

• ultraviolet light irradiation for excitation (the band gap of anatase is about 3.2 eV) and low quantum yield (due to the fast recombination of electron–hole pairs) [7]. These restrictions on its application could be overcome by modifying TiO2, which results in increased activity and ability to work under

• surface properties and the charge carrier recombination processes is presented in Figure 8. The results of the photodegradation significant differences between aqueous solution and gas phase. The quantum yield of the reaction in the gas phase is much higher than that one in aqueous solution due to lower

Co-reductive fabrication of carbon nanodots with high quantum yield for bioimaging of bacteria

• Jiajun Wang,
• Xia Liu,
• Gesmi Milcovich,
• Tzu-Yu Chen,
• Edel Durack,
• Sarah Mallen,
• Yongming Ruan,
• Xuexiang Weng and
• Sarah P. Hudson

Beilstein J. Nanotechnol. 2018, 9, 137–145, doi:10.3762/bjnano.9.16

• , leading to high quantum yield C-dots. The obtained C-dots are well-dispersed with a uniform size and a graphite-like structure. A synergistic reduction mechanism was investigated using Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy. The findings show that using both thiourea

• for bioimaging purposes thanks to their fluorescent features. In this context, the quantum yield (QY) is one of the most important features for C-dot performance. Although, at present, the actual mechanism of the photoluminescence of C-dots is still an open debate among researchers [6][7][8

• ][20]. Qu et al. obtained graphene quantum dots with a quantum yield of 78% and 71% using citric acid and urea or citric acid and thiourea as the precursors, respectively. They demonstrated that N or N/S doping led to the high QY of the C-dots. Zeng et al. prepared C-dots with a relatively high QY

PTFE-based microreactor system for the continuous synthesis of full-visible-spectrum emitting cesium lead halide perovskite nanocrystals

• Chengxi Zhang,
• Weiling Luan,
• Yuhang Yin and
• Fuqian Yang

Beilstein J. Nanotechnol. 2017, 8, 2521–2529, doi:10.3762/bjnano.8.252

• nanocrystals are continuously synthesized via a microreactor system consisting of poly(tetrafluoroethylene) (PTFE) capillaries. The synthesized nanocrystals possess excellent optical properties, including a full width at half maximum of 19–35 nm, high fluorescence quantum yield of 47.8–90.55%, and

• lengths of 15 nm. These materials exhibited tunable emission wavelength in a range of 410–700 nm, a narrow full width at half maximum (FWHM) of 12–42 nm, and high quantum yield (QY) of 50–90%. In comparison with the synthesis of II–VI and I–III–VI semiconductor QDs, Nedelcu et al. [19] and Akkerman et al

• spectra of the CsPbX3 nanocrystals cover the range of 450–700 nm. The prepared nanocrystals possess excellent optical properties with a FWHM of 19–35 nm and a high fluorescence quantum yield (FLQY) of 47.8–90.55%. The CsPbX3 nanocrystals prepared by the PTFE-based microreactor system exhibit three

Changes of the absorption cross section of Si nanocrystals with temperature and distance

• Michael Greben,
• Petro Khoroshyy,
• Sebastian Gutsch,
• Daniel Hiller,
• Margit Zacharias and
• Jan Valenta

Beilstein J. Nanotechnol. 2017, 8, 2315–2323, doi:10.3762/bjnano.8.231

• controlled. The emission properties such as quantum yield (QY) of such Si NC/SiO2 multilayer (ML) structures were studied as a function of inter-nanocrystal distance, temperature, excitation and emission wavelength [5][6]. However, there is still little knowledge about one of the most crucial optical

• . The quantum yield is a quantity that, in principle, must be independent on the number of absorbed photons [1]. In assumption that the internal quantum efficiency, ηI = τPL/τr, scales with the barrier thickness x in the same way as PL QY [5] (η = Nem/Nabs), i.e., the fraction of bright NCs Nem does not

Carbon nano-onions as fluorescent on/off modulated nanoprobes for diagnostics

• Stefania Lettieri,
• Marta d’Amora,
• Adalberto Camisasca,
• Alberto Diaspro and
• Silvia Giordani

