Oxygen Radical Coupling on Short-Range Ordered Ru Atom Arrays Enables Exceptional Activity and Stability for Acidic Water Oxidation.

The discovery of efficient and stable electrocatalysts for oxygen evolution reaction (OER) in acid is vital for the commercialization of the proton-exchange membrane water electrolyzer. In this work, we demonstrate that short-range Ru atom arrays with near-ideal Ru-Ru interatomic distances and a unique Ru-O hybridization state can trigger direct O*-O* radical coupling to form an intermediate O*-O*-Ru configuration during acidic OER without generating OOH* species. Further, the Ru atom arrays suppress the participation of lattice oxygen in the OER and the dissolution of active Ru. Benefiting from these advantages, the as-designed Ru array-Co3O4 electrocatalyst breaks the activity/stability trade-off that plagues RuO2-based electrocatalysts, delivering an excellent OER overpotential of only 160 mV at 10 mA cm-2 in 0.5 M H2SO4 and outstanding durability during 1500 h operation, representing one of the best acid-stable OER electrocatalysts reported to date. 18O-labeled operando spectroscopic measurements together with theoretical investigations revealed that the short-range Ru atom arrays switched on an oxide path mechanism (OPM) during the OER. Our work not only guides the design of improved acidic OER catalysts but also encourages the pursuit of short-range metal atom array-based electrocatalysts for other electrocatalytic reactions.

Tailored Fabrication of Full-Color Ultrastable Room-Temperature Phosphorescence Carbon Dots Composites with Unexpected Thermally Activated Delayed Fluorescence.

The development of single-system materials that exhibit both multicolor room-temperature phosphorescence (RTP) and thermally activated delayed fluorescence (TADF) with tunable after glow colors and channels is challenging. In this study, four metal-free carbon dots (CDs) are developed through structural tailoring, and panchromatic high-brightness RTP is achieved via strong chemical encapsulation in urea. The maximum lifetime and quantum yield reaches 2141 ms and 56.55%, respectively. Moreover, CDs-IV@urea, prepared via coreshell interaction engineering, exhibits a dual afterglow of red RTP and green TADF. The degree of conjugation and functional groups of precursors affects the binding interactions of the nitrogen cladding on CDs, which in turn stabilizes triplet energy levels and affects the energy gap between S1 and T1 (ΔEST) to induce multicolor RTP. The enhanced wrapping interaction lowers the ΔEST, promoting reverse intersystem crossing, which leads to phosphorescence and TADF. This strong coreshell interaction fully stabilizes the triplet state, thus stabilizing the material in water, even in extreme environments such as strong acids and oxidants. These afterglow materials are tested in multicolor, time, and temperature multiencryption as well as in multicolor in vivo bioimaging. Hence, these materials have promising practical applications in information security as well as biomedical diagnosis and treatment.

One-Dimensional Non-coplanar Nitrogen Chains in Manganese Tetranitride under High Pressure.

Transition metal nitrides have great potential applications as incompressible and high energy density materials. Various polymeric nitrogen structures significantly affect their properties, contributing to their complex bonding modes and coordination conditions. Herein, we first report a new manganese polynitride MnN4 with bifacial trans-cis [N4]n chains by treating with high-pressure and high-temperature conditions in a diamond anvil cell. Our experiments reveal that MnN4 has a P-1 symmetry and could stabilize in the pressure range of 56-127 GPa. Detailed pressure-volume data and calculations of this phase indicate that MnN4 is a potential hard (255 GPa) and high energy density (2.97 kJ/g) material. The asymmetric interactions impel N1 and N4 atoms to hybridize to sp2-3, which causes distortions of [N4]n chains. This work discovers a new polynitride material, fills the gap for the study of manganese polynitride under high pressure, and offers some new insights into the formation of polymeric nitrogen structures.

Electrocatalytic Activity of CO2 Reduction to CO on Cadmium Sulfide Enhanced by Chloride Anion Doping.

