For producing Zno thin film on the ITO glasses at the cathode, we use the electrochemical method to proceed oxidation reduction. It forms Zn(OH)2 at the first, and dehydrates to form ZnO after heating. We use smaller voltage to grow ZnO seeds at the beginning .It can help ZnO to grow stably on the glasses. ZnO has many different characters, when we change solution temperature, contents of disperser(PVP) or the annealing temperature, so my work is to do some research on these factors and discovers how they affect the Zno thin films¡¦ structures ,conductivity, mobility, and the opticals. We found if we don¡¦t grow seeds on the glasses ,the ZnO doesn¡¦t grow well .It grows thicker at the center than the edge. And the disperser changes the morphology of ZnO .The diameter of ZnO particle became smaller. Different annealing temperature and environment also affect the crystallinity, roughness and the character of optical and electricity. We use every type of the ZnO thin films we did on the DSSC to research what is the factor that affects the efficiency.

Using liquid phase deposition (LPD) fluorine nitrogen altogether doping porous titanium dioxide nanoparticle, general has not doped the titanium dioxide to be able the step to be 3~3.2eV, is opposite to the absorption spectrum for ultraviolet ray 380nm about, but sunlight energy only then 6% in ultraviolet ray, but the visible light has occupied about 52% energy, because grows the titanium dioxide which comes out mainly is applies in the light catalyst and the solar cell, all hoped may enhance to the luminous energy absorption, therefore only then dopes the fluorine, the nitrogen in the titanium dioxide, the goal is in order to adjust the titanium dioxide the light to absorb the boundary (optical absorption edge), at present dopes the method can dope the impurity only then minority produces the key with the titanium dioxide to binding thus result not well, penetrates ammonium hexafluorotitanate and the boric acid by the liquid phase sedimentation mixes under 40 degrees grows ammonium oxofluorotitanate discoid crystal, in the middle of this forerunner fills the very many fluorine nitrogen, after annealing and then produces the titanium dioxide to penetrate the fluorine nitrogen which the ESCA analysis contains compared to, again applies in the solar cell when can observe the annealing temperature differently when remains the fluorine nitrogen which and the key ties to the solar cell efficiency. At present the titanium dioxide light absorbs the boundary to be possible to reach the blue light region, applies the porous titanium dioxide in the dye sensitization solar cell anode, present fill factor may reach about 29.6%.

O presente trabalho apresenta resultados de preparação, caracterização e aplicação de membranas de DNA e DNA-PEDOT:PSS como material transportador de buracos (HTM) em células solares sensibilizadas por corante (DSSC). As análises por UV-Vis das amostras revelaram 80% de transparência em 600 nm para o DNA-isolado e diminuindo para 62% em 550 nm para o DNA-2% PEDOT:PSS. As análises das amostras por FTIR revelaram os picos característicos tanto do DNA quanto do PEDOT:PSS, confirmando a incorporação deste último nas membranas. Os resultados de análises térmicas DSC evidenciaram a presença de Tg em -67ºC e o seu desaparecimento com a adição de PEDOT:PSS na formulação de HTM. As análises de TGA mostraram o aumento da estabilidade das amostras com a adição de PEDOT:PSS atingindo 200ºC. Todas as amostras apresentaram 19% de resíduos em 900ºC. As membranas a base de DNA também foram submetidas às medidas de condutividade iônica revelando o maior valor de 3,2x10-4 S/cm2 em temperatura ambiente e aumentando para 0,1x10-3 S/cm2 em temperatura de 75ºC, para a amostra de DNA-isolado. As amostras de DNA-PEDOT:PSS mostraram valores de condutividade de 4,67x10-5 S/cm2 para a amostra DNA -2% PEDOT:PSS, em temperatura ambiente e diminuíram com o aumento de porcentagem de PEDOT:PSS. Dos difratogramas de raios-X observou-se um aumento da cristalinidade das amostras com a adição de PEDOT:PSS sendo o maior valor encontrado de 77,8% foi para a amostra de DNA-10% PEDOT:PSS. As DSSCs apresentaram a diminuição de eficiência solar após a introdução de membranas de DNA de 2.04% para 1,49% fenômeno explicado em termos de aumento de reflectância e rugosidade das amostras que dificultou o transporte de carga e recombinação do par redox do eletrólito nas células solares sensibilizadas por corante. / This paper presents results of preparation, characterization and application of DNA and DNA-PEDOT:PSS-based membranes as hole-carrier material (HTM) in dye-sensitized solar cells (DSSC). The UV-Vis analysis of the samples revealed 80% of transparency at 600 nm for the isolated DNA and 62% at 550 nm for DNA-2% PEDOT:PSS. The FTIR analysis of the samples showed characteristic peaks of both the DNA and PEDOT:PSS, confirming its incorporation into membranes. The results of DSC analysis revealed the presence of Tg at -67ºC and its disappearance with the addition of PEDOT:PSS to the formulation of HTM. The TGA analysis showed increased stability of the samples with the addition of PEDOT:PSS reaching 200ºC. All samples showed 19% of ashes at 900ºC. The DNA-based membranes were also subjected to ionic conductivity measurements showing the highest value of 3.2x10-4 S/cm2 at room temperature and of 0.1x10-3 S/cm2 at 75ºC for the isolated DNA. Samples of DNA-PEDOT:PSS showed conductivity value of 4.67x10-5 S/cm2 for DNA-2% PEDOT:PSS sample at room temperature which decreased with increasing percentage of PEDOT:PSS. X-ray diffraction revealed an increase of the crystallinity of the samples with the addition of PEDOT:PSS and the highest value found was 77.8% for the sample of DNA-10% PEDOT:PSS. The DSSCs showed a reduction of solar efficiency from 2.04% to 1.49% after the introduction of DNA-based membranes. This phenomenon was explained in terms of increased reflectance and surface roughness of the samples that difficult the transport and recombination of charge carrier species.

