TiO2-Coated Carbon Nanotube-Silicon Solar Cells with Efficiency of 15%

Abstract

Combining carbon nanotubes (CNTs), graphene or conducting polymers with conventional silicon wafers leads to promising solar cell architectures with rapidly improved power conversion efficiency until recently. Here, we report CNT-Si junction solar cells with efficiencies reaching 15% by coating a TiO₂ antireflection layer and doping CNTs with oxidative chemicals, under air mass (AM 1.5) illumination at a calibrated intensity of 100 mW/cm² and an active device area of 15 mm². The TiO₂ layer significantly inhibits light reflectance from the Si surface, resulting in much enhanced short-circuit current (by 30%) and external quantum efficiency. Our method is simple, well-controlled, and very effective in boosting the performance of CNT-Si solar cells.