Reiss, P.; Haschke, J.; Korte, L.; Mingirulli, N.; Amkreutz, D.; Leendertz, C.; Teodoreanu, A.-M.; Rech, B.: Short Circuit Current Loss Analysis of Electron Beam Crystallized Silicon Solar Cells on Glass by Numerical Computer Simulation. In: Nowak, S. [Ed.] : 27th European Photovoltaic Solar Energy Conference and Exhibition ; Frankfurt, Main: EU PVSEC ; 24.9.2012-28.9.2012München: WIP, 2012. - ISBN 3-936338-28-0, p. 2396-2399
10.4229/27thEUPVSEC2012-3CV.2.9
Abstract:
In polycrystalline thin film cells on glass with an electron beam crystallized absorber (ERA) of only 10μm thickness and an amorphous silicon hetero-emitter an open circuit voltage of 545 mV [1] has been achieved which proves the high electronic quality of the absorber material. However efficiencies are currently at moderate 4.7%, mainly due to low short circuit currents. In this work a simulation model to describe the a-Si/c-Si heterostructure is developed and validated by a comparison of the simulation with measured IQE data as well as IV-characteristics. On the basis of the model a study on the loss mechanisms responsible for the low jsc is carried out. As a result, insufficient charge carrier diffusion length, a high reflection at the front surface and incomplete absorption of the IR-light are the main reasons for a low jsc. Furthermore, the cell's efficiency potential is evaluated for a set of parameters that are realistically achievable in the near future: an improved absorber quality (diffusion length > absorber thickness), an improved backside passivation, an optimized front reflection and a back contact concept. This would lead to a j sc increase by more than a factor of two and a conversion efficiency of above 11%.