Highest Photoluminescence Emission Intensity Research Articles

Resonance photoemission in pure and Tb doped CePO4 luminescent nanowires

The resonance photoemission spectroscopy (RPES) studies on pure and Terbium doped CePO4 nanowires (NWs) are reported here with the supporting characterizations using structural, optical and morphological properties. The NWs with varying Terbium (Tb) doping concentrations were synthesized using chemical synthesis route. Photoluminescence (PL) showed high PL emission intensity in the visible wavelength range indicating strong green luminescence due to efficient Ce3+ to Tb3+ energy transfer. The PL intensity increased up to a doping concentration of 15 wt% Tb3+, beyond which it decreased due to concentration quenching or cross-relaxation effect. Based on PL studies, pure, 5 wt% (the lowest doping amount) and 15 wt% (that shows the highest PL) doped samples were chosen for RPES studies. To understand the comparative contribution of Ce3+ and Ce4+ in the valence band, RPES measurements performed around the Ce 4d →4 f resonance threshold indicated strong presence of Ce 4 f states in pure CePO4 NWs, which reduced upon 5 wt% Tb doping in CePO4 NWs. At 15 wt% Tb3+ doping, the sample did not show resonance of Ce 4 f feature, which may be because Tb3+ ions have replaced Ce3+ ions in the CePO4 lattice. The results are crucial to understand the relative participation of Ce3+ and Ce4+ oxidation states in the valence band, which is an important factor in defining the optical properties of the material that determine the PL intensity.

Direct mechanochemical synthesis of CaMoO4 and Dy3+ doped CaMoO4 nanoparticles and their photoluminescent properties

Calcium molybdate (CaMoO4) and Dy3+ doped CaMoO4 (Dy3+ = 0.5, 1, 1.5, 2 and 2.5 at.%) nanoparticles were successfully obtained by mechanochemical approach. The influence of Dy3+ ion concentration on the structure, morphology, and photoluminescent properties were investigated. The CaMoO4 and Dy3+ doped CaMoO4 phases with tetragonal structure were completely prepared after 30 min milling time with applied milling speed of 850 rpm. TEM analysis shows that the synthesized samples consist of mainly spherical particles with narrow particle size distribution. According to both XRD and TEM analysis, the average particles size is below 40 nm. The UV–vis absorption spectra show one peak at 240–245 nm. The calculated optical band gap of pure CaMoO4 is 3.96 eV and it decreases to 3.65 eV with increasing the concentration of Dy3+ ion up to 2.5 at %. The excitation spectra of the Dy3+-doped CaMoO4 samples contain absorption peaks corresponding to the MoO4 group and to the Dy3+ ion. The green and blue light emissions were observed for pure CaMoO4 and Dy3+ doped CaMoO4 samples under different wavelengths excitation (250 and 350 nm) typical for absorption of the host matrix. Emission spectra of all doped powders consist of the characteristic peaks of Dy3+ in the blue (∼480 nm) and yellow (∼575 nm) regions which are assigned to the 4F9/2 → 6H15/2 and 4F9/2 → 6H13/2 transitions, respectively. The weak peak at 660 nm also is observed due to 4F9/2 → 6H11/2 transition of Dy3+ ion. The highest photoluminescence emission intensity was detected when the sample is doped with 1.5 at.% Dy3+ concentration. It was found that the color coordinates (x and y) of 1.5 at.% and 2 at.% Dy3+-doped CaMoO4 fall close to the white light region in the CIE diagram. The results indicate that the mechanochemically obtained Dy3+ doped CaMoO4 nanoparticles can find application in different optical instruments.

Solution-processed Er3+-Doped GeS2 chalcogenide glass films with NIR photoluminescence towards functional flexibility and integration.

Rare-earth doped chalcogenide films are major components in flexible and integrated photonic and optoelectronic devices for modern communication systems, metrology, and optical sensing. However, it is still challenging to develop a high concentration of rare-earth doping chalcogenide film with a smooth surface to realize efficient photoluminescence (PL). Here, we demonstrate that Er3+-doped GeS2 films are prepared by spin-coating based on a two-step dissolution process. Such a two-step process provides the high solubility of Er3+ in GeS2 films and exhibits efficient emission at ∼1.5 µm crossing the telecommunication C-band. The highest PL emission intensity is obtained in GeS2 films doped with 1.4 mol% of Er3+, and this PL in GeS2 films is reported for the first time. We propose adjustments of annealing parameters for improving the PL characteristics in such materials. Through the control precision of the heating rate and annealing temperature, the smooth surface of GeS2 films enables efficient photo-luminescence. This two-step dissolution-based strategy would pave a new path to design luminescent chalcogenide films for application in flexible and integrated optoelectronics and photonics.

