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The use of blends of small molecule organic semiconductors (OSCs) with insulating binding polymers has been shown to be a promising route to facilitate the processing of OSCs over large areas using printing techniques. Here we fabricated organic field-effect transistors (OFETs) and phototransistors using the benchmark OSC 7-decyl-2-phenyl[1]benzothieno[3,2-b][1]benzothiophene (Ph-BTBT-10) and blends of this material with polystyrene (PS), poly(pentafluorostyrene) (PFS) and poly(methyl methacrylate) (PMMA). We show that the nature of the binding polymer has a significant impact on the device performance. The OFETs showing the best performance are the ones based on blends of PS since they reveal less interfacial traps, leading to devices with higher mobility, threshold voltage close to zero and high bias stress stability. The lowest OFET performance is found in the devices based on PMMA blends due to the higher density of majority charge carrier (i.e., holes) traps. On the other hand, regarding the response of the devices to UV light, the PFS and pristine films exhibited the highest photoresponse, which was attributed to the higher density of minority charge carrier (i.e., electrons) traps. Therefore, this work demonstrates that the binding polymer is a useful tool to optimise the OFET electrical characteristics as well as its photoresponsivity.

In this study, unique layered Fe(III)-Cr(III) oxides were formed during the Cr(VI) removal by sulfate green rust (GRSO4). Solid state characterization confirmed that the hexagonal plate and layered structure of GRSO4 remained after fast reduction of Cr(VI). Then, sodium dithionite was further employed to reduce the Fe(III) to Fe (II) in these layered Fe(III)-Cr(III) oxides, enabling stable Fe(II)/Fe(III) cycle in the hexagonal plates. As the Fe(II) content increased in the layered Fe(III)-Cr(III) oxides, there was no significant Fe(II) and Cr(III) release into the solution and the GR-like plate remained intact, indicating that this hexagonal layer Fe-Cr oxides has stable structure during the reduction of Fe(III). Interestingly, better crystallinity was observed at higher Fe(III) reduction rate, and the layered metal oxide structure was confirmed with a basal spacing of 0.935 nm when ~ 100 % of Fe(III) was reduced to Fe(II). Multiple treatment cycles experiment demonstrated that Cr(III) loading on the layered Fe(III)-Cr(III) oxides could be increased in the following 6 runs of Fe(II)/Fe(III) redox cycle. This study provides new evidence to confirm the electron conductivity and redox reactivity of the Fe(III)-Cr(III) residues under ambient condition, which might help to formulate novel strategies for elimination of Cr(VI) or related heavy metals, In this study, unique layered Fe(III)-Cr(III) oxides were formed during the Cr(VI) removal by sulfate green rust (GRSO4). Solid state characterization confirmed that the hexagonal plate and layered structure of GRSO4 remained after fast reduction of Cr(VI). Then, sodium dithionite was further employed to reduce the Fe(III) to Fe(II) in these layered Fe(III)-Cr(III) oxides, enabling stable Fe(II)/Fe(III) cycle in the hexagonal plates. As the Fe(II) content increased in the layered Fe(III)-Cr(III) oxides, there was no significant Fe(II) and Cr(III) release into the solution and the GR-like plate remained intact, indicating that this hexagonal layer Fe-Cr oxides has stable structure during the reduction of Fe(III). Interestingly, better crystallinity was observed at higher Fe(III) reduction rate, and the layered metal oxide structure was confirmed with a basal spacing of 0.935 nm when ∼ 100 % of Fe(III) was reduced to Fe(II). Multiple treatment cycles experiment demonstrated that Cr(III) loading on the layered Fe(III)-Cr(III) oxides could be increased in the following 6 runs of Fe(II)/Fe(III) redox cycle. This study provides new evidence to confirm the electron conductivity and redox reactivity of the Fe(III)-Cr(III) residues under ambient condition, which might help to formulate novel strategies for elimination of Cr(VI) or related heavy metals.