We explored the feasibility of wafer-scale
two-dimensional (2D)
molybdenum disulfide (MoS2) layers toward futuristic environmentally
friendly electronics that adopt biodegradable substrates. Large-area
(> a few cm2) 2D MoS2 layers grown on silicon
dioxide/silicon (SiO2/Si) wafers were delaminated and integrated
onto a variety of cellulose-based substrates of various components
and shapes in a controlled manner; examples of the substrates include
planar papers, cylindrical natural rubbers, and 2,2,6,6-tetramethylpiperidine-1-oxyl-oxidized
cellulose nanofibers. The integrated 2D layers were confirmed to well
preserve their intrinsic structural and chemical integrity even on
such exotic substrates. Proof-of-concept devices employing large-area
2D MoS2 layers/cellulose substrates were demonstrated for
a variety of applications, including photodetectors, pressure sensors,
and field-effect transistors. Furthermore, we demonstrated the complete
“dissolution” of the integrated 2D MoS2 layers
in a buffer solution composed of baking soda and deionized water,
confirming their environmentally friendly transient characteristics.
Moreover, the approaches to delaminate and integrate them do not demand
any chemicals except for water, and their original substrates can
be recycled for subsequent growths, ensuring excellent chemical benignity
and process sustainability.
Flexible smart electronics require their energy storage device to be flexible in nature. Developing high-performance flexible energy storage devices require direct integration of electrode active materials on current collectors to satisfy the high electronic/ionic conductivity and long-term durability requirements. Herein, we develop a flexible all-solid-state asymmetric supercapacitor comprised of reduced graphene oxide (rGO) and core/shell tungsten trioxide/tungsten disulfide (WO 3 /WS 2 ) nanowire based electrodes. The electrodes synthesized via electrochemical deposition and chemical vapor deposition avoided the necessity to use non-conductive binders and offered excellent cyclic stability. The structural integrity provided by the rGO and WO 3 /WS 2 electrodes facilitated excellent electrochemical stability with capacitance retention of 90% and 100% after 10 000 charge-discharge cycles, respectively. An all-solid-state device provides a voltage window of 1.5 V and more than 70% capacitance retention after 10 000 charge-discharge cycles. Providing 97% capacitance retention upon mechanical bending reveals its potential to be used as an energy storage devices in flexible electronics.
Tellurium (Te) has recently been rediscovered as an attractive semiconducting material for a wide range of electronic and optoelectronic applications. However, thermal instability of Te-based devices has not been investigated and introduces major drawbacks for their practical applications. Toward this goal, this work explores the influence of annealing temperatures on Te transistors and their two failure mechanisms, related to the sublimation of the Te channel and the degradation of the contacts. To overcome these challenges, we fabricated a Te device that is graphene-contacted and SiOx-encapsulated such that the Te channel and the contacts remain intact and stable at high temperatures. The device exhibits an effective mobility of ∼50 cm2 V−1 s−1, which is comparable to traditional metal-contacted Te transistors. The traditional Te devices have performance degradation with increasing temperature and failure at 200 °C. Through the graphene contact and SiOx encapsulation, our device shows improved thermal stability despite the repeated annealing processes for temperatures up to 250 °C, making it suitable for practical use.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.