Eu3+-doped gadolinium borate glass system development for optical and scintillation applications

This paper describes the development and characterization of the Eu3+-doped Ba-Na-B glass system with the varying of Gd2O3 concentrations from 0 to 10 mol%. The photoluminescence emission spectra, excited with 393 nm at Eu3+ ions, show strong luminescence with a peak emission wavelength of 613 nm (5D0→7F2). The highest emission intensity is belonged to the glass sample with 2.5 mol% of Gd2O3. The phonon energy of the host glasses, evaluated from the phonon sideband analysis, is 1017 cm−1. The emission spectra, excited with 275 nm at Gd3+ ions, show the emission band according to the Gd3+→Gd3+ transition at 311 nm (4P7/2→8S7/2) and show the Gd3+→Eu3+ energy transfer, resulting in the emission of light at the characteristic wavelengths of the Eu3+. The highest photoluminescence emission intensity is belonged to the glass sample with 2.5 mol% of Gd2O3, due to its highest energy transfer efficiency at 59.10%. The emitting light of all the glass samples for both excited with 393 nm (Eu3+) and 275 nm (Gd3+) can be all represented by the x,y color coordinates at (0.65, 0.35) in reddish-orange region. The radioluminescence emission spectra, excited by 50 kV, 30 mA X-ray generator, show the emission bands with Eu3+ characteristics. The highest radioluminescence emission intensity is belonged to the glass sample with 7.5 mol% of Gd2O3 with the highest scintillation efficiencies at 20.61% compared to the BGO sample.

Ultraviolet-C AlGaN Resonant-Cavity Light-Emitting Diodes with Thermal Stability Pipe-AlGaN-Distributed Bragg Reflectors.

Ultraviolet-C AlGaN resonant-cavity light-emitting diodes with top and bottom pipe-AlGaN-distributed Bragg reflectors (DBRs) have been demonstrated. For the top/bottom DBR structures, 20 pairs of n+-AlGaN:Si/n-AlGaN:Si stack structures were transformed into the pipe-AlGaN:Si/n-AlGaN:Si DBRs through a doping-selective electrochemical wet etching process. The reflectivity of the pipe-AlGaN DBR structure was measured as 90% at 276.7 nm with a 20.9 nm flat stopband width. The anisotropic optical properties of the pipe-AlGaN DBR structure had been analyzed through the polarization-dependent reflectance spectra. For temperature-dependent reflectance spectra, the central wavelengths were slightly redshifted from 275 nm (100 K) to 281 nm (600 K) due to thermal expansion, refractive index increase, and partial strain release phenomena in the pipe-DBR structure. High photoluminescence emission intensity and line-width reducing phenomena were observed at 10 K in the UVC-LED with the resonant-cavity structure, which has potential for high-efficiency UV-C light source applications.

Optimum chemical states and localized electronic states of SnO2 integrated PTh– SnO2 nanocomposites as excelling emissive layer (EML)

Luminescent PTh–SnO2 nanocomposite was synthesized via chemical oxidative polymerization technique in presence of thiophene monomer with varying concentrations of SnO2 nanoparticles. The physico-chemical and morphological studies revealed the integration of SnO2 nanoparticles in the polythiophene matrix of PTh–SnO2 nanocomposites. Particle size of the derived nanocomposite laid in the 16–31 nm range and it was examined using HR-TEM. The optimized binary nanocomposite (15% PTh–SnO2) showed inflated thermal stability than pure PTh due to integration of SnO2 nanoparticles in PTh matrix. Further, it exhibited reduced optical band gap of 2.07 eV that was attributed to the inserted SnO2 nanoparticles which formed the localized electronic states in the optical band gap of PTh. Highest photoluminescence emission intensity was recorded for yellow-green band (∼562 nm) of 15% PTh–SnO2 and three emission bands (∼451 nm, ∼468 nm and ∼620 nm) of notable intensities were also observed. Photometric analysis of 15% PTh–SnO2 sample finally gives the emission color in blue-green region (near to white light) which enabled it to be used as successful emissive layer for its application in organic light emitting diodes (OLEDs).

