Research into dye sensitised solar cells has increased in recent years as the search for a viable low cost, renewable energy source continues. The synthesis and characterisation of an array of symmetrical and asymmetrical zinc and ruthenium centred phthalocyanines and naphthalocyanines are presented in this work. Certain compounds were designed so that they would possess a carboxylic acid group which could be utilised to chemisorb the compound to a titanium dioxide surface. The dye sensitised titania electrodes were studied as potential photoanodes in dye sensitised solar cells. The use of symmetrical and asymmetrical compounds in the solar cells enabled conclusions to be drawn about the effects on electron injection of the HOMO energy level and the number and position of binding groups. The highest incident photon-to-current conversion efficiency (IPCE) of 4 % and overall conversion efficiency (η) of 0.09 % were obtained when 2,3:9,10-(22,92-carboxyl)benzo(b,k)-15,18,22,25-tetrakis(octyl)phthalocyaninatozinc(II) (63) was utilised as a sensitiser. This response was concluded to be due to the molecule possessing two binding groups and phthalocyanine like energy levels. When the ruthenium centred and zinc centred compounds were compared as sensitisers in DSCs, an increase in photovoltage and photocurrent was observed with the use of the ruthenium centred compounds. This is due to the binding group being attached to the axial ligand and therefore being situated closer to the LUMO electron density which is found at the centre of the molecule. As the binding group is closer there is less hindrance to electron injection into the TiO2 conduction band. Aggregation studies were also conducted on the acid and ester substituted zinc naphthalocyanine with and without the use of additives. It was found that the ester existed primarily as a dimer whose formation is concentration dependent. The acid also existed as a dimer but produced a "fake" monomer peak due to the formation of J aggregates. It was found that upon dilution the angle of the J aggregates shifted so that they formed face-to-face aggregates. It was found that the peripherally binding additive cetyltrimethylammonium bromide (CTAB) prevented aggregation at a concentration 20 times that of the compound but upon dilution rearranged itself so that aggregation was no longer inhibited.

Thesis (M.S.)--West Virginia University, 2008. / Title from document title page. Document formatted into pages; contains v, 37 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 33-37).

Thesis (Ph. D.)--Rutgers University, 2010. / "Graduate Program in Materials Science and Engineering." Includes bibliographical references.

Thesis--Wisconsin. / Includes bibliographical references (leaves 166-168).

Thesis (Ph. D.)--Rutgers University, 2008. / "Graduate Program in Physics and Astronomy." Includes bibliographical references (p. 153-161).

Thesis (Ph.D.)--Hong Kong University of Science and Technology, 2005. / Includes bibliographical references (leaves 222-236). Also available in electronic version.

This thesis describes the development of an intracavity frequency doubled dye laser from a commercial Spectra-Physics 380D single frequency ring dye laser, and the application of this system to a number of spectroscopic studies in discharges. Evaluation of the stability of the laser cavity is carried out, by computer calculation, in order to optimise the optical component set used in the frequency doubled dye laser. Using an ADA (ammonium dihydrogen arsenate) crystal, 17 mW of continuous wave ultra-violet, tunable over the range 292-302 nm, has been produced. The linewidth, when the laser is stabilised, is about 500 kHz in the UV. The CW UV output has been used to measure helium triplet (23S) metastable densities in a positive column discharge as a function of pressure (1-8 Torr) and current (2.5-80 mA). A maximum density of 10x10¹² cm-3 is measured for a pressure of 2 Torr and current of 60mA. The measured metastable densities are used in a rate equation analysis to extract values of the rate coefficient for distraction (by collisions with electrons) of the 23S metastables (1.6x10^-8 cm3s-1 for p = 2 Torr). A study of the optogalvanic signal generated when irradiating a neon positive column discharge with laser light of wavelength 588.2 nm, corresponding to the ls5-2p2 transition, is carried out. The signal is found to change sign as the dye laser power is increased, for some discharge conditions. Spatial studies of the optogalvanic signal in conjunction with absorption and emission studies are carried out to investigate the evolution of the population densities of levels connected to the 1s5 and 2p2 levels. A rate equation model is developed which demonstrates the importance of the 1s3 population density in explaining the observed sign reversal. A high resolution study of two transitions in the UV, in the tungsten spectrum, is presented. The even isotope splittings and the hyperfine splitting between the two strongest hyperfine components on transitions at 294.4 nm and 294.7 nm have been resolved by saturated absorption spectroscopy. From centre of gravity considerations the hyperfine splittings of the three levels involved in the two transitions have been predicted as 1630 MHz for the7s3 level, -506 MHz for the 3692 level and 225 MHz for the 3683 level. A simple wavemeter using a corner-cube Michelson interferometer is described. Digital counting circuits to provide a direct reading of either the fundamental or second harmonic wavelength have been designed and constructed. Wavelength readings accurate to 1 part in 106 are achieved.

