We have measured electron mobility in vacuum-deposited films of 4,7-diphenyl-1,10phenanthroline (bathophenanthroline, or BPhen) using a time-of-flight technique. Electron transport was highly dispersive for BPhen with a dispersion parameter of a value 0.30. The electron mobility in excess of 10−4 cm2/V s has been observed at electric fields of the order of 105 V/cm with weakly dependent on the electric field. The characteristic energy of the distribution is obtained a value 0.09 eV. It is directly confirmed that the BPhen has superior electron-transport capability.

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We fabricated nondoped white organic electroluminescent devices using vacuum-deposited thin films of blue-emitting 4,4′-bis[N-1-napthyl-N-phenyl-amino]biphenyl (α-NPD) and orange-emitting 4-(dicyanomethylene)-2-metyl-6-(p-dimethyl aminostyryl)-4H-pyran (DCM), a hole-blocking layer of 2-(4-biphenyl)-5-(p-tert-butylphenyl)-1,3,4-oxadiazole (tBu-PBD) and electron-transporting tris(8-quinolinolato) aluminum (III). Excitons formed at the α-NPD/tBu-PBD interface sequentially transfer their energy to α-NPD via the Förster mechanism. The exciton is captured by an ultrathin DCM layer located within the pure α-NPD layer. The position of the DCM determines the device spectrum, and enables a white emission to be achieved. The spectrum is not sensitive to the voltage applied, and the devices show maximum luminance of about 1000 cd/m2.

We report on the enhanced carrier injection in pentacene thin-film transistors with a thin MoO3-doped pentacene layer between pentacene semiconductor and the source-drain electrodes. Device performance including drain current, field effect mobility, and threshed voltage are improved by employing a MoO3-doped pentacene thin layer. The barrier height at the Au/pentacene interface is lowered from 0.12 to 0.05 eV after inserting a MoO3-doped pentacene thin layer between them. The reduced barrier height is attributed to the formation of a good contact between MoO3-doped pentacene and Au owing to smoothed surface morphology of pentancene and suitable band bending by MoO3 doping.

Electroluminescent devices with mixed single-layer organic materials that consist of hole transport meterial, electron transport material and dopant material are studied. High luminance could be obtained by optimizing the weight ratios of hole and electron transport materials.