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Interpretation of TOF‐SIMS data based on information entropy of spectra
Author(s) -
Aoyagi Satoka,
Mizomichi Keisuke,
Kamochi Keisuke,
Miisho Ako
Publication year - 2022
Publication title -
surface and interface analysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.52
H-Index - 90
eISSN - 1096-9918
pISSN - 0142-2421
DOI - 10.1002/sia.7047
Subject(s) - entropy (arrow of time) , analytical chemistry (journal) , secondary ion mass spectrometry , chemistry , multivariate statistics , mass spectrum , ion , statistics , mathematics , physics , thermodynamics , chromatography , organic chemistry
Time‐of‐flight secondary ion mass spectrometry (TOF‐SIMS), when used for the analysis of complex material samples, typically provides data that are complicated and challenging to understand. Therefore, additional data analysis techniques, such as multivariate analysis, are often required to facilitate the interpretation of TOF‐SIMS data. In this study, a new method based on the information entropy (Shannon entropy) is proposed as an indicator of the outline characteristics of an unknown sample, such as changes in the material within the sample and mixing conditions. The Shannon entropy values are calculated using the relative intensity of every secondary ion normalized to the total ion count and reflect the diversity of secondary ions in the spectrum. Mixed samples containing two organic electroluminescence materials of different ratios, multilayers of Irganox 1010, and other organic materials were employed to evaluate the utility of Shannon entropy in the analysis of TOF‐SIMS data. The findings demonstrate that the Shannon entropy of a spectrum indicates differences in materials and changes in the conditions of a material in a sample without the need for peak identification or the knowledge of specific peaks corresponding to the materials in the sample.