title: High-efficiency, broad-band and wide-angle optical absorption in ultra-thin organic photovoltaic devices.
abstract: Metal nanogratings as one of the promising architectures for effective light trapping in organic photovoltaics (OPVs) have been actively studied over the past decade. Here we designed a novel metal nanowall grating with ultra-small period and ultra-high aspect-ratio as the back electrode of the OPV device. Such grating results in the strong hot spot effect in-between the neighboring nanowalls and the localized surface plasmon effect at the corners of nanowalls. These combined effects make the integrated absorption efficiency of light over the wavelength range from 400 to 650 nm in the active layer for the proposed structure, with respect to the equivalent planar structure, increases by 102% at TM polarization and by 36.5% at the TM/TE hybrid polarization, respectively. Moreover, it is noted that the hot spot effect in the proposed structure is more effective for ultra-thin active layers, which is very favorable for the exciton dissociation and charge collection. Therefore such a nanowall grating is expected to improve the overall performance of OPV devices.
authors.forename: Wenyan
authors.initials: W
authors.lastname: Wang
authors.forename: Yuying
authors.initials: Y
authors.lastname: Hao
authors.forename: Yanxia
authors.initials: Y
authors.lastname: Cui
authors.forename: Ximin
authors.initials: X
authors.lastname: Tian
authors.forename: Ye
authors.initials: Y
authors.lastname: Zhang
authors.forename: Hua
authors.initials: H
authors.lastname: Wang
authors.forename: Fang
authors.initials: F
authors.lastname: Shi
authors.forename: Bin
authors.initials: B
authors.lastname: Wei
authors.forename: Wei
authors.initials: W
authors.lastname: Huang