Author: please provide academic titles for all authorsThe field of printed wearable electronics has witnessed spectacular growth due to its promise to offer low-cost, high-performance devices for a broad range of applications. Among the sub-fields of printed wearable electronics, printed wearable electrochemical systems are of special importance due to their widespread applications in healthcare, energy and security fields. These systems have opened up new avenues for body-integrated electronics that were earlier impossible to achieve. These include wearable This article is protected by copyright. All rights reserved. 2 energy systems and sensors for a wide variety of applications. Much of the success of printed wearable electrochemical systems can be attributed to innovations in materials engineering that have led to novel inks comprising of new nanomaterials, polymers and composites. New generation of printed electrochemical devices include soft, stretchable and anatomically-compliant devices that enable efficient bio-integration and withstand high tensile stress associated with on-body applications. Progress in materials science has also led to the development of self-healing printed electrochemical systems for wearable applications. This review provides an overview of the key material requirements for ink formulations for realizing efficient wearable electrochemical systems such as batteries, supercapacitors, biofuel cells and sensors. Finally, major challenges impeding the field of wearable electrochemical systems are discussed along with future prospects of this exciting field.

Additive patterning of transparent conducting metal oxides at low temperatures is a critical step in realizing low cost transparent electronics for display technology and photovoltaics. In this work, inkjet printed metal oxide transistors based on pure aqueous chemistries are presented. These inks readily convert to functional thin films at lower processing temperatures (T ≤ 250 °C) relative to organic solvent-based oxide inks, facilitating the fabrication of high-performance transistors with both inkjetprinted transparent electrodes of aluminum-doped cadmium oxide (ACO) and semiconductor (InO x ). The intrinsic fluid properties of these water-based solutions enable the printing of fine features with This article is protected by copyright. All rights reserved. 2 coffee-ring free line profiles and smoother line edges than those formed from organic solvent-based inks. The influence of low temperature annealing on the optical, electrical, and crystallographic properties of the ACO electrodes is investigated, as well as the role of aluminum doping in improving these properties. Finally, we characterize the all-aqueous printed TFTs with inkjet-patterned semiconductor (InO x ) and source/drain (ACO) layers, which show ideal low contact resistance (R c < 160 Ω-cm) and competitive transistor performance (µ lin up to 19 cm 2 V -1 s -1 , SS ≤ 150 mV dec -1 ) with only low temperature processing (T ≤ 250 °C).

Spinel-structured LiMn 2 O 4 (LMO) is a desirable cathode material for Li-ion batteries due to its low cost, abundance, and high power capability. However, LMO suffers from limited cycle life that is triggered by manganese dissolution into the electrolyte during electrochemical cycling. Here, it is shown that single-layer graphene coatings suppress manganese dissolution, thus enhancing the performance and lifetime of LMO cathodes. Relative to lithium cells with uncoated LMO cathodes, cells with graphene-coated LMO cathodes provide improved capacity retention with enhanced cycling stability. X-ray photoelectron spectroscopy reveals that graphene coatings inhibit manganese depletion from the LMO surface. Additionally, transmission electron microscopy demonstrates that a stable solid electrolyte interphase is formed on graphene, which screens the LMO from direct contact with the electrolyte. Density functional theory calculations provide two mechanisms for the role of graphene in the suppression of manganese dissolution. First, common defects in single-layer graphene are found to allow the transport of lithium while concurrently acting as barriers for manganese diffusion. Second, graphene can chemically interact with Mn 3+ at the LMO electrode surface, promoting an oxidation state change to Mn 4+ , which suppresses dissolution. 1500646(2 of 10) wileyonlinelibrary.com power applications. Furthermore, LMO offers improved thermal stability relative to LiCoO 2 , especially in a highly delithiated state, resulting in safer batteries. [ 6 ] However, a major disadvantage of LMO spinel cathodes is that they lose capacity following long term cycling due to Mn 2+ dissolution from the surface of the cathode into the electrolyte during charge/discharge as a result of the disproportionation reaction: 2Mn 3+ → Mn 4+ + Mn 2+ . [ 7,8 ] Approaches that have shown promise in combating manganese dissolution include modifi cation of the composition of the parent LMO electrode by cation substitution (e.g., LiM x Mn 2x O 4 , M = Li, Co, Ni, Zn) [9][10][11][12][13][14] to reduce the amount of Mn 3+ in the structure, thereby increasing the average oxidation state on the manganese ions in the electrode above 3.5+. In addition, a variety of protective surface oxide coatings have been employed such as Al 2 O 3 , [ 15 ] ZrO 2 , [ 16 ] Y 2 O 3 , [ 17 ] and TiO 2 . [ 7 ] However, the realization of a thin and uniform surface fi lm that does not compromise surface conductivity remains an outstanding challenge.Here, we explore single-layer graphene coatings as an alternative strategy for suppressing manganese dissolution form spinel LMO cathodes. Graphene is a promising candidate for this application since it is an effective diffusion barrier for atomic-scale species [ 18,19 ] and can withstand numerous lithiation charge/discharge cycles. [ 20 ] In addition, graphene is an excellent conductor, which facilitates electron transfer and cycling rate. [ 21 ] Graphene is also known to yield a well-defi ned and stable solid electrolyte interphase (SEI) l...

Inorganic transparent metal oxides represent one of the highest performing material systems for thin-film flexible electronics. Integrating these materials with low-temperature processing and printing technologies could fuel the next generation of ubiquitous transparent devices. In this work, we investigate the integration of UV-annealing with inkjet printing, demonstrating how UV-annealing of high-k AlO x dielectrics facilitates the fabrication of high-performance InO x transistors at low processing temperatures and improves bias-stress stability of devices with all-printed dielectrics, semiconductors, and source/drain electrodes. First, the influence of UV-annealing on printed metal–insulator–metal capacitors is explored, illustrating the effects of UV-annealing on the electrical, chemical, and morphological properties of the printed gate dielectrics. Utilizing these dielectrics, printed InO x transistors were fabricated which achieved exceptional performance at low process temperatures (<250 °C), with linear mobility μlin ≈ 12 ± 1.6 cm2/V s, subthreshold slope <150 mV/dec, I on/I off > 107, and minimal hysteresis (<50 mV). Importantly, detailed characterization of these UV-annealed printed devices reveals enhanced operational stability, with reduced threshold voltage (V t) shifts and more stable on-current. This work highlights a unique, synergistic interaction between low-temperature-processed high-k dielectrics and printed metal oxide semiconductors.

Solution-processed semiconductor and dielectric materials are attractive for future lightweight, low-voltage, flexible electronics, but their response to ionizing radiation environments is not well understood. Here, we investigate the radiation response of graphene field-effect transistors employing multilayer, solution-processed zirconia self-assembled nanodielectrics (Zr-SANDs) with ZrOx as a control. Total ionizing dose (TID) testing is carried out in situ using a vacuum ultraviolet source to a total radiant exposure (RE) of 23.1 μJ/cm(2). The data reveal competing charge density accumulation within and between the individual dielectric layers. Additional measurements of a modified Zr-SAND show that varying individual layer thicknesses within the gate dielectric tuned the TID response. This study thus establishes that the radiation response of graphene electronics can be tailored to achieve a desired radiation sensitivity by incorporating hybrid organic-inorganic gate dielectrics.