- Title
- Development of a solar fabric energy system
- Creator
- Hart, Andrew Spencer
- Relation
- University of Newcastle Research Higher Degree Thesis
- Resource Type
- thesis
- Date
- 2020
- Description
- Research Doctorate - Doctor of Philosophy (PhD)
- Description
- Organic photovoltaics have the potential to be a cheap, lightweight, and mechanically flexible source of renewable energy. In addition, organic photovoltaics have the ability to be produced roll-to-roll at extremely high throughput which lowers the cost of production per square metre. While laboratory scale organic photovoltaic devices are achieving power conversion efficiencies above 18 %, roll-to-roll produced devices are still developing the efficiencies required to compete with traditional photovoltaics at a commercial level for mains power generation. For organic photovoltaics to be commercially viable the unique properties of the technology must be utilised to produce a product that fulfils a niche use that does not compete with traditional photovoltaics. This thesis has investigated the potential to use the lightweight and mechanically flexible nature of organic photovoltaics to allow for direct integration of this technology on fabric substrates. The potential use for fabric integrated flexible solar cells includes solar tents, solar sails, and solar shade cloths but this work specifically addresses solar blinds. Several problems need to be addressed to achieve this aim. Firstly, the problem of device encapsulation is addressed. Organic photovoltaics need the protection of a water and oxygen barrier to prevent degradation of the device, however, the barrier must conform to the light weight and flexibility of organic photovoltaics which allows these devices to be integrated with fabric substrates. Finding a suitable encapsulation barrier film requires a method of testing barrier films resistance to water transfer. While methods exist to determine the water vapour transmission rate of a barrier film, the work presented in this thesis improves upon those designs in such a way to allow for easier fabrication and assembly of testing units and to provide additional information on barrier film quality and consistency. This new method of barrier film testing was capable of creating a water vapour transmission map of the sample in order to identify the location and severity of defects. Secondly, a method of improving organic photovoltaic device efficiency on the roll-to-roll scale that does not rely on high temperatures is presented. Eliminating the high temperature annealing steps traditionally used on the roll-to-roll scale to improve device performance is vital for integration of organic photovoltaics on fabrics due to the low heat tolerance of the substrate. Canvas, for example, will start to warp at 80°C while annealing is traditionally performed by exposure to 120°C – 140°C temperatures for several minutes at a time. To overcome this limitation of fabric substrates a solvent annealing approach was employed, which allows for increased crystallisation of poly(3-hexylthiophene) on the roll-to-roll scale to increase device performance without the use of heat. The solvent annealing presented in this work has been shown to improve organic photovoltaics power conversion efficiency by a factor of 4 over unannealed devices. Thirdly, new device structures have been developed specifically for use on fabric substrates. Traditional roll-to-roll fabricated organic photovoltaics are illuminated through the substrate they are printed on. This structure is unsuitable for use on fabric due to the opaque nature of the substrate material which prevents light transmission. As the surface properties of the material that the ink is deposited on are vital for suitable wettability, simply flipping the device architecture is not possible. Instead, the device architecture needs to be changed to allow for ink wettability on previously printed layers. Fabrication methods and a device structure is developed which results in a device with power conversion efficiency parity when comparing between the same structure fabricated on either a plastic or canvas substrate, indicating the fabric substrate has no detrimental effect on device performance. Finally, organic photovoltaics are incorporated into a flexible solar blind capable of automatically operating to decrease the amount of heat infiltration through a window in order to reduce power consumption on cooling of internal spaces. The blind is capable of automatic operation without the need for connection to a power supply or manual charging. This work has shown that the blind can reduce the amount of heat extraction required to maintain an internal temperature of 22°C by more than 40 % and will recharge the energy cost of operating with less than 1 hour of light exposure per day. The ease of installation without the need for an electrician and the flexibility of the blind makes the solar blind a unique product with practical real world applications.
- Subject
- organic photovoltaics; solar fabric; barrier film testing; solar blind; plastic solar cell
- Identifier
- http://hdl.handle.net/1959.13/1422000
- Identifier
- uon:37793
- Rights
- Copyright 2020 Andrew Spencer Hart
- Language
- eng
- Full Text
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| Thumbnail | File | Description | Size | Format | |||
|---|---|---|---|---|---|---|---|
| View Details Download | ATTACHMENT01 | Thesis | 12 MB | Adobe Acrobat PDF | View Details Download | ||
| View Details Download | ATTACHMENT02 | Abstract | 343 KB | Adobe Acrobat PDF | View Details Download |