12CaO·7Al2O3 doped indium-tin-oxide thin film for transparent cathode in organic light-emitting devices

12CaO·7Al2O3 (C12A7) doped indium-tin-oxide (ITO) (ITO:C12A7) thin film was deposited on glass substrates in an optimum gaseous mixtures flow rate (O2:0.8 sccm, 4% H2·Ar:49.2 sccm) by an rf magnetron co-sputtering system with various numbers of C12A7 chips. The carrier concentration of the ITO:C12A7 thin film was decreased from 2.8 × 1020 to 1.1 × 1010 cm− 3 as the number of C12A7 chips was increased from 1 to 9. An increase in the resistivity of the ITO:C12A7 thin film from 3.4 × 10− 3 Ω cm to 1.4 × 107 Ω cm was observed as the number of C12A7 chips was increased. The optical transmittance of the ITO:C12A7 thin film was above 80% in the wavelength range from 400 nm to 700 nm. The work function of the ITO:C12A7 thin film determined by UV spectrometer was in the range from 4.7 eV to 4.5 eV depending on the number of C12A7 chips, which is lower than the range of values of 4.8–5.0 eV for ITO film.