Charge transfer dynamics in poly(3-hexylthiophene): nanodiamond blend films

The introduction of nanodiamond (ND) into regioregular poly(3-hexylthiophene) (P3HT) can vary the conformational structure of the polymer. The microstructure of the blend films was analyzed by various techniques, such as absorption spectra, Raman spectra and X-ray diffraction. It is shown that the presence of ND improves the crystallinity and increases the effective conjugation length of P3HT in the blend films. Furthermore, the photo-excited dynamics between P3HT and ND were studied by the steady-state and time-resolved photoluminescence techniques. An obvious fluorescence quenching in the blend films demonstrates the high efficiency of photoinduced charge transfer between P3HT and ND. The energy transfer dynamics could be excluded owing to the bandgap of ND is larger than P3HT. The morphology of the blend films was investigated by Kelvin probe force microscope and transmission electron microscopy. The interpenetrating network of P3HT fibrils and ND domains facilitates charge transfer between the two materials, resulting in the obvious fluorescence quenching of the polymer. The enhanced photocurrent in a prototypical device based on P3HT:ND blends may be correlated with the high efficiency of charge transfer from P3HT to ND.