O presente trabalho apresenta resultados de preparação, caracterização e aplicação de membranas de DNA e DNA-PEDOT:PSS como material transportador de buracos (HTM) em células solares sensibilizadas por corante (DSSC). As análises por UV-Vis das amostras revelaram 80% de transparência em 600 nm para o DNA-isolado e diminuindo para 62% em 550 nm para o DNA-2% PEDOT:PSS. As análises das amostras por FTIR revelaram os picos característicos tanto do DNA quanto do PEDOT:PSS, confirmando a incorporação deste último nas membranas. Os resultados de análises térmicas DSC evidenciaram a presença de Tg em -67ºC e o seu desaparecimento com a adição de PEDOT:PSS na formulação de HTM. As análises de TGA mostraram o aumento da estabilidade das amostras com a adição de PEDOT:PSS atingindo 200ºC. Todas as amostras apresentaram 19% de resíduos em 900ºC. As membranas a base de DNA também foram submetidas às medidas de condutividade iônica revelando o maior valor de 3,2x10-4 S/cm2 em temperatura ambiente e aumentando para 0,1x10-3 S/cm2 em temperatura de 75ºC, para a amostra de DNA-isolado. As amostras de DNA-PEDOT:PSS mostraram valores de condutividade de 4,67x10-5 S/cm2 para a amostra DNA -2% PEDOT:PSS, em temperatura ambiente e diminuíram com o aumento de porcentagem de PEDOT:PSS. Dos difratogramas de raios-X observou-se um aumento da cristalinidade das amostras com a adição de PEDOT:PSS sendo o maior valor encontrado de 77,8% foi para a amostra de DNA-10% PEDOT:PSS. As DSSCs apresentaram a diminuição de eficiência solar após a introdução de membranas de DNA de 2.04% para 1,49% fenômeno explicado em termos de aumento de reflectância e rugosidade das amostras que dificultou o transporte de carga e recombinação do par redox do eletrólito nas células solares sensibilizadas por corante. / This paper presents results of preparation, characterization and application of DNA and DNA-PEDOT:PSS-based membranes as hole-carrier material (HTM) in dye-sensitized solar cells (DSSC). The UV-Vis analysis of the samples revealed 80% of transparency at 600 nm for the isolated DNA and 62% at 550 nm for DNA-2% PEDOT:PSS. The FTIR analysis of the samples showed characteristic peaks of both the DNA and PEDOT:PSS, confirming its incorporation into membranes. The results of DSC analysis revealed the presence of Tg at -67ºC and its disappearance with the addition of PEDOT:PSS to the formulation of HTM. The TGA analysis showed increased stability of the samples with the addition of PEDOT:PSS reaching 200ºC. All samples showed 19% of ashes at 900ºC. The DNA-based membranes were also subjected to ionic conductivity measurements showing the highest value of 3.2x10-4 S/cm2 at room temperature and of 0.1x10-3 S/cm2 at 75ºC for the isolated DNA. Samples of DNA-PEDOT:PSS showed conductivity value of 4.67x10-5 S/cm2 for DNA-2% PEDOT:PSS sample at room temperature which decreased with increasing percentage of PEDOT:PSS. X-ray diffraction revealed an increase of the crystallinity of the samples with the addition of PEDOT:PSS and the highest value found was 77.8% for the sample of DNA-10% PEDOT:PSS. The DSSCs showed a reduction of solar efficiency from 2.04% to 1.49% after the introduction of DNA-based membranes. This phenomenon was explained in terms of increased reflectance and surface roughness of the samples that difficult the transport and recombination of charge carrier species.

