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ELECTROCHEMICAL CHARACTERIZATION OF NANOSTRUCTURED DIAMOND LAYERS FOR
ENERGY CONVERSION APPLICATION
Silviya Pehlivanova
ОПЕРАТИВНА ПРОГРАМА„РАЗВИТИЕ НА ЧОВЕШКИТЕ РЕСУРСИ“
ПРОЕКТ BG051PO001-3.3.06-0014ЦЕНТЪР ПО МАТЕМАТИЧНО МОДЕЛИРАНЕ И КОМПЮТЪРНА
СИМУЛАЦИЯ ЗА ПОДГОТОВКА И РАЗВИТИЕ НА МЛАДИ ИЗСЛЕДОВАТЕЛИ
Европейски социален фондЕвропейски съюз
Use of Solar energyConversion of solar energy into electricity by artificial photosynthesis
natural photosynthesis artificial photosynthesis
Efficient use of sunlight Materials with improved physical, chemical and biological properties
MaterialsDiamond Phthalocyanine (PhC) Structure and properties of the
diamond
Nanocrystalline diamond layers (NCD)
Diamond layers doped with boron
Organic dyes PhotosensitivityHigh chemical and thermal
stability
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
PressureTime
880…890 °C > 2000 °C 25 mbar 180 min
NCD-layer HFCVD-installation
Modification of diamond layers
Immobilization with photosensitive molecules (Why Phthalocyanines? )
Immobilization of
Mn-PhC
-Preparation of the solution
-Treatment of the NCD-layers (about 12 hours)
chlorophyll Mn-phthalocyanine
(C96H144ClMnN8S8 )
Fotoelektrochemical characterisationProducing of diamond electrodes
•P-doped NCD-layers
•Immobilization of phthalocyanine
Testing
•Performance of the experiments
•Three-electrode cell
•PBS-solution as electrolyte
NCD-electrodes and a using light source
Three-electrode cell
Cyclic voltammetry
• Cyclic curves of unmodified NCD-sample without phthalocyanine
• Under illumination the electrode surface is stable and changes are not observed
-6000 -5000 -4000 -3000 -2000 -1000 0 1000 2000 3000
-12
-10
-8
-6
-4
-2
0
2
4
6
8
in the dark under illumination
I, m
A
E, mV
unmodified sample without PhC
(C80H96ClMnN8О16)
Cyclic voltammetry
• 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.
unmodified sample with PhC
(C80H96ClMnN8О16)
-3000 -2000 -1000 0 1000 2000
-3
-2
-1
0
1
2
3
4
5
6
in the dark under illumination
I, m
A
E, mV
El-d 2a, -2.5V - +1.8V, 100 mVs,
Change of the electrochemical potential with time for short-duration illumination
0 200 400 600 800 1000 1200 1400 1600 18000
20
40
60
80
100
120
140
160
180
200
Pot
entia
l, m
V
Time, sec
turn
on
turn
off
• Change of the potential at every switch on and off of the light source
• The obtained results show that the functionalized diamond films are photosensitive
THANK YOU FOR YOUR ATTENTIONTHANK YOU FOR YOUR ATTENTION
ОПЕРАТИВНА ПРОГРАМА„РАЗВИТИЕ НА ЧОВЕШКИТЕ РЕСУРСИ“
ПРОЕКТ BG051PO001-3.3.06-0014ЦЕНТЪР ПО МАТЕМАТИЧНО МОДЕЛИРАНЕ И КОМПЮТЪРНА
СИМУЛАЦИЯ ЗА ПОДГОТОВКА И РАЗВИТИЕ НА МЛАДИ ИЗСЛЕДОВАТЕЛИ
Европейски съюз Европейски социален фонд