A stretchable electronic device can retain its functionalities during high-level mechanical deformation, and stimulates the applications in the field of wearable and bio-implantable electronics. Efficient energy storage devices are an indispensable component in stretchable electronic systems. To integrate power supplies together with electronic devices that are mechanically flexible and stretchable, we demonstrate a new kind of stretchable all-solid-state supercapacitor, which consists of two slightly separated polyaniline/graphene electrodes in a wavy shape, with a phosphoric acid/polyvinyl alcohol gel as the solid-state electrolyte and separator. The as-fabricated wavy shaped supercapacitor was encapsulated in an elastomeric substrate which can be stretched to a large extent without mechanical degradation. The supercapacitor exhibited a maximum specific capacitance of 261 F g⁻¹. Electrochemical cycling testing with the supercapacitor showed 89% capacitance retention over 1000 charge–discharge cycles at a current density of 1 mA cm⁻². The bending and stretching tests showed that the supercapacitor maintained high mechanical strength and high capacitance simultaneously, even under a strain of 30%. This stretchable all-solid-state supercapacitor shows great potential as an energy storage device for stretchable electronic systems.

Two-dimensional (2D) semiconductors, such as ultrathin layers of transition metal dichalcogenides (TMDs), offer a unique combination of electronic, optical and mechanical properties, and hold potential to enable a host of new device applications spanning from flexible/wearable (opto)electronics to energy-harvesting and sensing technologies. A critical requirement for developing practical and reliable electronic devices based on semiconducting TMDs consists in achieving a full control over their charge-carrier polarity and doping. Inconveniently, such a challenging task cannot be accomplished by means of well-established doping techniques (e.g. ion implantation and diffusion), which unavoidably damage the 2D crystals resulting in degraded device performances. Nowadays, a number of alternatives are being investigated, including various (supra)molecular chemistry approaches relying on the combination of 2D semiconductors with electroactive donor/acceptor molecules. As yet, a large variety of molecular systems have been utilized for functionalizing 2D TMDs via both covalent and non-covalent interactions. Such research endeavours enabled not only the tuning of the charge-carrier doping but also the engineering of the optical, electronic, magnetic, thermal and sensing properties of semiconducting TMDs for specific device applications. Here, we will review the most enlightening recent advancements in experimental (supra)molecular chemistry methods for tailoring the properties of atomically-thin TMDs – in the form of substrate-supported or solution-dispersed nanosheets – and we will discuss the opportunities and the challenges towards the realization of novel hybrid materials and devices based on 2D semiconductors and molecular systems.