In our works , we used P3HT and PCBM blended in xylene as donor and acceptor materials for polymer solar cells . For the standard devices with the configuration of ITO/PEDOT/P3HT¡GPCBM/Al , the power conversion efficiency of 2.3% is achieved under AM1.5 100 mW/cm2 illumination . In order to enhance the hole transportation , we used PANi nanotube , which has high conductivity , as an anode interlayer between the PEDOT¡GPSS layer and the organic active layer . The device structure was ITO/PEDOT/PANi/P3HT:PCBM/Al , and the power conversion efficiency increased from 2.3% to 2.6% . The efficiency of polymer solar cell was also increased with different rpm by using spin-coating process . For devices , at the process parameters under 4000rpm and 100Å thickness of PANi , the power conversion efficiency was 60% higher than that of standard device . We suggested that PANi can act as a good anode interlayer material for polymer solar cells .

In this study, P3HT and PCBM were used as donor and acceptor materials for polymer solar cells. The standard device was constructed of ITO / PEDOT:PSS / P3HT:PCBM / Al and the power conversion efficiency of 2% was achieved under AM1.5G 100mW/cm2 illumination. In order to increase the hole transporting ability, we used PEDOT nanorods with high conductivity as an anode interlayer between the PEDOT:PSS and the P3HT:PCBM layer, with a configuration of ITO / PEDOT:PSS / PEDOT nanorods / P3HT:PCBM / Al. According to experimental results. PEDOT nanorods dispersed well on the PEDOT:PSS surface through the spin-coating process. As the concentration of PEDOT nanorods 1wt% casting film, the conductivity of anode buffer layer raised about two times and the power conversion efficiency of device reached 2.63%. The short-circuit current and the power conversion efficiency of the polymer solar cell containing 1wt% PEDOT nanorods were obtained about 170% and 30% increasement, respectively. In conclusion, it is quite useful to apply the PEDOT nanorods into polymer solar cells as an interlayer. The improvement in the short-circuit current which resulted in an enhancement of the power conversion efficiency originated from the increased conductivity of the buffer layer.

Recently, a variety of conducting polymer have great potentials for practical utility. Among these polymers, polyaniline (polyaniline,PANI) has the widest applications . Using electrochemical synthesis to fabricate Aniline copolymer has several kind of advantages (i) Aniline is cheap and easy to polymerize¡F (ii) High stability¡F(iii) The conductivity of the polymer can be modulated¡F(iv) The thickness of PANI film can be controlled. In conclusion, it is quite useful to apply the PANI into polymer solar cells as the hole transporting layer. We used Cyclic Voltammetry to grow the PANI thin film. Then, we investigated the performance of the device affected by morphology with different sweep rate and the difference of electric characteristic and transmission between PEDOT and PANI. P3HT was used as a donor material because of its high stability and high absorption in visible light. PCBM was used as a acceptor material because of its high stability and high electron transportation. The device was constructed of ITO (150 nm) / PANI (50 nm) / P3HT:PCBM (100 nm) / Al (200 nm). When the sweep speed is lower, the particle of PANI thin film is closer and its scale size is more similar. When the sweep rate is 0.01 V/s, PANI thin film would grow about 80 nm, and the power conversion efficiency of 1.83% was achieved under AM1.5G 100mW/cm2 illumination.

