A method for synthesizing ultrafine silver nanowires by low temperature nucleation

Abstract

The invention relates to a method for synthesizing ultrafine silver nanowires by using low-temperature nucleation, which uses low-temperature nucleation, does not require strict nucleation control conditions, can better control the size of the seed crystal, and is beneficial to The enlarged synthesis of ultra-fine silver nanowires, that is, at room temperature, first dissolve polyvinylpyrrolidone in ethylene glycol, then add ethylene glycol solution dissolved with sodium chloride, then add substances containing aldehyde groups, and finally add nitric acid Silver, keep stirring to get a mixed solution. After heating the mixed solution to the nucleation temperature, stay for a certain period of time, and then continue to heat up to the reaction temperature for reaction. After the reaction is completed, it is rapidly cooled to obtain a stock solution containing ultra-fine silver nanowires. The synthesized silver The diameter of nanowires is 20-30nm, which can effectively reduce the diameter of silver nanowires. The synthesis method is simple, does not require harsh reaction conditions, does not introduce difficult-to-handle substances, and can be applied industrially. It is suitable for applications in the field of silver processing.

Description

technical field [0001] The invention relates to the technical field of synthesis of one-dimensional materials, in particular to a method for synthesizing ultrafine silver nanowires by using low-temperature nucleation, which is suitable for application in the field of silver processing. Background technique [0002] Silver nanowire (Ag NWs) transparent conductive film has excellent conductivity, light transmission and good flexibility, which has significant advantages in large-scale flexible touch and display, and is considered to be the most likely to replace traditional indium tin oxide ( ITO) material for transparent conductive electrodes. The size (diameter and aspect ratio) of silver nanowires is an important factor affecting the sheet resistance, light transmittance, haze and other properties of silver nanowire transparent conductive film. Relevant theories show that the diameter of 25nm is the minimum size requirement for the comprehensive performance of silver nanowi...

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Problems solved by technology

[0003] In order to reduce the diameter of silver nanowires, researchers have developed various improved polyol methods to synthesize ultra-fine silver nanowires, for example: Benjamin J.Wiley et al synthesized under the joint action of two nucleation inhibitors NaCl and NaBr Silver nanowires with a diameter of about 20nm (Nano Lett.2015, 15, 6722-6726); Chinese patent CN 109622984 A discloses "a method for preparing ultra-pure and ultra-fine silver nanowires", which is at room temperature, under stirring, Mix the aqueous solution of polyvinylpyrrolidone, the aqueous solution of silver nitrate, the aqueous solution of the control agent and distilled water, then add the aqueous solution of citrate, under the seal, hydrothermal reaction, naturally cool to room temperature, dilute, shake or sonicate, filter , rinse the filter membrane with distilled water, collect the intercepted material on the filter membrane and shake it to obtain ultra-fine silver nanowires of 20-30nm. Because the hydrothermal reaction is a high-temperature and high-pressure reaction process, there are high requirements for reaction equipment, large investment and low cost. Suitable for enlarged synthesis and other shortcomings; Chinese patent CN110355359A discloses "an ultra-fine silver nanowire and its preparation method", which is based on a typical method for synthesizing silver nanowires with polyols, introducing free The long-chain carbon organic compound of the base reduces silver ions, accelerates the reduction rate of the reaction, and makes the reduction process of silver ions proceed at a lower reaction temperature, thereby inhibiting the lateral growth of silver nanowires. At the same time, sodium bromide is added during the reaction , control the growth of the wire diameter, and prepare silver nanowires with a diameter of about 13nm, but there are still some shortcomings such as difficult disposal of waste liquid; Kaili Zhang et al. reported a "two-pot method" to prepare silver nanowires with a diameter of less than 40nm. Nucleation at high temperature (160°C) followed by growth at low temperature (120°C) (Journal of Nanoscience and Nanotechnology 2016, 16, 480-488), there are deficiencies such as fine optimization of nucleation time at high temperature to control the number of nucleation; Younan Xia et al. Silver nanowires (ACS Nano 2016, 10, 7892-7900) with a diameter of less than 20nm were prepared by the "dropping method", which was achieved by reducing the reduction kinetics of Ag ions and inhibiting the lateral growth under the action of adding Br ions. Realize the preparation of ultra-fine silver nanowires

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