High-efficiency, hybrid Si/C60 heterojunction solar cells

Abstract

Hybrid solar cells, based on combinations of organic and inorganic semiconductors, constitute a promising avenue to harness solar energy by taking advantage of the strengths of both organic and inorganic materials. In this work, we report the first high-efficiency hybrid solar cell of its type comprising p-type silicon with an organic n-type C60 layer. High efficiencies based on the Si/C60 heterojunction were realized by utilizing an ultra-thin, doped and highly conductive C60 layer. Fabrication parameters were thoroughly investigated and critical factors for the efficient operation of this type of device were found to include the C60 thickness, doping of the C60 layer (using tetrabutyl ammonium iodide, TBAI), age-induced surface passivation and the incorporation of anti-reflection coatings (ARCs). From current density-voltage (J-V) and capacitance-voltage (C-V) characteristics, we have characterized the influence of C60 doping and device aging on the depletion region width and electrical parameters. An optimal power conversion efficiency of 8.43% was realized after 4 days of aging and TBAI treatment, with the application of a quarter-wave Sb2O3 ARC.