Atomic Electron Research Articles

First-principle study on the photoelectric properties of monolayer h-BN under different strain types.

Two-dimensional materials are a new and promising research field in materials science. This is mainly attributed to their unique photoelectric and chemical properties. In addition to possessing unique optoelectronic and chemical properties, two-dimensional materials also have important application prospects in the field of field-effect devices. Based on density functional theory, the effects of uniaxial strain and equibiaxial strain on the mechanical properties, electronic structure, and optical properties of monolayer h-BN were studied using first principles. The results indicate that compressive strain has a significant impact on the stability of monolayer h-BN. The band gap width of monolayer h-BN decreases with increasing strain, and the optical properties of monolayer h-BN exhibit a relative trend under tensile and compressive strains. The influence of biaxial strain on the mechanical properties, electronic structure, and optical properties of monolayer h-BN is greater than that of uniaxial strain. All the calculations were done by the VASP software based on density functional theory. The interaction between atomic nuclei and electrons is described by the projected added wave pseudopotential (PAW), using the generalized gradient approximation (GGA) to exchange the Perdew-Burke-Ernzerhof (PBE) of the functional. To avoid interlayer interactions, a 15-Å vacuum layer was set up. The Brillouin zone selects the Monkhorst-Pack method to generate 9 × 9 × 1 of k-point grid, the cut off energy is set to 500eV, the energy convergence standard of the system is 1 × 10-5eV, and the interaction force between atoms is 0.01eV/Å.

The impact of environmentally friendly supramolecular coordination polymers as carbon steel corrosion inhibitors in HCl solution: synthesis and characterization

Two 3D-supramolecular coordination polymers (SCP1 & SCP2) have been synthesized and characterized by physicochemical and spectroscopic methods. In a solution of 1.0 M HCl, SCPs were used to prevent corrosion of carbon steel (CS). The inhibition productivity (%η) rises as the synthetic inhibitor dose rises, and the opposite is true as the temperature rises. The study was carried out using chemical (mass loss, ML) and electrochemical ( potentiodynamic polarization, PDP and electrochemical impedance microscopy, EIS) techniques, which showed %η reached to 93.1% and 92.5% for SCP1 & SCP2, respectively at 21 × 10−6 M, 25 °C. For the polarization results, SCPs behave as mixed-type inhibitors. With increasing doses of SCPs, the charge transfer resistance grew and the double layer's capacitance lowered. The creation of a monolayer on the surface of CS was demonstrated by the finding that the adsorption of SCPs on its surface followed the Henry adsorption isotherm. The parameters of thermodynamics were computed and explained. The physical adsorption of SCPs on the surface of CS is shown by the lowering values of free energy (∆Goads < − 20 kJ mol−1) and increasing the activation energy (E*a) values in presence of SCP1 & SCP2 than in their absence. Atomic force microscope (AFM) and scanning electron microscopy (SEM) demonstrated the development of a protective thin film of SCPs precipitated on the surface of CS. There is a strong matching between results obtained from experimental and theoretical studies. Results from each approach that was used were consistent.

Iodinated Electron Acceptor with Significantly Extended Exciton Diffusion Length for Efficient Organic Photovoltaic Cells.

Iodination has unlocked new potentials in organic photovoltaics (OPVs). A newly designed and synthesized iodinated non-fullerene acceptor, BO-4I, showcases exceptional excitation delocalization property with the exciton diffusion length increased to 80 nm. The enhanced electron delocalization property is attributed to the larger atomic radius and electron orbit of the iodine atom, which facilitates the formation of intra-moiety excitations in the acceptor phase. This effectively circumvents the charge transfer state-related recombination mechanisms, leading to a substantial reduction in non-radiative energy loss (ΔEnr ). As a result, OPV cell based on PBDB-TF : BO-4I achieves an impressive efficiency of 18.9 % with a notable ΔEnr of 0.189 eV, markedly surpassing their fluorinated counterparts. This contribution highlights the pivotal role of iodination in reducing energy loss, thereby affirming its potential as a key strategy in the development of advanced next-generation OPV cells.

