title: Rear interface engineering of hybrid organic-silicon nanowire solar cells via blade coating.
abstract: In this work, we investigate blade-coated organic interlayers at the rear surface of hybrid organic-silicon photovoltaics based on two small molecules: Tris(8-hydroxyquinolinato) aluminium (Alq(3)) and 1,3-bis(2-(4-tert-butylphenyl)-1,3,4-oxadiazol-5-yl) benzene (OXD-7). In particular, soluble Alq(3) resulting in a uniform thin film with a root-mean-square roughness < 0.2nm is demonstrated for the first time. Both devices with the Alq(3) and OXD-7 interlayers show notable enhancement in the open-circuit voltage and fill-factor, leading to a net efficiency increase by over 2% from the reference, up to 11.8% and 12.5% respectively. The capacitance-voltage characteristics confirm the role of the small-molecule interlayers resembling a thin interfacial oxide layer for the Al-Si Schottky barrier to enhance the built-in potential and facilitate charge transport. Moreover, the Alq(3) interlayer in optimized devices exhibits isolated phases with a large surface roughness, in contrast to the OXD-7 which forms a continuous uniform thin film. The distinct morphological differences between the two interlayers further suggest different enhancement mechanisms and hence offer versatile functionalities to the advent of hybrid organic-silicon photovoltaics.
authors.forename: Yi-Chun
authors.initials: YC
authors.lastname: Lai
authors.forename: Yu-Fan
authors.initials: YF
authors.lastname: Chang
authors.forename: Pei-Ting
authors.initials: PT
authors.lastname: Tsai
authors.forename: Jan-kai
authors.initials: JK
authors.lastname: Chang
authors.forename: Wei-Hsuan
authors.initials: WH
authors.lastname: Tseng
authors.forename: Yi-Cheng
authors.initials: YC
authors.lastname: Lin
authors.forename: Chu-Yen
authors.initials: CY
authors.lastname: Hsiao
authors.forename: Hsiao-Wen
authors.initials: HW
authors.lastname: Zan
authors.forename: Chih-I
authors.initials: CI
authors.lastname: Wu
authors.forename: Gou-Chung
authors.initials: GC
authors.lastname: Chi
authors.forename: Hsin-Fei
authors.initials: HF
authors.lastname: Meng
authors.forename: Peichen
authors.initials: P
authors.lastname: Yu