The electrocatalytic CO2 reduction (ECR) to produce valuable fuel is a promising process for addressing atmospheric CO2 emissions and energy shortages. In this study, Cl-anion doped cadmium sulfide structures were directly fabricated on a nickel foam surface (Cl/CdS-NF) using an in situ hydrothermal method. The Cl-anion doping could significantly improve ECR activity for CO production in ionic liquid and acetonitrile mixed solution, compared to pristine CdS. The highest Faradaic efficiency of CO is 98.1 % on a Cl/CdS-NF-2 cathode with an excellent current density of 137.0 mA cm-2 at -2.25 V versus ferrocene/ferrocenium (Fc/Fc+ , all potentials are versus Fc/Fc+ in this study). In particular, CO Faradaic efficiencies remained above 80 % in a wide potential range of -2.05 V to -2.45 V and a maximum partial current density (192.6 mA cm-2 ) was achieved at -2.35 V. The Cl/CdS-NF-2, with appropriate Cl anions, displayed abundant active sites and a suitable electronic structure, resulting in outstanding ECR activity. Density functional theory calculations further demonstrated that Cl/CdS is beneficial for increasing the adsorption capacities of *COOH and *H, which can enhance the activity of the ECR toward CO and suppress the hydrogen evolution reaction.

Removal of Silicon from Magnesite by Flotation: Influence of Particle Size and Mechanical Mechanism.

The feasibility of producing high-density sintered magnesia with a one-step sintering method was investigated by utilizing finely ground magnesite as raw materials for direct flotation. The mechanism of flotation desilication of microfine grain magnesite was investigated by combining microstructure and chemical properties. The results showed that dodecylamine (DDA) has a sorting effect on magnesite reverse flotation desilication. Under the premise of 150 mg/L sodium polyacrylate (PAANa) as an inhibitor and 300 mg/L DDA as a collector, the content and recovery rate of MgO can reach 83.91% and 78.78%, respectively. When sodium oleate (NaOL) was used as a collector, the recovery rate of MgO was only 49.22%; therefore, it is unsuitable for magnesite purification. The flotation effect was affected because MgO particles and SiO2 particles agglomerated in the flotation process. The flotation agent cannot work for a single element but works for the mineral agglomerate. While collecting Si elements, the agglomerated MgO was also brought into the froth layer, making flotation impossible.

Preparation of Self-Coating Al2O3 Bonded SiAlON Porous Ceramics Using Aluminum Dross and Silicon Solid Waste under Ambient Air Atmosphere.

Al2O3-bonded SiAlON ceramic with self-coating was prepared using aluminum dross and silicon solid waste as starting materials under ambient air conditions. The changes in phase, microstructure, and physical properties of the ceramic with temperature were analyzed and the formation mechanism of the SiAlON phase was elucidated. The results showed that higher temperature was more suitable for the preparation of SiAlON ceramics. As the temperature increased from 1400 to 1600 °C, the main phases in the ceramic transformed from mullite, Al2O3, and SiAlON to Al2O3 and SiAlON. An Al2O3-rich layer spontaneously coated the surface of the porous ceramic as Al melted and oxidized at high temperature. The thickness of this layer decreased as the temperature increased. The presence of Al2O3-rich coating layer impeded air flow, allowing nitriding of Si and Al, and the formation of the SiAlON phase in ambient air conditions. This study not only presents a strategy to successfully recycle aluminum dross and silicon solid waste but also offers a straightforward approach to preparing SiAlON material in air atmosphere.

A Fe Single Atom Seed-Mediated Strategy Toward Fe3 C/FeNC Catalysts with Outstanding Bifunctional ORR/OER Activities.

The discovery of low-cost and high-performance bifunctional oxygen electrocatalysts is vital to the future commercialization of rechargeable zinc-air batteries (ZABs). Herein, a Fe single atom seed-mediated strategy is reported for the fabrication of Fe3 C species closely surrounded by FeN4 C active sites with strong electronic interactions built between them and more importantly, creating optimized coordination environment, via subtly adjusting their ratio, for favorable adsorption energies of oxygen intermediates formed during oxygen reduction reaction (ORR) and oxygen evolution reaction (OER). Concretely, the voltage difference (ΔE) between the ORR half-wave and OER potential at a current density of 10 mA cm-2 for the compositionally-optimized FeNC/Fe3 C-op electrocatalyst is only 0.668 V, endowing itself one of the best bifunctional OER/ORR benchmarks. As a demo, ZABs assembled with FeNC/Fe3 C-op as the air cathode deliver a remarkable specific capacity (818.1 mAh gZn -1 ) and a power density (1013.9 mWh gZn -1 ), along with excellent long-term durability (>450 h). This work extends the methodology to modulate the activity of FeN4 C atomic site, undoubtedly inspiring wide explorations on the precise design of bifunctional oxygen electrocatalysts.

