One way of reducing the cost of crystalline silicon solar cell fabrication is by increasing the conversion efficiency of the device. However, most high efficiency solar cell designs require more complex fabrication methods that also increase the fabrication cost. Photolithography is an example of such an indispensable but costly process. The most common use for photolithography in solar cell fabrication is for dielectric patterning. In this thesis, inkjet printing is proposed as an alternative method for dielectric patterning in solar cell fabrication. There are two inkjet printing methods developed in this thesis. The indirect inkjet patterning method involves the deposition of a suitable plasticiser droplet onto an intermediate resin coating layer on top of the dielectric surface. Diethylene glycol and novolac resin are used as the plasticiser and coating layer respectively. The plasticiser changes the permeability of the affected region of the resin such that it becomes permeable to liquid dielectric etchants. When the resin layer is removed, the printed pattern is transferred to the dielectric layer. The optimised process produces round openings with diameters as small as 30-35 μm and continuous line patterns with width as narrow as 40-50 μm. The direct inkjet patterning method involves the deposition of liquid phosphorus dopant sources onto both silicon and dielectric surfaces. Two types of phosphorus sources are used: phosphoric acid and specially-formulated dopant sources. Narrow lines as wide as 15-20 μm are produced after appropriate surface treatments on both silicon and dielectric surfaces. Using this method, a process that simultaneously pattern the dielectric layer and diffuse the silicon underneath is developed. Various high efficiency solar cell structures such as selective emitter, localised contacts, surface texturing and edge isolation are demonstrated using the indirect inkjet patterning method. Both inkjet patterning methods are then used in the fabrication of a selective emitter solar cell. Fill factors in the range of 0.79-0.80 are shown to be achievable with both patterning methods, thus indicating the high quality metal-silicon contacts formed by these inkjet techniques.
| Identifer | oai:union.ndltd.org:ADTP/258300 |
| Date | January 2009 |
| Creators | Utama, Roland Yudadibrata, Photovoltaics & Renewable Energy Engineering, Faculty of Engineering, UNSW |
| Publisher | Publisher:University of New South Wales. Photovoltaics & Renewable Energy Engineering |
| Source Sets | Australiasian Digital Theses Program |
| Language | English |
| Detected Language | English |
| Rights | http://unsworks.unsw.edu.au/copyright, http://unsworks.unsw.edu.au/copyright |
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