Influence of Temperature on the Formation of Silver Nanoparticles by using a Seed‐Free Photochemical Method under Sodium‐Lamp Irradiation

Abstract

Silver nanoparticles can be prepared by using a seed-free photo-assisted citrate reduction method under the irradiation of a sodium lamp. Under the same irradiation intensity, bath temperatures are crucial in influencing the reaction rate, morphologies of final products, and shape evolution of the silver nanostructures. For example, when the bath temperature is 80 °C, the product yields of silver nanoplates, nanorods, and nanodecahedra are 38±6 %, 35±10 %, and 12±8 %, respectively. However, when the bath temperature is 30 °C, the product yields of silver nanoplates, nanorods, and nanodecahedra are 6±3 %, 0 %, and 83±16 %, respectively. Time-dependent UV/Vis spectra and TEM images show that silver nanoplates were formed at the earlier reaction stage and greatly decreased in amount at the later stage when the bath temperatures are less than or equal to 40 °C. This indicates that the silver nanoplates, which can be regarded as intermediates, are kinetically favored products. They are not thermodynamically favored products at these relatively low bath temperatures. The SERS spectra of crystal violet (CV) show that all the silver colloids synthesized at various temperatures exhibit good enhancement factors and that the colloids prepared at lower bath temperatures have a higher enhancement factor.

One‐Pot Synthesis of Icosahedral Silver Nanoparticles by Using a Photoassisted Tartrate Reduction Method under UV Light with a Wavelength of 310 nm

“…This observation indicates that plate-like or rod-liken anostructures are the kinetically favored products but not the thermodynamically favored products in this experimental condition. [38] These kinetically favored products play the roles of intermediates that were formed first and then dissolved graduallyt op rovides ilver elements for the growth of seeds to form icosahedral NPs.…”

“…[38] Compared with plasmon-mediated reactions, the photoassisted citrate reduction method has the advantages of fewer processes, higherr eproducibility,a nd higher throughput. [37,38] It has been found that different reduction agentsw ill strongly affect the shape distributionsa nd product yields of AgNPsb yu sing direct chemical reduction methods. [39] However,n ot many photoreduction reagents other than sodium citrate have been used or studied in the literature.…”

“…found that the photoassisted citrate reduction method also can be applied with a sodium lamp to synthesize AgNPs with various morphologies depending on the bath temperature . Compared with plasmon‐mediated reactions, the photoassisted citrate reduction method has the advantages of fewer processes, higher reproducibility, and higher throughput . It has been found that different reduction agents will strongly affect the shape distributions and product yields of AgNPs by using direct chemical reduction methods .…”

Deposition of Silver Nanoparticles on Indium Tin Oxide Substrates by Plasma-Assisted Hot-Filament Evaporation

“…This is in contrast to the other nanoparticles formation methods obtained by other research studies which illustrated the nanoparticles formation of different sizes and interparticle separation as the temperature increased. Also, those methods required subsequent process of annealing temperature as an additional process that showed indirect deposition on the substrate surface [35][36][37][38]. Moreover, the substrate temperature provides sufficient surface mobility to the deposited Ag nanoparticles for diffusion into their growth sites and coalescing to form larger particles [39].…”

Chlortetracycline-Functionalized Silver Nanoparticles as a Colorimetric Probe for Aminoglycosides: Ultrasensitive Determination of Kanamycin and Streptomycin

“…Thus, the productivity of AgNPs was dependent on the temperature conditions; the higher the temperature, the more productivity. Although, temperature influences the formation and productivity of AgNPs [16], the role of the reaction temperature in the growth rate of AgNPs is yet to be well understood [17].…”