TY - JOUR

T1 - Diffusion dynamics and characterization of attogram masses in optically trapped single nanoparticles using laser-induced plasma imaging

AU - Purohit, Pablo

AU - Fortes, Francisco J. J.

AU - Laserna, Javier

PY - 2023/2/22

Y1 - 2023/2/22

N2 - In the present work, a wavelength-selected plasma imaging analysis system is presented and used to track photons emitted from single-trapped nanoparticles in air at atmospheric pressure. The isolated nanoentities were atomized and excited into plasma state using single nanosecond laser pulses. The use of appropriate wavelength filters alongside time-optimized acquisition settings enabled the detection of molecular and atomic emissions in the plasma. The photon detection efficiency of the imaging line resulted in a signal > 400 times larger than the simultaneously-acquired dispersive spectroscopy data. The increase in sensitivity outlined the evolution of diverse physicochemical processes at the single particle scale which included heat and momentum transfer from the plasma into the particle as wells as chemical reactions. The imaging detection of excited fragments evidenced different diffusion kinetics and time frames for atoms and molecules and their influence upon both the spectroscopic emission readout and fabrication processes using the plasma as a reactor. Moreover, the origin of molecular species, whether naturally-occurring or derived from a chemical reaction in the plasma, could also be studied on the basis of compositional gradients found on the images. Limits of detection for the inspected species ranged from tens to hundreds attograms, thus leading to an exceptional sensing principle for single nanoentities that may impact several areas of science and technology.

AB - In the present work, a wavelength-selected plasma imaging analysis system is presented and used to track photons emitted from single-trapped nanoparticles in air at atmospheric pressure. The isolated nanoentities were atomized and excited into plasma state using single nanosecond laser pulses. The use of appropriate wavelength filters alongside time-optimized acquisition settings enabled the detection of molecular and atomic emissions in the plasma. The photon detection efficiency of the imaging line resulted in a signal > 400 times larger than the simultaneously-acquired dispersive spectroscopy data. The increase in sensitivity outlined the evolution of diverse physicochemical processes at the single particle scale which included heat and momentum transfer from the plasma into the particle as wells as chemical reactions. The imaging detection of excited fragments evidenced different diffusion kinetics and time frames for atoms and molecules and their influence upon both the spectroscopic emission readout and fabrication processes using the plasma as a reactor. Moreover, the origin of molecular species, whether naturally-occurring or derived from a chemical reaction in the plasma, could also be studied on the basis of compositional gradients found on the images. Limits of detection for the inspected species ranged from tens to hundreds attograms, thus leading to an exceptional sensing principle for single nanoentities that may impact several areas of science and technology.

KW - single nanoparticle inspection

KW - wavelength-selected laser-induced plasma imaging

KW - laser fabrication

KW - attogram characterization

KW - atomic

KW - molecular diffusion

KW - BREAKDOWN SPECTROSCOPY LIBS

KW - PARTICLE INTERACTIONS

KW - ABLATION

KW - SIMULATION

KW - EMISSION

U2 - 10.1007/s12274-022-5355-3

DO - 10.1007/s12274-022-5355-3

M3 - Journal article

VL - 16

SP - 7470

EP - 7480

JO - Nano Research

JF - Nano Research

SN - 1998-0124

ER -