Oxygen 1s for Organic Compounds

Figure 1. Summary of the mean, maximum, and minimum oxygen 1s binding energies for different organic functionalities according to the work of Beamson and Briggs [1].  Binding energy calibration presented here have been adjusted to the main aliphatic C 1s peak at 284.8 eV [2].

Figure 2. Oxygen 1s binding energy means and ranges for various organic compound types. Plotted from data supplied in Beamson and Briggs [1]. Referenced to main aliphatic C 1s peak at 285.0 eV as in the original source data.

Additional Notes: 
C-OH (aliphatic) Ref to C 1s at 284.8 eV: Average 532.7 eV, Min. 532.5 eV, Max. 532.9 eV

C-OH (aliphatic) Ref to C 1s at 285.0 eV: Average 532.9 eV, Min. 532.7 eV, Max. 533.1 eV

C-OH (aromatic) Ref to C 1s at 284.8 eV: 533.4 eV 
C-OH (aromatic) Ref to C 1s at 285.0 eV: 533.6 eV 

Also note that Si 2p3/2 for PDMS (silicone) is at 101.79 eV (Si 2p = 102.0 eV) with the C 1s at 284.38 eV and O 1s at 532.00 eV (referenced to aliphatic C at 285.0 eV).  If we shift the C 1s to 285.0 eV then Si 2p3/2 is at 102.41 eV (Si 2p = 102.6 eV) and O 1s is at 532.62 eV for silicone. If we then shift the C 1s to 284.8 eV then Si 2p3/2 is at 102.21 eV (Si 2p = 102.4 eV) and O 1s is at 532.42 eV for silicone.

References:
[1] G. Beamson, D. Briggs, High Resolution XPS of Organic Polymers - The Scienta ESCA300 Database, Wiley Interscience, 1992, Appendices 3.1 and 3.2.

[2] J.D. Henderson, B.P. Payne, N.S. McIntyre, M.C. Biesinger, Surf. Interface Anal. 57 (2025) 214-220.

Calculating Oxygen Content from Adventitious Carbon 1s Spectra

Adventitious carbon (AdC) is commonly detected in X-ray photoelectron spectroscopy (XPS) analyses of most samples. While AdC can be beneficial in some cases, such as for charge correction purposes during the analysis of insulators, its associated C–O functionalities can complicate the interpretation of O 1s spectra. Accurately accounting for AdC’s contribution within the O 1s spectrum is essential but challenging due to significant spectral overlap and poorly resolved components in the high-resolution O 1s spectrum.

Rather than assigning multiple components without clear physical meaning—potentially leading to misinterpretations—incorporating stoichiometry offers a more reliable approach to improving data accuracy. However, applying stoichiometry can be tedious and challenging, particularly for novice users.

A recently published article [1] describes an approximation to enhance oxygen spectra interpretation by estimating oxygen linked to AdC. This publication provides background information, key assumptions, and an easy-to-use Excel calculator to assist XPS researchers in analyzing their own O 1s spectra.

This approach is particularly useful for accurately quantifying survey spectra when AdC influence must be minimized and for modelling high-binding-energy components in the oxygen 1s spectrum. The latter example is important to many transition metal oxides which have overlapping hydroxide and/or defect oxide components in the same binding energy window. Detailed examples of these applications are presented and discussed in reference [1]. These types of calculations were originally introduced in [2].

This Excel based calculator (also available at supplementary material in [1]) takes information from the survey and high resolution carbon 1s spectra and determines the amount of oxygen that is present from adventitious carbon species. This amount can then be deducted from the overall oxygen concentration.
(Note: you must download the file to Excel to use it - it is locked in Google Docs).

References:

[1] J.D. Henderson, B.P. Payne, N.S. McIntyre, M.C. Biesinger, Surf. Interface Anal. 57 (2025) 214-220.
[2] B.P. Payne, M.C. Biesinger, N.S. McIntyre, J. Electron Spectrosc. Relat. Phenom. 184 (2011) 29-37.

Oxygen 1s Curve-Fitting Video

Video showing curve-fitting of the oxygen 1s (O 1s) spectrum for metallic surfaces using CasaXPS.

Common O 1s Values

Table 1. A series of common O 1s binding energy values.

From reference [1] it is found that oxygen bound to organic components can range in binding energy from as low as 530.9 eV to as high as 533.8 eV (corrected here to C 1s (C-C, C-H) at 284.8 eV).  The more common organic oxygen species (alcohols, esters, ketones, ethers and organic acids) are found in a range from 532.0 - 533.7 eV. This post shows a very handy table of organic oxygen species.

Reference:

[1] G. Beamson, D. Briggs, High Resolution XPS of Organic Polymers - The Scienta ESCA300 Database Wiley Interscience, 1992.

Oxygen 1s for Transition Metals

The O 1s BE and FWHM values obtained for the standard Sc, Ti, V, Cu and Zn samples[1] are presented in Table 1. The O 1s BE and FWHM values obtained for the standard Cr, Mn, Fe, Co and Ni samples[2] are presented in Table 2.

For many of the pure oxide samples there is a second higher BE peak that can be ascribed to contributions from a defective oxide component inherent in these oxide surfaces. Other work has shown that this is a defective oxide peak and not hydroxide as the presence of hydroxide has been ruled out by other methods[3,4]. For all of the oxides studied here this peak has an area contribution between 20 and 40 % consistent with other powdered oxides including nickel[5] and chromium[6]. These contributions from defective sites are unlikely to compromise the assignment of chemical states. It should be noted that this second peak could result from carbonates species. Inspection of the C 1s spectrum should confirm if this is occurring.

Pure oxide samples were not heated to remove possible surface hydroxides before analysis to avoid reduction of the oxide. In one related experiment in this laboratory with MnO heated to 600°C for 12 h, there was no significant change in the higher BE component ascribed to defective oxide, indicating little or no surface hydroxides are present.

Table 1. Selected O 1s values for Sc, Ti, V, Cu and Zn compounds [1].

Table 2. Selected O 1s values for Cr, Mn, Fe, Co and Ni compounds [2].

References:

[1] M.C. Biesinger, L.W.M. Lau, A.R. Gerson, R.St.C. Smart, Appl. Surf. Sci. 257 (2010) 887.
[2] M.C. Biesinger, B.P. Payne, A.P. Grosvenor, L.W.M. Lau, A.R. Gerson, R.St.C. Smart, Appl. Surf. Sci. 257 (2011) 2717.

[3] H.A.E. Hagelin-Weaver, J.F. Weaver, G.B. Hoflund, G.N.Salaita, J. Electron Spec. Rel. Phenom. 134 (2004) 139.
[4] P.R. Norton, G.L. Tapping, J.W. Goodale, Surf. Sci. 65 (1977) 13.

[5] M.C. Biesinger, B.P. Payne, L.W.M. Lau, A.R. Gerson, R.St.C. Smart, Surf. Interface Anal. 41 (2009) 324.
[6] M.C. Biesinger, C. Brown, J.R. Mycroft, R.D. Davidson, N.S. McIntyre, Surf. Interface Anal. 36 (2004) 1550.