Open AccessVersailles Project on Advanced Materials and Standards Interlaboratory Study on Measuring the Thickness and Chemistry of Nanoparticle Coatings Using XPS and LEIS
Author(s) -
Natalie A. Belsey,
David J. H. Cant,
Caterina Minelli,
Joyce R. Araújo,
B. Böck,
Philipp Brüner,
David G. Castner,
Giacomo Ceccone,
Jonathan Counsell,
Paul Dietrich,
Mark H. Engelhard,
Sarah Fearn,
Carlos Galhardo,
Henryk Kalbe,
Jeong Won Kim,
L. Lartundo-Rojas,
H. S. Luftman,
Tim Nunney,
Johannes Pseiner,
Emily F. Smith,
Valentina Spampinato,
Jacobus Marinus Sturm,
Andrew G. Thomas,
Jon Treacy,
Lothar Veith,
Michael Wagstaffe,
Hai Wang,
Meiling Wang,
Yung-Chen Wang,
Wolfgang Werner,
Yang Li,
Alexander G. Shard
Publication year - 2016
Publication title -
journal of physical chemistry. c./journal of physical chemistry. c
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.401
H-Index - 289
eISSN - 1932-7455
pISSN - 1932-7447
DOI - 10.1021/acs.jpcc.6b06713
Subject(s) - x ray photoelectron spectroscopy , wafer , nanoparticle , analytical chemistry (journal) , materials science , nanotechnology , chemistry , chemical engineering , environmental chemistry , engineering
We report the results of a VAMAS (Versailles Project on Advanced Materials and Standards) inter-laboratory study on the measurement of the shell thickness and chemistry of nanoparticle coatings. Peptide-coated gold particles were supplied to laboratories in two forms: a colloidal suspension in pure water and; particles dried onto a silicon wafer. Participants prepared and analyzed these samples using either X-ray photoelectron spectroscopy (XPS) or low energy ion scattering (LEIS). Careful data analysis revealed some significant sources of discrepancy, particularly for XPS. Degradation during transportation, storage or sample preparation resulted in a variability in thickness of 53 %. The calculation method chosen by XPS participants contributed a variability of 67 %. However, variability of 12 % was achieved for the samples deposited using a single method and by choosing photoelectron peaks that were not adversely affected by instrumental transmission effects. The study identified a need for more consistency in instrumental transmission functions and relative sensitivity factors, since this contributed a variability of 33 %. The results from the LEIS participants were more consistent, with variability of less than 10 % in thickness and this is mostly due to a common method of data analysis. The calculation was performed using a model developed for uniform, flat films and some participants employed a correction factor to account for the sample geometry, which appears warranted based upon a simulation of LEIS data from one of the participants and comparison to the XPS results.