Abstract: Even though improvements in the efficiency of organic solar cells encouraged the
commercialization of this technology in the past two decades, the stability of organic solar
cells is still an active area of research. The effect of photo-oxidative degradation on the
performance of organic solar cell devices is significant. One way to lower the rate of photooxidation
degradation is by preventing oxygen molecules from reaching the active layer of
organic solar cells. This could be achieved by fabricating the devices in an inert
environment in the absence of oxygen. Once the devices are fabricated, they would be
encapsulated in a transparent material.1, 2 Even though this is a viable solution, there are
two main issues. First, it was shown that oxygen molecules could diffuse through the
encapsulating material and degrade the devices.3 Second, implementing this solution would
increase the fabrication cost of these devices, which would make this solution
commercially unfeasible compared to other solar cell technologies.3 Speller and his
colleges reported a possible mechanism of the photo-oxidative degradation and showed a
relationship between the rate of degradation and LUMO energy levels of electron acceptor
molecule4. In this thesis, we report the photo-oxidative degradation rate of O-IDTBR and
O-IDTBR-(C3N2)2. The later electron acceptor is analogous to O-IDTBR with deeper
LUMO by 0.1 eV. After four hours of constant irradiation from a 1-sun intensity xenon
solar simulator, the maximum UV-Vis absorbance of O-IDTBR is reduced by 12% relative
to O-IDTBR-(C3N2)2. Lower absolute degradation rates were observed when 1-sun LED
solar simulator was used compare to xenon solar simulator.
Date of Award | Mar 2020 |
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Original language | English (US) |
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Awarding Institution | - Physical Sciences and Engineering
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Supervisor | Iain Mcculloch (Supervisor) |
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- Organic electron acceptors
- Organic solar cells
- Non Fulerane aceeptors