Plasmon Enhanced Emission of Perovskite Quantum Dot Films

MRS Advances ◽  
2018 ◽  
Vol 3 (14) ◽  
pp. 733-739 ◽  
Author(s):  
Seyma Dadı ◽  
Yemliha Altıntas ◽  
Emre Beskazak ◽  
Evren Mutlugun
Keyword(s):  
Quantum Dot ◽  
Au Nanoparticles ◽  
Au Nanoparticle ◽  
X Ray Diffraction ◽  
Time Resolved ◽  
X Ray ◽  
Transmission Electron ◽  
Coating Method ◽  
Photoluminescence Enhancement ◽  
Time Resolved Photoluminescence

ABSTRACTWe propose and demonstrate the photoluminescence enhancement of CsPbBr3 perovskite quantum dot films in the presence of Au nanoparticles. Embedded into a polymer matrix, Au nanoparticle- quantum dot film assemble prepared by an easy spin coating method enabled the photoluminescence enhancement of perovskite quantum dot films up to 78%. The properties of the synthesized perovskite QDs and gold nanoparticles have been analysed using high resolution transmission electron microscopy, X-ray diffraction, energy dispersive X- ray spectroscopy, UV-Vis absorption spectrophotometer, steady state and time-resolved photoluminescence spectrometer.

Effect of Au on the Performance of Porous Silicon/V2O5 Nanorods Heterojunctions to NO2 Gas

NANO ◽  
2016 ◽  
Vol 11 (07) ◽  
pp. 1650079 ◽  
Author(s):  
Wenjun Yan ◽  
Ming Hu ◽  
Jiran Liang ◽  
Dengfeng Wang ◽  
Yulong Wei ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Porous Silicon ◽  
Room Temperature ◽  
Au Nanoparticles ◽  
Analytical Techniques ◽  
Heating Process ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Scanning Electron

A novel composite of Au-functionalized porous silicon (PS)/V2O5 nanorods (PS/V2O5:Au) was prepared to detect NO2 gas. PS/V2O5 nanorods were synthesized by a heating process of pure vanadium film on PS, and then the obtained PS/V2O5 nanorods were functionalized with dispersed Au nanoparticles. Various analytical techniques, such as field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), have been employed to investigate the properties of PS/V2O5:Au. Herein, the PS/V2O5:Au sample exhibited improved NO2-sensing performances in response, stability and selectivity at room temperature (25[Formula: see text]C), compared with the pure PS/V2O5 nanorods. These phenomena were closely related to not only the dispersed Au nanoparticles acting as a catalyst but also the p-n heterojunctions between PS and V2O5 nanorods. Whereas, more Au nanoparticles suppressed the improvement of response to NO2 gas.

Perspectives and limitations of symmetric X-ray Bragg reflections for inspecting polytypism in nanowires

2016 ◽  
Vol 23 (2) ◽  
pp. 487-500 ◽  
Author(s):  
Martin Köhl ◽  
Philipp Schroth ◽  
Tilo Baumbach
Keyword(s):  
Statistical Significance ◽  
Large Set ◽  
X Ray Diffraction ◽  
Free Standing ◽  
Time Resolved ◽  
X Ray ◽  
Transmission Electron ◽  
Gaas Nanowires ◽  
High Statistical Significance ◽  
Proper Interpretation

X-ray diffraction, possibly time-resolved during growth or annealing, is an important technique for the investigation of polytypism in free-standing nanowires. A major advantage of the X-ray diffraction approach for adequately chosen beam conditions is its high statistical significance in comparison with transmission electron microscopy. In this manuscript the interpretation of such X-ray intensity distribution is discussed, and is shown to be non-trivial and non-unique given measurements of the [111]cor [333]creflection of polytypic nanowires grown in the (111)cdirection. In particular, the diffracted intensity distributions for several statistical distributions of the polytypes inside the nanowires are simulated and compared. As an example, polytypic GaAs nanowires are employed, grown on a Si-(111) substrate with an interplanar spacing of the Ga (or As) planes in the wurtzite arrangement that is 0.7% larger than in the zinc blende arrangement along the (111)cdirection. Most importantly, ambiguities of high experimental relevance in the case of strongly fluctuating length of the defect-free polytype segments in the nanowires are demonstrated. As a consequence of these ambiguities, a large set of deviations from the widely used Markov model for the stacking sequences of the nanowires cannot be detected in the X-ray diffraction data. Thus, the results here are of high relevance for the proper interpretation of such data.

