This study demonstrates the impact of water-in-salt (WIS) electrolytes on the performance of a supercapacitor using nitrogen and sulphur co-doped activated carbon as the electrode material, highlighting its potential for enhanced energy storage capabilities. The electrolyte (WIS) used is 12 m NaNO3 and the electrode material is a previously reported nitrogen and sulphur co-doped activated carbon sourced from mangosteen shells (NS-MSAC). Furthermore, the three-electrode test of NS-MSAC demonstrates a high specific capacitance of 206 F g-1 at a current density of 0.5 A g-1 within a potential window of 0 to -1.0 V. The symmetric supercapacitor built with NS-MSAC achieved a voltage range of 0-2.0 V by exploiting the beneficial electrochemical properties of 12 m NaNO3, which include a higher potential window, low viscosity, high conductivity, and electrochemical stability. The assembled symmetric device featuring NS-MSAC//NS-MSAC delivered a specific energy of 25 W h kg-1 at a power density of 512 W kg-1. Additionally, after 8000 charge/discharge cycles, approximately 85% of the capacitance was retained. This highly concentrated aqueous electrolyte strategy is promising for achieving remarkable supercapacitor performance.

In this study, we investigate the use of swift heavy ions to modify the structural and optical properties of PANIgraphene nanocomposite (PANI-G NC) films. PANI-G NC films were synthesized on Indium Tin Oxide (ITO)coated glass by electrochemical polymerization of aniline in the presence of CVD-grown graphene. The films were then irradiated with 36 MeV Cu8+ ions at fluences between 5.4 x 1012 and 6.4 x 1013 ions/cm2. SEM results show that irradiation up to 1.6 x 1013 ions/cm2 leads to the formation of a porous interconnected network, with graphene nanoparticles adhering to the PANI matrix. Beyond this fluence, a dense and compact granular structure appears. Raman spectroscopy reveals enhanced Raman scattering of the polaronic lattice and the introduction of defects in graphene. At fluences exceeding 2.1 x 1013 ions/cm2, the obtained spectra reveal a distinctive broad envelope centered at the D and G positions of graphene, characteristic of nanocrystalline graphite. X-ray diffraction shows an increase in both crystallinity and crystallite size of the PANI-G NC film with increasing fluence, followed by a decrease beyond a critical ion fluence. Optical modifications were characterized by a red shift in the UV-Vis spectrum with increased fluence. The optical band gap shows a decreasing trend with ion dose, attributed to the formation of carbonaceous clusters along the latent tracks of energetic ions. In short, this study demonstrates that swift heavy ion irradiation could be an effective tool for enhancing the structural and optical properties of PANI-G NC films and tailoring them for specific applications.

Porous carbon materials used as electrode materials could benefit from heteroatom co-doping to enhance their electrochemical properties. A one-step carbonization/co-doping procedure was developed to produce a nitrogen and sulfur (NS) co-doped activated carbon material from mangosteen shells (MS). Mangosteen is a tropical fruit globally well spread and cultivated in at least three continents and its shells represent an excellent porous carbon precursor. The amount of the doping agent (thiourea) was examined in relation to the morphological, structural, textural, and electrochemical performances of the material. The characterization results revealed that the 0.25 NS-doped MS AC electrode material was optimal and displayed a BET-specific surface area of 2308 m2 g-1. As measured by three-electrode configurations, this sample showed higher electrochemical performances than the non-doped MS AC with a specific capacity of 60.0 mAh g-1 at 0.5 A g-1. An increase in voltage (3.6 V) was observed in a symmetric supercapacitor using the doped material compared to the non-doped (2.8 V) in the same ionic liquid electrolyte. Further, the device demonstrated a specific capacity of 111.3 mAh g-1, a remarkable specific energy of 41.3 Wh kg-1 at 0.5 A g-1, and specific power of 7333.5 W kg-1 at 5 A g-1. These results pave the way for developing highly porous carbon materials with improved surface chemistry. The material can be used in different applications, including supercapacitors, batteries, and electrocatalysis at a reduced cost.

