Efficient and chromaticity stable green and white organic light-emitting devices with organic-inorganic hybrid materials.

Efficient inverted bottom emissive organic light emitting diodes (IBOLEDs) with tin dioxide and/or Cd-doped SnO nanoparticles as an electron injection layer at the indium tin oxide cathode:electron transport layer interface have been fabricated. The SnO NPs promote electron injection efficiently because their conduction band (-3.6 eV) lies between the work function ( ) of ITO (4.8 eV) and the LUMO of the electron-transporting molecule (-3.32 eV), leading to enhanced efficiency at low voltage. The 2.0% SnO NPs (25 nm) with Ir(ddsi)(acac) emissive material (SnO NPs/ITO) have an enhanced current efficiency ( , cd A) of 52.3/24.3, power efficiency ( , lm W) of 10.9/3.4, external quantum efficiency ( , %) of 16.4/7.5 and luminance (, cd m) of 28 182/1982. A device with a 2.0% Cd-doped SnO layer shows higher (60.6 cd A), (15.4 lm W), (18.3%) and (26 858 cd m) than SnO devices or control devices. White light emission was harvested from a mixture of Cd-SnO NPs and homoleptic blue phosphor Ir(tsi); the combination of blue emission ( = 428 nm) from Ir(tsi) and defect emission from Cd-SnO NPs ( = 568 nm) gives an intense white light with CIE of (0.31, 0.30) and CCT of 6961 K. The white light emission [CIE of (0.34, 0.35) and CCT of 5188 K] from colloid hybrid electrolyte BMIMBF-SnO is also discussed.