Quantum dots have innate advantages as the key component of optoelectronic devices. For white light–emitting diodes (WLEDs), the modulation of the spectrum and color of the device often involves various quantum dots of different emission wavelengths. Here, we fabricate a series of carbon quantum dots (CQDs) through a scalable acid reagent engineering strategy. The growing electron-withdrawing groups on the surface of CQDs that originated from acid reagents boost their photoluminescence wavelength red shift and raise their particle sizes, elucidating the quantum size effect. These CQDs emit bright and remarkably stable full-color fluorescence ranging from blue to red light and even white light. Full-color emissive polymer films and all types of high–color rendering index WLEDs are synthesized by mixing multiple kinds of CQDs in appropriate ratios. The universal electron-donating/withdrawing group engineering approach for synthesizing tunable emissive CQDs will facilitate the progress of carbon-based luminescent materials for manufacturing forward-looking films and devices.

In recent times, high-performance flexible pressure sensors that can be fabricated in an environmentally friendly and low-cost manner have received considerable attention owing to their potential applications in wearable health monitors and intelligent soft robotics. This paper proposes a highly sensitive flexible piezoresistive pressure sensor based on hybrid porous microstructures that can be designed and fabricated using a bio-inspired and low-cost approach employing the Epipremnum aureum leaf and sugar as the template. The sensitivity and detection limit of the obtained pressure sensor can be as high and low as 83.9 kPa–1 (<140 Pa) and 0.5 Pa, respectively. According to the mechanism and simulation analyses, the hybrid porous microstructures lower the effective elastic modulus of the sensor and introduce an additional pore resistance, which increases the contact area and conductive path with loads, thereby contributing to the high sensitivity that exceeds that of traditional microstructured pressure sensors. Real-time monitoring of human physiological signals such as finger pressing, voice vibration, swallowing activity, and wrist pulse is demonstrated for the proposed device. The high performance and easy fabrication of the hybrid porous microstructured sensor can encourage the development of a novel approach for the design and fabrication of future pressure sensors.

Owing to the enlarged exciton binding energy and the ability to confine charge carriers compared to their three-dimensional (3D) counterparts, research on quasi-two-dimensional (quasi-2D) perovskite materials and the correlative application in light-emitting diodes (LEDs) has attracted considerable attention. However, high density of defects, exciton emission trapping, and unbalanced charge injection are still the main intractable obstacles to their further development and practical application. Herein, we report an efficient multifunctional interlayer, lithium fluoride (LiF), to boost the performance of green-emitting quasi-2D perovskite LEDs (PeLEDs) by simultaneously overcoming the aforementioned issues. The introduced LiF interlayer not only eliminates the defects at perovskite grain boundaries and the surface by reinforcing the chemical bonds with uncoordinated lead ions but also restrains the emission of perovskite from quenching triggered by the electron transport layer and reduces excess electron injections to effectively balance carriers in the device. As a result, the resulting green quasi-2D PeLED shows a maximum external quantum efficiency of 16.35%, which is the best value obtained for quasi-2D perovskite-based LEDs reported so far, with simultaneous improvement in the operating lifetime of the device.

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An all-solution processed inverted green quantum dot-based light-emitting diode with concurrent high efficiency and long lifetime is obtained by precisely controlled double shell growth of quantum dots.