Search results for "luminescence."
showing 10 items of 1568 documents
Hybrid LEDs based on ZnO nanowire structures
2017
Abstract This paper summarized the research, development, and state of the art of hybrid ZnO nanowire LEDs, in which electroluminescence is generated at the junction between n-type doped ZnO nanowire structures and specific p-type doped polymers (in particular PEDOT, PEDOT:PSS, or PFO). Different device architectures will be reviewed and discussed with a particular emphasis on the electronic transport through the hybrid structures and the microscopic processes of light emission. Finally, a gas-phase deposition technique for conductive polymers will be presented which might help improve the performance of hybrid ZnO nanowire LEDs in the future.
Multilayer Thin Films by Layer-by-Layer Assembly of Hole- and Electron-Transport Polyelectrolytes: Optical and Electrochemical Properties
2006
In this paper, we pressent the synthesis of a series of p-type and n-type semicondnctring polyelectrolytes with triarylamine, oxadiazole, thiarliazole and triazine moictes. The synthesized polymeric hole and electrom iransport materials were examined optically and electrochemically using UV/Vis spectroscopy. PL spectroscopy and CV. Based on the optical and electrochemical data, each of the energy levels were calculated and all values suggested that the were promising hole-(p-type) or alectron=transprot (n-type) materials for devices. Moreover, the synthesized ionie polymers were suitable for LBL thin film deposition from ditute polymer solutions and the multilayers were fully characterized …
Effect of t-BuS vs. n-BuS on the topology, Cu⋯Cu distances and luminescence properties of 2D Cu4I4/RS(CH2)4SR metal–organic frameworks
2011
CuI reacts with RS(CH2)4SR (R = n-Bu (L1); t-Bu (L2)) to afford the 2D coordination polymers [Cu4I4{μ-RS(CH2)4SR}2]n (R = n-Bu (1); t-Bu (2)). Their grid networks exhibit nodal Cu4(μ3-I)4 clusters interconnected by dithioethers with mean Cu⋯Cu distances of 2.7265(10) and 2.911(2) A for 1 and 2, respectively. This difference translates in a blue shift of the solid state emission bands and a decrease in emission lifetimes when trading R = n-Bu to the bulky t-Bu.
Multilayers of CdSe/CdS/ZnCdS Core/Wings/Shell Nanoplatelets Integrated in a Polymer Waveguide
2017
In this work, fabrication of multilayers of colloidal CdSe/CdS/ZnCdS core/wings/shell nanoplatelets (NPls) on solid substrates by layer-by-layer deposition technology is successfully demonstrated for the first time. Integration of multilayers of nanoplatelets into polymeric waveguide resulted in strong dichroism in absorption and polarization effects in photoluminescence with preferable absorption and emission of TE (horizontal) mode that evidences about in-plane orientation of NPls relative to the planar waveguide. The propagation of the excitation and emission light along the waveguide was thoroughly investigated both theoretically and experimentally for different number of NPl layers.
Interpenetrated Luminescent Metal-Organic Frameworks based on 1H-Indazole-5-carboxylic Acid
2020
Herein we report the formation and characterization of two novel Zn-based multifunctional metal-organic frameworks (MOFs) based on 1H-indazole-5-carboxylic acid and bipyridine-like linkers, synthesized by soft solvothermal routes. These materials possess isoreticular 2-fold interpenetrated three-dimensional structures that afford a flexible character and allow porosity modulation of the MOFs as confirmed by CO2 sorption measurements. Apart from this attractive structural feature, the MOFs exhibit fascinating luminescent properties involving both luminescence thermometry and long-lasting phosphorescence.
Mixed Iodide-Bromide Methylammonium Lead Perovskite-based Diodes for Light Emission and Photovoltaics.
2015
Vacuum deposition techniques are used to prepare mixed iodide–bromide methylammonium lead perovskite diodes via an intermediate double layer of the pure iodide and bromide perovskites. The diodes lead to bright electroluminescence, whose emission spectra maxima shift from the infrared toward the visible with increasing bromide content. When illuminated with AM1.5 simulated sunlight the devices function as efficient solar cells with power conversion efficiencies as high as 12.9%.
Robust Lanthanoid Picolinate-Based Coordination Polymers for Luminescence and Sensing Applications
2021
Picolinate-based segmented dianionic ligands L12– (5-((4-carboxyphenyl)ethynyl)picolinate) and L22– (5,5′-(ethyne-1,2-diyl)dipicolinate) have been used in the synthesis of the highly robust and luminescent europium(III) coordination polymers [(CH3)2NH2][Eu(H2O)2(L1)2] (1) and [(CH3)2NH2][Eu(L2)2]·H2O·CH3COOH (2). Both 1 and 2 exhibit high selectivity for detection of nitroaromatic compounds since they act as quenchers of the Eu3+ emission. Stern–Volmer plots, using nitrobenzene as a quencher, yielded values of KSV = 150 M–1 and 160 M–1 for 1 and 2, respectively. Luminescence studies in the presence of different metal ions indicate a high selectivity for Fe3+ detection, with KSV values of 47…
Light emitting and electrical properties of pure amorphous thin films of organic compounds containing 2-tert-butyl-6-methyl-4H-pyran-4-ylidene
2013
Abstract Low molecular weight organic compounds which make thin films from organic solutions would be a great benefit in future organic light emitting systems. Two most important advantages should be mentioned. First – repeatability of synthesis of small molecules is better than of polymers. Second – wet casting methods can be applied. In this paper we present optical and opto-electrical properties of three glassy forming compounds containing 2-tert-butyl-6-methyl-4H-pyran-4-ylidene fragment as a backbone. They have the same N,N-dialkylamino electron donating group with attached bulky trityloxyethyl groups. The difference between these compounds is in an electron acceptor group. One has ind…
Modification of Polymer-Magnetic Nanoparticles by Luminescent and Conducting Substances
2014
The polymer encapsulated magnetic nanoparticles were obtained by suspension polymerization of styrene in the aqueous dispersion of magnetite. Functionalization of capsules was carried out by adsorp...
Molecular Iodine for a General Synthesis of Binary and Ternary Inorganic and Hybrid Organic-inorganic Iodide Nanocrystals
2018
We report the synthesis of various binary and ternary inorganic and hybrid organic–inorganic iodide nanocrystals (NCs) starting from molecular iodine (I2). The synthesis described herein utilizes a reaction between I2 and oleylamine, which results in oleylammonium iodide, an iodide precursor that can be directly used in the preparation of iodide-based NCs. The generality of the synthesis was demonstrated by synthesizing KI, RbI, CsI, AgI, CsPbI3, FAPbI3, Cs4PbI6, Cs3Bi2I9, FA3Bi2I9, and RbAg4I5 NCs. Furthermore, the syntheses are facile and are carried out in vials heated on a hot plate in air. They exhibit not only narrow size distributions, but also, in the case of lead-based perovskites …