Electrospray atomization is a method that uses electrical stresses as the means of generating charged droplets. The fundamental working principles of electrospray have previously been extensively studied and demonstrated to have monodisperse droplet size distribution, good stability and scalability. Electrospray is a bottom-up deposition method which opens up the possibility of a roll-to-roll compatible process and is functional at regular atmospheric conditions. Due to this set of positive qualities, this atomization method holds promise as a means of solution based material processing that is cost effective and scalable. Conjugated polymers are among the solution processable materials of most interest, poly(3-hexylthiophene)(P3HT) standing out as one of the most extensively studied. Applications of P3HT as a p-type semiconductor have been demonstrated in devices like organic solar cells, light emitting diodes and transistors. Improvements in the performance of the mentioned devices have been correlated with a higher degree of crystallinity as well as the film structure in the case of organic solar cells. The effects of different electrospray process parameters are investigated and various P3HT film structures are presented in this study. Electric repulsion present within the droplets in electrospray and evaporation of the solvent were used to obtain high aspect ratio features on the P3HT films. A clever design for the electrospray nozzle devised to improve the process stability is presented. Also, the crystallinity of the films was characterized using grazing incidence x-ray diffraction (GIXRD) and ultraviolet visible spectroscopy. All results in this study are presented as a comparison to spin coated control process. The GIXRD results suggest that the electrospray process produces crystallites that have an orientation opposite of the orientation observed in the spin coated process. Analysis of the ultraviolet visible spectroscopy absorption spectrum shows a red-shift, signaling an increase in the crystallinity. Lastly, good contact between the deposited P3HT and the substrate was confirmed using conductive atomic force microscopy (CAFM).

Organic solar cells have emerged as an important cheap photovoltaic technology. In this thesis work, a study of P3HT:PCBM heterojunction solar cells was presented. By incorporation of photo-active film slow growth, PEDOT:PSS (Poly(3,4-ethylenedioxythiophene) poly(styrenesulfonate)) de-water treatment and application of highly conductive PEDOT:PSS (HC-PEDOT), a maximum PCE (power conversion efficiency) of 4% was achieved. Inkjet printing technique was on the other hand introduced into fabrication process. The morphological, electrical and optical properties of printed HC-PEDOT were investigated. Fine silver girds with well-designed pattern, combining with a transparent thin film of HC-PEDOT, was inkjet-printed to form the anode of solar cells. A functional device with printed anode and printed photo-active layer was demonstrated, showing the possibility of realizing fully printed organic solar cells.

<p>Organic solar cells have emerged as an important cheap photovoltaic technology. In this thesis work, a study of P3HT:PCBM heterojunction solar cells was presented. By incorporation of photo-active film slow growth, PEDOT:PSS (Poly(3,4-ethylenedioxythiophene) poly(styrenesulfonate)) de-water treatment and application of highly conductive PEDOT:PSS (HC-PEDOT), a maximum PCE (power conversion efficiency) of 4% was achieved.</p><p>Inkjet printing technique was on the other hand introduced into fabrication process. The morphological, electrical and optical properties of printed HC-PEDOT were investigated. Fine silver girds with well-designed pattern, combining with a transparent thin film of HC-PEDOT, was inkjet-printed to form the anode of solar cells. A functional device with printed anode and printed photo-active layer was demonstrated, showing the possibility of realizing fully printed organic solar cells.</p><p> </p>

In this study, two kinds of homopolymers (PPDOT, and P3HT), and three different proportions of copolymers (PPDOT-co-P3HT=1:1, PPDOT-co-P3HT=3:1, and PPDOT-co-P3HT=1:3) have been synthesized successfully by Grignard metathesis. PDOT and 3HT, which are both of monomers, are electron-donating. Due to the fact that PDOT was caused larger than 3HT by pushing effect, it can change the conjugation length to be much longer, resulting in lower energy level of HOMO, and thus reduce energy gap of high molecular. These polymers possess optical bandgaps in the range of 1.908 to 1.922 eV. The desirable absorption attributes of these materials make them to be the excellent candidates for use in organic solar cells. In this study, the analysis and discussion of these polymers were measured by TGA, DSC, XRD, GPC, NMR, UV, PL, and AC-2 for thermal stability, crystallinity, structure and optical properties. From the XRD, materials of main chain ordered are well crystalline, which can increase the absorption of thiophene ring. By UV, we could find absorption region of infrared light increase that is beneficial to enhance ISC, but led to lower HOMO, and thus reduced VOC. However, the overall device power conversion efficiencies indicate that increasing ISC is much greater than decreasing VOC. Hence, power conversion efficiency increased. However, in PL, intensity of the emission is large, and it will cause components to quenching that lead to reduce its efficiency. We knew HOMO-LUMO energy level matching relations of polymer materials which were mixed with PCBM as the active layer of organic solar cells by UV-VIS and AC-2. From the instructions of device power conversion efficiency, because efficiency is not high, it causes the short circuit. The reason is (1) energy level can not match (2) the solubility of PPDOT is not very good, hence the film is not easy even. The way to improve is to identify a better solvent to increase its solubility.

