Generation of uniform tetrapod-shaped zincoxide nanoparticles by gas-phase reaction with using flow restrictor

A Novel Method for Continuous Synthesis of ZnO Tetrapods

“…ZnO-Ts can be produced in the lab scale by a hydrothermal process 9 , from the mixture of ZnO and C 12 , in a chemical vapor transport and deposition system 13 . Moreover, ZnO-Ts can be synthesized from Zn powder 14 and collected from reactor walls 15,16 or filtered at the outlet of the reactor 4,17 . Direct synthesis of ZnO-Ts from the metal vapor has obvious advantages of low temperature process and high yield.…”

“…4,20 The process control during the vapor-phase synthesis is quite challenging; the concentration gradient and flow rate of reagents fluctuate in the reactor during the synthesis because of unevenness in the flow. To increase mixing inside the reactor, flow restrictors 17 or baffles 21 are used. However, this complicates the process, and fine control of zinc precursor flow is needed; thus, small diameter ZnO-Ts are difficult to obtain.…”

“…ZnO-Ts can be produced in a lab scale by a hydrothermal process, from a mixture of ZnO and C, and in a chemical vapor transport and deposition system . Moreover, ZnO-Ts can be synthesized from Zn powder and collected from reactor walls , or filtered at the outlet of the reactor. , Direct synthesis of ZnO-Ts from the metal vapor has obvious advantages: low temperature process and high yield. However, for mass production, the technique should allow continuous synthesis, in which products can be unceasingly obtained without interrupting the process.…”

Synthesis of ZnO tetrapods for flexible and transparent UV sensors

“…Zinc oxide tetrapods (ZnO-Ts) were discovered in smoke from zinc-smelting plants and first studied in chemical vapor deposition systems [21,22]. ZnO-Ts were produced on the lab scale through a hydrothermal process [11], vapor synthesis from ZnO and a C mixture [23], or directly from Zn powder, when tetrapods are collected on reactor walls [13,16] or filtered at the outlet [17]. Direct synthesis of ZnO-Ts from the metal vapor has obvious advantages of being a low temperature process with high yield, but still the control of uniform concentration is rather difficult.…”

“…It has gained significant attention because of the unique optical, piezoelectric and magnetic properties, as well as its capability of band gap tuning [1,2]. Non-catalytically grown ZnO nanostructures can be observed in various morphologies such as nanowires [3], nanobelts [4], nanobridges and nanonails [5], nanoshells [6], tetrapods [1,[7][8][9][10][11][12][13][14][15][16][17][18][19]. The latter is one of the most gorgeous structures with many promising applications in solar cells [9], lasers [10,20], field emitters [14], UV and gas sensors [7,11].…”