Improving Photophysical Properties of White Emitting Ternary Conjugated Polymer Blend Thin Film via Additions of TiO2 Nanoparticles

The effect of TiO2 nanoparticles on the photophysical properties of ternary conjugated polymer (CP) blends of poly(9,9-dioctylfluorene-2,7-diyl) (PFO), poly 9,9-dioctylfluorene-alt-benzothiadiazole (F8BT) and poly(2-methoxy-5(2-ethylhexyl)-1,4 -phenylenevinylene (MEH-PPV) thin films was investigated. This ternary blend used a fixed amount of PFO as the donor with MEH-PPV and F8BT in various ratios as the acceptors. The solution-blending method and the spin-coating technique were used to prepare the blends and the thin films, respectively. Through efficient Förster Resonance Energy Transfer (FRET), the desired white emission was achieved with PFO/0.3 wt.% F8BT/0.5 wt.% MEH-PPV ternary blend thin film. Additions of nanoparticles up to 10 wt.% dramatically intensified the white emission which then dimmed at higher contents due to agglomerations. The current density–voltage characteristics of the nanocomposite thin films exhibited dependency on the content and distributions of the nanoparticles. Finally, a possible underlying mechanism for the intensification of emission is proposed

Effects of electrode materials on solution-processed polyvinylidene fluoride-based piezoelectric nanogenerators: do they matter?

Numbers of energy harvesting studies have reported that using the appropriate electrode materials could enhance the electrical output performance of the energy harvesters. In this work, we fabricated polyvinylidene fluoride (PVDF)-based piezoelectric nanogenerators (PENGs) using the solution-process method. Different combinations of silver nanowires, indium-tin-oxide (ITO), and poly(3,4-ethylenedioxythiophene) polystyrene sulfonate were used as top and bottom electrodes to investigate the effect of electrode materials on the electrical output performance. The open-circuit voltage (VOC), short-circuit current (ISC), the charge generated, instantaneous areal power measured, and internal impedance were measured. The obtained data reveal no significant difference between the different electrode combinations, with a mean absolute deviation of 0.21 V, and 0.03 μA for VOC and ISC, respectively. Thereby, an equivalent circuit for a real capacitor is adopted to analyze further and identify the impedance manifestation attributed to the PVDF layer and electrode materials. Overall, the electrode materials have an insignificant impact on the electrical output performance of PVDF-based PENGs in this study. Nevertheless, the obtained data inciting that tuning the PVDF impedance by introducing the 2D MXene nanofillers approach could be useful information to improve the performance of solution-processed PVDF-based PENGs