BODIPY COMPOUNDS AS NON-INNOCENT π- SPACERS FOR DSSC DYES Devin D. Machin, Catherine Bonnier, Bryan...
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Transcript of BODIPY COMPOUNDS AS NON-INNOCENT π- SPACERS FOR DSSC DYES Devin D. Machin, Catherine Bonnier, Bryan...
BODIPY COMPOUNDS AS NON-INNOCENT π-SPACERS FOR DSSC
DYESDevin D. Machin, Catherine Bonnier, Bryan D. Koivisto*
Science at the Interface August 14, 2012
Department of Chemistry and BiologyRyerson University
The Opportunities For Solar Technology
• Crystalline silicon photovoltaics (PV’s) dominate the solar technology market
• They are a mature technology, efficient and robust
• However, they are expensive and have limited design potential.
2
Solar energy haspromising potential
3
The Dye Sensitized Solar Cell (DSSC)
The DSSC is a promising next generation PV technology
• 1. A photon is absorbed• 2. The excited e- is injected
into TiO2
• 3. The e- enters the circuit• 4. The dye molecule is
reduced by the electrolyte
4
The Dye Molecule
N
S
O
OH
CN
n = 2.75%
• The dye molecule is the powerhouse of the DSSC
• The use of BODIPY and a non-innocent π-spacer for DSSC dyes is explored
ADspacer
NB
N
F F
AD
BODIPY
• Organic dyes typically follow a Donor-π-spacer-Acceptor motif
Sun, L. et al., J. Org. Chem., 2007, 9550.
5
NB
N
F F
N N
NC
OHO
n = 1.66%
Boron-Dipyrromethene (BODIPY)
• A robust moiety, that is redox stable and therefore can be used to increase the absorption envelope and long-term stability of DSSC dyes.
NB
N
F F
Erten-Ela, S. et al., Org. Lett., 2008, 3300.
Mau, M. et al., Dyes Pigments., 2012, 231.
O
O
N
HN
NB
N
F F
NC O
OH
n = 2.26%
Conjugation is interrupted by the orientation of theIndicated phenyl group
Indicated group is a poor electron donor
6
Target molecules• A family of BODIPY dyes with modified conjugation
lengths for red-shifted absorption
NB
N
F F
N
OR
CNHO
O
OR2a R = Me2b R = Hex
NB
N
F FCNHO
O
N
RO
ORS
3a R = Me3b R = Hex
NB
N
F F
N
OR
OR
NC
HO
O
S
4a R = Me4b R = Hex
NB
N
F F
N
RO
ORS
NC
OH
O S
5a R = Me5b R = Hex
7
Synthesis of Target 2a & 2b
NB
N
F F
N
OR
OR
CNO
HO
NC
O
OH
CHCl3reflux 36h
2a R = Me2b R = Hex
NB
N
F F1
NB
N
F F
I
6
NBO
O
OR
OR
Pd(PPh3)4
K2CO3
THF:H2O 9:1reflux 12 h
NB
N
F F
N
OR
OR
NB
N
F F
N
OR
OR
ODMFPOCl3
1,2-dichloroethane,rt, 3 h
7a R = Me7b R = Hex
8a R = Me8b R = Hex
DCMrt, 12 h
NIS
piperdine
NI
O
O
= NIS
2b in DCM• Fluorescence of BODIPY
is quenched through the addition of donor and anchor groups
8
NB
N
F F
NB
N
F F
IIN
BN
F F
S
S
NB
N
F F
S
SI
SB
O
O
Pd(PPh3)4
K2CO3
THF:H2O 9:1reflux 12 h
1 9 10
11
DCMrt, 12 h
NIS
DCMrt, 12h
NIS
BO
O
Pd(PPh3)4
K2CO3
THF:H2O 9:1reflux 12 h
NB
N
F F
S
S
DMFPOCl3
1,2-dichloroethane,rt, 3 h
NB
N
F F
S
S
O
NB
N
F F
S
NC
O
OH
CHCl3reflux 36 h
5a R = Me5b R = Hex
S
CN
O
OH
12a R = Me12b R = Hex
13a R = Me13b R = Hex
R
N
OR
ORD
DD
D =
piperdine
Synthesis of Target 5a & 5b
5b in DCM
9
Cyclic Voltammetry and DFT
HOMO
LUMO
NB
N
F F
N
OMe
OMe
CNO
HO
B3LYP/6-31G Calibrated vs Ferrocene (not shown)
10
230 330 430 530 630 7300
1
2
3
4
5
6
7
8
9
BODIPY
2b
5b
/l nm
10
4 (
-1-1)
eM
cm
UV-vis Spectra Comparison
Hagfelt, A. et al., Chem Rev., 2010, 6595.
• Dyes 2b and 5b show red shifted absorptions tailing off to 630 nm
Summary and Future work • 6 of 8 target molecules were
successfully synthesized.• These dye molecules have promising
physical properties (UV-vis, CV)
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• Dyes will be used in prototype devices to determine conversion efficiency
• Future synthesis utilizing other organic frameworks as non-innocent π-spacers
NB
N
F F14
NB
N
C8H17
C8H17 C8H76
15
Acknowledgements
Current GroupDr. Bryan Koivisto (PI)Dr. Catherine Bonnier (PDF)Devin Machin (BSc)Omar Abdi (BSc)Muhammad Yousaf (MSc)
Left to Right: Devin, Catherine, Bryan, Muhammad, & Omar
People
Funding
12