x-ray photoelectron spectroscopy (xps)€¦ · a result of released energy due to atom from higher...
TRANSCRIPT
X-ray Photoelectron Spectroscopy (XPS)
Contents
WHAT is XPS?
HOW does it work? An
in-depth look at each
component of the
instrument
WHERE can this
technique be applied?
WHAT is XPS?
https://slideplayer.com/slide/13488710/
• Quantitative surface analysis technique
• Provides spatial distribution information
via mapping or depth profiling
• Binding energy is measured giving
information on the origin of the
photoelectron
HOW does this instrument work?
Applications: Elemental
composition in wide scans
A result of released
energy due to atom
from higher energy
level filling gap of
emitted electron
from same
Laura Trapiella-Alfonso, Fanny D’Orlye, Philani Mashazi, Anne Varenne*, Tebello Nyokong. Physical and in-solution characterisation of graphitic carbon nitride, graphene and nitrogen-doped graphene quantum dots*, work in progress
S.R Nxele, T. Nyokong, Conjugation of Azide-functionalised CdSe/ZnS Quantum Dots with Tetrakis(5-hexyn-oxy) Fe(II)
phthalocyanine via Click Chemistry for Electrocatalysis, Electrochim. Acta 194 (2016) 26-39.
1200 1000 800 600 400 200 0
Inte
nsi
ty (
cps)
Binding Energy (eV)
Bare GCP
N(1s)
Zn(2p)
S(2p)
Se(3d)
GSH-capped QDs
N(1s)Cd(3d)
Cd(3d)
Azide-QDs
Fe(2p) N(1s)
C(1s)
O(1s)
clicked FePc-QDs
Analysis done on glassy carbon plates
Applications: Elemental
composition and bond-types in
high resolution scans
Physical characterisation: XPS N1s/C1s high
resolution scans & RNH/COOH values
GQDs
0
2
4
6
8
10
12
280282284286288290292
Inte
ns
ity (
x 1
03
cp
s)
Binding energy (eV)
C 1s
0
1
2
3
4
5
6
7
396398400402404
Inte
ns
ity (
x1
03
cp
s)
Binding Energy (eV)
N 1s
Element Binding energy (eV) Peak assignment
C1s 287.5 COOH
286.2 C-O
284.8 C=O
283.9 C=N
N1s 400.9 NH
402.1 NC=O
399.3 N=C
397.4 C-N-C
RNH/COOH = 0.20
9Laura Trapiella-Alfonso, Fanny D’Orlye, Philani Mashazi, Anne Varenne*, Tebello Nyokong. Physical and in-solution characterisation of graphitic carbon nitride, graphene and nitrogen-doped graphene quantum dots*, work in
progress
Physical characterisation: XPS N1s/C1s high
resolution scans & RNH/COOH values
GQDs
0,0
0,5
1,0
1,5
2,0
2,5
280282284286288290292
Inte
ns
ity (
x 1
04
cp
s)
Binding Energy (eV)
C 1s
0
0,4
0,8
1,2
1,6
2
396398400402404
Inte
ns
ity (
10
3c
ps
)
Binding Energy (eV)
N 1s
Element Binding energy (eV) Peak assignment
C1s
288.4 COOH
286.8 C-O
284.9 C=N
N1s
401.1 NH
399.4 N=C
398.1 C-N-C
RNH/COOH = 0.0410
Physical characterisation: XPS N1s/C1s high
resolution scans & RNH/COOH values
GQDs
Element Binding energy (eV) Peak assignment
C1s 288.6 COOH
287.2 C=O
285.8 C-O
284.7 C=N
283.4 C-C
N1s 402.4 N-C=O
401.1 N-H
399.2 N=C
398.4 C-N-C
RNH/COOH = 0.4511
12
390 392 394 396 398 400 402 404 406 408 410
Inte
nsit
y (
cp
s)
Binding Energy (eV)
Azide QDs
Clicked FePc-QDs
405.5
404.6
399.6
399.4
N=N+=N
-
N=N+=N
-
S.R Nxele, T. Nyokong, Conjugation of Azide-functionalised CdSe/ZnS Quantum Dots with Tetrakis(5-hexyn-oxy) Fe(II)
phthalocyanine via Click Chemistry for Electrocatalysis, Electrochim. Acta 194 (2016) 26-39.
13
David O. Oluwolea*, Sello L. Manotob, Patience Mthunzi-Kufab and Tebello Nyokong, Evaluation of the
Photophysicochemical Properties and Photodynamic Therapy of Zinc Phthalocyanine–Metallic Nanoparticles
Conjugates
Final remarks
XPS is one of the best techniques to characterize molecules and
determine their elemental composition
It also is good for determining bonds formed between molecules
It is also a useful technique as it gives quantitative data or
information
