Moisture-enabled electricity generation (MEG) is an emerging energy-harvesting technology that continuously generates electricity by interacting with ubiquitous ambient water vapor in a pollution-free manner. Its integrable and miniaturizable nature makes it a promising candidate for future scalable and decentralized energy systems. This comprehensive review examines the evolution of MEG devices, focusing on the underlying mechanisms of moisture-material interactions, particularly ion diffusion and streaming potentials. We also provide a detailed analysis of novel carbon-based hygroscopic materials by discussing their types, characteristics, and merits/drawbacks. Finally, we summarize recent advances in MEG applications across various fields.

Moisture-electric generation (MEG) holds promise for sustainable energy, but it usually suffers from low output and poor stability. Herein, we report a high-performance MEG device fabricated by depositing aminated carbon dots (CDs) onto a flexible fabric substrate. A key improvement involves a thermal-induced crosslinking strategy, where heat treatment triggers covalent bonding between aminated CDs and the substrate. This process creates a stable network that enhances interfacial adhesion, removes inactive groups, and inhibits CDs migration, thereby promoting sustained moisture adsorption and efficient hydroxide ion transport, collectively boosting electrical output and device stability. Consequently, the thermal treated device delivers a markedly increased output voltage of 0.90 V, surpassing the 0.56 V of the untreated control. Moreover, the device exhibits outstanding flexibility, wash fastness, and long-term durability, maintaining stable electrical output for up to 120 h. We further demonstrate that multiple devices can be integrated into a scalable power system via series/parallel circuits, highlighting their practical potential for real-world energy harvesting.

Three-dimensional (3D) porous reduced graphene oxide (rGO) aerogels are promising for broadband terahertz (THz) modulation due to their low density, high porosity, and tunable conductivity. However, conventional methods for reducing graphene oxide often cause graphene layer agglomeration and stacking, limiting its THz applications. Here, a novel method for fabricating lightweight porous rGO aerogels is proposed based on a thiol-functionalized carbon dot (SH-CD)-enabled "self-catalytic reduction-dynamic assembly" strategy. As a dual-functional agent, SH-CDs enable efficient in situ reduction and controlled crosslinking of GO sheets under mild reaction conditions, thereby facilitating the construction of aerogels featuring high electrical conductivity, a fully developed 3D interconnected porous network, and abundant interfacial domains. This well-designed structure effectively suppresses excessive densification of the graphene layer while enhancing the internal reflection and scattering of THz waves at multiple interfacial domains. Consequently, the rGO aerogels exhibit outstanding THz shielding and absorption, achieving a maximum reflection loss of -37 dB and a shielding effectiveness of -44 dB, with average values of -26 and -37 dB, respectively-exceeding those of most reported materials. THz transmission and reflection imaging further confirm the material's potential for electromagnetic stealth, shielding, and related applications.

Lanthanide nanocrystals offer unique advantages for electroluminescence (EL) applications, including narrow-band emission, high colour purity and compositionally tunable output1-4. However, their insulating nature poses a challenge for carrier transport and injection, impeding their application in electrically driven optoelectronic devices5. Here we demonstrate efficient EL from insulating lanthanide fluoride nanocrystals (4 nm; NaGdF4:X; X = Tb3+, Eu3+ or Nd3+) coated with a series of functionalized 2-(diphenylphosphoryl)benzoic acids (ArPPOA). These ligands, featuring donor-phosphine oxide acceptor hybrids with carboxyl and P=O coordination sites, effectively sensitize the luminescence of lanthanide nanocrystals by modulating the intraligand charge transfer characteristics. Ultrafast spectroscopic investigations reveal that strong coupling between ArPPOA and lanthanide nanocrystals facilitates intersystem crossing (ISC; <1 ns) and highly efficient triplet energy transfer to nanocrystals (up to 96.7%). Through careful control of dopant composition and concentration in nanocrystals, we also achieve wide-ranging multicolour EL without altering the device architecture, reaching an external quantum efficiency exceeding 5.9% for Tb3+. This ligand-functionalized nanocrystal platform provides a modular strategy for exciton control in insulating nanocrystal systems, offering a pathway for spectrally precise electroluminescent materials.