Iodinated Electron Acceptor with Significantly Extended Exciton Diffusion Length for Efficient Organic Photovoltaic Cells

AbstractIodination has unlocked new potentials in organic photovoltaics (OPVs). A newly designed and synthesized iodinated non‐fullerene acceptor, BO‐4I, showcases exceptional excitation delocalization property with the exciton diffusion length increased to 80 nm. The enhanced electron delocalization property is attributed to the larger atomic radius and electron orbit of the iodine atom, which facilitates the formation of intra‐moiety excitations in the acceptor phase. This effectively circumvents the charge transfer state‐related recombination mechanisms, leading to a substantial reduction in non‐radiative energy loss (ΔEnr). As a result, OPV cell based on PBDB‐TF : BO‐4I achieves an impressive efficiency of 18.9 % with a notable ΔEnr of 0.189 eV, markedly surpassing their fluorinated counterparts. This contribution highlights the pivotal role of iodination in reducing energy loss, thereby affirming its potential as a key strategy in the development of advanced next‐generation OPV cells.

Adhesion of electron-beam evaporated SiO2/TiO2 anti-reflective coating on ion-treated polycarbonate substrate under xenon arc accelerated weathering test

Anti-reflective (AR) coatings on polymer substrates enhance light transmittance and minimize reflectance loss. However, durability of multi-layered AR coatings on polymer substrates under various weathering conditions (temperature, radiation, and humidity) can be challenging and affecting adhesion of the coating to the substrate. Therefore, in the present work, Xenon arc accelerated weathering test followed ISO 16474 guidelines was used to investigate durability of electron-beam evaporated SiO2/TiO2 stacking layer as the AR coating on an ion-treated polycarbonate (PC) substrate by varying anode voltage of the ion treatment, oxygen flow rate during the treatment, and thickness of a binding layer (Chromium-based alloy) sandwiched between AR coating and PC substrate. Crosshatch tape test based on ASTM D3359 was used to evaluate the adhesion performance. Physical changes of ion-treated PC surface were characterized by atomic force microscopy and scanning electron microscopy, whereas Fourier transform infrared spectroscopy was adopted to identify chemical functional groups on the treated PC surface. Residual stress and optical reflection of AR coating on the PC were measured by laser interferometry and UV–Vis spectrophotometry, respectively. As anode voltage increased with no oxygen flow, average surface roughness of PC increased but the roughness decreased as oxygen flow rate increased when the highest anode voltage (100 V) was applied. A reversed trend of the roughness achieved with the lowest anode voltage (80 V). Amount of C–O functional group on treated PC increased when the average surface roughness decreased. The adhesion improved by incorporating a binding layer, depending on anode voltage and oxygen flow rate, that can alter residual compressive stress of the material system, reduce moisture and UV attack without sacrificing optical performance of the AR coating. Generally, a better AR coating adhesion can be achieved with smoother PC surface having higher amount of C–O bonding, and higher overall residual compressive stress.

Corrosion inhibition mechanisms of triazole derivatives on copper chemical mechanical polishing: Combined experiment and DFT study

The impact of triazole derivative groups on corrosion inhibition performance of copper (Cu) film is studied by using 3-amino-1,2,4-triazole-5-carboxylicacid (ATA-O), 1H-1,2,4-triazole-3,5-diamine (ATA-N) and 3-amino-5-mercapto-1,2,4-triazole (ATA-S) as environment-friendly inhibitors. Electrochemical analysis showed that anti-corrosion passivation layer is formed on Cu surface after adding inhibitors with high inhibition efficiency of 54 %, 87 % and 98 % respectively, and improve the surface quality which is verified by atomic force microscope (AFM) and scanning electron microscopy (SEM) tests. Such results are consisted with static etch experiments. The mechanism of corrosion inhibition was revealed by theoretical calculation, which prove that the lone electron pair in empty orbitals of the O, N, S atoms on inhibitors hybridize with the Cu-d orbital to form covalent bonds and enhance the adsorption passivation action. Such study dissects the reasons for the potent inhibitory effect of triazole derivatives at the atomic level, and provides new method for efficient selection of inhibitors.

Enhancement of NiO/Si solar cell by adding porous silicon and a silicon dioxide SiO2 carrier selective layer

In this work, we fabricated a novel heterojunction, Silicon-based solar cell. We used nickel oxide NiO thin films on porous silicon PS separated by a thin silicon dioxide SiO2 carrier-selective layer p-NiO/(SiO2) PS/(n+) Si (Silicon). For comparison, we also manufactured a p-NiO/(n+) Si device. The Atomic Force microscopy AFM and scanning electron microscopy SEM images highlighted the nanoporous pyramidal like structures for p-NiO/(SiO2) PS/(n+) Si devices that decreased the optical reflectivity to 2 %. From the electrochemical study, low resistance and high minority carrier lifetime (1.44 ms) were estimated for p-NiO/(SiO2) PS/n+-Si. The results are promising and agree with a high power conversion efficiency of 19.52 % for p-NiO/(SiO2) PS/n+-Si versus 3.8 % for p-NiO/Si.

