Graphene/Si solar cells employing triethylenetetramine dopant and polymethylmethacrylate antireflection layer

We report the use of triethylenetetramine (TETA) as a dopant of graphene transparent conducting electrodes (TCEs) for Si heterojunction solar cells. The molar concentration (n _D ) of TETA is varied from 0.05 to 0.3 mM to optimize the graphene TCEs. The TETA-doped graphene/Si Schottky solar cells show a maximum power-conversion efficiency (PCE) of 4.32% at n _D = 0.2 mM, resulting from the enhanced electrical and optical properties, as proved from the n _D -dependent behaviors of sheet resistance, transmittance, reflectance, series resistance, and external quantum efficiency. In addition, polymethylmethacrylate is employed as an antireflection layer to enhance the light-trapping effect on graphene/Si solar cells, resulting in further enhancement of the maximum PCE from 4.32 to 5.48%. The loss of the PCE is only within 2% of its original value during 10 days in air.