Enhanced the Efficiency of Electrocatalytic CO2 -to-CO Conversion by Cd Species Anchored into Metal-Organic Framework.

Metal-organic frameworks (MOFs) as a promising platform for electrocatalytic CO2 conversion are still restricted by the low efficiency or unsatisfied selectivity for desired products. Herein, zirconium-based porphyrinic MOF hollow nanotubes with Cd sites (Cd-PCN-222HTs) are reported for electrocatalytic CO2 -to-CO conversion. The dispersed Cd species are anchored in PCN-222HTs and coordinated by N atoms of porphyrin structures. It is discovered that Cd-PCN-222HTs have glorious electrocatalytic activity for selective CO production in ionic liquid-water (H2 O)-acetonitrile (MeCN) electrolyte. The CO Faradaic efficiency (FECO ) of >80% could be maintained in a wide potential range from -2.0 to -2.4 V versus Ag/Ag+ , and the maximum current density could reach 68.0 mA cm-2 at -2.4 V versus Ag/Ag+ with a satisfied turnover frequency of 26 220 h-1 . The enhanced efficiency of electrocatalytic CO2 conversion of Cd-PCN-222HTs is closely related to its hollow structure, anchored Cd species, and good synergistic effect with electrolyte. The density functional theory calculations indicate that the dispersed Cd sites anchored in PCN-222HTs not only favor the formation of *COOH intermediate but also hinder the hydrogen evolution reaction, resulting in high activity of electrocatalytic CO2 -to-CO conversion.

Brightening Blue Photoluminescence in Nonemission MOF-2 by Pressure Treatment Engineering.

As equally essential as the synthesis of new materials, maneuvering new structure configurations can endow the brand-new functional properties to existing materials, which is also one of the core goals in the synthesis community. In this respect, pressure-induced emission (PIE) that triggers photoluminescence (PL) in nonemission materials is an emerging stimuli-responsive smart materials technology. In the PIE paradigms, harvesting bright PL at ambient conditions, however, has remained elusive. Herein, a remarkable PIE phenomenon is reported in initially nonemission Zn(BDC)(DMF)(H2 O) (MOF-2), which shows bright blue-emission at 455 nm under pressure. Intriguingly, the bright blue PL with an excellent photoluminescence quantum yield up to 70.4% is unprecedentedly retained to ambient conditions upon decompression from 16.2 GPa. The detailed structural analyses combined with density functional theory calculations reveal that hydrogen bonding cooperativity effect elevates powerfully the rotational barrier of the linker rotor to 3.87 eV mol-1 from initial 0.91 eV mol-1 through pressure treatment. The downgrade rotational freedom turns on PL of MOF-2 after releasing pressure completely. This is the first case of harvesting PIE to ambient conditions. These findings offer a new platform for the creation of promising alternatives to high-performance PL materials based on initially nonemission counterparts.

Electron Delocalization of Au Nanoclusters Triggered by Fe Single Atoms Boosts Alkaline Overall Water Splitting.

The rational design and in-depth understanding of the structure-activity relationship (SAR) of hydrogen and oxygen evolution reaction (HER and OER) bifunctional electrocatalysts are vital to decreasing the energy consumption of hydrogen production by electrochemical water splitting. Herein, we report an inducing electron delocalization method where Fe single atoms as inducers are used to regulate the electron structure of Au nanoclusters by the M-Nx-C substrate to acquire satisfactory intrinsic HER activity. Meanwhile, Fe single atoms also serve as efficient OER active sites to construct bifunctional electrocatalysts. On account of the strong synergistic effect between Au nanoclusters and Fe single atoms, the hybrid catalyst Au-Fe1NC/NF performs an outstanding alkaline HER and OER activity. Only 35.6 mV, 246 mV, and 1.52 V are needed to reach 10 mA cm-2 for alkaline HER, OER, and two-electrode electrolytic cells, respectively. In addition, the bifunctional electrocatalysts also display excellent electrochemical stability. DFT calculations demonstrate that the strong synergistic effect can enhance the O-H bond activation ability of Au nanoclusters and upshift the d-band center of the Fe single atom to promote alkaline electrocatalytic water splitting. The strong synergistic effect is proven to arise from the electron delocalization of Au nanoclusters triggered by Fe single atoms.

Solid-state Fluorescence from Carbon Dots Widely Tunable from Blue to Deep Red through Surface Ligand Modulation.

