Preparation of active layer of solar cells device by F8T2 blending with PCBM

The conjugated polymer blending system has been attracting much attention in recent years due to their potential applications in optoelectronic devices, thin-film transistors, and photovoltaic devices with many advantages like easy preparation, low-cost, and the possibility to fabricate flexible devices for large area applications. In this study, Conjugated polymer Poly(9,9´-n-dioctylfluorene-alt-bithiophene) (F8T2) blended with [6,6]-phenyl-C61-butyric acid methyl Ester (PCBM) to prepare as the active layer in solar cells device. The basic thermal characteristic and phase transitions of the polymer blending layers were examined by using of Differential Scanning Calorimeter (DSC) and Thermo gravimeteric Analyzer (TGA). Morphology evolutions of casting submicron layers via different annealing conditions were observed by atomic force microscopy (AFM), field-emission scanning electron microscopy (FE-SEM). The optical properties of active Layer of polymer solar cells by different stacked mode designs also investigated by UV-Vis absorption and photoluminescence (PL) spectra. It is found that the maximum absorption wavelength of liquid F8T2 and of PCBM were located at 436 nm and 342 nm, respectively. The corresponding conversion efficiency of devices specimens were prepared by screen printing in different stacking modes. In the present study, the experimental works focus on investigating the influence of thermal annealing conditions and stacking mode design on morphology and corresponding conversion efficiency performance of solar cell devices. The results will provide plenty of valuable information for the future optoelectronic applications.