Dye-sensitized solar cells (DSSC) have drawn much attention due to their
higher versatility and lower production cost compared to inorganic photovoltaics.
The top performers of DSSC have achieved power conversion efficiency over
10%, which is comparable to amorphous silicon solar cells. In this work, new
photosensitizers and nanostructure for improving the photovoltaic performance of
DSSC were developed and evaluated.
Two series of cyclometalated ruthenium(II) complex photosensitizer were
presented and their photosensitizing properties in DSSC were studied. Eight
cyclometalated ruthenium(II) terpyridine complexes with three carboxylic acid
groups on the terpyridine ligand were synthesized. Series A (M1 to M4) consist of
C,N,N’ ligands substituted with phenyl group whereas series B (M5 to M8)
consist of C,N,N’ ligands substituted with m-fluorophenyl group. All of the
complexes exhibited broad aborption spectra covering the whole visible spectrum.
The complexes in series B generally showed better photovoltaic performance than
those in series A in the DSSCs. DSSC fabricated from M7 achieved the highest
Voc, Jsc and power conversion efficiency among other DSSC, which were 0.56 V,
7.30 mAcm-2 and 2.63 % respectively.
Truxene-core donor--acceptor dyes were presented and their
photosensitizing properties in DSSC were studied. Eight dyes with either one
donor two acceptors system (T2, B2, T2R and B2R) or two donor one acceptor
system (T1, B1, T1R and B1R) were synthesized. Dyes with two acceptors have
high molar extinction coefficients originated from the charge-transfer transition
band, which are almost two times higher than those with only one accceptors.
Both the enhanced absorption and better anchoring geometry on TiO2 contribute
to the better photovoltaic performance of the two acceptors dyes in the DSSCs.
Devices fabricated from B2 and volatile solvent electrolyte exhibited the best
photovoltaic performance among the truxene-core dyes. The Voc, Jsc, FF and
power conversion efficiency of the device were 0.59 V, 9.69 mAcm-2, 0.63 and
3.62 % respectively. Dyes based on cyanoacrylic acid anchoring groups (T1, T2,
B1 and B2) were found to perform better than those based on rhodanine-3-acetic
acid dyes (T1R, T2R, B1R and B2R) in both donor--acceptor configurations.
ITO nanorod/TiO2 nanoparticle composite films with the three different
types of ITO nanorod with different length (150 nm, 600 nm and 1.5 μm) were
fabricated on FTO glass substrate. The transmittance and sheet resistance of the
ITO nanorod array on the FTO glass substrate were found decreased with
increasing the length of the ITO nanorod. When the ITO nanorod/TiO2
nanoparticle composite films were applied as the anode in DSSCs, the device
fabricated from 600 nm ITO nanorod with TiO2 ‘double layer‘ film showed
enhanced photocurrent generation. The improved photocurrent generation is
suggested to be due to an improved charge collection efficiency at the ITO
nanorod back electrode. / published_or_final_version / Chemistry / Doctoral / Doctor of Philosophy
| Identifer | oai:union.ndltd.org:HKU/oai:hub.hku.hk:10722/181606 |
| Date | January 2012 |
| Creators | Chan, Hung-tat., 陳鴻達. |
| Publisher | The University of Hong Kong (Pokfulam, Hong Kong) |
| Source Sets | Hong Kong University Theses |
| Language | English |
| Detected Language | English |
| Type | PG_Thesis |
| Source | http://hub.hku.hk/bib/B47849344 |
| Rights | The author retains all proprietary rights, (such as patent rights) and the right to use in future works., Creative Commons: Attribution 3.0 Hong Kong License |
| Relation | HKU Theses Online (HKUTO) |
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