ZnO Nanocrystal Thin Films for Quantum-Dot Light-Emitting Devices

Abstract

Zinc oxide nanocrystals (ZnO NCs) were synthesized via a sol−gel method. After the synthesis, their surface was modified using 2,2,2-trifluoroacetic acid followed by ultraviolet (UV) treatment of the resulting fluorinated ZnO (F-ZnO) NC thin films. The chemical bonding therein and their structural and electrical properties were investigated. Moreover, the oxygen vacancy and electroluminescence properties of the densified ZnO NCs were evaluated. The effects of both UV treatment and fluorination on the morphological and electrical characteristics of the F-ZnO NC thin films were established. Based on the results, the ligand on the NCs was decomposed, and the thin film was densified. The mobility of the UV-treated F-ZnO NC thin film, which is 20.48 cm 2 •V −1 •s −1 , is four orders higher than the pristine ZnO NC thin film. By UV irradiation, the recombination of oxygen vacancies in ZnO was controlled. With the oxygen vacancies decreased, the core electroluminescence of ZnO was enhanced and the band gap of the ZnO NCs was widened from 3.25 to 3.51 eV. Therefore, the core electroluminescence of ZnO was enhanced while the interlayer emission was decreased for quantum-dot lightemitting device applications.

Electronic and Excitonic Processes in Quantum Dot Light-Emitting Diodes

“…Nevertheless, the electrons are commonly dominant carriers compared to holes in the ZnO-based QLEDs, , which implies that eeh AR should frequently occur in such ZnO-based devices, hence decreasing the device performance. Unexpectedly, QLEDs based on the ZnO electron-transport layer (ETL) always deliver excellent performance, − whereas TiO 2 ETL-based devices exhibit relatively poor performance . Therefore, we deduce that the outstanding performance of ZnO-based devices must be closely related to the type of AR and/or carrier-injection sequence.…”

Fluorescent Hydrogel Producing ZnO for Colorimetric Detection of Glutathione and Cysteine

“…[56] The as-prepared ZnO presented a higher catalytic activity than natural enzymes, HRP (curves 1 and curves 2), because of the high electron mobility and more active sites of the ZnO. [51] Steady-state kinetic analysis with the substrate of TMB and H 2 O 2 was performed to investigate the mechanism of the catalytic activity of ZnO. The catalytic behavior of ZnO was investigated by determining the steady-state kinetic parameters (Michaelis-Menten constant, K m , and maximal reaction velocity, V max ).…”

“…By comparation the literature method (coprecipitation method, solid state reaction method, hydrothermal method, hydrothermal method, and chemical bath deposition) for preparing ZnO, the presented method do not need complicated procedure, toxic organometallic reactants, and organic solvents. [51][52][53] Therefore, we developed a convenient, green and sustainable approach for preparing ZnO.…”

“…The high electron mobility and good thermal stability of ZnO facilitate its application as a catalyst to catalyze chemical reactions. [51] As a well-known semiconducting materials, ZnO has been widely applied in photocatalytic degradation of organic contaminants and photo-/electrocatalytic water splitting. [54,55] Scheme 1.…”

Study on the nanoscale current of ZnO film by photoassisted peak force tunnel atomic force: A novel technique for UV detection

“…Zinc oxide (ZnO) is one of the most promising metal oxides as a type of n-type semiconductor, owing to its direct wide band-gap energy of 3.37 eV and high exciton binding energy of 60 meV. 1 It has wide application in ultraviolet (UV) detector, [2][3][4][5] gas sensor, 6,7 solar cells, 8,9 quantum dot light-emitting diodes (QLEDs), 10,11 and so on. In particular, ZnO-based UV sensor caused much attention thanks to the nontoxic and low cost of ZnO.…”