A majority of the reported electrografting of aryldiazonium salts result in the formation of covalently attached films with a limited surface coverage of below 5 nmol·cm. Herein, we report the preparation of higher-thickness redox-active viologen-grafted electrodes from the electroreduction of viologen phenyl diazonium salts, by either cyclic voltammetric (CV) sweeps or electrolysis using a fixed potential. Both of the methodologies were successfully applied for various conductive surfaces, including glassy carbon (GC), gold disc, indium tin oxide glass, mesoporous TiO electrodes, and 3D compacted carbon fibers. A robust maximal viologen coverage, Γ = 9.5 nmol·cm, was achieved on a GC electrode by CV electroreduction. Electroreduction held at a fixed potential at E = -0.3 V can fabricate viologen-grafted electrodes with Γ in the range of 0-37 nmol·cm in a controllable way, by simply adjusting the electrodeposition time t. Time-dependent Γ were found to be 10 nmol·cm@2 min, 20 nmol·cm@4.2 min, and 30 nmol·cm@7 min. Furthermore, a TiO electrode coupled with Γ of 140 nmol·cm exhibited electrochromic performance, with the color changing from pale yellow to blue and red brown.

Given the importance of epoxy cyclohexyl polyhedral oligomeric silsesquioxane (epoxy‐POSS) as a silica‐like hybrid material of optical clarity, high thermal and mechanic stability, the two‐photon initiated polymerization of epoxy‐POSS using diphenyliodonium hexafluorophosphate as photoacid generators for UV lithography and femtosecond laser direct writing is studied. The hybrid resist exhibits high thermal stability: decomposition temperatures are found at ≈350 and 400 °C when calcined in air and argon, respectively. The corresponding calcined products are found as silica‐like structures with chemical formulas of C1.5SiO3.5 and C5SiO3, evidenced by energy dispersive X‐ray analysis (EDX), fourier‐transform infrared spectroscopy (FTIR), and elemental analysis. An equation regarding the two‐photon polymerized line width as functions of intensity of laser (Plaser) and scanning speed (V) is proposed in describing the effect of Gaussian light on polymerized lines. Experimental verification of the equation is given to prove a nonlinear optical process. Line width with a resolution of 250 nm is achieved on a glass substrate, while the resolution is 400 nm when fabricated on a silicon wafer. 3D structured woodpiles are fabricated and show no volumetric shrinkage upon 300 °C calcination in air environment, demonstrating a high thermal stability.

One potential way to fabricate battery-on-chip is photopatterning electrochemical energy storage materials directly on electronics through lithography, but applicable materials are primarily limited to transparent photocurable resins. The transparency of the photoresist would be sacrificed after extra addition of insoluble inorganic battery materials and conductors. Given the importance of radical polymers for their appropriate solubility, optical transparency, and radical robustness, they may have potential application in on-chip energy storage, transport, and conversion devices. Herein, an anodic photoresist is proposed by modifying the MicroChem SU8 resist with a radical polymer poly(2,2,6,6-tetramethyl-4-piperidinyl-N-oxyl methacrylate) and an ionic conductor lithium perchlorate. It can be photopatterned on silicon wafer with 10 μm scale resolution, and it exhibits charge/discharge potentials at ca. 0.68 V versus silver chloride electrode; the coulomb efficiency is regarded as nearly equaling 100%. Although the specific capacity of the photopatterned film electrode is found to be modest, 1 × 10 −5 mA h•cm −2 , it presents 1/8 of its theoretical electron storage ability. All-solid-state half-cells with circular features 30 μm in diameter are prepared by means of overlay exposure using the as-prepared photoresist and lithium perchlorate-modified SU8 as the anodic electrode and solid electrolyte, respectively. These results suggest a promising way of using radical polymers for the integration of electrochemical energy in microelectronics.

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