Electrical charge transport and optical properties of iron pyrite
Iron pyrite is among the promising solar materials owing to its remarkably high optical absorption, optimal band gap, abundance, and non-toxicity. However, its solar conversion efficiency is limited to about 3 % mainly due to its low photovoltage. To address that, thin films prepared by spray pyr...
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| Format: | Thesis-Doctor of Philosophy |
| Language: | English |
| Published: |
Nanyang Technological University
2017
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| Online Access: | http://hdl.handle.net/10356/70587 |
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| Institution: | Nanyang Technological University |
| Language: | English |
| Summary: | Iron pyrite is among the promising solar materials owing to its remarkably high optical
absorption, optimal band gap, abundance, and non-toxicity. However, its solar conversion
efficiency is limited to about 3 % mainly due to its low photovoltage. To address that, thin
films prepared by spray pyrolysis, spin-coating of hot-injection synthesized nanocubes and
pulsed laser deposition were sulfurized to obtain the pure pyrite phase. The film showed
similar electrical properties and degenerate semiconducting behavior with Mott-VRH
charge transport over a wide temperature range. Charge carrier dynamics in nanocube thin
film revealed fast carrier localization and long-lived trap states in the pure pyrite.
Temperature dependent electrical and magnetic behaviors supported the existence of
intrinsic localized gap states. A non-standard, electrical experiment was carried out on a
natural pyrite single crystal to assess the surface and bulk resistivities of pyrite which showed
a significant difference in them for temperatures less than 120 K. It is concluded that the poor
photovoltage generated by pyrite solar devices is due to the intrinsic defects in the material
rather than to impurities or secondary phases. |
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