In this research we produce a multi-layer Dye-Sensitized Solar Cell (DSSC) and formulate electrolyte to reduce electric leakage. In general, DSSC compound from FTO/ dense layer/ porous layer with Dye / electrolyte / counter Pt electrode. In this study, we use commercial dye Ruthenium N719, and own Lab-synthesized Coumarin series as dye. Ordinary DSSC use singular size TiO2 and mono-layer as active layer, but we demonstrate a multi-layer and multi-scale TiO2 particle of DSSC for increasing IPCE (incident photon-to- electron conversion efficiency). Compare with standard mono-layer DSSC, multi-layer DSSC has successful gotten promotion about 15%. We use FTO (SnO2:F) as substrate, because after annealing it has low resistance, and it is better to anti-erosion from electrolyte compare with ITO. Ruthenium N719 absorb photon to generate exciton, that separate off into electron and hole. Electron deliver to the FTO substrate through TiO2. But electrons also can deliver to electrolyte result in electron leakage. In order to decrease electron leakage, one solution is to mixed electrolyte with some chemicals. For example, tert-butylpyridine (TBP), that can adhere to sphere of TiO2 reducing electron leakage and promote the IPCE. Because of liquid state of electrolyte is hard to seal DSSC. Our future work is making gel-state electrolyte and improving its efficiency.

No description available.

No description available.

We use different methods to deposit Ti thin film on the ITO glass substrate. Under the circumstances of using fixed concentration of electrolyte, changing anodic time, and applying voltage, we are able to use anodic method to make ordered nano TiO2 thin film,of which the smallest pore size is 18nm and the thickness is 4500

This project employs the biological compounds hemin, melanin, and retinoic acid as photoactive dyes in dye-sensitized solar cells (DSSCs). These dyes are environmentally and economically superior to the standard ruthenium-based dyes currently used in DSSCs because they are nontoxic and widely available. Characterization by linear sweep voltammetry yielded averaged maximum overall conversion efficiency values of 0.059% for retinoic acid, 0.023% for melanin, and 0.015% for hemin. Absorption spectra of hemin and retinoic acid suggest that they would complement each other well when used in tandem in one cell because hemin has a secondary maximum absorption peak at 613nm and retinoic acid has maximum absorption at 352nm. Cells made with hemin or melanin performed better with the use of lower temperatures to seal the cells, and hemin cells performed exceptionally well with exclusion of the sealing procedure. These biologically-derived cells have the potential to advance the development of inexpensive and safer solar energy sources, which promise to serve as clean energy sources in the near future.

abstract: The sun provides Earth with a virtually limitless source of energy capable of sustaining all of humanity's needs. Photosynthetic organisms have exploited this energy for eons. However, efficiently converting solar radiation into a readily available and easily transportable form is complex. New materials with optimized physical, electrochemical, and photophysical properties are at the forefront of organic solar energy conversion research. In the work presented herein, porphyrin and organometallic dyes with widely-varied properties were studied for solar energy applications. In one project, porphyrins and porphyrin-fullerene dyads with aniline-like features were polymerized via electrochemical methods into semiconductive thin films. These were shown to have high visible light absorption and stable physical and electrochemical properties. However, experimentation using porphyrin polymer films as both the light absorber and semiconductor in a photoelectrochemical cell showed relatively low efficiency of converting absorbed solar energy into electricity. In separate work, tetra-aryl porphyrin derivatives were examined in conjunction with wide-bandgap semiconductive oxides TiO2 and SnO2. Carboxylic acid-, phosphonic acid-, and silatrane-functionalized porphyrins were obtained or synthesized for attachment to the metal oxide species. Electrochemical, photophysical, photoelectrochemical, and surface stability studies of the porphyrins were performed for comparative purposes. The order of surface linkage stability on TiO2 in alkaline conditions, from most stable to least, was determined to be siloxane > phosphonate > carboxylate. Finally, porphyrin dimers fused via their meso and beta positions were synthesized using a chemical oxidative synthesis with a copper(II) oxidant. The molecules exhibit strong absorption in the visible and near-infrared spectral regions as well as interesting electrochemical properties suggesting possible applications in light harvesting and redox catalysis. / Dissertation/Thesis / Ph.D. Chemistry 2012