Eu-Doped Gd2MoB2O9 Phosphors for Latent Fingerprints Detection

The luminescent powders from rare-earth ions doped oxides have been successfully used for latent fingerprint detection due to high efficiency, high contrast and low background interface. The Gd2MoB2O9:Eu3+ phosphors with varying compositions of Eu3+ions were synthesized by solid state reaction method. These phosphors were investigated by X-ray diffraction (XRD), diffuse reflectance spectroscopy, photoluminescence (PL), and decay curves studies. Multiphoton relaxation decay rate and coupling strength was evaluated using phonon side band spectrum showing 0.4 mol% doped samples show less non radiative decay rate. The 0.40 mol% of Eu3+ ion concentration doped in the Gd2MoB2O9 host lattice show highest photoluminescence emission intensity at 613 nm, in orange red region, monitored at 394 nm excitation. The Gd2MoB2O9:Eu3+ phosphors samples were optimized to 900 °C sintering temperature and optimum milling time at 3 min in the present work. The latent fingerprints detection that developed from Gd2MoB2O9:Eu3+ phosphors in this work exhibited clearly ridge characteristics under UV illumination. The results revealed thatGd2MoB2O9:Eu3+ phosphors are potential practical forensic science applications.

Ag-CsPbBr3 quantum dots/PMMA composite film for tunable white light emitting diodes

We demonstrated a colloidal perovskite Ag-CsPbBr3 quantum dots /PMMA (Ag-CsPbBr3 CPQDs/PMMA) composite film. Compared to the traditional CsPbBr3 CPQDs, the Ag-CsPbBr3 CPQDs exhibits two advantages: i) enhanced photoluminescence (PL) emission intensity approaching 40%; ii) up to 94% of photoluminescence quantum yield (PLQY). More importantly, the polymethylmethacrylate (PMMA) film makes the Ag-CsPbBr3 CPQDs/PMMA film still have a 56% of PLQY and high PL emission intensity at a storage time of 5 months. And through changing the ratio of CsPbI3 CPQDs in the Ag-CsPbBr3 CPQDs, the Ag-CsPbBr3 CPQDs/PMMA film can easily tune the correlated color temperature (CCT) from cold to warm light.

Optimized NIR and MIR emission properties of Tm3+/Ho3+ ions in lead sulfo phosphate glasses

The Tm3+/Ho3+ co-doped sodium-sulfo lead phosphate glasses (GTmHo-x) were synthesized by melt-quenching technique. The basic characterizations like XRD, FTIR are performed to analyse the structural behaviour in the glasses. The optical absorption studies were carried out. The NIR and MIR photoluminescence (PL) spectra were recorded at 797 nm excitation for GTmHo-x (x = 0.3, 0.6, 0.9, 1.2 and 1.2 mol%) glasses. The properties of emission bands at 1.4 μm, 1.8 μm and 2.0 μm corresponding to Tm3+:3H4, Tm3+:3F4, and Ho3+:5I7 transitions respectively, were studied. The NIR, Tm3+:3H4 (1.4 μm) emissions with broad full width half-maxima for single Tm3+ (121 nm) and Tm3+/Ho3+ co-doped (126 nm) were noticed in sodium-sulfo lead phosphate glasses. The highest PL emission intensity was obtained for GTmHo-0.9 glass. Moreover, the intensities of the Tm3+:1.8 μm and Ho3+:2.0 μm exhibited reverse trend in GTmHo-x glasses. To analyse the fluorescence behaviour, the energy transfer mechanism from various levels of Tm3+ → Ho3+ ions have been figured out and discussed. Further, the stimulated emission cross-section of Tm3+:1.8 μm and Ho3+:2.0 μm in single Tm3+ and Tm3+/Ho3+ co-doped glasses were calculated. The highest emission intensity, gain coefficient and emission cross-section of 0.9 mol% Ho3+ ion concentration suggests that GTmHo-0.9 glass is the favourable glass to perform highest MIR 2.0 μm emission. In short, the prepared GTmHo-x glasses might be a promising material for S-band (1.4 μm) amplifier in telecommunications and MIR (2.0 μm) solid-state lasers.

