Multiphoton induced photoluminescence during time-resolved laser-induced incandescence experiments on silver and gold nanoparticles

Abstract

In conventional time-resolved laser-induced incandescence (TiRe-LII) measurements, a laser pulse heats the nanoparticles within a probe volume of aerosol, and the particle size distribution and other characteristics are inferred from the observed incandescence decay rate, which is connected to the change in sensible energy through a spectroscopic model. There is strong evidence, however, that for some aerosol systems, the incandescence signal is contaminated with other non-incandescent emission sources. Recent TiRe-LII measurements on polydisperse aerosolized silver and gold nanoparticles energized with a 1064 nm laser pulse exhibit broadband emission that is temporally aligned with the temporal profile of the laser pulse, suggesting that the signal is due to non-thermal emission. One candidate for this emission phenomenon is multiphoton-induced upconversion luminescence, in which the conduction-band electron gas is heated up to an effective lattice temperature, resulting in luminescence due to high-energy intraband transitions.

Time-Resolved Laser-Induced Incandescence Measurements on Aerosolized Nickel Nanoparticles

“…This suggests a possible corruption of the prompt signal by nonincandescent laserinduced emission, which has been observed in LII signals from plasmonic nanoparticles. 77 On the other hand, the pyrometrically inferred peak temperatures evaluated at various times after the peak signal exhibit the expected behavior as a visible plateau regime, in the vicinity of the boiling point of the metal, begins to appear. This occurs starting at 26 ns after the peak incandescence signal obtained laser-heated Ni nanoparticles.…”

“…On the contrary, the peak temperatures appear to increase linearly with fluence. This suggests a possible corruption of the prompt signal by nonincandescent laser-induced emission, which has been observed in LII signals from plasmonic nanoparticles …”

Airborne Gold Nanoparticle Detection Using Photoluminescence Excited with a Continuous Wave Laser

“…While conducting LII on gas-borne gold and silver nanoparticles, Talebi-Moghaddam et al recently studied the broadband emission from nanoparticles excited with a pulsed (ns) laser operating at 1064 nm. 22 The emission was attributed to multiphoton-induced upconversion photoluminescence rather than LII, due to its instantaneous response and power-law dependence on laser fluence. Typical peak intensities for pulsed lasers used in LII (10 ns pulse duration, 1 mJ pulse energy) are in the order of 10 6 to 10 8 W cm À2 , 20 or approximately two to four orders of magnitude stronger than where we start to observe the broadband signal.…”

Time-resolved laser-induced incandescence on metal nanoparticles: effect of nanoparticle aggregation and sintering

“…Although this technique is highly promising, there remain some anomalies in the data that cannot be explained with current measurement models (cf. Figure 1) [8,9,16]. One such anomaly is excessive absorption, in which the peak experimental temperatures reached by laser-heated nanoparticles exceed those that are theoretically predicted based on the absorption cross-section of the particles determined through electromagnetic theory [8,9].…”