Tuning the atomic and electronic structures of mirror twin boundaries in molecular beam epitaxy grown MoSe2 monolayers via rhenium doping

Interplay between defects like mirror twin boundaries (MTBs) and dopants may provide additional opportunities for furthering the research on two-dimensional monolayer (ML) transition metal dichalcogenides. In this work, we successfully dope rhenium (Re) into molecular beam epitaxy grown ML MoSe2 and confirm the formation of a new type of MTBs, named 4|4E-M (M represents metal, Mo/Re) according to the configuration. Data from statistic atomic resolution scanning transmission electron microscopy also reveals a preferable MTB enrichment of Re dopants, rather than intra-domain. In conjunction with density functional theory calculation results, we propose the possible routes for Re doping induced formation of 4|4E-M MTBs. Electronic structures of Re doped MTBs in ML MoSe2 are also predicted theoretically and then preliminarily tested by scanning tunneling microscopy and spectroscopy.

Pure and barium substituted bismuth ferrite as ethanol gas sensor

Pure and Barium substituted bismuth ferrite thin films are developed on glass substrate via spray pyrolysis technique. The outcome of barium substitution to bismuth ferrite for the ethanol gas detecting capability is carried out in this study. The Energy Dispersive X-Ray (EDS) results confirmed the occurrence of Barium, Bismuth and Ferrous in the developed thin film. The X-Ray Diffraction (XRD) results confirmed the perovskite structure of the bismuth ferrite thin film. The modification of the surface roughness and particle sizes are seen in the developed thin film from the results of Atomic Force Microscopy (AFM) and Field Emission Scanning Electron Microscopy (FESEM). The gas sensing characterization carried out on the developed thin films disclose that, it is more selective to ethanol gas. It is found that operating temperature at which the gas is detected, reduced with barium substitution. The results obtained from the characterization study confirm that the developed thin films can be used for ethanol gas sensing applications.

Undergraduate students’ models of single- and multi-electron atoms

ABSTRACT Quantum physics forms the basis for exciting new technologies, including quantum computers, quantum encryption, and quantum entanglement. The advancement of science and technology highlights the importance of mastering quantum physics and its applications, not only at the college level but also as early as high school. In this multiple case study, we investigated first- and second-year undergraduate college students’ models of single and multi-electron atoms after completing a modern mechanics course, which addressed basic QM topics. The students’ models were categorised into four primary categories: the discrete entity (particle) model, hybrid model, quantum-like model, and quantum model, and subcategories for atom structure and electron attribution and motion. Despite being introduced to quantum concepts in high school and first-year undergraduate calculus-based physics classes, many students constructed incomplete, inaccurate, or incoherent models. Seven of eight students’ atomic structure models and six of eight students’ electron attribution and motion models were classified as discrete entity and hybrid models. The findings of this study reveal students’ conceptual challenges in explaining the structure of single and multiple-electron atoms and shed light on the factors contributing to the persistent difficulties in their understanding of atomic structure in the realm of quantum mechanics.

Insights into the Heterogeneous Nuclei of an Ultrafast‐Crystallizing Glassy Solid

AbstractCrystallization determines the programming speed of phase‐change memory devices; while, the nucleation phenomenon of many phase‐change materials (PCMs) is not entirely understood, especially concerning the atomic structures and dynamic behaviors of the subcritical nuclei. This is undoubtedly an insurmountable challenge for scandium antimony telluride (ScxSb2Te3) PCM as its subnanosecond‐crystallization nature impedes the real‐time observation of the transient nucleation process. To solve the puzzle, atomic probe tomography and transmission electron microscopy are employed to circumvent the technical difficulties; for the first time, the atomistic information of the heterogeneous nuclei in ScxSb2Te3 is unveiled, such as enriched Sc ≈ 25 at% in core composition, ≈1.0 nm in geometric size, and ≈1023–1024 m−3 in spatial density. The unique nanoscale chemical inhomogeneity ensures the unusual stabilities and dynamics of the early‐stage nuclei, reinforcing them to survive the melt‐quenching action and greatly suppressing the nucleating randomness, thereby facilitating simultaneous and prompt crystal growth throughout the amorphous phase to achieve ultrafast crystallization. The present study offers a new insight into the nonclassical pathways, which will improve understanding and promote better regulation of the nucleation phenomenon in functional materials.

