Stretchable and/or flexible electrodes and their associated electronic devices have attracted great interest because of their possible applications in high-end technologies such as lightweight, large ...area, wearable, and biointegrated devices. In particular, metal nanowires and graphene derivatives are chosen for electrodes because they show low resistance and high mechanical stability. Here, we review stretchable and flexible soft electrodes by discussing in depth the intrinsic properties of metal NWs and graphenes that are driven by their dimensionality. We investigate these properties with respect to electronics, optics, and mechanics from a chemistry perspective and discuss currently unsolved issues, such as how to maintain high conductivity and simultaneous high mechanical stability. Possible applications of stretchable and/or flexible electrodes using these nanodimensional materials are summarized at the end of this review.
Stretchable and/or flexible electrodes and their associated electronic devices have attracted great interest because of their possible applications in high-end technologies such as lightweight, large area, wearable, and biointegrated devices.
Smart textiles consist of discrete devices fabricated from-or incorporated onto-fibres. Despite the tremendous progress in smart textiles for lighting/display applications, a large scale approach for ...a smart display system with integrated multifunctional devices in traditional textile platforms has yet to be demonstrated. Here we report the realisation of a fully operational 46-inch smart textile lighting/display system consisting of RGB fibrous LEDs coupled with multifunctional fibre devices that are capable of wireless power transmission, touch sensing, photodetection, environmental/biosignal monitoring, and energy storage. The smart textile display system exhibits full freedom of form factors, including flexibility, bendability, and rollability as a vivid RGB lighting/grey-level-controlled full colour display apparatus with embedded fibre devices that are configured to provide external stimuli detection. Our systematic design and integration strategies are transformational and provide the foundation for realising highly functional smart lighting/display textiles over large area for revolutionary applications on smart homes and internet of things (IoT).
Recent advances in the synthesis and processing of perovskite materials have led to significant improvements in their stability under harsh conditions, making them increasingly attractive for use as ...photo and photoelectrochemical catalysts. In particular, core-shell structured perovskite nanocrystals have greatly enhanced chemical stability, enabling their use in aqueous environments; however, their low conductivity remains a challenge. To address this issue, this study developed two-time cross-linkable core-shell perovskite nanocrystals using two types of silanes, resulting in excellent chemical stability and high conductivity. The first cross-linking reaction was spontaneously initiated in the solution state, forming an ultrathin Si-O-Si amorphous matrix on the surface of the perovskite nanocrystals. The second cross-linking reaction was intentionally induced in the film state by exposing it to UV light. The resulting cross-linked perovskite/SiO2 nanocrystal films exhibited a high packing density, and among four different dopants, the Ag-doped film demonstrated the lowest onset potential for HER in a 0.5 M H2SO4 aqueous solution due to effective band modulation. These findings suggest that the two-time cross-linking approach can significantly enhance the performance of perovskite nanocrystals in photoelectrochemical applications.
Recently, silver nanowires (AgNWs) have attracted considerable interest for their potential application in flexible transparent conductive films (TCFs). One challenge for the commercialization of ...AgNW-based TCFs is the low conductivity and stability caused by the weak adhesion forces between the AgNWs and the substrate. Here, we report a highly bendable, conductive, and transparent AgNW film, which consists of an underlying poly(diallyldimethyl-ammonium chloride) (PDDA) and AgNW composite bottom layer and a top layer-by-layer (LbL) assembled graphene oxide (GO) and PDDA overcoating layer (OCL). We demonstrated that PDDA could increase the adhesion between the AgNW and the substrate to form a uniform AgNW network and could also serve to improve the stability of the GO OCL. Hence, a highly bendable, conductive, and transparent AgNW–PDDA–GO composite TCF on a poly(ethylene terephthalate) (PET) substrate with Rs ≈ 10 Ω/sq and T ≈ 91% could be made by an all-solution processable method at room temperature. In addition, our AgNW–PDDA–GO composite TCF is stable without degradation after exposure to H2S gas or sonication.
Recently, Ag nanowires (AgNWs) has had a great interest as a conducting material for flexible and transparent devices, but it still shows several problems such as the ultimate detachment of AgNWs ...from substrate and a high contact resistance on AgNW junctions. Therefore, the novel concept to enhance permanent and closed attachment of AgNWs by silane modification to polydimethylsilaoxane (PDMS) substrate well known as high stretchable film with extremly low adhesive is suggested. According to this experiment, higher sigma (σ)‐donating ability and hydrophilicity indicate better electrical and mechanical properties in real device. Especially, densely amine self‐assembled PDMS surface exhibits the strongest contact force to the AgNWs, especially for junction side, and the longest maintenance of hydrophilicity by coordination‐type bonding. In addition, AgNWs adhere permanently to stretchable substrates while simultaneously maintaining high transparency (87%) and high conductivity (27 Ω sq–1). Consequently, the resulting AgNW film shows excellent mechanical durability which includes enhanced performance of both flexibility and stretchability.
