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