Carbon nanodots (CDs) have emerged as a promising luminescent material, showing significant potential in biological imaging, information security, and illumination displays within the internet of things (IoT). However, CDs-based electroluminescent devices, especially flexible and self-powered white displays, remain scarcely reported, which limit their applications in human-machine interactions and wearable optoelectronics in the IoT. Herein, we present a pioneering CDs-based flexible and self-powered white display system with a Commission Internationale de L’Eclairage (CIE) coordinate of (0.31, 0.39) by integrating CDs-based alternating current electroluminescent (ACEL) devices with triboelectric nanogenerators. The CDs-based white ACEL devices can be dynamically modulated from light green to white under various supplied frequencies ranging from 50 to 500 Hz. The devices also render from cold white to warm white with correlated color temperature from 9705 to 4538 K, as the concentration ratios of ZnS:Cu phosphors to CDs change from 22:2 to 22:8. Furthermore, these devices exhibit excellent flexibility and stability, maintaining over 95% of their electroluminescent intensities after 4500 cycles even under a large bending angle of 180° with a bending radius of 4.9 mm. Finally, this CDs-based flexible and self-powered white display system is worn on the human body to realize real-time illumination display powered by biomechanical energy, such as hand slapping and walking. This work provides a novel design strategy toward high-performance CD-based flexible and self-powered white displays and expands their potential applications in wearable optoelectronics for the IoT.

The effective acquisition of hydrogen energy from the ocean offers a promising sustainable solution for increasing global energy shortage. Herein, a self-powered high-efficient hydrogen generation system is proposed by integrating a triboelectric–electromagnetic hybrid nanogenerator (TEHG), power management circuit (PMC), and an electrolytic cell. Under the wind triggering, as-fabricated TEHG can effectively convert breeze energy into electric energy, which demonstrates a high output current of 20.3 mA at a speed rotation of 700 rpm and the maximal output power of 13.8 mW at a load of 10 MΩ. Remarkably, as-designed self-powered system can perform a steady and continuous water splitting to produce hydrogen (1.5 μL·min⁻¹) by adding a matching capacitor between the PMC and electrolytic cell. In the circuit, the capacitor can not only function as a charge compensation source for water splitting, but also stabilize the working voltage. Unlike other self-powered water splitting systems, the proposed system does not need catalysts or the complex electrical energy storage/release process, thus improving the hydrogen production efficiency and reducing the cost. This work provides an effective strategy for clean hydrogen energy production and demonstrates the huge potential of the constructed self-powered system toward carbon neutralization.

Continuous mechanoluminescence (ML) fibers and fiber-woven textiles have the potential to serve as new wearable devices for sensors, healthcare, human–computer interfacing, and Internet of Things. Considering the demands on wearability and adaptability for the ML textiles, it is essential to realize the continuous synthesis of fiber, while maintaining a desired small diameter. Here, we develop a novel adhere-coating method to fabricate ML composite fiber, consisting of a thin polyurethane (PU) core and ZnS:Cu/polydimethylsiloxane (PDMS) shell, with the outer diameter of 120 μm. By diluting PDMS to tune the thickness of liquid coating layer, droplets formation has been effectively prevented. The composite fiber exhibits a smooth surface structure and superior ML performances, including high brightness, excellent flexibility, and stability. In addition, a weft knitting textile fabricated by the continuous ML fiber can be easily delighted by manually stretching, and the ML fibers can emit visible signals upon human motion stimuli when woven into commercial cloth. Such continuous ultra-fine ML fibers are promising as wearable sensing devices for human motion detection and human–machine interactions.

As a typical two-dimensional material, graphitic carbon nitride (g-CN) has attracted great interest because of its distinctive electronic, optical, and catalytic properties. However, the absence of a feasible route toward large-area and high-quality films hinders its development in optoelectronics. Herein, high-quality g-CN films have been grown on Si substrate via a vapor-phase transport-assisted condensation method. The g-CN/Si heterojunction shows an obvious response to ultraviolet–visible-near infrared photons with a responsivity of 133 A·W⁻¹, which is two orders of magnitude higher than the best value ever reported for g-CN photodetectors. A position-sensitive detector (PSD) has been developed using the lateral photovoltaic effect of the g-CN/Si heterojunction. The PSD shows a wide response spectrum ranging from 300 to 1,100 nm, and a position sensitivity and rise/decay time of 395 mV·mm⁻¹ and 3.1/50 μs, respectively. Moreover, the application of the g-CN/Si heterojunction photodetector in trajectory tracking and acoustic detection has been realized for the first time. This work unveils the potential of g-CN for large-area photodetectors, and prospects for their applications in trajectory tracking and acoustic detection.

Ultraviolet position-sensitive detectors (PSDs) are expected to undergo harsh environments, such as high temperatures, for a wide variety of applications in military, civilian, and aerospace. However, no report on relevant PSDs operating at high temperatures can be found up to now. Herein, we design a new 2D/3D graphitic carbon nitride (g-C₃N₄)/gallium nitride (GaN) hybrid heterojunction to construct the ultraviolet high-temperature-resistant PSD. The g-C₃N₄/GaN PSD exhibits a high position sensitivity of 355 mV mm⁻¹, a rise/fall response time of 1.7/2.3 ms, and a nonlinearity of 0.5% at room temperature. The ultralow formation energy of −0.917 eV atom⁻¹ has been obtained via the thermodynamic phase stability calculations, which endows g-C₃N₄ with robust stability against heat. By merits of the strong built-in electric field of the 2D/3D hybrid heterojunction and robust thermo-stability of g-C₃N₄, the g-C₃N₄/GaN PSD delivers an excellent position sensitivity and angle detection nonlinearity of 315 mV mm⁻¹ and 1.4%, respectively, with high repeatability at a high temperature up to 700 K, outperforming most of the other counterparts and even commercial silicon-based devices. This work unveils the high-temperature PSD, and pioneers a new path to constructing g-C₃N₄-based harsh-environment-tolerant optoelectronic devices.

Flexible photodetectors (PDs) are indispensable components for next-generation wearable electronics. Recently, two-dimensional (2D) materials have been implemented as functional flexible optoelectronic devices due to their characteristics of atomically thin layers, excellent flexibility, and strain sensitivity. In this work, we developed a flexible photodetector based on MoS₂/NiO heterojunction, and Fabry-Perot (F-P) and piezo-phototronic effect have been employed to enhance the responsivity (R) and external quantum efficiency (EQE) of the devices. The F-P effect is utilized to improve the optical absorption of the MoS₂, resulting in an enhancement in the photoluminescence (PL) of monolayer MoS₂ and the EQE of the photodetector by 30 and 130 times, respectively. The flexible photodetector exhibits an ultrahigh detectivity (D*) of 2.6 × 10¹⁴ Jones, which is the highest value ever reported for flexible MoS₂ PDs. The piezo-potential of monolayer MoS₂ decreases the valence band offset at the interface of MoS₂/NiO, which increases the transfer efficiency of the photon-generated carriers significantly. Under 1.17% tensile strain, the R of the flexible photodetector can be enhanced by 271%. This research may provide a universal strategy for the design and performance optimization of 2D materials heterostructures for flexible optoelectronics.