The development of stimulus-responsive room-temperature phosphorescence (RTP) materials with wide color ranges is crucial but challenging. A new strategy that integrates acid-triggered carbon dots (CDs) protonation and assembly to realize a wide color RTP variable among green, orange, and near-infrared (NIR) was reported. The synthesized neutral CDs solution exhibited bright green RTP after being printed on paper and dried. Upon acidic treatment, the phosphate groups on the CD surfaces undergo protonation and trigger their self-assembly. As a result, the originally green RTP transforms into orange and NIR dual-mode emission, accompanied by enhanced emission intensity. Notably, the phosphorescence quantum yield increased from 10.3% to 26.0%. Upon further stimulation with water, only NIR RTP is observed. Detailed investigations revealed that acid-induced protonation of phosphate groups enhances pi-electron delocalization, resulting in a redshift of RTP emission to the orange region; moreover, the large conjugated core state induced by assembly leads to NIR RTP emission even in the presence of water. Additionally, acid-triggered CDs protonation and assembly greatly enhance hydrogen bond interactions, effectively suppress nonradiative decay, and increase the RTP intensity. Furthermore, tamper-evident labels with multiple dimensions have been developed and further applied to the fields of information authentication and food freshness detection.

Solar-driven interfacial evaporation has emerged as a promising strategy to produce freshwater via seawater desalination. While cellulose-based photothermal materials have garnered significant attention in solar steam generation, conventional surface modification techniques (e.g., coating and carbonization) often suffer from cumbersome preparation and limited design flexibility. This study pioneers a non-destructive laser-processing strategy to simultaneously induce spatially controlled graphene domains and iron oxide nanostructures on chemically modified cellulose matrices. Through synergistic integration of broadband light absorption (∼93.28% solar-weighted absorptance) with hierarchical water channels, the two-dimensional evaporator achieves exceptional evaporation performance (1.62 kg m-2 h-1, 99.0% efficiency) under 1 sun irradiation. Remarkably, the evaporation performance increases to 1.82 kg m-2 h-1 when configured into a three-dimensional architecture via simple single folding. Detailed characterizations reveal that laser-induced carbothermal reduction generates iron oxide-graphene composites as light absorbers, while preserving cellulose's inherent hydrophilicity for rapid capillary pumping. Notably, the engineered architecture demonstrates enhanced mechanical robustness (234% improvement in tensile strength) and programmable foldability, expanding applicability across diverse desalination scenarios. This laser-direct-writing paradigm establishes a sustainable pathway for developing next-generation cellulose-based solar evaporators.

Lanthanide nanocrystals are promising candidates for electrically powered light-emitting diodes (LEDs) due to their narrow-band emission, high color purity, and broad color turnability. However, their insulating nature poses a challenge for carrier transport and injection, impeding their application in optoelectronic devices. Here we demonstrate efficient electroluminescence from insulating lanthanide fluoride nanocrystals (5 nm; NaGdF4:Tb3+ or NaGdF4:Eu3+) coated with a series of functionalized 2-(diphenylphosphoryl)benzoic acids (ArPPOA). These ligands, featuring donor-phosphine oxide acceptor hybrids with carboxyl and P=O coordination sites, effectively sensitize the luminescence of lanthanide nanocrystals. By modulating the intensity of intra-ligand charge transfer, the first singlet (S1) and triplet (T1) energy levels of ArPPOA are precisely adjusted to optimize intersystem crossing (ISC), reverse ISC, and the interplay between singlet Förster resonance energy transfer and triplet Dexter energy transfer to the nanocrystals. Through careful control of dopant composition and concentration in nanocrystals, we also achieve wide-ranging multicolor electroluminescence without altering the device architecture, reaching an external quantum efficiency exceeding 5% for Tb3+. This ligand-functionalized nanocrystal platform provides a versatile and efficient approach for realizing wide-band tunable electroluminescent emissions.

Phosphorescent materials that exhibit high efficiency and intensity are crucial for practical applications. In this study, we devised a novel strategy to enhance carbon dots (CDs) phosphorescence based on a crosslink-enhanced emission (CEE) and layer-by-layer self-assembly (LBL) synergistic enhancement design. The seed CDs are initially functionalized with cationic polymers on their surfaces, followed by assembly with negatively charged matrices to enhance their phosphorescence. This leads to a significant phosphorescence intensity enhancement by a factor of more than 88, enabling visual readability even in bright fields. Their lifetime is prolonged from 0.13 to 0.41 s and the maximum phosphorescence quantum yield reached up to 27.2 %. Detailed investigations revealed that CEE and LBL significantly inhibited molecular vibrations and protected the triplet excitons of CDs from oxygen quenching, enhancing phosphorescence emission. The loading capacity of the CDs in the matrix was significantly enhanced owing to the uniform dispersion induced by the electrostatic interactions between CDs and the substrate. Furthermore, we envision potential applications of these CDs for anti-counterfeiting and crack detection in bright fields.

