Crystalline silicon thin film photovoltaic solar cells based on energy efficient nanomembrane transfer process

We report here experimental demonstration of crystalline semiconductor Si nanomembrane thin film solar cells based on room temperature frame-assisted membrane transfer (FAMT) process. Low-temperature compatible annealing processes have also been investigated for optimal metal contact formation. For two micrometer thick p-n junction Si solar cells, we obtained an open circuit voltage of 0.38 V and power efficiency of 1.64%, without any anti-reflection coating or light trapping schemes. Incorporating optimal anti-reflection coating, light trapping and plasmonic structures, we expect the cell efficiency to approach 10% and more for 2 μm thick Si cells. The results demonstrate a promising future for such a new type of cost effective flexible thin film solar cells, based on crystalline semiconductor membranes.