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McIntosh, Noah

University of British Columbia

Global commitments to reduce fossil-based carbon emissions and invest in clean energy technologies have brought about an increased interest in solar photovoltaic (PV) technology. Current market-leading and top-performing solar panels are fabricated through expensive, time and energy-intensive vacuum-based fabrication routes, incurring high costs. In contrast, liquid-based solution processing techniques offer enormous potential for cost reduction but must improve performance to become competitive on the market. To this end, the present work analyses a liquid-based fabrication method for CuIn(S,Se)₂ – short CISSe – absorber films, aiming to improve the quality and performance of the produced materials. The study includes the use of a non-toxic alternative chemical etchant and a novel component design in the proposed fabrication system, as well as an investigation of the effect of different elemental compositions in molecular ink precursors. This is achieved by producing a sample batch of CISSe absorber films using the primary experimental variables: chemical etchant and precursor composition respectively. CISSe absorber films are fabricated using the solution-based molecular ink approach at four different compositions, defined by the elemental ratio Cu/In = 0.7, 0.85, 1.0, and 1.15, and compared in a non-etched, standard-etched (KCN), and alternative-etched ((NH₄)₂S) iteration for each composition. Materials characterization is done using X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy dispersive spectroscopy (EDS) analyses. It is found that this fabrication method can produce high quality absorber films with the desired CISSe material at all respective compositions. Increasing size of crystal grains was observed as the Cu/In ratio was increased up to 1.15 (~7.5 μm average grain size). At Cu/In ratios 1.0 and above, detrimental secondary phases of copper selenide compounds were found to be present. Both the (NH₄)₂S and KCN etchants were found to effectively etch these secondary phases. This work strongly supports the use of the presented solution-based fabrication method, validating both the alternative furnace system design and benign chemical etchant alternative. Future works should use this research as a base with primary focus on completion of a complete CISSe solar cell device for further study.

Text

2022-11-14

Attribution-NonCommercial-NoDerivatives 4.0 International

http://hdl.handle.net/2429/83152

Mechanical Engineering

University of British Columbia

UBCO

http://creativecommons.org/licenses/by-nc-nd/4.0/