Stimulus-responsive afterglow materials refer to a class of substances whose afterglow characteristics alter under external stimuli, showing considerable potential for advanced applications in anti-counterfeiting, optoelectronic displays, chemical sensing, and bioimaging. Carbon dots (CDs), as an emerging category of afterglow materials, have garnered significant attention due to their stable photophysical and chemical properties, low toxicity, and tunable luminescent energy bands. In recent years, significant progress has been made in the development of stimulus-responsive afterglow CDs, underscoring the need for a systematic summary of this rapidly advancing field. This review summarizes recent advances in CD-based afterglow, encompassing luminescence mechanisms and synthesis strategies. A particular focus is placed on the types of stimulus-responsive afterglow behaviors in CDs, their influence on afterglow performance, and the underlying response mechanisms. The potential applications of these stimulus-responsive afterglow CDs in sensing and information encryption are also discussed in detail. Finally, current challenges and future prospects are outlined, aiming to guide the rational design and development of next-generation stimulus-responsive afterglow CDs.

Achieving thermochromic afterglow (TCAG) in a single material for advanced information encryption remains a significant challenge. Herein, TCAG in carbon dots (CDs)-inked paper (CDs@Paper) is achieved by tuning the temperature-dependent dual-mode afterglow of room temperature phosphorescence (RTP) and thermally activated delayed fluorescence (TADF). The CDs are synthesized through thermal treatment of levofloxacin in melting boric acid with postpurification via dialysis. CDs@Paper exhibit both TCAG and excitation-dependent afterglow color properties. The TCAG of CDs@Paper exhibits dynamic color changes from blue at high temperatures to yellow at low temperatures by adjusting the proportion of the temperature-dependent TADF and phosphorescence. Notably, two-photon afterglow in CDs-based afterglow materials and time-dependent two-photon afterglow colors are achieved for the first time. Moreover, leveraging the opposite emission responses of phosphorescence and TADF to temperature, CDs@Paper demonstrate TCAG with temperature-sensing capabilities across a wide temperature range. Furthermore, a CDs@Paper-based 3D code containing color and temperature information is successfully developed for advanced dynamic information encryption.

AbstractOrganic ultralong room-temperature phosphorescence (RTP) usually emerges instantly and immediately decays after excitation removal. Here we report a new delayed RTP that is postponed by dozens of milliseconds after excitation removal and decays in two steps including an initial increase in intensity followed by subsequent decrease in intensity. The delayed RTP is achieved through introduction of phosphines into carbazole emitters. In contrast to the rapid energy transfer from single-molecular triplet states (T1) to stabilized triplet states (Tn*) of instant RTP systems, phosphine groups insert their intermediate states (TM) between carbazole-originated T1 and Tn* of carbazole-phosphine hybrids. In addition to markedly increasing emission lifetimes by ten folds, since TM → Tn* transition require >30 milliseconds, RTP is thereby postponed by dozens of milliseconds. The emission character of carbazole-phosphine hybrids can be used to reveal information through combining instant and delayed RTP, realizing multi-level time resolution for advanced information, biological and optoelectronic applications.

Carbonized polymer dots (CPDs) with white-light-emitting property have greatly promising application in next generation of lighting and display technologies. However, most of the reported CPD materials exhibit single peak emission and narrow emission band, resulting in difficulty to obtain white-light emission. In this work, the ultrabroadband triple-peak emission (red, green, and blue) CD-based materials with high-efficiency white lightemitting property are realized for the first time by the Forster resonance energy transfer (FRET). Blue and green emissions are derived from the fluorescence and phosphorescence of donor CPDs, while the red light is derived from receptor by FRET. Remarkably, the fabricated CPD materials show bright pure white-light emission with high overall quantum yield (QY) of 36% and the full width at half maximum of 235 nm. Besides, afterglow colors of CPD-based materials can be tuned from green to red by adjusting the ratio of donor and acceptor. Based on the high-efficiency and wide-spectrum pure white light emission characteristics of CPD-based composites, white light emitting diodes were fabricated and they exhibit bright warm white light with CIE and CCT of (0.35, 0.31) and 4041 K.

Multicolor afterglow patterns with transparent and traceless features are important for the exploration of new functionalities and applications. Herein, we report a direct in situ patterning technique for fabricating afterglow carbon dots (CDs) based on laser direct writing (LDW) for the first time. We explore a facile step-scanning method that reduces the heat-affected zone and avoids uneven heating, thus producing a fine-resolution afterglow CD pattern with a minimum line width of 80 μm. Unlike previous LDW-induced luminescence patterns, the patterned CD films are traceless and transparent, which is mainly attributed to a uniform heat distribution and gentle temperature rise process. Interestingly, by regulating the laser parameters and CD precursors, an increased carbonization and oxidation degree of CDs could be obtained, thus enabling time-dependent, tunable afterglow colors from blue to red. In addition, we demonstrate their potential applications in the in situ fabrication of flexible and stretchable optoelectronics.

