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.