ОПЕРАТИВНА ПРОГРАМА
Европейски социален фонд
„РАЗВИТИЕ НА ЧОВЕШКИТЕ РЕСУРСИ“
ПРОЕКТ BG051PO001-3.3.06-0014
ЦЕНТЪР ПО МАТЕМАТИЧНО МОДЕЛИРАНЕ И КОМПЮТЪРНА
СИМУЛАЦИЯ ЗА ПОДГОТОВКА И РАЗВИТИЕ НА МЛАДИ
ИЗСЛЕДОВАТЕЛИ
Европейски съюз
ELECTROCHEMICAL CHARACTERIZATION OF
NANOSTRUCTURED DIAMOND LAYERS FOR
ENERGY CONVERSION APPLICATION
Silviya Pehlivanova
Use of Solar energy
Conversion of solar energy into electricity by artificial photosynthesis
natural photosynthesis
artificial photosynthesis
 Efficient use of sunlight
 Materials with improved physical, chemical and
biological properties
Materials
Diamond
Phthalocyanine (PhC)
 Structure and properties of the
diamond
 Organic dyes
 Photosensitivity
High chemical and thermal
stability
 Nanocrystalline diamond layers
(NCD)
 Diamond layers doped with boron
NCD+PhC
Chlorophyll
Sequence of the experiment
1. Deposition of nanocrystalline layers
2. Modification of diamond surfaces
- O2-plasma
- NH3-plasma
- UV/O3-treatment
3. Immobilization with photosensitive molecules
4. Analyzing the effectiveness of the modification
- Measurement of contact angles
- X-ray photoelectron spectroscopy
- Raman spectroscopy
5. Fotoelektrochemical research
Deposition of diamond layers
 Substrate preparation
 Hot-Filament CVD-method
 Operating parameters (gas Mixture 1% CH4 + 99% H2)
Substrate’s
Temperature
Filament’s
Temperature
Pressure
880…890 °C
> 2000 °C
25 mbar
NCD-layer
HFCVD-installation
Time
180 min
Modification of diamond layers
• Unmodified sample
• H-Terminierung
• UV/O 3 -treatment
• Irradiation with UV-light (wave length
175-210 nm); time t = 10 min
• Modification with O 2 -plasma
• time t = 5 min;
• power P = 200 W; pressure P = 0,67 mbar
• Modification with NH3/N2 -плазма
• gas mixture (5% NH3, 95% N2)
• time t = 5 min; pressure P = 1.8 x 10-2 mbar
• power P=150 W
Immobilization with photosensitive
molecules (Why Phthalocyanines? )
(C96H144ClMnN8S8 )
Immobilization of
Mn-PhC
chlorophyll
Mn-phthalocyanine
-
Preparation of
the solution
-
Treatment of the
NCD-layers
(about 12 hours)
Fotoelektrochemical characterisation
Producing of diamond electrodes
Testing
•P-doped NCD-layers
•Performance of the experiments
•Immobilization of phthalocyanine
•Three-electrode cell
•PBS-solution as electrolyte
NCD-electrodes and a using light
source
Three-electrode cell
Cyclic voltammetry
(C80H96ClMnN8О16)
8
in the dark
under illumination
6
4
I, mA
2
•
Cyclic curves of unmodified
NCD-sample without
phthalocyanine
•
Under illumination the
electrode surface is stable
and changes are not
observed
0
-2
-4
-6
-8
-10
-12
-6000
-5000
-4000
-3000
-2000
-1000
0
1000
2000
E, mV
unmodified sample without PhC
3000
Cyclic voltammetry
(C80H96ClMnN8О16)
6
5
in the dark
under illumination
4
•
Cyclic curves of NCD-sample
with phthalocyanine under
and without illumination
•
There
is
a
difference
between the measurements
obtained in dark and under
illumination
The voltammetric curves
clearly indicate both oxidation
and reduction processes
answerable for the detected
photocurrent.
I, mA
3
2
1
0
-1
-2
•
-3
-3000
-2000
-1000
0
1000
E, mV
unmodified sample with PhC
2000
Change of the electrochemical potential
with time for short-duration illumination
200
• Change of the potential at every
switch on and off of the light source
180
turn off
Potential, mV
140
120
100
turn on
160
• The obtained results show that the
functionalized diamond films are
photosensitive
80
60
40
20
0
0
200
400
600
800
1000
Time, sec
1200
1400
1600
1800
THANK YOU FOR YOUR ATTENTION
ОПЕРАТИВНА ПРОГРАМА
„РАЗВИТИЕ НА ЧОВЕШКИТЕ РЕСУРСИ“ Европейски социален фонд
ПРОЕКТ BG051PO001-3.3.06-0014
ЦЕНТЪР ПО МАТЕМАТИЧНО МОДЕЛИРАНЕ И КОМПЮТЪРНА
СИМУЛАЦИЯ ЗА ПОДГОТОВКА И РАЗВИТИЕ НА МЛАДИ
ИЗСЛЕДОВАТЕЛИ
Европейски съюз