Studies on the Processing and Stabilisation of Chromophores

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  • Leo Furnell

Abstract

This project focused on a range of sensitisers used in dye sensitised solar cells (DSSC) and tested their suitability in two main areas. The first was the stability of the dye which is essential for the long term success of DSSC devices. The second was to study dye sorption onto mesoporous TiO2 films for the construction of DSSC devices. First the stability of D35, N719, Cyanine, D131, methylene blue and the squaraine 1 and 2 dyes in ethanolic solutions were investigated by exposing to natural light for 64 days. Images after 0 days, 21 days and 64 were processed using RGB analysis and showed significant variation between dye stability. N719 showed the highest stability and squaraine 1 showed the lowest. The stability of N719, squaraine 1 and squaraine 2 was then compared on mesoporous TiO2 films exposed under an artificial light for 4 hours. The results were concordant with the previous data that N719 was the most stable but also showed a higher stability for squaraine 2 than squaraine 1. Finally DSSC devices of N719 and D35 were constructed and exposed to artificial light. The devices were monitored by solar simulation and image analysis. Results confirmed N719 was again the most stable and showed a link between the efficiency and the colour of the device. A process to achieve fast dye sorption to TiO2 films on 15 cm long DSSC devices was developed. The process was conducted by passing the dye through the DSSC device cavity using a peristaltic pump. This method was tested individually with N719, squaraine 2, D131, half squaraine, rhodamine B dyes and also used to co-sensitise half squaraine and SQ1. The time taken for complete sorption was measured using image analysis. Data show that time taken for complete dye uptake varied greatly, with the shortest sorption time of 2 minutes achieved using rhodamine B dye with full coverage after two minutes and a longest sorption time of 1 hour for SQ2. The co-sensitisation of half squaraine and squaraine 1 showed that the order of the dyes was significant, with a dyeing time of 40 minutes for half squaraine first and 50 minutes with SQ1 first.

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Original languageEnglish
Awarding Institution
Supervisors/Advisors
Thesis sponsors
  • Engineering and Physical Sciences Research Council (EPSRC)
Award dateJan 2016