A study has been conducted on the electrochemical properties of 1-ethyl-3-methylimidazolium trifluoromethanesulfonate (EmimTFO) protic ionic liquid enhanced by adding potassium nitrate (2.5 M) aqueous solution. The properties of EmimTFO as well as mixtures diluted by molar fractions of 0.6, 0.7, 0.8, and 0.9 of KNO 3 were also investigated through measurements of viscosity, density, and conductivity. In a three-electrode test run at 0.25 A g -1 , the addition of 2.5 M KNO 3 solution generated peak specific capacities of ~40.2 and ~85.8 mAh g -1 on the positive and negative potentials, respectively. These performances surpassed the specific capacities obtained for EmimTFO in a three-electrode run at 0.25 A g -1 using the same electrode material (activated carbon). The top-performing electrolyte mixture ([EmimTFO] 0.8 [2.5 M KNO3] 0.2 ) was then used to assemble a symmetric supercapacitor, which could run at a voltage of ~2.1 V. The device was able to retain 71.35% of its capacitance after 10,000 cycles of charge and discharge. It also displayed higher specific energy and power of 22.21 Wh kg -1 and 520 W kg -1 , respectively, at 0.5 A g -1 as compared to specific energies of 4.73 Wh kg -1 and 11.2 Wh kg -1 for the devices assembled with single EmimTFO and 2.5 M KNO 3 as the electrolytes, respectively.

In this study, we have reported the effect of different activating agents, temperatures, and impregnation ratios on the porosity of mangosteen shell-derived activated carbons (M-S AC). The sample's characterization comprised of scanning electron microscopy (SEM), X-ray diffraction (XRD), Raman spectroscopy, and N2 physisorption analysis. The M-S AC synthesized with K2CO3 as the activating agent displayed a high specific surface area of 2802.6 m2 g-1 and a flower-like morphology. Electrochemical measurements of the M-S AC synthesized with K2CO3 revealed a specific capacitance of 298.13 F g-1 at 0.5 A g-1 in a potential window of -0.9-0.0 V vs Ag/ AgCl using 2.5 M KNO3 electrolyte in a three-electrode measurement. An initial symmetric supercapacitor assembled with the optimized M-S AC as electrode material and 2.5 M KNO3 as the electrolyte delivered a specific energy of 11.5 Wh kg- 1 corresponding to a specific power of 0.4 kW kg-1 at 0.5 Ag-1 in a potential window of 1.6 V. A second assembled symmetric device using the same M-S AC as electrode material and 1-Ethyl-3-methylimidazolium-bis(fluoroSulfonyl)imide (EmiFSI) ionic liquid as the electrolyte demonstrated high spe-cific energy of 28.03 Wh kg- 1 corresponding to a specific power of 0.7 kW kg- 1 at 0.5 Ag-1 in a wider potential window of 2.8 V.

This study has investigated the effect of the incorporation of graphene foam (GF) into the matrix of a ternary transition-metals hydroxide containing nickel, cobalt, and manganese for optimal electrochemical performances as electrodes for supercapacitors applications. An adopted simple, low-cost co-precipitation synthesis method involved the loading a mass of the ternary metal hydroxides (NiCoMn-TH) onto various GF mass loading so as to find ints effect on the electrochemical properties of the hydroxides. Microstructural and chemical composition of the various composite materials were investigated by employing scanning/transmission electron microscopy (SEM/TEM), x-ray diffraction (XRD), Raman spectroscopy, and N2 physisorption analysis among others. Electrochemical performances of the NiCoMn-TH/200 mg GF composite material evaluated in a three-electrode system using 1 M KOH solution revealed a maximum specific capacity around 178.6 mAh g−1 compared to 76.2 mAh g−1 recorded for the NiCoMn-TH pristine material at a specific current of 1 A g−1. The best mass loading of GF nanomaterial (200 mg GF), was then utilised as a positive electrode material for the design of a novel hybrid device. An assembled hybrid NiCoMn-TH/200 mg GF//CSDAC device utilizing the NiCoMn-TH/200 mg GF and activated carbon derived from the cocoa shell (CSDAC) as a positive and negative electrode, respectively, demonstrated a sustaining specific capacity of 23.4 mAh g−1 at a specific current of 0.5 A g−1. The device also yielded sustaining a specific energy and power of about 22.32 Wh kg−1 and 439.7 W kg−1, respectively. After a cycling test of over 15,000 cycles, the device could prove a coulombic efficiency of ~ 99.9% and a capacity retention of around 80% within a potential range of 0.0–1.6 V at a specific current of 3 A g−1. These results have demonstrated the prodigious electrochemical potentials of the as-synthesized material and its capability to be utilized as an electrode for supercapacitor applications.