Beilstein J. Nanotechnol. 2017, 8, 1878–1888, doi:10.3762/bjnano.8.188

• are protonated (BODIPY 4). Despite the desired NIR window emission spectrum of BODIPY 3, its quantum yield (ΦF) in DMSO is very low (ΦF = 0.05), due to the active PET groups (amino groups), which causes a pH-dependent quenching of the fluorescent dyes. Overall, the non-protonated form of the dye

• acetonitrile. Fluorescence quantum yield Fluorescence quantum yields were determined by the comparative method published by Williams et al. [29]. The integrated fluorescence intensities of a known dye and the tested compound were compared and the fluorescence quantum yields were calculated using the following

• equation: Φx, where st and x denote the standard and test respectively, while Φ is the fluorescence quantum yield. Grad is the gradient obtained from the plot of integrated fluorescence intensity vs absorbance of the dye at the excitation wavelength. η represents the refractive index of the used solvents

Optical techniques for cervical neoplasia detection

• Tatiana Novikova

Beilstein J. Nanotechnol. 2017, 8, 1844–1862, doi:10.3762/bjnano.8.186

• lesions with spectral autofluorescence measurements depends on several factors including (i) changes in autofluorescence background, which may influence the quantum yield of fluorophore, (ii) inhomogeneities in the optical properties of tissue, (iii) alterations of the tissue architecture (e.g., variable

Two-dimensional carbon-based nanocomposites for photocatalytic energy generation and environmental remediation applications

• Suneel Kumar,
• Ashish Kumar,
• Ashish Bahuguna,
• Vipul Sharma and
• Venkata Krishnan

Beilstein J. Nanotechnol. 2017, 8, 1571–1600, doi:10.3762/bjnano.8.159

• separation rate of photogenerated charge carriers to enhance the quantum yield. Notably, such heterojunction formation with semiconductors also enhances the light absorption efficiency of photocatalysts from UV to visible region of the solar energy spectrum. Furthermore, it is noteworthy to mention here that

Bright fluorescent silica-nanoparticle probes for high-resolution STED and confocal microscopy

• Isabella Tavernaro,
• Christian Cavelius,
• Henrike Peuschel and
• Annette Kraegeloh

Beilstein J. Nanotechnol. 2017, 8, 1283–1296, doi:10.3762/bjnano.8.130

• available carbopyronine dye Atto647N was selected as a model dye [50]. It matches the preferred spectral characteristics and has gained popularity as fluorescence label due to its strong absorption, excellent fluorescence, quantum yield and good solubility [51][52]. However, Atto647N had to be modified

• identical number of dye molecules (Figure 4). In addition, the quantum yields were determined. For the quantum yield measurements the comparative method of Williams et al. [56] was utilized, which involves the use of a well characterised standard with a known quantum yield (ΦF) and fitting absorption and

• emission spectra. Normally, this method cannot be used for samples that exhibit significant scattering since the additional light emission leads to an overestimation of the quantum yield [57]. Nevertheless, the method can be still applied if a scattering correction is performed with the reference sample

AgCl-doped CdSe quantum dots with near-IR photoluminescence

• Pavel A. Kotin,
• Sergey S. Bubenov,
• Natalia E. Mordvinova and
• Sergey G. Dorofeev

Beilstein J. Nanotechnol. 2017, 8, 1156–1166, doi:10.3762/bjnano.8.117

• investigated. The optimal conditions for maximizing both the reaction yield and IR photoluminescence quantum yield are found. Keywords: Ag doping; CdSe quantum dots; doped semiconductor nanocrystals; IR photoluminescence; tetrapods; Introduction Colloidal quantum dots (QDs) have attracted considerable

ZnO nanoparticles sensitized by CuInZn_xS_2+x quantum dots as highly efficient solar light driven photocatalysts

• Florian Donat,
• Serge Corbel,
• Halima Alem,
• Steve Pontvianne,
• Lavinia Balan,
• Ghouti Medjahdi and
• Raphaël Schneider