The well‐ordered and high density coordination‐type bonding silane molecule self‐assembled on PDMS surface exhibits the strongest contact force with silver nanowire (AgNW), especially on junction side, and the longest maintenance of hydrophilicity. As a result, the AgNW PDMS film shows high conductivity with high transparency, excellent mechanical durability, and high stretchability.
Solution-processed perovskite quantum dots (QDs) have been intensively researched as next-generation photocatalysts owing to their outstanding optical properties. Even though the intrinsic physical ...properties of perovskite QDs have been significantly improved, the chemical stability of these materials remains questionable. Their low long-term chemical stability limits their commercial applicability in photocatalysis. In this study, we investigated the photodegradation mechanisms of perovskite QDs and their hybrids via photoluminescence (PL) by varying the excitation power and the ultraviolet (UV) exposure power. Defects in perovskite QDs and the interface between the perovskite QD and the co-catalyst influence the photo-stability of perovskite QDs. Consequently, we designed a stable perovskite QD film via an in-situ cross-linking reaction with amine-based silane materials. The surface ligand comprising 2,6-bis(N-pyrazolyl)pyridine nickel(II) bromide (Ni(ppy)) and 5-hexynoic acid improved the interface between the Ni co-catalyst and the perovskite QD. Then, ultrathin SiO2 was fabricated using 3-aminopropyltriethoxy silane (APTES) to harness the strong surface binding energy of the amine functional group of APTES with the perovskite QDs. The Ni co-catalyst content was further increased through Ni doping during purification using a short surface ligand (3-butynoic acid). As a result, stable perovskite QDs with rapid charge separation were successfully fabricated. Time-correlated single photon counting (TCSPC) PL study demonstrated that the modified perovskite QD film exhibited slow photodegradation owing to defect passivation and the enhanced interface between the Ni co-catalyst and the perovskite QD. This interface impeded the generation of hot carriers, which are a critical factor in photodegradation. Finally, a stable red perovskite QD was synthesized by applying the same strategy and the mixture between red and green QD/Ni(ppy)/SiO2 displayed an CO2 reduction capacity for CO (0.56 µmol/(g∙h)).
We introduce a facile method to prepare an n-type reduced graphene oxide field effect transistor at room temperature via a typical Benkeser reduction using lithium and ethylenediamine.
Many studies have accompanied the emergence of a great interest in flexible or/and stretchable devices for new applications in wearable and futuristic technology, including human‐interface devices, ...robotic skin, and biometric devices, and in optoelectronic devices. Especially, new nanodimensional materials enable flexibility or stretchability to be brought based on their dimensionality. Here, the emerging field of flexible devices is briefly introduced using silver nanowires and graphene, which are famous nanomaterials for the use of transparent conductive electrodes, as examples, and their unique functions originating from the intrinsic property of these nanomaterials are highlighted. It is thought that this work will evoke more interest and idea exchanges in this emerging field and hopefully can trigger a breakthrough on a new type of optoelectronics and optogenetic devices in the near future.
The latest developments regarding the use of graphene and AgNWs for flexible and stretchable electronic devices are introduced in the field of optoelectronics‐related applications, with a focus on flexible and stretchable devices with novel structures driven by the intrinsic properties of the nanodimensional materials. The specialty of these applications is discussed in comparison with other flexible devices.
A blend of perovskite quantum dots (QDs) and a hole transport layer (HTL) is a feasible candidate to solve the long-standing issues in light-emitting diodes (LEDs) such as charge injection, energy ...state matching, and defect passivation. However, QD:HTL blend structures for QD-based LEDs suffer from fast charge and energy transfers due to an inhomogeneous distribution of QDs and the HTL matrix. Here we report new cross-linkable spacer ligands between QDs and TFB that result in a highly emissive QD:TFB-blended LED device. We synthesize three representative spacer ligands to control the charge and energy transfers between QDs and the HTL. The first spacer ligand is used for controlling the molecular distance between QDs and TFB, and the second spacer ligand is designed to investigate how molecular interaction between QDs and the spacer ligand affects the optical property of the QD:TFB blend. Subsequently, the best spacer ligand, a 10-((2-benzoylbenzoyl)oxy)decanoic acid, is designed to anchor TFB (via a benzophenone group) and simultaneously bond to QDs (with a carboxylic acid functional group). The carboxylic acid group strongly interacts with QDs, dramatically improving the cross-linking rate between QDs and TFB. Due to the direct interaction between QDs and TFB, hole carriers can be effectively injected to perovskite QDs through the conductive backbone of TFB, resulting in the highest luminance values of 10917 cd/m2 at 7.4 V due to carrier injection balance. This is at least 10 times better LED performance compared with a pristine QD device.
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