Microstructural and compositional evolutions in γ-LiAlO2 pellets during ion irradiation at an elevated temperature

This study reports on the microstructural, phasic and compositional evolutions of γ-LiAlO2 during ion irradiation. Polycrystalline γ-LiAlO2 pellets were irradiated sequentially with He+ and D2+ ions to the same combined fluences of up to 3 × 1017 (He++D+)/cm2 at 773 K. The irradiated pellets were characterized using scanning transmission electron microscopy and atom probe tomography. Surface amorphization likely due to radiolysis and planar defects as a possible precursor for formation of precipitates are created at 5 × 1016 (He++D+)/cm2, followed by the formation of nano-sized precipitates and fractures at higher doses. Spinel-like precipitates of non-stoichiometric LiAl5O8 and gas-filled cavities are observed to grow with increasing dose. Faceted precipitates and rounded cavities appear at 2 × 1017 (He++D+)/cm2. With further increasing ion fluence to 3 × 1017 (He++D+)/cm2, amorphization of the precipitates takes place and micron-sized fractures appear. Surface exfoliation could occur at an extremely high ion fluence. There are compositional changes in the γ-LiAlO2 pellets during the microstructural evolution. In the precipitate and amorphized regions, Li concentrations decrease to ∼7 and 3.7 at.% from 25 at.% in γ-LiAlO2, respectively. This study reveals a full-cycle microstructural evolution with corresponding compositional changes in γ-LiAlO2 pellets during ion irradiation at 773 K. The data could help model, assess, and predict the material performance during neutron irradiation in reactors.

Impacts of atmospheric deposition on the heavy metal mobilization and bioavailability in soils amended by lime

Atmospheric deposition is an important source of heavy metal in agricultural soils, but there is limited research on the mobility of these metals in soil and their impact on soil amendment. Here, we performed a dust incubation experiment in soils in the laboratory and a factorial transplant experiment at three field sites with a gradient of atmospheric deposition to examine the impacts of atmospherically deposited heavy metals (Cu, Cd, and Pb) on the mobility and bioavailability in soils with and without lime applications. Results showed that the atmospherically deposited heavy metals showed high mobility and were primarily presented in the soluble ionic fractions in the wet part and acid-exchangeable and reducible fractions in the dry part of atmospheric deposition. Atmospheric dust addition caused the 2p3/2 and 2p1/2 electrons of Cu atoms in uncontaminated soils to transition the 3d vacant states, resulting in similar copper absorption peaks as atmospheric particles by the observation of X-ray absorption near-edge spectroscopy (XANES). In the field, atmospheric deposition can only increase the mobile fractions in the surface soils, but not in the deeper layers. However, the deposition can increase the soluble and diffusive gradients in thin films (DGT)-measured bioavailable fractions in profile along with the soil depth. Lime applications cannot significantly reduce the mobile fractions of heavy metals in the surface soils exposed to atmospheric deposition, but significantly reduce the heavy metal concentrations in soil solutions and the DGT-measured bioavailable concentrations, particularly in the deeper layer (6–10 cm). The major implication is that atmospherically deposited heavy metals can significantly increase their bioavailable concentrations in the plough horizon of soil and constrain the effects of soil amendments on heavy metal immobilization, thereby increasing the risks of crop uptake.

Natural-Origin Betaine Surfactants as Promising Components for the Stabilization of Lipid Carriers.

In the present work, we demonstrate studies involving the influence of the formulation composition on the physicochemical properties of nanocarriers: solid lipid nanoparticles (SLNs) and nanostructured lipid carriers (NLCs). Novel lipid-origin platforms were prepared using two "green" betaine-based surfactants, cocamidopropyl betaine (ROKAmina K30) and coco betaine (ROKAmina K30B), in combination with three different solid lipids, cetyl palmitate (CRODAMOL CP), trimyristin (Dynasan 114), and tristearin (Dynasan 118). Extensive optimization studies included the selection of the most appropriate lipid and surfactant concentration for effective SLN and NLC stabilization. The control parameters involving the hydrodynamic diameters of the obtained nanocarriers along with the size distribution (polydispersity index) were determined by dynamic light scattering (DLS), while shape and morphology were evaluated by atomic force microscopy (AFM) and transmission electron microscopy (TEM). Electrophoretic light scattering (ELS) and turbidimetric method (backscattering profiles) were used to assess colloidal stability. The studied results revealed that both betaine-stabilized SLN and NLC formulations containing CRODAMOL CP as lipid matrix are the most monodisperse and colloidally stable regardless of the other components and their concentrations used, indicating them as the most promising candidates for drug delivery nanosystems with a diverse range of potential uses.