The development of advanced electrode materials derived from biomass for the next generation of energy storage devices, such as supercapacitors with high specific energy and specific power coupled with a good cycle stability, is required to meet the high demand for electric vehicles and portable devices. In this study, sustainable binary vanadium pentoxide carbon-graphene foam composites (V 2 O 5 @C-R 2 HS/GF) were synthesized using a solvothermal method. The X-ray diffraction, Raman and FTIR techniques were used to study the structural properties of the composites (V 2 O 5 @C-R 2 HS/20 mg GF and V 2 O 5 @C-R 2 HS/40 mg GF). The SEM micrographs displayed an accordion-like morphology resulting from the graphene foam-modified V 2 O 5 @C-R 2 HS composite. The V 2 O 5 @C-R 2 HS, V 2 O 5 @C-R 2 HS/20 mg GF and V 2 O 5 @C-R 2 HS/40 mg GF composites were evaluated in a three-electrode configuration using 6 M potassium hydroxide (KOH) as an aqueous electrolyte. Furthermore, a two-electrode device was carried out by fabricating an asymmetric device (V 2 O 5 @C-R 2 HS/GF//AC) where V 2 O 5 @C-R 2 HS/20 mg GF was used as a positive electrode and activated carbon (AC) as a negative electrode at a cell voltage of 1.6 V in 6 M KOH. The V 2 O 5 @C-R 2 HS/GF//AC showed a high specific energy and specific power values of 55 W h kg −1 and 707 W kg −1 , respectively, at a specific current of 1 A g −1 . The asymmetric device presented a good stability test showing 99% capacity retention up to 10 000 cycles and was confirmed by the floating time up to 150 h with specific energy increasing 23.6% after the first 10 h. This article is part of the theme issue ‘Bio-derived and bioinspired sustainable advanced materials for emerging technologies (part 2)’.

Portable electronic devices require a small volume self-powered energy system that can combine fabrication of energy harvesting and storage devices in one plane. This study focuses on fabricating novel all-oxide photovoltaic and supercapacitor devices based on MoO3, V2O5, and CoxOy thin electrodes prepared by a two-electrode cell arrangement. The fabricated devices were tested using solar simulator and potentiostat at ambient temperature. The power conversion efficiencies of the fabricated photovoltaic devices were found in the range of 0.17-0.39% depending on buffer layer characteristics. It therefore suggests that V2O5 and MoO3 can buffer photovoltaic processes by lowering the conduction band offset in the proximate CoxOy absorber. Pseudocapacitive behavior of MoO3/CoxOy parallel to MoO3/CoxOy and V2O5/CoxOy parallel to V2O5/CoxOy planar devices showed that they delivered maximum specific areal capacity values of 0.694 and 0.778 mu Ahcm(-2) respectively at discharge current density of 0.1 mAcm(-2). They also showed considerably low reduction in energy density (about 38.7%) even at a remarkable increase in power density of about 450% (at a high current density of 1.0 mAcm(-2)). In addition, the symmetric microsupercapacitors showed excellent retention of capacity even after 5000 cycles. These results generally indicate the reliability of the fabricated devices in the development of portable electronic components for energy application.

A simple low-cost electrochemical deposition technique has been used to grow molybdenum oxide (MoO3) and vanadium oxide (V2O5) nanostructures separately on cobalt oxide (CoxOy) thin film to form two different bilayer films. The samples were characterized by some surface probing techniques. Morphological and crystal structural studies revealed that the deposited α-MoO3 and V2O5 layers completely laminated the underlying cubic CoxOy film to form compact structures without any significant lattice distortion. The average particle sizes were estimated to be between 34 nm and 41 nm. Optical studies revealed the presence of two energy band transitions in the spinel CoxOy structure which can be attributed to the occurrence of ligand-to-metal charge transfer (LMCT). The electrical studies showed a trap-filled limit voltage (VTFL) in the CoxOy layer which was explained on the basis of space charge limited current (SCLC) behavior of porous film, and it was corrected with lamination by the overlayer. This study also reaffirmed the role of transition metal oxides as a recipe for window and buffer layers capable of minimizing photon absorption loss and recombination of charge carriers between absorber and the contact electrodes in optoelectronic devices.

The carbonized iron-polyaniline/nickel graphene foam (C-Fe/PANI/Ni-GF) electrode was prepared by pasting a mixture of iron-polyaniline (Fe/PANI) on nickel graphene foam (Ni-GF) and carbonized under the nitrogen. For electrochemical characterization, the as-prepared electrode material was evaluated in both three and two-electrode (i.e. symmetric) cell configurations using 1 M NaNO3 electrolyte. The symmetric device exhibited a maximum energy density of 68.0 W h kg(-1) and power density of 718.2 W kg(-1), at a specific current of 1.0 A g(-1) and the maximum potential of 1.7 V. The device further displayed long-term cycling stability with capacity retention of 91% over 10 000 galvanostatic charge-discharge cycles at 5 A g(-1). The stability of the device was also tested using the voltage holding and self-discharge approach whereby a slow-discharging process was observed, which suggests the practical application of the device. (C) 2019 Elsevier B.V. All rights reserved.