Carbon dots (CDs) find widespread attention due to their remarkable fluorescent and electronic properties. However, aggregation-caused quenching currently limits the application of CDs in colored displays. The construction of CDs with color-tunable solid-state fluorescence (SSF) is rarely reported, since the preparation of SSF CDs is technically challenging. Herein, through surface ligand modulation, SSF CDs with an emission-color span of almost 300 nm (from blue to deep red) were obtained. In-depth structure-property studies reveal that intra- and inter-molecular hydrogen-bonding inside SSF CDs provokes the emission properties in the aggregated state. Photodynamic characterizations demonstrate emission wavelengths can be switched smoothly by deliberately altering conjugation ability between substituent ligands and CDs core. Three-dimensional printing patterning is used to create a range of emissive objects, demonstrating the commercial potential for use in optical lamps.

Full-Color Circularly Polarized Luminescence of CsPbX3 Nanocrystals Triggered by Chiral Carbon Dots.

Chiral carbon dots (Ch-CDs) trigger the full-color circularly polarized luminescence (CPL) of CsPbX3  nanocrystals (NCs). Ch-CDs-CsPbBr3  NCs are successfully synthesized via simple ligand-assisted coprecipitation of Ch-CDs and metal halides precursors at room temperature. Ch-CDs-CsPbBr3  retains emission characteristics of the CsPbBr3  with near-unity photoluminescence quantum yield, and meanwhile has special CPL, with a maximum luminescence dissymmetric factor (glum ) of -3.1 × 10-3 , which is induced by Ch-CDs. This is the first report of chiral perovskite which is induced by other chiral nanomaterials. By anion exchange, CPL can cover almost the entire visible light band. Surprisingly, the chiral signal of Ch-CDs-CsPbBr3  NCs is in-versed under excitation state, which can be induced by the charge transfers between Ch-CDs and perovskite NCs. The combination of perovskites and Ch-CDs pave away for the design of new chiral perovskite on multifunctional applications.

Photoluminescence mechanisms of red-emissive carbon dots derived from non-conjugated molecules.

Red-emissive carbon dots (R-CDs) have been widely studied because of their potential application in tissue imaging and optoelectronic devices. At present, most R-CDs are synthesized by using aromatic precursors, but the synthesis of R-CDs from non-aromatic precursors is challenging, and the emission mechanism remains unclear. Herein, different R-CDs were rationally synthesized using citric acid (CA), a prototype non-aromatic precursor, with the assistance of ammonia. Their structural evolution and optical mechanism were investigated. The addition of NH3·H2O played a key role in the synthesis of CA-based R-CDs, which shifted the emission wavelength of CA-based CDs from 423 to 667 nm. Mass spectrometry (MS) analysis indicated that the amino groups served as N dopants and promoted the formation of localized conjugated domains through an intermolecular amide ring, thereby inducing a significant emission redshift. The red-emissive mechanism of CDs was further confirmed by control experiments using other CA-like molecules (e.g., aconitic acid, tartaric acid, aspartic acid, malic acid, and maleic acid) as precursors. MS, nuclear magnetic resonance characterization, and computational modeling revealed that the main carbon chain length of CA-like precursors tailored the cyclization mode, leading to hexatomic, pentatomic, unstable three/four-membered ring systems or cyclization failure. Among these systems, the hexatomic ring led to the largest emission redshift (244 nm, known for CA-based CDs). This work determined the origin of red emission in CA-based CDs, which would guide research on the controlled synthesis of R-CDs from other non-aromatic precursors.

Self-Supporting Carbon Nanofibers with Ni-Single-Atoms and Uniformly Dispersed Ni-Nanoparticles as Scalable Multifunctional Hosts for High Energy Density Lithium-Sulfur Batteries.

The energy density of lithium-sulfur batteries (LSBs) is currently hampered by modest sulfur loadings and high electrolyte/sulfur ratios (E/S). These limitations can potentially be overcome using easy-to-infiltrate sulfur hosts with high catalytic materials. However, catalytic materials in such hosts are very susceptible to agglomeration due to the lack of efficient confinement in easy-to-infiltrate structures. Herein, using carbon dots as an aggregation limiting agent, the successful fabrication of self-supporting carbon nanofibers (CNF) containing Ni-single-atoms (NiSA ) and uniformly dispersed Ni-nanoparticles (NiNP ) of small sizes as multifunctional sulfur hosts is reported. The NiSA sites coordinated by such NiNP offer outstanding catalytic activity for sulfur reactions and CNF is an easy-to-infiltrate sulfur host with a large-scale preparation method. Accordingly, such hosts that can be prepared on a large scale enable sulfur cathodes to exhibit high sulfur utilization (66.5 mAh cm-2 at ≈0.02 C) and cyclic stability (≈86.1% capacity retention after 100 cycles at ≈0.12 C) whilst operating at a high sulfur loading (50 mg cm-2 ) and low E/S (5 µL mg-1 ). This work provides a blueprint toward practical LSBs with high energy densities.

