One of the main contributions of this thesis is the improvement on the overall performance of the solar cells due to the impact of the surface engineering of silicon nanocrystals (SiNCs) and also down conversion of high energy photons by SiNCs. It is demonstrated that surface engineering techniques by using microplasma processing improve the capabilities of the SiNCs for different opto-electronic applications and in particular for solar cells. Surface engineering of SiNCs in water shows long term stability, which could allow the deployment of SiNCs for a wider range of applications. Microplasma-induce liquid chemistry on SiNCs in ethanol and water shows very unique surface properties which are not achievable by other techniques. The optical and electronic properties of SiNCs/polymer colloid and nanocomposites have been analyzed. It has been found that microplasma processed SiNCs/polymer nanocomposite shows improved optical properties and also exhibits enhanced photogeneration and conductivity. This thesis is focused on the application of SiNCs in photovoltaic devices. Hybrid bulk heterojunction solar cells and SiNCs-Schottkey barrier photo voltaic devices have been developed. Hybrid bulk heterojunction solar cells have polymers and SiNCs as an active layer. A range of different device structures have been produced and investigated with support from current-voltage characteristics, which contributed to identify band alignment and the suitability of the architectures for the solar cells. The results also explain the limitations of the solar cells due to either dissociation and/or transport properties. SiNCs based nanocomposites are being employed as an optical converter first time in organic solar cell. SiNCs/polymer nanocomposite allows down conversion of high energy photons demonstrating a drastic improvement in solar cell efficiency with concentrated light.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:629076 |
| Date | January 2014 |
| Creators | Mitra, Somak |
| Publisher | Ulster University |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
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