Effects of annealing temperature and neodymium concentration on structural and photoluminescence properties of Nd3+-doped Y2O3-SiO2 powders

We report the structural and photoluminescence (PL) properties of Nd3+-doped Y2O3-SiO2 powders (Y2O3-SiO2:Nd3+) as functions of annealing temperature and Nd3+ ion doping concentration. Y2O3-SiO2:Nd3+ powders were prepared using the high-energy ball-milling (HEBM) method, and their structural and PL properties were investigated using X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, and PL spectroscopy. The XRD results reveal a cubic phase without impurities, and the peak broadening decreases with an increase in annealing temperature due to the increase in the crystallite size. The PL emission intensity increases with an increase in annealing temperature. The highest PL emission intensity is observed for the 300-min milled mixture annealed at 1000 °C for 1 h with a Nd3+ concentration of 1 mol%. The PL peaks excited by 800 nm radiation were detected, centered at 1080 nm (4F3/2 → 4I11/2) and 1350 nm (4F3/2 → 4I13/2).

Design of a nanoprobe for high field magnetic resonance imaging, dual energy X-ray computed tomography and luminescent imaging

The combination of different bioimaging techniques, mainly in the field of oncology, allows circumventing the defects associated with the individual imaging modalities, thus providing a more reliable diagnosis. The development of multimodal endogenous probes that are simultaneously suitable for various imaging modalities, such as magnetic resonance imaging (MRI), X-ray computed tomography (CT) and luminescent imaging (LI) is, therefore, highly recommended. Such probes should operate in the conditions imposed by the newest imaging equipment, such as MRI operating at high magnetic fields and dual-energy CT. They should show, as well, high photoluminescence emission intensity for their use in optical imaging and present good biocompatibility. In this context, we have designed a single nanoprobe, based on a core-shell architecture, composed of a luminescent Eu3+:Ba0.3Lu0.7F2.7 core surrounded by an external HoF3 shell that confers the probe with very high magnetic transverse relaxivity at high field. An intermediate, optically inert Ba0.3Lu0.7F2.7 layer was interposed between the core and the shell to hinder Eu3+–Ho3+ cross-relaxation and avoid luminescence quenching. The presence of Ba and Lu, with different K-edges, allows for good X-ray attenuation at high and low voltages. The core-shell nanoparticles synthesized are good potential candidates as trimodal bioprobes for MRI at high field, dual-energy CT and luminescent imaging.

Synthesis, characterization, and in vitro toxicity evaluation of upconversion luminescence NaLuF4:Yb3+/Tm3+ nanoparticles suitable for medical applications

AbstractSynthesis, characterization, and in vitro toxicity evaluation of upconversion luminescence NaLuF4:Yb3+/Tm3+ nanoparticles (UCLNPs) are reported in the current study. Initially, the synthesized lanthanide trifluoroacetate (Ln(OOCCF3)3) precursor was used to fabricate NaLuF4 nanoparticles doped with Yb3+ and Tm3+ metal ions. The nanoparticles were coated with calcium carbonate (CaCO3) after removing the hydrophobic species on them to enhance their biocompatibility. The in vitro methylthiazolyldiphenyl‐tetrazoliumbromide (MTT) test was used to evaluate the toxicity of synthesized NaLuF4:Yb3+/Tm3+ nanoparticles (NLF‐5) on L929 mouse fibroblast cell lines. The transmission electron microscopy image showed that the particle size of NaLuF4:Yb3+/Tm3+ was 32 nm. The synthesized NLF‐5 nanoparticles have both α‐cubic and β‐hexagonal crystalline structures that provided a superb near‐infrared‐to‐near‐infrared upconversion luminescence signal when excited at 980 nm. MTT test results show that the death of L929 fibroblast cells was observed only at concentrations above 250 μg/mL of NaLuF4:Yb3+/Tm3+ nanoparticles. In addition, with an increase in patrol time of 24, 48, and 72 hr, cell toxicity increased significantly, while the coated nanoparticles did not have any toxic effects. The synthesized nanoparticles could be used as a suitable material for medical applications due to their small particle size, high photoluminescence emission intensity, and low toxicity.