Electron-phonon coupling-assisted universal red luminescence of o-phenylenediamine-based carbon dots.

Due to the complex core-shell structure and variety of surface functional groups, the photoluminescence (PL) mechanism of carbon dots (CDs) remain unclear. o-Phenylenediamine (oPD), as one of the most common precursors for preparing red emissive CDs, has been extensively studied. Interestingly, most of the red emission CDs based on oPD have similar PL emission characteristics. Herein, we prepared six different oPD-based CDs and found that they had almost the same PL emission and absorption spectra after purification. Structural and spectral characterization indicated that they had similar carbon core structures but different surface polymer shells. Furthermore, single-molecule PL spectroscopy confirmed that the multi-modal emission of those CDs originated from the transitions of different vibrational energy levels of the same PL center in the carbon core. In addition, the phenomenon of "spectral splitting" of single-particle CDs was observed at low temperature, which confirmed these oPD-based CDs were unique materials with properties of both organic molecules and quantum dots. Finally, theoretical calculations revealed their potential polymerization mode and carbon core structure. Moreover, we proposed the PL mechanism of red-emitting CDs based on oPD precursors; that is, the carbon core regulates the PL emission, and the polymer shell regulates the PL intensity. Our work resolves the controversy on the PL mechanism of oPD-based red CDs. These findings provide a general guide for the mechanism exploration and structural analysis of other types of CDs.

Which kind of nitrogen chemical states doped carbon dots loaded by g-C3N4 is the best for photocatalytic hydrogen production.

Recently, g-C3N4 (CN) loaded N-doped carbon dots (NCDs) have been widely studied as promising metal-free photocatalysts due to their impressive performance in hydrogen production. However, deep understanding of the effect of nitrogen chemical states on photocatalytic activity is still lacked. In this work, NCDs doped with pyrrole nitrogen, graphite/pyrrole nitrogen, and pyrrole/pyridine nitrogen were prepared and hybridized with g-C3N4. The characterizations revealed that, incorporation of pyrrole N-doped CDs into g-C3N4 (CN/NCDs-en) effectively enhanced the visible light absorption, facilitated electron-hole separation, and promoted the participation of photoexcited electrons in H2 evolution reaction. Moreover, theoretical calculation showed that, compared with graphite N and pyridine N, pyrrole N has the most appropriate H adsorption ability, which is conducive to the H2 formation. Under visible light irradiation, the CN/NCDs-en exhibited the best hydrogen evolution of 3028 µmol h-1 g-1. These results shed a light on the design and optimization of N-doped metal-free photocatalysts for H2 evolution reaction.

Identification and construction of a 13-gene risk model for prognosis prediction in hepatocellular carcinoma patients.

We attempted to screen out the feature genes associated with the prognosis of hepatocellular carcinoma (HCC) patients through bioinformatics methods, to generate a risk model to predict the survival rate of patients. Gene expression information of HCC was accessed from GEO database, and differentially expressed genes (DEGs) were obtained through the joint analysis of multi-chip. Functional and pathway enrichment analyses of DEGs indicated that the enrichment was mainly displayed in biological processes such as nuclear division. Based on TCGA-LIHC data set, univariate, LASSO, and multivariate Cox regression analyses were conducted on the DEGs. Then, 13 feature genes were screened for the risk model. Also, the hub genes were examined in our collected clinical samples and GEPIA database. The performance of the risk model was validated by Kaplan-Meier survival analysis and receiver operation characteristic (ROC) curves. While its universality was verified in GSE76427 and ICGC (LIRI-JP) validation cohorts. Besides, through combining patients' clinical features (age, gender, T staging, and stage) and risk scores, univariate and multivariate Cox regression analyses revealed that the risk score was an effective independent prognostic factor. Finally, a nomogram was implemented for 3-year and 5-year overall survival prediction of patients. Our findings aid precision prediction for prognosis of HCC patients.