Achieving a stimulus-responsive, multi-colour, long-lived luminescence based on single-emissive-center carbon dots (CDs) is highly desirable for numerous promising applications. However, the fabrication of such materials remains a formidable challenge because of the limited paths of exciton transfer. Herein, we report a facile strategy to achieve a colour-tuneable afterglow by selectively activating different exciton transfer channels in a carbon dot-cyanuric acid (CA) composite (CD@CA) by alkali induction. Upon alkali treatment, CD@CA exhibited a noticeable afterglow colour change from cyan to yellow with an excellent reversible pH response. Remarkably, the yellow afterglow efficiency is as high as 34.8% and its average lifetime can reach 0.535 s. Detailed analyses revealed the existence of two exciton transport pathways within the system. Excitons can be transduced from CA to CDs via F & ouml;rster resonant energy transfer, leading to a cyan afterglow. In an alkaline environment, this channel was destroyed, and the inherent phosphorescence exciton transport channel of CDs was simultaneously activated and enhanced. Alkali-induced CD ionization and the formation of rigid crystal networks boost intersystem crossing rates and reduce non-radiative transitions, resulting in a bright yellow afterglow. Furthermore, based on the colour-tuneable afterglow properties of the system, we illustrated the potential applications of CD@CA in advanced information encryption. This study provides guidance in the development of multi-colour afterglow materials with stimulus-responsive characteristics to meet the growing demand for highly secure information storage materials. Achieving a colour-tuneable afterglow by selectively activating different exciton transfer channels in a carbon dot-cyanuric acid composite by alkali induction.

Mechano-luminescent materials that exhibit distinct luminescence responses to force stimuli are urgently anticipated in view of application needs in the fields of sensing, anti-counterfeiting, optoelectronic devices, etc. However, most of the reported materials normally exhibit force-induced changes in luminescent intensity, whereas materials that possess force-induced color-variable luminescence remain rarely reported. Herein, for the first time, a novel mechanical force-induced color-variable luminescence material from carbon dots (CDs) in boric acid (CD@BA) is reported. At low CDs concentration, the luminescence of CD@BA exhibits a grinding-induced color variable from white to blue. This grinding-induced color variable can be switched to yellow-to-white changing by increasing the CDs concentration in BA. The grinding-induced color-variable luminescence originates from dynamic variation in emission ratio of fluorescence and room temperature phosphorescence, due to the influence of oxygen and water vapor in the air. At high CDs concentration, short-wavelength fluorescence undergoes more severe reabsorption compared to room temperature phosphorescence, leading to grinding-induced color-variable switching from white-to-blue to yellow-to-white. Based on the unique properties of CD@BA powder, the applications of recognizing and visualizing fingerprints on the surfaces of various of materials are demonstrated.

Multi‐functional wearable electrical materials have been regarded as one of the most pivotal cornerstones for the booming internet of things (IoTs), biomimetic robotics/science, and sensory e‐skins. Nevertheless, customizable, high‐throughput, batch‐fabricated, function‐integrated wearable electronics remain technologically challenging to traditional material engineering. Hereby, a cellulose‐converted active amorphous carbon nanomaterial is developed via a transfer‐free, precursor‐free rapid laser synthesis method incorporating deformation‐tolerant waste papers. The lattice fringe spacing of laser‐synthesized carbon nanoflake is ≈0.305 nm topologically distinct from graphene or carbon dots. The nanostructured three‐dimensional (3D) carbon network exhibits desirable mechanical flexibility, high hygroscopicity/electrical conductivity, large ion storing capacity for Zn 2+ or Na + , high sensitivity to pressure, and a natural microwave absorbing ratio (> 37 dB at the terahertz range). Abundant percolation pathways inside cellulose/carbon composite networks offered fast electrolyte diffusion and carrier mobility. A series of low‐cost highly‐deformable interdigitated supercapacitors, tactile sensors, electrical circuits, and functional coatings are experimentally fabricated and identified, enabling waste paper as a function‐magnified meta platform for e‐skins, wearable energy devices, or IoTs interfaces.

