Poly(3-hexylthiophene)-functionalized silsesquioxane nanoparticles were prepared from direct hydrolysis and condensation of P3HT-silane precursor using “grafting from” and “grafting to” methods. The size, shape, and surface morphology of these polymer grafts particles were visualized using transmission electron microscopy and scanning electron microscopy. Their compositions confirmed by FTIR, thermogravimetric analysis and elemental analysis. The XRD analysis revealed the polymer orientation and packing pattern of the nanocomposites, indicating the highly ordered lamella stacks of P3HT polymer chains. The photovoltaic performance of the blends of P3HT-nanohybrid with the C60 derivative PCBM was evaluated upon annealation in different temperatures, ranging from 50°C to 150 °C. The power conversion efficiency of the best test device was 2.46% (3.8%) for the device configuration of ITO/PEDOT:PSS/P3HT-NPs:PCBM/LiF/Al