Improvement of nuclear photon and neutron shielding performance of Tm2O3 and Dy2O3 doped ceramics: An experimental study

In this study, 60KAlSi3O8+10Al2Si2O5(OH)4+(30-x)SiO2+xA2O3 (x = 0, 10, 20, 30 wt% and A = Tm, Dy) ceramics were produced by conventional method to determine their usability as shielding material against ionized gamma radiation. To investigate the ionized photon shielding properties of the fabricated materials, the photon intensities (I and I0) were experimentally measured at 81, 160, 223, 302, 356, and 383 keV energies emitted from 133Barium radioisotope, and then the mass attenuation coefficient (μρ), The linear attenuation coefficients (μ, cm−1), half-value thickness (Δ0.5), mean free path (λ), effective atomic numbers (Zeff) and electron densities (Nel) were derived experimentally. The obtained results were benchmarked with the calculated values from the EpiXS program. Also equivalent absorbed dose (EAD) values for fast neutrons were measured using BF3 gas proportional neutron detector from the Canberra NP-100B series and a241Am/Be neutron source with a 10 mCi activity. In addition, fast neutron shielding parameters (ΣR) of ceramics were also computed theoretically. The density of the fabricated ceramics varied from 2.607 g/cm3 to 4.392 g/cm3 when the Tm2O3 was raised from 0 wt% to 30 wt%. Likewise, with the addition of Dy2O3 compound, the densities of ceramics varied between 2.607 g/cm3 to 4.152 g/cm3. It was found that nuclear radiation shielding properties evolved by adding Tm2O3 and Dy2O3 compounds in the present ceramic.

Determining the Structural Properties and Vibrational Modes of Annealed Lead Composite Material Deposit

Techniques for effectively harnessing lead (Pb) deposits for optimum utilization have attracted a lot of research interest. Results obtained from investigating the elemental composition, vibrational modes, and structural properties of a fired Pb composite deposit, which is purified using an electric kiln furnace and further annealed in palladium‐diffused hydrogen ambient, are reported in the present study. Both atomic force microscopy and scanning electron microscopy analysis on the deposit indicate that the Pb composite is composed of crystal‐like morphology. The vibrational modes obtained from the material are identical to the Raman spectrum reported for PbSO4. Also, data acquired from the energy‐dispersive X‐ray analysis of the annealed Pb composite material confirm the presence of zinc, carbon, silicon, sulfur, and oxygen in the material. At the same time, Pb appears to be the primary constituent with reference to its weight percentage composition compared to other elements. The findings from the present study may be vital for providing an improved understanding of the electronic and structural properties of the annealed Pb composite deposit while promoting the development of a feasible approach for the recovery and recycling of Pb for future related applications.

Low energy ion irradiation induced Au/Ag multilayer nanostructured substrates for SERS-based molecular sensing

Au and Ag are the most prominent plasmonic materials to study Surface-Enhanced Raman Spectroscopy (SERS) because of their wide tuning of localized surface plasmon resonance in the broad wavelength range. In the present work, the formation of nanostructures of Au single-layer, Au/Ag bi-layer, and Au/Ag/Au/Ag four-layer thin films on silicon substrates by low energy Kr++ ion irradiation with fluences of 1 × 1015 and 3 × 1015 ions/cm2 was systematically studied and were used for the detection of dye molecules. The surface morphology and microstructural analysis indicated the formation of different nanostructures with different ion fluences by atomic force microscopy and field emission scanning electron microscopy. Rutherford backscattering spectrometry results indicate a considerable change in film thickness after ion irradiation, mainly due to the removal of surface atoms due to sputtering. The maximum enhancement in Raman intensity of R6G was observed in the Bi-layer Au–Ag substrate compared to other substrates with an enhancement factor of 4.78 × 106 corresponding to a 1516 cm−1 characteristic peak in SERS analysis. Coumarin 343 molecules trace amount were detected to determine the versatility of the substrate. A finite-difference time-domain simulation was performed to provide a better understanding of the nanostructure hot-spots formation and support the obtained SERS results.