The removal of toxic organic compounds from aqueous media through reduction reactions using nonnoble catalysts has attracted much attention in recent years. In this study, a simple method for the synthesis of pure-phase Ni12P5 nanoparticles supported on N, P-codoped carbon (NPC) sheets was developed, in which a nickel phosphine complex was selected as the precursor due to its high Ni/P ratio, air stability and easy preparation. By controlling the pyrolysis temperature, NixPy@NPC700 with a high dispersity and exposed active sites can be obtained, which was characterized by XRD, HRTEM, EDS, XPS, Raman and NH3-TPD. The catalytic performance of the composite in the reaction of 4-nitrophenol (4-NP) was assessed under mild conditions, exhibiting excellent catalytic activity with a low apparent activation energy E-a (29.87 KJ center dot mol(-1) ). In addition, the catalyst can be recycled without obvious loss of activity for up to ten successive cycles. The outstanding hydrogenation activity is ascribed to the exposed Ni12P5(312) crystal plane of NixPy@NPC700, which is attributed to the lower energy barrier required to form a hydrogen splitting state according to DFT calculations. Moreover, NixPy@NPC700 was creatively coated in a Teflon tube with Nafion as the adhesive and constructed as a fixed-bed device. The continuous-flow catalytic reaction shows that the catalyst can maintain a satisfactory efficiency for approxi-mately 6 h in the reduction of 4-NP and methyl orange (MO). These findings suggest that NixPy@NPC700 is an ideal catalyst for industrial applications for the chemical reduction of toxic compounds from wastewater.

Moisture‐enabled electricity generation (MEG) is highly promising in next‐generation energy conversion. However, the practical applications of existing MEG devices are limited due to their low current and voltage outputs, strong dependence on high moisture, and inflexible nature. Herein, an efficient MEG integrated with flexible, all‐weather, and scalable fabrication characteristics based on the rational combination of carbonized polymer dots (CPDs) and liquid metal (LM) active electrodes is developed for the first time. Remarkably, the fabricated MEG device can produce a stable voltage output of 800 mV and a record high current density of 1640 µA cm −2 . Even at a low air humidity of 15%, the MEG device can provide a high voltage output of 0.65 V and a considerable current density of 12 µA cm −2 . The prompted diffusion of hydrogen ions in CPDs and the additional metal ions ionized from the LM electrode contribute synergistically to the high electricity generation. Additionally, the device can be easily integrated on various flexible substrates and generate an ultrahigh voltage of 210 V to power commercial electronics, showing great potential in large‐scale fabrication and application.

Multi-color phosphorescence carbon dots (CDs) show enormous potential in advanced information encryption, yet the achievement of wide-range, fine-tunable phosphorescence CDs, especially with near-infrared (NIR) phosphorescence emission, confront numerous challenges. Herein, for the first time, the phosphorescence CD-based composites with fine-color tunable property ranging from green to NIR are obtained via regulating CDs contents in annealed boric acid (BA). The synthesized CDs are fully passivated by BA molecular and form uniform surface state, which avoids aggregation-induced quenching to some extent. By increasing the CDs contents in BA during thermal treatment, the aggregation degree of CDs is gradually increased, causing substantial electronic interactions. This leads to energy splitting and form low-energy aggregation states, resulting in phosphorescence continuously shifts from 530 to 555, 585, 625, 645 and 750 nm. Based on aggregation-induced discoloration, we further explore solvent-triggered evolutionary discoloration property of CDs, that is, trace methanol could induce phosphorescence color change from green to red, and illustrate their potential applications in advanced anti-counterfeiting and information encryption.

Benefiting from the large Stokes shift between fluorescence and phosphorescence,fluores-cence/phosphorescence dual-emitting carbon dots(CDs)have gradually entered at the stage of single-phase white light-emitting diodes(WLEDs)as'green material'.However,most of the developed dual-emitting CDs have weak phosphorescence,short emission wavelength and narrow emission band,resulting in relatively bluish white light emission and low color rendering index(CRI).Herein,an ultrabroad-band fluorescence/phosphorescence dual-emitting CD-based material(UB-CD@BA)is pre-pared by thermal treatment of boric acid(BA)and CDs with large conjugated structure.The stable covalent bonding between CDs and BA,as well as three-dimensional spatial restriction effect of self-polymerization BA molecules around CDs during long-term heating efficiently rigidified the single/triplet excited states of CDs from non-radiative deactivation,thus producing strong dual emissive materials with the high phosphorescence quantum yield of 21％.Remarkable,the prepared UB-CD@BA powders exhibit bright pure white light emission with Commission Internationale de l'Eclairage(CIE)coordinates of(0.32,0.33)and the highest reported full width at half maximum of 250 nm.Based on the unique characteristics of UB-CD@BA,it was used as a color conversion layer to prepare a WLED with CIE coordinates of(0.35,0.33)and the CRI value of 87.