title: Sub-50-nm self-assembled nanotextures for enhanced broadband antireflection in silicon solar cells.
abstract: Materials providing broadband light antireflection have applications as highly transparent window coatings, military camouflage, and coatings for efficiently coupling light into solar cells and out of light-emitting diodes. In this work, densely packed silicon nanotextures with feature sizes smaller than 50 nm enhance the broadband antireflection compared with that predicted by their geometry alone. A significant fraction of the nanotexture volume comprises a surface layer whose optical properties differ substantially from those of the bulk, providing the key to improved performance. The nanotexture reflectivity is quantitatively well-modelled after accounting for both its profile and changes in refractive index at the surface. We employ block copolymer self-assembly for precise and tunable nanotexture design in the range of ~10-70 nm across macroscopic solar cell areas. Implementing this efficient antireflection approach in crystalline silicon solar cells significantly betters the performance gain compared with an optimized, planar antireflection coating.
authors.affiliation: Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, New York 11973, USA.
authors.forename: Atikur
authors.initials: A
authors.lastname: Rahman
authors.affiliation: 1] Sustainable Energy Technologies Department, Brookhaven National Laboratory, Upton, New York 11973, USA [2] Department of Physics and Astronomy, Stony Brook University, Stony Brook, New York 11794, USA.
authors.forename: Ahsan
authors.initials: A
authors.lastname: Ashraf
authors.affiliation: Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, New York 11973, USA.
authors.forename: Huolin
authors.initials: H
authors.lastname: Xin
authors.affiliation: Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, New York 11973, USA.
authors.forename: Xiao
authors.initials: X
authors.lastname: Tong
authors.affiliation: Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, New York 11973, USA.
authors.forename: Peter
authors.initials: P
authors.lastname: Sutter
authors.affiliation: 1] Sustainable Energy Technologies Department, Brookhaven National Laboratory, Upton, New York 11973, USA [2] Department of Physics and Astronomy, Stony Brook University, Stony Brook, New York 11794, USA [3] Department of Electrical and Computer Engineering, Stony Brook University, Stony Brook, New York 11794, USA.
authors.forename: Matthew D
authors.initials: MD
authors.lastname: Eisaman
authors.affiliation: Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, New York 11973, USA.
authors.forename: Charles T
authors.initials: CT
authors.lastname: Black