Exosome Marker Proteins of Tumor-Associated Fibroblasts and Exosome-Derived miR-92a-3p Act as Potential Biomarkers for Liver Cancer.

Many recent studies have shown that microRNAs (miRNAs) in exosomes can be absorbed by nearby or distant cells, and the abnormal expression of these exosomal miRNAs is associated with most pathological progresses. In this study, we explored the diagnostic value of exosome marker proteins and exosome-derived miR-92a-3p in liver cancer. The clinicopathological data of 60 patients with liver cancer admitted to Tanghan Gongren Hospital from October 2017 to October 2019 were collected. Tumor tissue and adjacent tissue were collected during surgery. Quantitative reverse transcription polymerase chain reaction and Western blot were used to detect the expression levels of miR-92a-3p in exosomes of fibroblasts and tumor tissue, and exosome marker proteins. In liver cancer tissue and fibroblast exosomes, the expression of miR-92a-3p was significantly increased. The receiver operator characteristic curve of the expression level of miR-92a-3p in exosomes and tissue showed that the area under the curve was 0.906 and 0.911, respectively. HSP70 and CD63 were highly expressed in the tissue of liver cancer and fibroblast exosomes. miR-92a-3p was positively correlated with HSP70 and CD63 in the exosomes of liver cancer fibroblasts. In addition, miR-92a-3p and exosome marker proteins (HSP70 and CD63) were highly expressed in tumors with a diameter greater than 5 cm, and were higher in liver cancer patients with BCLC stage B/C. Tumor fibroblast-derived exosome marker proteins and miR-92a-3p have good diagnostic value in liver cancer, indicating that they may be new diagnostic markers for liver cancer.

m5C RNA methyltransferase-related gene NSUN4 stimulates malignant progression of hepatocellular carcinoma and can be a prognostic marker.

Hepatocellular carcinoma (HCC) is a cancer with relatively high mortality, yet little attention has been devoted for related prognostic biomarkers. This study analyzed differential expression of m5C RNA methyltransferase-related genes in normal samples and tumors samples in TCGA-LIHC using Wilcoxon test. K-means consensus clustering analysis was implemented to subdivide samples. Independent prognostic factors were screened by univariate and multivariate Cox regression analyses. KEGG pathway enrichment analysis was performed on the screened independent prognostic factor using GSEA tools. qPCR was conducted to test mRNA expression of key m5C RNA methyltransferase-related genes in tissues and cells. There were 7 m5C RNA methyltransferase-related genes (NOP2, NSUN4, etc.) differentially expressed in HCC tumor tissues. HCC samples were classified into 3 subgroups through clustering analysis according to the expression mode of m5C RNA methyltransferase-related genes. It was also discovered that patients in different subgroups presented significant differences in survival rate and distribution of grade. Additionally, NOP2, NSUN4 and NSUN5 expression notable varied in different grades. Through regression analyses combined with various clinical pathological factors, it was displayed that NSUN4 could work as an independent prognostic factor. KEGG analysis showed that NSUN4 mainly enriched in signaling pathways involved in ADHERENS JUNCTION, RNA DEGRADATION, MTOR SIGNALING PATHWAY, COMPLEMENT and COAGULATION CASCADES. As examined by qPCR, NSUN4 was conspicuously upregulated in HCC patient's tissues and cells. Altogether, our study preliminarily developed a novel biomarker that could be independently used in prognosis of HCC, which may provide a new direction for the study of related molecular mechanism or treatment regimen.

Solid-State Red Laser with a Single Longitudinal Mode from Carbon Dots.

Miniaturized solid-state lasers with a single longitudinal mode are vital for various photonic applications. Here we prepare red-emissive carbon dots (CDs) with a photoluminescence quantum yield (PLQY) of 65.5 % by combining graphitic nitrogen doping and surface modification. High-concentration doping alters the CDs' emission from blue to red, while the electron-donating groups and polymer coating on their surfaces improve the PLQY and photostability. The CDs exhibit excellent stimulated emission characteristics, with a low threshold of amplified spontaneous emission (ASE) and long gain lifetime. A planar microcavity with only one resonant mode, which fitted with the CDs' ASE peak, was constructed. Combining the CDs and microcavity produced a solid-state laser with a single longitudinal mode, a linewidth of 0.14 nm and a signal-to-noise ratio of 14.8 dB (Q∼4600). Our results will aid the development of colorful solid-state micro/nano lasers with potential use in practical photonics.