A numerical analysis of interdigitated back contacted silicon solar cells

Thesis Type: Postgraduate

Institution Of The Thesis: Middle East Technical University, Turkey

Approval Date: 2018

Thesis Language: English

Student: Beran Acar



The state-of-the-art solar cells manufactured using crystalline silicon (c-Si) are highly cost-effective, competing with fossil fuel-based energy sources. However, relatively more complex cell structures (i.e. interdigitated back contact, IBC) need to be developed to further increase the efficiency/cost ratio. In this thesis, the effects of structural parameters such as cell dimensions, metal contact geometry and contact resistances on the efficiency of IBC and bifacial IBC silicon solar cells were studied by numerical simulations. Light absorption in IBC and bifacial IBC solar cells was simulated using ray optics method in Opal 2 simulation software. The extracted generation profiles were embedded into Silvaco TCAD. Efficiency (), open circuit voltage (VOC), short circuit current density (JSC) and fill factor (FF) of solar cells were calculated for various device configurations. The results showed that the usage of high quality bulk Si providing longer carrier lifetime values up to 10 ms is more effective on cell efficiency than changing the base doping between the limits 1x1014 to 1x1017 atoms/cm3. Furthermore, the effect of the ratio of emitter width to cell width was investigated and the optimum ratio is found to be 79%. An optimum structure for a minority carrier lifetime of 1 ms and base doping concentration of 1x1016 cm-3 is obtained when an emitter width of 1500 μm and a back surface field width of 300 μm is realized. Finally, the effects of contact widths of bifacial IBC solar cells on efficiency were studied. A contact coverage fraction around 20% yields the highest efficiency for a floor reflection of 30%.