| dc.description.abstract | Organic materials have enormous relevance in material science and have many advantages over materials such as metals, ceramics and glass due to their physical and mechanical properties. They offer a viable alternative to their inorganic counterparts due to their low manufacturing costs and their mechanical and electrical properties.
Polymer / fullerene composites are really interesting organic material candidates for photovoltaic devices as they are chemically very stable and have excellent electrical properties. In order to get a good balance between hole and electron conduction, polymers can assume the function of hole transport materials, and fullerenes can function as an optimal electron transport.
In this project, several electron donor semiconducting polymers, such as poly[2,5-dimethoxy-(2’-ethylhexyloxy)-1,4-phenylenevinylene] (MEH-PPV), poly(3-hexylthiophene-2,5-diyl), (P3HT), combined with fullerenes such as C60 or the derivative [6,6]-phenyl-C61 (PCBM), were selected for use in the manufacture organic solar cells. Charge transport of these blends was investigated. (Poly (3,4-ethylenedioxythiophene) (PEDOT:PSS) was used as a hole transport conducting polymer. Indium Tin Oxide (ITO) and Aluminium (Al) were used as electrodes. Spectral response and current-voltage measurements using 80 mW/cm2 white illumination, simulating solar energy illumination, were analysed in order to determine the photovoltaic behaviour of organic solar cells. Absorption spectroscopy was carried out to analyse the charge transfer within the composites and at the interface between the composites and the other polymer layers. Also, calorimetric studies helped us to characterise these polymer and fullerene composites. An optimum photovoltaic response and relative efficiency of 2.3 % was obtained for ITO / PEDOT:PSS / P3HT:PCBM / Al devices after annealing treatment.
The effect of incorporating single-walled and multi-walled carbon nanotubes (SWNT and MWNT) in to organic solar cells had been also studied. Free-standing carbon nanotube / polymer composite films, using chemical vapour deposition (CVD) in order to grow nanotubes on substrates, were also investigated as candidates for organic solar cells.
The project aims to, together with understanding the underlying physics, determine which materials and device architectures are more appropriate to obtain better power conversion efficiencies. | en |
