Aqueous organic redox flow battery represents a potential solution to significantly reduce the cost of flow batteries. An ideal organic redox active material for flow battery application shall possess good stability in supporting electrolyte, fast redox reaction speed, and low manufacturing cost. In this work, a commercially available dye material was modified and evaluated in aqueous organic redox flow battery as anolyte. The desalted Basic Red 5 dye (d-BR5) exhibited reasonable solubility in acidic supporting electrolyte and stable redox performance. Two aqueous organic redox flow batteries with d-BR5 as anolyte and two different catholytes (4,5dihydroxybenzene-1,3-disulfonic acid (BQDS) and cerium methanesulfonate (Ce(CH 3 SO 3 ) 3 )) were evaluated in this work. The later system reached satisfactory stability in long-term cycling experiments. The cell of d-BR5 and (Ce(CH 3 SO 3 ) 3 ) exhibited an operating voltage ∼ 1.4 V, with 99.9% capacity retention after 200 cycles. The results indicated that organic dye molecules could be potential low-cost active materials for aqueous organic redox flow batteries.

The electrical memory characteristics of the n-channel organic field-effect transistors (OFETs) employing diverse polyimide (PI) electrets are reported. The synthesized PIs comprise identical electron donor and three different building blocks with gradually increasing electron-accepting ability. The distinct charge-transfer capabilities of these PIs result in varied type of memory behaviors from the write-one-read-many (WORM) to flash type. Finally, a prominent flexible WORM-type transistor memory is demonstrated and shows not only promising write-many-read-many (WMRM) multilevel data storage but also excellent mechanical and retention stability.

A novel π-conjugated monomer tert-butyl 3,8-di([2,2′-bithiophen]-5-yl)-6-oxophenanthridine-5(6H)carboxylate (PNBTH-Boc) with a labile side chain was synthesized. The monomer was electropolymerized to form redoxactive polymer (Poly-PNBTH-Boc) on the current collector. The labile side chains on the polymer were then removed by thermal annealing, resulting in the porous electroactive film (Poly-PNBTH). The annealed polymer exhibited a stable oxidation process and high specific areal capacitance. Asymmetric supercapacitors were fabricated with the polymer as the positive electrode and vertically aligned carbon nanotubes as the negative electrode. The supercapacitor exhibited outstanding cyclability with 85% capacitance retention after 10 000 cycles. The thin film supercapacitor device demonstrated an energy density of 23.5 μWh/cm 2 and a power density of 14 mW/cm 2 .

Three novel donor-acceptor alternating polymers containing ladder-type pentacyclic heteroacenes (PBo, PBi, and PT) are synthesized, characterized, and further applied to organic field effect transistors (OFETs) and polymer solar cells. Significant aspects of quinoidal characters, electrochemical properties, optical absorption, frontier orbitals, backbone coplanarity, molecular orientation, charge carrier mobilities, morphology discrepancies, and the corresponding device performances are notably different with various heteroarenes. PT exhibits a stronger quinoidal mesomeric structure, linear and coplanar conformation, smooth surface morphology, and better bimodal crystalline structures, which is beneficial to extend the π-conjugation and promotes charge transport via 3-D transport pathways and in consequence improves overall device performances. Organic photovoltaics based on the PT polymer achieve a power conversion efficiency of 6.04% along with a high short-circuit current density (J) of 14.68 mA cm, and a high hole mobility of 0.1 cm V s is fulfilled in an OFET, which is superior to those of its counterparts, PBi and PBo.

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