scholarly journals Surface Modification of LiMn2O4for Lithium Batteries by Nanostructured LiFePO4Phosphate

2012 ◽  
Vol 2012 ◽  
pp. 1-7 ◽  
Author(s):  
B. Sadeghi ◽  
R. Sarraf-Mamoory ◽  
H. R. Shahverdi
Keyword(s):  
Electron Microscopy ◽  
Sol Gel ◽  
Dip Coating ◽  
X Ray Diffraction ◽  
X Ray ◽  
Electrochemical Tests ◽  
Transmission Electron ◽  
Coating Method ◽  
Dip Coating Method ◽  
Spinel Cathode

LiMn2O4spinel cathode materials have been successfully synthesized by solid-state reaction. Surface of these particles was modified by nanostructured LiFePO4via sol gel dip coating method. Synthesized products were characterized by thermally analyzed thermogravimetric and differential thermal analysis (TG/DTA), X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and energy dispersive X-ray spectroscopy (EDX). The results of electrochemical tests showed that the charge/discharge capacities improved and charge retention of battery enhanced. This improved electrochemical performance is caused by LiFePO4phosphate layer on surfaces of LiMn2O4cathode particles.

LASER-INDUCED PHOTOLUMINESCENT STUDIES OF Al-DOPED ZINC OXIDE NANOPARTICLES

2010 ◽  
Vol 09 (05) ◽  
pp. 439-445
Author(s):  
DHIRAJ KUMAR ◽  
SUNIL KUMAR ◽  
H. S. BHATTI
Keyword(s):  
Zinc Oxide ◽  
Zinc Oxide Nanoparticles ◽  
Oxide Nanoparticles ◽  
Nitrogen Laser ◽  
X Ray Diffraction ◽  
Electron Microscopic ◽  
Time Resolved ◽  
X Ray ◽  
Aluminum Ions ◽  
Transmission Electron

In this paper, addition of aluminum in zinc oxide is incorporated using low-temperature chemical synthesis route. Aluminum ions help in crystallization of zinc oxide nanoparticles. Characterization of the synthesized nanoparticles of zinc oxide has been done using Transmission electron microscope (TEM), and X-ray diffraction (XRD) analysis, Energy-resolved photoluminescence (PL) spectra and Time-resolved laser-induced photoluminescence (TRPL) at room temperature. Transmission electron microscopic observations and X-Ray diffraction studies indicate highly crystalline nature and particle size of the order of 20 nm in ZnO:Al . Time-resolved laser-induced photoluminescence measurements have been done using pulsed nitrogen laser as an excitation source, operated at wavelength 337.1 nm and having high peak output power of 1 MW. The results show that at higher concentrations of Al doping in host ZnO phosphor, emission intensity is more by several orders of magnitude and lifetime shortening indicates that these nanoparticles are more efficient as compared with lower concentrations of dopant.

scholarly journals Synthesis of Dandelion-like Porous Au Nanoparticles for Catalytic Reduction of Nitrophenol

2020 ◽  
Vol 01 ◽  
Author(s):  
Huiying Wu ◽  
Feng Liang
Keyword(s):  
Active Sites ◽  
Au Nanoparticles ◽  
Catalytic Reduction ◽  
Molar Ratio ◽  
Void Space ◽  
X Ray Diffraction ◽  
Uniform Size ◽  
Templating Method ◽  
X Ray ◽  
Transmission Electron

