This paper presents 2-(hydroxyl) quinoline lithium (Liq) used as an n-type dopant to improve white hybrid organic light-emitting diode (WHOLEDs) performance. The Liq doped tris(8-hydroxyquinolinato) aluminum (Alq$_{3})$ layer possessed enhanced electron injection, efficient hole and electron balance in the emitting layer, as one of the most essential issues for device applications. This work investigates the optimum recipe (Liq concentration and thickness) of Alq$_{3}$:Liq n-type doped electron injection layer (EIL) for WHOLED devices by comparing the current density and efficiency results with conventional Alq$_{3}$/LiF technique. A blocking layer or interlayer is inserted between emitting layer and EIL to avoid excitons quenched. In this work suitable material and optimum thickness for blocking layer are studied, a white small-molecular organic light-emitting diode (SM-OLEDs) based on a 1,3,5-tris (N-phenylbenzimidazol-2-yl) benzene (TPBi) stamping transfer process is investigated. The proposed stamping transfer process can avoid the complexity of the vacuum deposition process.

The characteristics of violet-sensitive organic photodetectors (OPDs) utilizing polyalkylfluorene and triplet materials have been studied as a host and a dopant material, respectively. For the photo absorption layer, poly(9,9-dioctylfluorene) [PFO] and a phosphorescent iridium complex (Iridium (III) bis(2-(4,6-difluorophenyl)pyridinato-N,C2) [FIrpic] or Iridium (III) bis(2-(2'-benzothienyl)pyridinato-N,C3')(acetyl-acetonate) [(btp)2Ir(acac)]) were used as a host and a dopant material, respectively. PFO: (btp)2Ir(acac) device showed less photocurrent than PFO device because (btp)2Ir(acac) enhances recombination of the photo generated carriers in the photo absorption layer. On the other hand, PFO : FIrpic device showed larger photocurrent than PFO device due to triplet energy transfer from FIrpic to PFO. A cutoff frequency of 20 MHz was observed using a sinusoidal modulated violet laser light illumination under the reverse bias of 8 V.