title: High-Performance Silver Window Electrodes for Top-Illuminated Organic Photovoltaics Using an Organo-molybdenum Oxide Bronze Interlayer.
abstract: We report an organo-molybdenumn oxide bronze that enables the fabrication of high-performance silver window electrodes for top-illuminated solution processed organic photovoltaics without complicating the process of device fabrication. This hybrid material combines the function of wide-band-gap interlayer for efficient hole extraction with the role of metal electrode seed layer, enabling the fabrication of highly transparent, low-sheet-resistance silver window electrodes. Additionally it is also processed from ethanol, which ensures orthogonality with a large range of solution processed organic semiconductors. The key organic component is the low cost small molecule 3-mercaptopropionic acid, which (i) promotes metal film formation and imparts robustness at low metal thickness, (ii) reduces the contact resistance at the Ag/molybdenumn oxide bronze interface, (iii) and greatly improves the film forming properties. Silver electrodes with a thickness of 8 nm deposited by simple vacuum evaporation onto this hybrid interlayer have a sheet resistance as low as 9.7 Ohms per square and mean transparency ∼80% over the wavelength range 400-900 nm without the aid of an antireflecting layer, which makes them well-matched to the needs of organic photovoltaics and applicable to perovskite photovoltaics. The application of this hybrid material is demonstrated in two types of top-illuminated organic photovoltaic devices.
authors.affiliation: Department of Chemistry, University of Warwick , Coventry CV4 7AL, U.K.
authors.forename: Martin S
authors.initials: MS
authors.lastname: Tyler
authors.affiliation: Department of Physics, University of Warwick , Coventry CV4 7AL, U.K.
authors.forename: Marc
authors.initials: M
authors.lastname: Walker
authors.affiliation: Department of Chemistry, University of Warwick , Coventry CV4 7AL, U.K.
authors.forename: Ross A
authors.initials: RA
authors.lastname: Hatton
keywords: charge transport layer; electrode; molybdenum oxide; photovoltaic; top-illuminated