Pressure Welding of Silver Nanowires Networks at Room Temperature as Transparent Electrodes for Efficient Organic Light-Emitting Diodes

Abstract

In this work, polymethylmethacrylate (PMMA) as a superior mediate for the pressure welding of silver nanowires (Ag NWs) networks as transparent electrodes without any thermal treatment is demonstrated. After a pressing of 200 kg cm^-2 , not only the sheet resistance but also the surface roughness of the PMMA-mediated Ag NWs networks decreases from 2.6 kΩ sq^-1 to 34.3 Ω sq^-1 and from 76.1 to 12.6 nm, respectively. On the other hand, high transparency of an average transmittance in the visible wavelengths of 93.5% together with a low haze value of 2.58% can be achieved. In terms of optoelectronic applications, the promising potential of the PMMA-mediated pressure-welded Ag NWs networks used as a transparent electrode in a green organic light-emitting diode (OLED) device is also demonstrated. In comparison with the OLED based on commercial tin-doped indium oxide electrode, the increments of power efficiency and external quantum efficiency (EQE) from 80.1 to 85.9 lm w^-1 and 19.2% to 19.9% are demonstrated. In addition, the PMMA-mediated pressure welding succeeds in transferring Ag NWs networks to flexible polyethylene naphthalate and polyimide substrates with the sheet resistance of 42 and 91 Ω sq^-1 after 10 000 times of bending, respectively.

Keywords: OLED; polymethylmethacrylate; silver nanowires networks; transparent electrode.