Made available in DSpace on 2014-06-11T19:25:33Z (GMT). No. of bitstreams: 0 Previous issue date: 2006-12-13Bitstream added on 2014-06-13T19:12:24Z : No. of bitstreams: 1 freitas_fr_me_ilha.pdf: 2092589 bytes, checksum: 7ec036717ae650efd365ca13f290d709 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Este trabalho é dedicado à preparação e a caracterização de célula solar nanocristalina do tipo Grätzel ativada com corante orgânico. O presente desenvolvimento envolveu a deposição da camada condutora transparente SnO2, deposição da camada nanoporosa de TiO2, preparação do eletrólito, escolha e preparação do corante e por fim o fechamento e a caracterização da célula. O método de deposição empregado para a obtenção dos filmes foi a técnica spray pirólise, sendo a deposição realizada a temperatura de 400 oC. Para desenvolver a camada condutora transparente, foram preparadas soluções de SnO2:Sb dopadas com as seguintes concentrações: 1, 2, 3, 4, 5, 6, 7 e 8 mol % e uma solução de SnO2:F dopada com 15% em peso. Os filmes foram caracterizados por medidas de UV-vis, FTIR, DRX, MEV e medidas de resistência elétrica. O filme escolhido para ser utilizado como camada condutora transparente, foi o SnO2:F que apresentou melhor uniformidade, uma transmitância de 70% e resistência de 9 /O. A deposição do TiO2, foi feita sobre o filme de SnO2:F, pela técnica spray pirólise em 250 oC, e em seguida sinterizado a 400 0C durante 30 minutos. Os filmes de SnO2/TiO2 assim preparados em seguida foram imersos em corantes orgânicos. Concluída a adsorção dos corantes pelos filmes foi realizada montagem da célula. Foi colocado o eletrólito, que consistia de uma solução de etileno glicol de 0.5 M de iodeto de potássio misturado com 0.05 M iodo. Depois de concluídos, os processos descritos, a célula foi vedada para que se efetuassem medidas de caracterização elétrica. Esta caracterização esteve baseada no levantamento da curva I-V com e sem iluminação. / This work is dedicated to the development and characterization of the solar cell nanocrystaline of the type Grätzel activated with organic dye. The present development involved the decomposition of the layer SnO2 transparent conductor, decomposition of TiO2 nonporous layer, preparation of the electrolyte, choice and preparation of the dye and finally the closing and characterization of the cell. The decomposition method used to the obtainment of the films was the technique spray pyrolisis, being the decomposition performed in the temperature of 400 ºC. To develop the layer transparent conductor, were prepared solutions of SnO2 Sb full of the following concentrations: 1,2,3,4,5,6,7, and 8 mol % and a solution of SnO2 F full of 15 % in weight , the films were characterized by measures of UV- v is FTIR, MEV and measures of electric resistance. The film chosen to be used as layer transparent conductor was the SnO2: F which presented a better uniformity, a transmissibility of 70% and resistance of 9 /O. The decomposition of TiO2, was performed on a film of SnO2: F, by the technique spray pyrolisis in a 250 ° C and afterwards synthesized to 400ºC during 30 minutes. The films of SnO2 / TiO2 were immersed in organic dyes. Concluded the absortion of the dyes by the films was performed the set up of the cell. It was put the electrolyte, which was a solution of etalon glycol of 0. 5 M of iodated of potassium mixture with 0.0 5 M iodated. After finishing, the descript process, the cell was enclosed so that measures of electric characterization occurred. This characterization was based on the lifting of the curve I-V with and without illumination.

No description available.

Dye-sensitised solar cells (DSCs) have the potential to be a low cost solar cell candidate due to the relatively low cost of materials and ease of processing. Also, unlike traditional silicon solar cells, DSCs can be lightweight and flexible, and perform well in diffuse sunlight and indoors which make them an extremely attractive prospect. This thesis investigates the time intensive heating stages associated with the fabrication of a DSC which are currently a bottleneck for translating this technology from the laboratory to an industrial scale. In addition some steps associated with the fabrication of a DSC share similarity to other technologies so these methods could be extremely applicable and versatile. Near infrared (NIR) radiative heating was used here to drastically reduce the heating times associated with DSC fabrication steps. NIR heating involves the absorption of NIR photons by the free electrons of an infrared absorbing substrate which releases thermal energy rapidly. NIR radiation has previously been used for the heating of metallic substrates but this is the first time it has been used to heat glass based substrates, which significantly broadens the potential applications of NIR heating. Upon 12.5 s of NIR exposure FTO and ITO coated glass reached significantly high temperatures, temperatures corresponding well to those required for the DSC heating steps. NIR radiation was used to sinter TiO2 working electrodes and thermally platinise counter electrodes on FTO glass in 12.5 s, 144 times faster than the conventional oven heating of 30 minutes. When assembled into DSC devices these electrodes performed identically to their oven equivalents. When combined with a faster dyeing process this enabled the overall laboratory manufacturing time of a DSC to be reduced from 123 min to 5 min with no compromise in efficiency which is an extremely promising step for the viability of DSC commercialisation.