Background: Porous Au nanomaterials show great potential in the fields of biomedicine, drug delivery and catalysis for the merits of low density, large void space and large specific surface area. The preparation of porous Au nanomaterials is usually carried out by using a hard-templating method which is cumbersome. Methods: Dandelion-like porous Au nanoparticles were synthesized through a soft-templating method in our work. The synthesized porous Au nanoparticles were characterized via transmission electron microscopy (TEM), X-ray diffraction (XRD), energy-dispersive X-ray (EDX) and cyclic voltammetry (CV). The reduction of nitrophenol was carried out to evaluate the catalytic behavior of porous Au nanoparticles. Results: Porous Au nanoparticles prepared were in uniform size (47.9±6.4 nm) and the morphology could be regulated by adjusting the molar ratio of reactants. The apparent rate constant (kapp) value of reducing nitrophenol catalyzed by porous Au nanoparticles was higher than Au nanospheres and nanobranches in similar size. It could be attributed to the large amount of active sites and high proportion of high-order crystal faces proved by CV and XRD. Conclusion: We developed a facile and reproducible method for synthesizing porous Au nanoparticles. The morphology of porous Au nanoparticles can be ajusted by changing the molar ratio of reactants. Porous Au nanoparticles we prepared behaved better in catalysis compared with Au nanospheres and Au nanobranches.

Photoinduced formation of colloidal Au by a near-infrared femtosecond laser

2003 ◽  
Vol 18 (7) ◽  
pp. 1710-1714 ◽  
Author(s):  
Chongjun Zhao ◽  
Shiliang Qu ◽  
Jianrong Qiu ◽  
Congshan Zhu
Keyword(s):  
Femtosecond Laser ◽  
Absorption Spectra ◽  
Near Infrared ◽  
Au Nanoparticles ◽  
X Ray Diffraction ◽  
Local Formation ◽  
X Ray ◽  
Transmission Electron ◽  
Red Color ◽  
Yellow Orange

A Au colloid was prepared in a 5 mM HAuCl4 solution through irradiation with a focused infrared femtosecond laser at 800 nm. The Au colloid was characterized by absorption spectra, transmission electron microscopy, and x-ray diffraction analysis. The appearance of absorption peak around 526 nm in the absorption spectra and the wine-red color of sample solution HAuCl4 under focused laser irradiation verified the formation of Au colloid. The solution color changed in the order of yellow → orange → wine-red due to the local formation of Au nanoparticles near the focus. The pulse energy, focus position of laser beam, and solvent composite play important roles in formation, grain size, and stability of the Au colloid. A mechanism for the precipitate of Au nanoparticles was proposed, and a multiphoton process of femtosecond laser was involved.

scholarly journals Retention Characteristics of CBTi144 Thin Films Explained by Means of X-Ray Photoemission Spectroscopy

2010 ◽  
Vol 2010 ◽  
pp. 1-7 ◽  
Author(s):  
G. Biasotto ◽  
A. Z. Simões ◽  
C. S. Riccardi ◽  
M. A. Zaghete ◽  
E. Longo ◽  
...  
Keyword(s):  
Thin Films ◽  
Polar Axis ◽  
Photoemission Spectroscopy ◽  
X Ray Diffraction ◽  
Axis Orientation ◽  
X Ray ◽  
Si Substrates ◽  
Transmission Electron ◽  
Coating Method ◽  
Retention Characteristics

CaBi4Ti4O15(CBTi144) thin films were grown on Pt/Ti/SiO2/Si substrates using a soft chemical solution and spin-coating method. Structure and morphology of the films were characterized by the X-ray Diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), Raman analysis, X-ray photoemission spectroscopy (XPS), and transmission electron microscopy (TEM). The films present a single phase of layered-structured perovskite with polar axis orient. Thea/b-axis orientation of the ferroelectric film is considered to be associated with the preferred orientation of the Pt bottom electrode. XPS measurements were employed to understand the nature of defects on the retention behavior of CBTi144 films. We have observed that the main source of retention-free characteristic of the capacitors is the oxygen environment in the CBTi144 lattice.

scholarly journals Conductivity Research on ABS & PC Converted Core Shell Quantum Dot Doped in ABS & PC

