Silver Nanowire Production via Two-Stage Temperature and Halide Control
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Solution Overview
Problem
Existing methods for producing nanowires, particularly those with high aspect ratios and small diameters, face challenges in achieving consistent morphology and high yields.
Innovation Solution
A method involving a reaction mixture with a solvent containing at least two hydroxyl groups, a metal-containing reagent, a templating agent, and a seed-promoting agent (SPA) that includes halide anions, where the mixture is heated at specific temperatures to produce silver nanowires with controlled morphology.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If existing methods are used to produce nanowires, then the production process is simple, but the yield is poor and desired morphology is difficult to attain
Solution Approach 1:
The patent employs a two-stage temperature process (seeding temperature followed by higher growth temperature) and controls the ratio of halide anion concentration to metal concentration (up to 10:1) to achieve high yield and consistent morphology. These parameter changes enable consistent production of nanowires with aspect ratios over 500 and diameters below 30 nm.
Solution Approach 2:
The patent introduces a seed-promoting agent (SPA) that acts as an intermediary substance. The SPA facilitates the formation of seeds and controls their growth into nanowires with desired morphology, mediating between the metal-containing reagent and the final nanowire product to achieve high yield and consistent characteristics.
2Manufacturing precision
If existing methods are used to produce high aspect ratio nanowires, then the target morphology is achieved, but consistency and yield remain poor
Solution Approach 1:
The patent employs feedback mechanisms through the seed-promoting agent that monitors and controls the growth process. The SPA ensures consistent formation of seeds and their transformation into nanowires with uniform morphology, providing feedback control that maintains manufacturing precision while improving yield.
Solution Approach 2:
The patent performs preliminary action by first forming seeds at a seeding temperature before proceeding to the growth stage. This preliminary seed formation step ensures uniform nucleation and sets the foundation for consistent nanowire morphology in the subsequent growth phase, improving both precision and yield.
3Shape
If nanowires with high aspect ratios and small diameters are produced, then the desired morphology is achieved, but the production consistency is poor
Solution Approach 1:
The patent uses specific parameter changes including a two-stage temperature protocol (seeding temperature then higher growth temperature) and controls the halide anion to metal concentration ratio (up to 10:1) to achieve consistent production of nanowires with aspect ratios over 500 and diameters below 30 nm.
Solution Approach 2:
The seed-promoting agent serves as an intermediary that ensures consistent seed formation and controlled growth. This mediator maintains production reliability by regulating the transformation from seeds to nanowires, ensuring morphological consistency across batches.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This method enables the production of silver nanowires with lengths of at least 10 μm and controlled diameters, achieving high yields and consistent morphology, suitable for applications in transparent conductive electrodes.
Implementation Method 1
heating a reaction mixture including (i) a solvent; (ii) a metal-containing reagent; (iii) a templating agent; and (iv) a seed-promoting agent (SPA) that is a source of halide anions, thereby producing a product that includes nanowires of the metal. The heating is carried out at a seeding temperature, followed by a growth temperature that is higher than the seeding temperature.
Data Source
AI summary
Methods of producing nanowires and resulting nanowires are described. In one implementation, a method of producing nanowires includes energizing (i) a metal-containing reagent; (ii) a templating agent; (iii) a reducing agent; and (iv) a seed-promoting agent (SPA) in a reaction medium and under conditions of a first temperature for at least a portion of a first duration, followed by a second temperature for at least a portion of a second duration, and the second temperature is different from the first temperature.