Controlling the blend morphology is one of the ways to achieve high power conversion efficiency in organic bulk heterojunction (BHJ) photovoltaic device. One sample yet effective method is ¡§ additive¡¨ approach, which involves the addition of a small concentrations of additive into the blend of donor/acceptor dissolved in solution. When adding small concentrations of additives in solution, we can change the donor/acceptor of internal micro-structure and films of morphology. In this work, we performed a systematic study of the effect of nanocrystals of phenolic additives, such as the small concentrations of 4,4'-Sulfonyldiphenol(BPDT), 4,4'-Dihydroxybiphenyl(BP) and Biphenyl-4,4¡¦-dithiol(BPS), on the nanoscals phase separation of and P3HT:PCBM blends and consequently, the power conversion efficiency(PCE) of the devices. The extent of the additive-induced phase separation and crystallize of P3HT is related to the additive acidity constant (pKa) and the degree of interaction between the additive and P3HT/PCBM, as evident from X-ray diffractmeter, UV-Vis spectrometer, Raman spectrometer and current density-voltage characteristic data. Lastly, PCE as increasing as 25% and short current increasing as 15% can be achieved in an optimally phase-separated blend due to an improvement in the charge dissociation and a dcrease in bimolecular recombination and parallel resistance.

No description available.

A une époque où les technologies nouvelles fleurissent chaque jour, un domaine particulier se détache : l’électronique organique. Par son utilité et sa facilité de mise en œuvre, l’électronique organique affiche de grandes promesses pour l’avenir. Dans le but d’améliorer le procédé de fabrication et la durée de vie de ces dispositifs, le travail de cette thèse s'est focalisé sur la synthèse de copolymères à architectures variées à base de poly(3-hexylthiophène) (P3HT). Après avoir exposé les problématiques et objectifs de la thèse dans une première partie, la synthèse de différents précurseurs P3HT est décrite. Ces matériaux représentent la base des travaux présentés dans cet ouvrage. Dans un premier temps, l'optimisation de la synthèse des copolymères à blocs rigide-flexible a été réalisée en suivant une stratégie adaptée pour une application en électronique organique. La conception de nouveaux matériaux semi-conducteurs à architectures ramifiées est traitée par la suite. Enfin, le dernier chapitre porte sur l'intégration d’un copolymère, le P3HT-b-Poly(4vinylpyridine), en cellule photovoltaïque organique en tant qu'additif de la couche active. Cette approche s’avère être particulièrement puissante, permettant notamment de diminuer le temps et le coût énergétique de la mise en œuvre de ces cellules en s’affranchissant d’une étape clé de la fabrication, le recuit. / At a time when new technologies emerge every day, a specific domain stands out: the organic electronic. Through its low cost processing or even its utility, the organic electronic constitutes a very promising future.In order to improve the fabrication process and the lifetime of the devices, the work of this thesis was focused on the synthesis of copolymers with various architectures based on poly(3-hexylthiophene) (P3HT). After a first part where main issues and objectives are presented, the synthesis of different P3HT-based precursors is described in a part which could be considered as the heart of these works. Starting with appropriated precursors, the optimization of rod-coil diblock copolymer synthesis was performed following a strategy designed specifically for organic electronic application. Moreover, the precursors were used for the conception of new semi-conducting materials with a variety of architectures, such as graft and star copolymers. Finally, the last part deals with the integration of the P3HT-b-Poly(4-vinylpyridine) copolymer into organic solar cell as an additive of the active layer. This approach turns out to be powerful, especially allowing decreasing the time and the energy cost by avoiding the key step of the fabrication process of those devices, the annealing step.