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Abstract: A new concept to stabilize the morphology of poly(3-hexylthiophene) (P3HT) and [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) blend through H-bond formation by using a hydroxyl group end-functionalized P3HT (HOC-P3HT-COH) as a compatibilizer is presented. Domain size of the PCBM crystals in the annealed P3HT/PCBM film is diminished with addition of HOC-P3HT-COH. Surface roughness of the P3HT/PCBM film also becomes smoother with addition of HOC-P3HT-COH. Thermal stability of solar cell device is improved significantly through the H-bond formation between HOC-P3HT-COH and PCBM. A high performance and thermal stable polymer solar cell with 4.06% power conversion efficiency under AM1.5G irradiation is fabricated with 5% HOC-P3HT-COH in P3HT/PCBM layer. [Copyright &y& Elsevier]

Abstract: Nanocomposites made from inorganic nanoparticles and polymers have many applications in optics, electronics and biomaterials. However, the glass transition temperature (Tg ) of a nanocomposite is very difficult to measure accurately by conventional thermal analysis such as DSC or TMA when the concentration of the nanoparticle reaches a threshold of the percolation network. At this threshold stage, the phase transition in the nano domains of the matrix is too small to be detected by macroscale thermal analysis. We have developed a methodology basis on thermal atomic force microscope (AFM) to monitor the nanophase transition of the nanocomposite in situ upon heating. This method has demonstrated the capability in determining the Tg of a nanocomposite made by spherical SiO2 nanoparticles dispersed in polyacrylate. The threshold of the percolation network of this nanocomposite is at 40wt% of SiO2 nanoparticles according to the results of refractive index, AFM, nanoindentation, DSC, TMA and TGA. [Copyright &y& Elsevier]