Layering in the sun: Layered graphene and quantum dot (QD) films can be fabricated simply on transparent conducting indium tin oxide (ITO) substrates from aqueous solutions. The structure and favorable work function of graphene make it effective for the collection and transfer of photogenerated charges to the electrode, resulting in a high‐performance photovoltaic device (see picture; IPCE=incident photon‐to‐charge‐carrier conversion efficiency, SWNT=single‐walled carbon nanotube).

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Multifunctional architecture with intriguing structural design is highly desired for realizing the promising performances in wearable sensors and flexible energy storage devices. Cellulose nanofiber (CNF) is employed for assisting in building conductive, hyperelastic, and ultralight Ti3C2Tx MXene hybrid aerogels with oriented tracheid-like texture. The biomimetic hybrid aerogels are constructed by a facile bidirectional freezing strategy with CNF, carbon nanotube (CNT), and MXene based on synergistic electrostatic interaction and hydrogen bonding. Entangled CNF and CNT “mortars” bonded with MXene “bricks” of the tracheid structure produce good interfacial binding, and superior mechanical strength (up to 80% compressibility and extraordinary fatigue resistance of 1000 cycles at 50% strain). Benefiting from the biomimetic texture, CNF/CNT/MXene aerogel shows ultralow density of 7.48 mg cm−3 and excellent electrical conductivity (~ 2400 S m−1). Used as pressure sensors, such aerogels exhibit appealing sensitivity performance with the linear sensitivity up to 817.3 kPa−1, which affords their application in monitoring body surface information and detecting human motion. Furthermore, the aerogels can also act as electrode materials of compressive solid-state supercapacitors that reveal satisfactory electrochemical performance (849.2 mF cm−2 at 0.8 mA cm−2) and superior long cycle compression performance (88% after 10,000 cycles at a compressive strain of 30%).

Light emission induced by chemical reactions, known as chemiluminescence (CL), has been widely used for bioassays, biosensors, imaging, and illumination applications. Most known CL systems exhibit flash-type single-color light emissions, which limit their applications. Long-lasting multicolor CL in aqueous solutions is highly desirable, especially for biological applications, but remains a challenge. Herein, we report a simple strategy of achieving highly efficient cascade Forster resonance energy transfer (FRET) in the dynamic nanoassembly of βcyclodextrin (β-CD), CL reagents, and fluorophores in aqueous solution, which emits intensive multicolor CL with adjustable wavelength within 410−610 nm. β-CD can bind CL reagents and fluorophores to form a dynamic nanoassembly. These nanoassemblies can bring the included luminescent intermediate and fluorophores into close proximity and proper alignment, which should greatly enhance the FRET efficiency between luminescent intermediate and fluorophores. Indeed, the cascade FRET efficiency in this supramolecular nanoassembly reaches up to 92%, which is comparable with the cascade FRET systems based on covalently linked donors and acceptors. By using hydroxypropyl methylcellulose as the thickener to slow the diffusion (to elongate the CL emission), and using Ca(OH) 2 solid (a low solubility strong base) as buffer to maintain the pH in the optimal range for the CL reaction, this nanoassembly system has been further developed to achieve slow-diffusion-controlled catalytic CL reactions, which enables long-lasting multicolor CL in aqueous solution that is visible to naked eyes and lasts for more than 20 h. The multicolor CL systems can be used to prepare transformable two-dimensional multicolor codes for encryption application.