2019 ◽  
Vol 8 (4) ◽  
pp. 7740-7742
Keyword(s):  
Quantum Dot ◽  
Core Shell ◽  
X Ray Diffraction ◽  
Visible Absorption ◽  
X Ray ◽  
Transmission Electron ◽  
Wet Chemical ◽  
Uv Visible ◽  
Lcr Meter ◽  
Absorption Characteristics

Zns: Mn / ZnO inverted shell quantum dots have been synthesized using a wet chemical process.The study used Mn of 4 percent weight. Transmission Electron Microscope (TEM) images show a 50 nm order for the quantum dot size. Confirmation of the ZnO capped ZnSMn was done by TEM and X ray diffraction (XRD).The test band distance is measured using the UV Visible absorption characteristics. Measurement of the dielectric constant is done using the LCR meter

scholarly journals Tuning the Photo-Luminescence Properties of WO3 Layers by the Adjustment of Layer Formation Conditions

Materials ◽  
2020 ◽  
Vol 13 (12) ◽  
pp. 2814 ◽  
Author(s):  
Milda Petruleviciene ◽  
Jurga Juodkazyte ◽  
Maliha Parvin ◽  
Alla Tereshchenko ◽  
Simonas Ramanavicius ◽  
...  
Keyword(s):  
Sol Gel ◽  
Photo Luminescence ◽  
X Ray Diffraction ◽  
Time Resolved ◽  
X Ray ◽  
Photoluminescence Decay ◽  
Formation Conditions ◽  
Sol Gel Synthesis ◽  
Time Resolved Photoluminescence ◽  
Dipping Time

In this research we have applied sol-gel synthesis for the deposition of tungsten (VI) oxide (WO3) layers using two different reductants (ethanol and propanol) and applying different dipping times. WO3 samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier Transform Infrared spectroscopy (FTIR), photoluminescence (PL) and time-resolved photoluminescence decay methods. Photoelectrochemical (PEC) behaviour of synthesized coatings was investigated using cyclic voltammetry in the dark and under illumination. Formation of different structures in differently prepared samples was revealed and significant differences in the PL spectra and PEC performance of the samples were observed. The results showed that reductant used in the synthesis and dipping time strongly influenced photo-electrochemical properties of the coatings. Correlation between the morphology, PL and PEC behaviour has been explained.

Emission Mechanism of the InGaN MQW Grown by MOCVD

1996 ◽  
Vol 449 ◽  
Author(s):  
Yukio Narukawa ◽  
Yoichi Kawakami ◽  
Shizuo Fujita ◽  
Shigeo Fujita ◽  
Shuji Nakamura
Keyword(s):  
Dynamical Behavior ◽  
Multiple Quantum Well ◽  
Multiple Quantum ◽  
Rich Region ◽  
Time Resolved ◽  
Tail State ◽  
X Ray ◽  
Transmission Electron ◽  
Valence Bands ◽  
Time Resolved Photoluminescence

ABSTRACTDynamical behavior of radiative recombination has been assessed in the In0.20Ga0.80N (3nm)/In0.05Ga0.95N (6 nm) multiple quantum well (MQW) structure by means of transmittance (TR), electroreflectance (ER), photoluminescence excitation (PLE) and time-resolved photoluminescence (TRPL) spectroscopy. The PL at 20 K was mainly composed of two emission bands whose peaks are located at 2.920 eV and 3.155 eV. The ER and PLE revealed that the transition at 3.155 eV is due to the excitons at quantized level between n=1 conduction and n=1 A(Γ9υ) valence bands, while the main PL peak at 2.920 eV is attributed to the excitons localized at the trap centers within the well. The TRPL features were well understood as the effect of localization where photo-generated excitons are transferred from the n=1 band to the localized centers, and then are localized further to the tail state. The origin of the localized centers were attributed to the In-rich region in the wells acting as quantum dots which could be observed by transmission electron microscopy (TEM) and energy-dispersive X-ray microanalysis (EDX).

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