electronics/optoelectronics, and artificial lighting technologies. [1] The advent of soft electronics has created a strong demand for the fabrication of highly flexible and stretchable WLEDs, [2] to support the development of advanced devices and systems with novel form factors. [3] In general, two main approaches, namely electroluminescence (EL) and photo luminescence (PL) or down-conversion, have been explored for fabricating white LEDs. [4] WLEDs based on EL have generated high expectations in the related research community in terms of efficiency and stability, and a few flexible light-emitting diodes (LEDs) have been reported. [5] However, the EL approach requires i) a multilayered structure design for transport/recombination of electrons and holes and ii) a complicated packaging process, which makes it hard to fabricate large-area devices in a cost-effective way. In particular, the multilayered structure contains interfaces of heterogeneous materials with different mechanical properties (e.g., elastic modulus and Poisson's ratio), which often result in mechanical failure under external stress. [3a,5a,6] On the other hand, down-conversion white LEDs have become increasingly popular in academic research and practical applications, due to their high performances and simple fabrication procedures. Owing to their high photostability, excellent color purity (with a narrow full width at half maximum, FWHM), high PL quantum yields (QYs, up to 100%), and color tunability from the ultraviolet to infrared region, semiconductor quantum dots (QDs) represent promising candidate materials for nextgeneration LEDs. [7] Various types of QDs encapsulated within solid matrices (e.g., silica particles, glass blocks, and polymer films) have been employed in down-conversion white LEDs, and high color rendering indexes (CRIs) and luminous efficacies (LEs) have been reported for LEDs based on InP/ZnS, carbon, perovskite, silicon, and cadmium-containing QDs. [8] However, owing to the poor mechanical reliability of the solid matrices, little progress has been made in developing stretchable down-conversion WLEDs using QDs. In addition, when the QDs are trapped into solid matrices, their performances, such as PL intensity and lifetime, usually decrease by 10-90% compared to those of QDs dispersed in liquid phases. [9] The Combining the characteristics of different materials offers exciting new opportunities for advanced applications in various fields. Herein, white lightemitting diodes (WLEDs) with >200% reversible stretchability are fabricated using six-color quantum dots (QDs) gel emitters. Stable aqueous-phase alloy core/shell QDs with high quantum yield are obtained via ligand exchange using a ternary solvent system. Transparent and highly stretchable gels with large pores are created by binary-solvent-based gelation at low temperatures. Importantly, the QDs and the gel originate from the same two solvents, which make the QDs highly compatible with the gelation process. Consequently, QDs of six different colors are incorpora...

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In this study, we demonstrated a strategy for fabricating unique 2D ternary nanohybrids comprising N-doped graphene (NG) and in-plane WSe2–WO3 (W–W) heterojunction nanosheets (NG/W–Ws) through heat treatment/oxidation processes using a graphene/PANI/WSe2 precursor. PANI served as an exfoliating and N-doping agent and played a crucial role along with graphene in developing a high effective surface area and pore volume. The NG/W–Ws showed a single kinetic reaction (the Volmer–Heyrovsky step) with a single onset potential for the hydrogen evolution reaction (HER) and decreased overpotentials; this was attributed to the intercalated NG. Density functional theory calculations indicated that NG decreases the energy gap between the LUMO and HOMO levels, and the differential Gibbs free energy of atomic hydrogen on the catalyst surface was close to zero. Therefore, the NG/W–Ws presented a linear relationship between their electrocatalytic performance (e.g., onset potential and overpotential) and mass loading (thickness). The total resistance and capacitance of the NG/W–Ws decreased and increased, respectively, with increasing electrode thickness, highlighting the synergy between the NG and W–W components. We believe that the proposed strategy will ensure the facile fabrication of multicomponent 2D heterostructured nanohybrids for high mass-loading electrocatalyst systems and will contribute to the practical commercialization of 2D nanohybrids as electrocatalysts.

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