Four-wire thin-film silicon devices: Towards high efficiency

A “four-wire” configuration thin-film silicon solar cell design is proposed. Front and middle TCO layers are optimized in order to be used, together with a Bragg reflector, to increase the useful current in the top cell (by about 1 mA/cm2 according to initial calculations) and hence the total photocurrent. Preliminary results from both experiments and numerical simulations are presented, showing the potential and challenges of the design. With reasonable assumptions, a stabilized efficiency of 14% could be achieved.