A spray-coating process for highly conductive silver nanowire networks as the transparent top-electrode for small molecule organic photovoltaics

Abstract

We present a novel top-electrode spray-coating process for the solution-based deposition of silver nanowires (AgNWs) onto vacuum-processed small molecule organic electronic solar cells. The process is compatible with organic light emitting diodes (OLEDs) and organic light emitting thin film transistors (OLETs) as well. By modifying commonly synthesized AgNWs with a perfluorinated methacrylate, we are able to disperse these wires in a highly fluorinated solvent. This solvent does not dissolve most organic materials, enabling a top spray-coating process for sensitive small molecule and polymer-based devices. The optimized preparation of the novel AgNW dispersion and spray-coating at only 30 °C leads to high performance electrodes directly after the deposition, exhibiting a sheet resistance of 10.0 Ω □(-1) at 87.4% transparency (80.0% with substrate). By spraying our novel AgNW dispersion in air onto the vacuum-processed organic p-i-n type solar cells, we obtain working solar cells with a power conversion efficiency (PCE) of 1.23%, compared to the air exposed reference devices employing thermally evaporated thin metal layers as the top-electrode.

Electrical limit of silver nanowire electrodes: Direct measurement of the nanowire junction resistance

“…1 Therefore, these networks have been implemented as transparent conducting electrodes in various optoelectronic devices, in particular, in small molecule or polymer-based solar cells and light emitting diodes. [1][2][3] Currently, they allow the fabrication of flexible lab-scale devices showing performance parity with devices comprising the considerably more brittle and sputter-deposited indium tin oxide (ITO). 4 Still, one important challenge is to further decrease the corresponding R S of AgNW networks, since future products are expected to be fabricated on large area and curved substrates.…”

Influence of bilayer resist processing on p-i-n OLEDs: towards multicolor photolithographic structuring of organic displays

“…15 Due to their low contribution in polar and hydrogen bonding, 16 hydrofluoroether (HFE) solvents have been demonstrated to be compatible with a wide range of organic semiconductor materials. 14,[17][18][19][20] Recently, 21 our group showed a photo-patterning of single color OLEDs using bilayer method combined with fluoropolymer processing in HFEs. The proposed approach was shown to exhibit all the advantages attributed to conventional photolithography.…”

Influence of the average molar mass of poly(N-vinylpyrrolidone) on the dimensions and conductivity of silver nanowires

“…Transparent conductive electrodes (TCEs) fabricated with silver nanowire (AgNW) networks are highly promising candidates for application in optoelectronic devices, such as solar cells, lightemitting-diodes, or touch screens. [1][2][3][4][5][6] The AgNW electrodes show comparable sheet resistances (R S ) and transmittances at 550 nm (%T 550 ) to commercially used indium tin oxide (ITO). Since ITO is a ceramic, its brittleness may cause electrode failure after bending or stretching.…”