Time-domain thermoreflectance measurement of the thermal diffusivity of Nb thin films

Nb-coated Cu superconducting radiofrequency (SRF) cavities are of interest as a possible alternative to bulk Nb cavities for particle accelerators due to the high thermal conductivity of Cu and its lower cost than Nb. Studying the thermal diffusion properties in Nb thin films on Cu is important for developing Nb-coated Cu SRF cavities. In the present study, the thermal diffusivity of 100‒800 nm Nb films on Cu is measured by time-domain thermoreflectance (TDTR). The thermal diffusivity is obtained from a curve fit of the TDTR signal to a one-dimensional Fourier heat diffusion model over a time extending from 25 to 985 ps after laser-surface interaction. The film was examined by atomic force microscopy and scanning electron microscopy. The grain size and thermal diffusivity increase with film thickness. The thermal diffusivity reaches a value similar to that reported for bulk Nb for the 400 and 800 nm films, for which the average grain size is 47 ± 13 nm and 68 ± 18 nm, respectively. TDTR measurement for the 400-nm film taken over the temperature range of 293 to 40 K showed that the thermal diffusivity increases as the temperature is reduced. The results indicate that grain boundaries reduce the thermal diffusivity of the Nb film and, therefore, must be considered in Nb-coated Cu SRF cavities.

Ultratrace Aromatic Anhydride Dopant as Intermediate Island to Promote Charge Transfer of Graphitic Carbon Nitride for Enhancing the Photocatalytic Degradation of Rhodamine B.

In this work, 0.75 wt ‰ 2,3-pyridinedicarboxylic anhydride (PDA) as a novel dopant was utilized to obtain modified graphitic carbon nitride with ultratrace doping (3MCN-PDA3) by facile thermal polymerization. Characterization of the microstructure, surface state, and porosity properties of the samples indicated that 3MCN-PDA3 has a thinner sheet-like, larger-scale, and tighter lamellar stacking structure than that of pristine graphitic carbon nitride (3MCN). Based on photo/electrochemical analysis, the PDA dopant formed an extended coplanar conjugated system by anhydride-amine thermal condensation with heptazine rings, and the channels of amide covalent bonds and superconjugation of the solitary pair of electrons of the nitrogen atoms of PDA synergistically promoted the charge transport performance of 3MCN-PDA3. Under visible light, the photodegradation efficiency of Rhodamine B (RhB) over 3MCN-PDA3 reached 92.4% in 60 min and realized almost entire removal in 200 min (99.2%), 1.43 times that of 3MCN. Furthermore, the experimental results and generalized density theory calculations confirmed that PDA acts as an intermediate molecular island and constructs an efficient carrier transfer pathway between different heptazine units. The results indicate that PDA is a promising candidate to enhance the charge transfer performance through ultratrace doping in the large-scale preparation and application of the graphitic carbon nitride photocatalyst.

Green to deep-red emissive carbon dot formation by C+ ion implantation on nitrogen beam created self-masked nano-template

We report the formation of green to red emissive arrays of carbon dot on silicon-nitride nano-templates by successive implantation of nitrogen and carbon broad ion beams. The patterned nano-templates are formed by 14 keV N2 + ion-bombardment at grazing incident (70°) on Si. Subsequently, 5 keV C+ ions are implanted at the selective sites of the pyramidal nano-template by taking advantage of the self-masking effect. The nano-pyramidal pattern and the implanted carbon dots at the specific sites are confirmed by atomic force microscopy and cross sectional transmission electron microscopy measurements. The developed carbon dots (CDs) are mostly amorphous and consists of SiC and graphitic nitrogen (CN). G-band and D-band carbons are identified by Raman spectroscopy, while the presence of SiC and CN are detected by XPS measurements. A change of band-gap is observed for C-implanted templates by the UV–vis spectroscopy. Excitation wavelength-dependent photoemission from the dots is found in the green to red region. Maximum intense PL is observed in the green–orange region for excitation wavelength of 425 nm and a redshift of PL with decreasing intensity is observed with the increase of excitation wavelength. The observed photoluminescence is described in terms of the combined effects of quantum confinement, graphitic nitrogen and defect induced additional states formation in the carbon dots. The potential applications of CDs are also addressed.