Beilstein J. Nanotechnol. 2017, 8, 1080–1093, doi:10.3762/bjnano.8.110

• CIS core QDs using the Zn(OAc)2-OA complex [23]. The obtained ZCIS QDs absorb light until ca. 700 nm and their PL maximum is located at ca. 620 nm (Supporting Information File 1, Figure S1). The PL quantum yield of these red-emitting dots is 50% in toluene and their bandgap, estimated through the

• increased production of 1O2 for the ZnO/ZCIS catalyst compared to ZnO was observed, especially during the first ten minutes of irradiation. The kinetic of SOSG-EP formation was used for the determination of the 1O2 quantum yield (Ф1O2) of ZnO/ZCIS particles. Rose Bengal (RB) was used as a reference

Performance of colloidal CdS sensitized solar cells with ZnO nanorods/nanoparticles

• Anurag Roy,
• Partha Pratim Das,
• Mukta Tathavadekar,
• Sumita Das and
• Parukuttyamma Sujatha Devi

Beilstein J. Nanotechnol. 2017, 8, 210–221, doi:10.3762/bjnano.8.23

• (150 W) as an excitation source with a bandpass of 5 nm at room temperature. The fluorescence quantum yield of the colloidal CdS solution was measured on the steady state fluorometer using an additional integrating sphere [32]. Zeta potential measurements were carried out on a Horiba Nanoparticle

• from 340 to 390 nm, as shown in Figure 2d. A green emission at 536 nm was observed against all the excitation wavelengths. The intensity of the emission band was maximum at the excitation wavelength of 390 nm. The solution of synthesized CdS in ethanol resulted in a quantum yield (QY) of 3.116% at room

Facile fabrication of luminescent organic dots by thermolysis of citric acid in urea melt, and their use for cell staining and polyelectrolyte microcapsule labelling

• Nadezhda M. Zholobak,
• Anton L. Popov,
• Alexander B. Shcherbakov,
• Nelly R. Popova,
• Mykhailo M. Guzyk,
• Valeriy P. Antonovich,
• Alla V. Yegorova,
• Yuliya V. Scrypynets,
• Inna I. Leonenko,
• Alexander Ye. Baranchikov and
• Vladimir K. Ivanov

Beilstein J. Nanotechnol. 2016, 7, 1905–1917, doi:10.3762/bjnano.7.182

• Supporting Information File 1, Figure S1). Thus, the hydrothermal treatment of an equimolar mixture of citric acid and sodium hydroxide solutions in an autoclave at 160 °C for 4 h leads to the formation of O-dots having a quantum yield of about 22% [21]. Similarly, hydrothermal treatment of a solution of

• sodium citrate and ammonium bicarbonate at 180 °C for 4 h leads to the formation of O-dots with excellent photostability [22]. When a 0.328 M solution of ammonium citrate was subjected to hydrothermal treatment in an autoclave at 160 °C for 6 h, the resulting dots had a quantum yield of about 13.5% [23

• ]. Bourlinos et al. [24][25] heated various citrate salts, e.g., ammonium citrate in air, up to 300 °C, to produce water-soluble carbon dots of 7 nm average diameter and a fluorescence quantum yield of 3% at 495 nm excitation [24]. Doping of citric acid-based organic dots with nitrogen greatly improves their

Photocurrent generation in carbon nanotube/cubic-phase HfO₂ nanoparticle hybrid nanocomposites

• Protima Rauwel,
• Augustinas Galeckas,
• Martin Salumaa,
• Frédérique Ducroquet and
• Erwan Rauwel

Beilstein J. Nanotechnol. 2016, 7, 1075–1085, doi:10.3762/bjnano.7.101

• nanoparticles [21]. Figure 3 shows room temperature PL spectra of the hybrid nanocomposites dispersed in ethanol as a colloidal suspension and of the free-standing HfO2 nanoparticles. As one can deduce from the PL intensity scales in Figure 3a,b, the total quantum yield in the case of nanocomposites is two