Keywords: Phosphorescence / Luminescence / Sensors / Density functional calculations / OLEDs / Platinum [(Aryl-ppy)Pt(acac)] (ppy = 2-phenylpyridine, acac = acetylacetonato) derivatives with triphenylamine (TPA) substituents on the ppy ligand have been prepared. The TPA fragment is either directly cyclometallated (Pt-1) or attached to the ppy ligand through a C-C single bond (Pt-2) or a novel α-diketo group (Pt-3). All the complexes show room-temperature phosphorescence in fluid solution with emission bands in the range of 530-590 nm, which are red-shifted relative to the model complex [ppyPt(acac)] (λ em = 486 nm). This emission colour tuning effect is attributed to either an elevated HOMO energy caused by electron-donating TPA substitu-

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In this work, we propose the application of liquid crystalline acceptors as a potential means to improve the performances of bulk heterojunction (BHJ) organic solar cells. LC-1, a structurally-simple perylene diimide (PDI), has been adopted as a model for thorough investigation. It exhibits a broad temperature range of liquid crystalline (LC) phase from 41 °C to 158 °C, and its LC properties have been characterized by differental scanning calorimetry (DSC), polarization optical microscopy (POM), and X-ray diffraction (XRD). The BHJ devices, using P3HT:LC-1 (1:2) as an organic photovoltaic active layer undergoing thermal annealing at 120 °C, shows an optimized efficiency of 0.94 %. By contrast, the devices based on PDI-1, a nonliquid crystalline PDI counterpart, only obtain a much lower efficiency of 0.22%. Atomic force microscopy (AFM) images confirm that the active layers composed of P3HT:LC-1 have smooth and ordered morphology. In space charge limited current (SCLC) devices fabricated via a spin-coating technique, LC-1 shows the intrinsic electron mobility of 2.85 × 10(-4) cm(2)/(V s) (at 0.3 MV/cm) which is almost 5 times that of PDI-1 (5.83 × 10(-5) cm(2)/(V s)) under the same conditions for thermal annealing at 120 °C.