High-Quality Transparent Electrodes Spin-Cast from Preformed Antimony-Doped Tin Oxide Nanocrystals for Thin Film Optoelectronics

We present the wet-chemical deposition of antimony-doped tin oxide (ATO) nanocrystals into films and demonstrate that these films have the required high quality to be used as transparent electrodes in thin film optoelectronic devices. Monodisperse, 3 nm diameter ATO nanocrystals, synthesized by an efficient microwave-assisted nonaqueous sol–gel method, are dispersed in tetrahydrofuran (THF) without any additives and processed into films by spin-coating on glass substrates. After thermal treatment, uniform and crack-free films with a low surface roughness of 1.6 nm and tunable thickness of 30 to 800 nm are obtained. A sheet resistance of 395 Ω/square is achieved for a 480 nm thick ATO film with a high transparency of 90% in the visible light range (380–780 nm). To demonstrate that these films are indeed viable as transparent electrodes, we show that an organic light emitting diode (OLED) fabricated on our nanoparticle-based ATO electrode exhibits an electrical and optical performance comparable to an OLED on a commercially available indium tin oxide (ITO) film.