Microwave-assisted synthesis and characterization of Y2O3 : Eu(III)-benzoate hybrid nanophosphors

The optical and structural characteristics of Y2O3 : Eu (III)-benzoate hybrid nanophosphors, synthesized by the microwave-assisted solvothermal technique, are reported in this work. Benzyl alcohol was used during the synthesis, carried out at low temperatures in the microwave reactor, to obtain the Y2O3 : Eu(III)-benzoate-layered hybrid nanophosphors. The benzyl alcohol led to the incorporation of benzene rings (belonging to benzoate group) around the Y2O3 : Eu(III) molecules, promoting a lamellar structure and showing the previously reported luminescent “antenna effect” in the nanophosphors. Y2O3 : Eu(III)-benzoate nanophosphors showed a high photoluminescence emission intensity at 590, 612, 650, and 697 nm due to the interelectronic D05 to F17, F27, F37, and F74 transitions of the europium ions. A stark split might be present due to the variation of the annealing temperature given to the Y2O3 : Eu(III)-benzoate nanophosphors. The nanostructured hybrids showed the appearance of complex morphologies similar to flower petals. The as-obtained nanophosphors were in the range of ∼20 nm and showed the reported x-ray diffraction reflections for these kinds of materials.

Crystallinity mediated variation in optical and electrical properties of hydrothermally synthesized boehmite (γ-AlOOH) nanoparticles

In this article, nanostructures of boehmite (γ-AlOOH) have been successfully synthesized in a time varied, facile and cost effective hydrothermal route. The samples have been characterized by using X-Ray Diffraction (XRD), Field Emission Scanning Electron Microscopy (FESEM), Transmission Electron Microscopy (TEM) and Fourier Transform Infrared (FTIR) spectroscopy. Our samples exhibit remarkably high photoluminescence emission intensity and dielectric constant (3.71 × 106 for BH12 sample) with a nominal dielectric tangent loss. A detailed growth mechanism including the nucleation and self assembly of our nanomaterial has been discussed. Moreover, we are the first to report here the electrical properties of the boehmite nanoparticles. Present investigation also explores temperature dependent dielectric property and ac conductivity of these samples. The role of crystallinity in the optical and electrical enhancement of our samples has been illustrated with proper analytical details. Not only high emission intensity in the blue and green region of the spectrum makes our sample a strong candidate for bio-imaging and bio-sensing applications, but also high dielectric constant makes them desirable for cost-effective energy storing devices, such as supercapacitors and solar cells.

Combustion synthesized YVO4:Eu3+ phosphors: Effect of fuels on nanostructure and luminescence properties

In this study, bright and red–emitting YVO4:Eu3+ phosphor nanostructures were synthesized by simple combustion method using aniline, hydrazine, triethylamine and urea as fuels. The applied fuels possessed a significant influence on the phosphors morphology and luminescence properties. It was found that hydrazine and aniline provide, respectively, the smallest and largest particle sizes of YVO4:Eu3+ phosphors. In addition, the highest photoluminescence emission intensity was achieved through applying aniline.

Photoluminescence and electrochemical properties of transparent CeO2–ZnO nanocomposite thin films prepared by Pechini method

Nanocomposite thin films of CeO2–ZnO with different molar ratios of Zn/Ce (=0, 0.25, 0.5, 0.75 and 1) were prepared by the Pechini sol–gel route. Various spectroscopic and electrochemical techniques were applied to investigate the films. XRD patterns of all the samples exhibited the peaks corresponding to cubic fluorite structure of ceria and the (101) and (103) peaks of ZnO with hexagonal structure was just observed in the sample with molar ratio of 1. EDS confirmed the presence of constituent of element in the samples. FESEM images of the films showed a surface composed of nanograins. AFM analysis revealed that root mean square roughness was enhanced as molar ratio of Zn/Ce increased. Moreover, fractal dimension of surfaces were calculated by cube counting approach. Optical measurements indicated that the film with molar ratio of 1 has the highest transmission and lowest reflectivity. The optical band gap values varied between 2.95 and 3.42 eV. The compositional dependence of refractive index and extinction coefficient were reported. The UV and blue emission appeared in PL spectra. The highest photoluminescence emission intensity was observed in the 1:1 molar ratio sample. The cyclic voltammetry measurements indicated the highest charge density (9.75 mC cm−2) and diffusion coefficient (3.507 × 10−17 cm2 s−1) belonged to the Ce/Zn (1:1) thin film.

