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On the self-damping nature of densification in photonic sintering of nanoparticles.

MacNeill W, Choi CH, Chang CH, Malhotra R - Sci Rep (2015)

Bottom Line: It is shown that smaller nanoparticles result in faster densification, with lower temperatures during sintering, as compared to larger nanoparticles.It is shown that photonic sintering is an inherently self-damping process, i.e., the progress of densification reduces the magnitude of subsequent photonic heating even before full density is reached.By accounting for this phenomenon, the developed coupled model better captures the experimentally observed sintering temperature and densification as compared to conventional photonic sintering models.

View Article: PubMed Central - PubMed

Affiliation: Department of Mechanical Engineering, Oregon State University, Corvallis, Oregon, USA.

ABSTRACT
Sintering of nanoparticle inks over large area-substrates is a key enabler for scalable fabrication of patterned and continuous films, with multiple emerging applications. The high speed and ambient condition operation of photonic sintering has elicited significant interest for this purpose. In this work, we experimentally characterize the temperature evolution and densification in photonic sintering of silver nanoparticle inks, as a function of nanoparticle size. It is shown that smaller nanoparticles result in faster densification, with lower temperatures during sintering, as compared to larger nanoparticles. Further, high densification can be achieved even without nanoparticle melting. Electromagnetic Finite Element Analysis of photonic heating is coupled to an analytical sintering model, to examine the role of interparticle neck growth in photonic sintering. It is shown that photonic sintering is an inherently self-damping process, i.e., the progress of densification reduces the magnitude of subsequent photonic heating even before full density is reached. By accounting for this phenomenon, the developed coupled model better captures the experimentally observed sintering temperature and densification as compared to conventional photonic sintering models. Further, this model is used to uncover the reason behind the experimentally observed increase in densification with increasing weight ratio of smaller to larger nanoparticles.

No MeSH data available.


Related in: MedlinePlus

Schematic of the experimental setup for photonic sintering used in this work.
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f1: Schematic of the experimental setup for photonic sintering used in this work.

Mentions: A custom-made experimental setup (schematically shown in Fig. 1) was used for photonic sintering of Ag nanoparticle inks with three different nominal diameters, i.e., 10 nm, 20 nm and 40 nm. Mixed nanoparticle inks with mixtures of (1) 10 nm and 20 nm and (2) 10 nm and 40 nm diameter nanoparticles in ratios by weight of 1:4, 2:3, 3:2 and 4:1 were also photonically sintered. The total solids loading content of all the inks was 50% by weight. No dispersant was used. A single droplet of nanoparticle ink was deposited onto a stainless steel substrate using a micropipette. A continuous xenon lamp was used as the light source for photonic sintering of the deposited droplet, with a fiber optic light guide used to direct the light to the deposited ink. The distance between the outlet of the light guide and the substrate, the commanded optical power and the lamp on-time, were fixed at the same value for every sintering experiment. The temperature of the deposited nanoparticles during sintering was monitored using a thermal camera. Further details of the experimental setup and procedures are provided in the methods section.


On the self-damping nature of densification in photonic sintering of nanoparticles.

MacNeill W, Choi CH, Chang CH, Malhotra R - Sci Rep (2015)

Schematic of the experimental setup for photonic sintering used in this work.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4595846&req=5

f1: Schematic of the experimental setup for photonic sintering used in this work.
Mentions: A custom-made experimental setup (schematically shown in Fig. 1) was used for photonic sintering of Ag nanoparticle inks with three different nominal diameters, i.e., 10 nm, 20 nm and 40 nm. Mixed nanoparticle inks with mixtures of (1) 10 nm and 20 nm and (2) 10 nm and 40 nm diameter nanoparticles in ratios by weight of 1:4, 2:3, 3:2 and 4:1 were also photonically sintered. The total solids loading content of all the inks was 50% by weight. No dispersant was used. A single droplet of nanoparticle ink was deposited onto a stainless steel substrate using a micropipette. A continuous xenon lamp was used as the light source for photonic sintering of the deposited droplet, with a fiber optic light guide used to direct the light to the deposited ink. The distance between the outlet of the light guide and the substrate, the commanded optical power and the lamp on-time, were fixed at the same value for every sintering experiment. The temperature of the deposited nanoparticles during sintering was monitored using a thermal camera. Further details of the experimental setup and procedures are provided in the methods section.

Bottom Line: It is shown that smaller nanoparticles result in faster densification, with lower temperatures during sintering, as compared to larger nanoparticles.It is shown that photonic sintering is an inherently self-damping process, i.e., the progress of densification reduces the magnitude of subsequent photonic heating even before full density is reached.By accounting for this phenomenon, the developed coupled model better captures the experimentally observed sintering temperature and densification as compared to conventional photonic sintering models.

View Article: PubMed Central - PubMed

Affiliation: Department of Mechanical Engineering, Oregon State University, Corvallis, Oregon, USA.

ABSTRACT
Sintering of nanoparticle inks over large area-substrates is a key enabler for scalable fabrication of patterned and continuous films, with multiple emerging applications. The high speed and ambient condition operation of photonic sintering has elicited significant interest for this purpose. In this work, we experimentally characterize the temperature evolution and densification in photonic sintering of silver nanoparticle inks, as a function of nanoparticle size. It is shown that smaller nanoparticles result in faster densification, with lower temperatures during sintering, as compared to larger nanoparticles. Further, high densification can be achieved even without nanoparticle melting. Electromagnetic Finite Element Analysis of photonic heating is coupled to an analytical sintering model, to examine the role of interparticle neck growth in photonic sintering. It is shown that photonic sintering is an inherently self-damping process, i.e., the progress of densification reduces the magnitude of subsequent photonic heating even before full density is reached. By accounting for this phenomenon, the developed coupled model better captures the experimentally observed sintering temperature and densification as compared to conventional photonic sintering models. Further, this model is used to uncover the reason behind the experimentally observed increase in densification with increasing weight ratio of smaller to larger nanoparticles.

No MeSH data available.


Related in: MedlinePlus