title: Poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate)/GaAs hybrid solar cells with 13% power conversion efficiency using front- and back-surface field.
abstract: Planar hybrid solar cells based on bulk GaAs wafers with a background doping density of 10(16) cm(-3) and poly(3,4-ethylenedioxythiophene): poly(styrenesulfonate) (
  PSS) demonstrated an excellent power conversion efficiency of 8.99%. The efficiency of the cell was enhanced to 9.87% with a back-surface field feature using a molecular beam epitaxially grown n-type GaAs epi-layer. The efficiency and fill factor reach 11.86% and 0.8 when an additional p + GaAs epi-layer is deposited on the surface of the solar cells, which provides a front-surface field. The interface between the high- and low-doped regions in the polymer/GaAs and GaAs formed an electric field that introduced a barrier to minority carriers flow to the substrate and effectively reduced front surface carrier recombination, thereby enhancing light-generated free carrier collection efficiency and open-circuit voltage. Compared with the device without the front- and back-surface field, the fill factor and open-circuit voltage of the hybrid solar cell were improved from 0.76 to 0.8 and from 0.68 V to 0.77V, respectively. The highest efficiency reaches a record 13% when the Zonyl fluorosurfactant-treated
  PSS is used as a hole-transporting conducting layer for hybrid cells.
authors.forename: C H
authors.initials: CH
authors.lastname: Lin
authors.forename: K W
authors.initials: KW
authors.lastname: Sun
authors.forename: Q M
authors.initials: QM
authors.lastname: Liu
authors.forename: H
authors.initials: H
authors.lastname: Shirai
authors.forename: C P
authors.initials: CP
authors.lastname: Lee