Flexible solar cells based on graphene-ultrathin silicon Schottky junction

Abstract

We developed a flexible graphene–silicon (Gr–Si) photovoltaic device with high reliability and stability. Ultrathin Si film was fabricated via an anisotropic Si etching method, and exhibited excellent flexibility. Different from the traditional graphene transfer approach, polymethylmethacrylate (PMMA) film remained, by which the physical damage of graphene resulting from the PMMA dissolution process is avoided. Moreover, PMMA film could serve as an antireflection layer that reduces the reflectance from 40% to lower than 20%. The power conversion efficiency of a PMMA–Gr–Si film solar cell reached 5.09%, which far exceeds the efficiency of a Gr–Si solar cell with the same thickness of Si film of 10.6 μm. More importantly, the PMMA film worked as a packaging material to improve the device stability. The PMMA–Gr–Si solar cell could keep 93% of the original efficiency after bending 60 times. The simple, low-cost and flexible photovoltaic device shows promising prospects in potential applications for portable and wearable electronic products.