Optical properties and chemical composition analyses of mixed rare earth oxyorthosilicate (R2SiO5, R=La, Gd and Y) doped Dy3+ phosphors prepared by urea-assisted solution combustion method

Dysprosium (Dy3+) doped lanthanum gadolinium oxyorthosilicate (LaGdSiO5), lanthanum yttrium oxyorthosilicate (LaYSiO5) and gadolinium yttrium oxyorthosilicate (GdYSiO5) phosphors (in powder form) were synthesized by urea-assisted combustion method. The X-ray diffractometer analysis confirmed that the LaGdSiO5, LaYSiO5 and GdYSiO5 crystalized in monoclinic phases. The chemical composition of the phosphors was analyzed by measuring the atomic and molecular ionic species using the time of flight secondary ion mass spectroscopy (ToF SIMS). In addition, ToF SIMS imaging technique was used to determine the distribution of the Dy3+ dopant ions on the surface on the phosphors. The average crystallite sizes and lattice strains of the phosphor were increased by Dy3+ doping. The field emission scanning electron microscope images showed that the powders were made up of an agglomeration of particles with no regular shape. The photoluminescence data showed narrow line emission peaks at the wavelengths of 485nm (minor emission) and 573nm (major emission) associated with the f→f transitions of Dy3+. The photoluminescence (PL) measurements showed that the emission peak of LaGdSiO5:Dy3+ was ~3× more intense than those of LaYSiO5:Dy3+ and GdYSiO5:Dy3+ when excited using monochromatic xenon lamp with a wavelength of 241nm. However, when the powders were excited using a 325nm He–Cd laser, the highest PL emission intensity was observed from GdYSiO5:Dy3+.

The influence of laser wavelength on the structure, morphology, and photoluminescence properties of pulsed laser deposited CaS: Eu2+ thin films

Europium-doped calcium sulfide thin films were grown on Si (100) substrates using the pulsed laser deposition technique. The influence of the laser wavelength on the structure, morphology, and photoluminescent properties of the films was studied. The X-ray diffraction data showed that the films were amorphous, except for the (200) diffraction peak observed from the films deposited at the wavelengths of 266 and 355 nm. The atomic force microscopy and Rutherford backscattering spectroscopy data showed that the film deposited at 355 nm was rougher and thicker than those deposited at 266 and 532 nm. As a result, the highest photoluminescence emission intensity around 650 nm was observed from the film deposited at 355 nm. This emission was attributed to the 4f65d1 → 4f7Eu2+ transitions of Eu2+ observed. These films were evaluated for blue light-emitting diodes.

Structural and luminescent properties of blue-emitting Sr2CeO4 phosphors by high-energy ball milling method

Sr2CeO4 phosphors were prepared by means of a high-energy ball milling method and sintered at various temperatures. The X-ray diffraction patterns of the as-prepared phosphors confirmed their orthorhombic structure. The FE-SEM images revealed that the Sr2CeO4 phosphors were composed of spherical particles with diameters of less than 2µm. The excitation spectra showed a broad band which peaks at 299nm and has a shoulder at 349nm due to the t1g–f and t1u–f charge transfer states of Ce4+ ions. The emission spectra exhibited a broad blue-emission band with a maximum at 478nm that originates from the Ce4+–O2− charge transfer transition resulting from the interaction of Ce4+ ion with the neighboring oxide ions. The highest photoluminescence emission intensity was observed when the powder was sintered at 1100°C. The results of this study indicate that Sr2CeO4 phosphors have the potential to be used in applications such as white light-emitting diodes (WLEDs) and optical display systems.

Vegetable-extracted carbon dots and their nanocomposites for enhanced photocatalytic H2production

In this work, we describe a facile construction of eco-friendly and effective nanocomposites from carbon dots (CDs), a novel type of carbon nanomaterial, for photocatalytic purposes. A series of benign CDs with favourable photoluminescence (PL) features were initially obtained from the hydrothermal treatment of natural vegetables including guava, red pepper, peas and spinach. The spinach-extracted CDs, with the highest PL emission intensity, were integrated with versatile TiO2 ensembles, i.e. nanoparticles (NPs) and nanotubes (NTs), to form desirable nanocomposites by further hydrothermal synthesis. TEM images, coupled with XPS spectra, confirm that the CDs are well decorated on the surfaces of TiO2. Due to the favourable electron transfer property of CDs, the H2 generation rates are enhanced to 75.5 and 246.1 μmol g−1 h−1 for TiO2 NP/CD and NT/CD nanocomposites, which are 21.6 and 3.3 times the rates of bare NPs and NTs, respectively. The strategy reported here may contribute to the fabrication of green and efficient nanocomposites for diverse applications.