This study reports on Ni and Ni-Cu graphene foam prepared by atmospheric pressure chemical vapour deposition. The Ni-Cu foam alloys were prepared using a three-dimensional (3D) scaffold template of polycrystalline nickel foam which is commonly used as a current collector in supercapacitor electrodes. The morphological, composition and structural characterization of as-grown Ni and Ni-Cu graphene foam were carried out using confocal Raman spectroscopy imaging, scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HR-TEM), energy-dispersive X-ray spectrometer (EDS) and X-ray photoelectron spectroscopy (XPS). The results demonstrated that Ni -Cu graphene foam is mainly monolayer and bilayer as compared to Ni graphene foam which is typically a few-layer graphene. The electrochemical performance of Ni and Ni-Cu graphene foam as current collectors were evaluated in a three-electrode electrochemical cell using 1 M NaSO4 aqueous electrolyte and porous activated carbon (AC) produced from lightweight material cork (Quercus suber) as the active electrode material. The AC on Ni-Cu graphene foam current collectors exhibited a high specific capacitance (250-300 F g(-1) at 1 A g(-1)) and good electrochemical stability (94-100% capacitance retention) over 6000 constant charge-discharge cycles at 5 A g(-1).

Cobalt phosphate Co-3(PO4)(2) and Cobalt phosphate/graphene foam composites Co-3(PO4)(2)/GF were synthesized via a co-precipitation technique. Co-3(PO4)(2)/GF composite was synthesized from Co-3(PO4)(2) with addition of different graphene foam (GF) mass loading to optimize the appropriate amount of GF which effectively synergized its properties with those of the phosphate materials. The structural, morphological and chemical bonding nature of the synthesized products were characterized extensively using various microscopy and spectroscopy techniques to confirm the successful integration of conductive GF with Co-3(PO4)(2) grains. The electrochemical properties of the prepared materials were tested in 1 M KOH electrolyte by cyclic voltammetry (CV), galvanostatic charge-discharge (GCD), and electrochemical impedance spectroscopy (EIS). Co-3(PO4)(2)/20 mg GF composite exhibited a remarkable gravimetric capacity of 57 mAh g(-1) higher than Co-3(PO4)(2) (21 mAh g(-1)) at 0.5 A g(-1) in a half-cell configuration. An asymmetric device was fabricated using Co-3(PO4)(2)/20 mg GF as a positive electrode) with biomass-derived activated carbon from pepper seed (ppAC) as negative electrode, which delivered a specific energy of 52 Wh kg(-1) with an equivalent power of 847 W kg(-1) at 1 A g(-1). The asymmetric device exhibited a capacity retention of 80% over 10 000 cycles at 10 A g(-1). The study demonstrates an adoption of a facile route for obtaining composite materials and interfaced with biomass-derived porous structures for assembly of a stable asymmetric device. (C) 2019 Elsevier B.V. All rights reserved.

We report the effect of hydrothermal synthesis conditions on the morphological, optical and electrochemical properties of as-prepared iron oxide (γ-Fe2O3) and hydroxide (α-FeOOH) nanostructures. The physico-chemical identification of these Fe-based nanostructures using X-ray diffraction, scanning/transmission electron microscopy, porosity and Raman spectroscopy analyses revealed a temperature-depended phase transformation. A maghemite and goethite iron-based nanostructured formation was observed in nanorod and trigonal nanofiber shape-like morphology with mean diameters ranging from 32 to 50 nm. The textural analysis of the nanofibers confirmed mesoporosity with a specific surface area of ~ 129 m2 g−1 (in γ-Fe2O3) and 23 m2 g−1 (in α-FeOOH). The electrochemical performance of the iron oxide and hydroxide nanofiber electrodes with and without the addition of activated carbon (AC) was also investigated. The sample electrodes composed of γ-Fe2O3, γ-Fe2O3/AC, α-FeOOH and α-FeOOH/AC showed remarkable specific capacities of 164 mAh g−1, 330 mAh g−1, 51 mAh g−1 and 69 mAh g−1 at 1 A g−1 gravimetric current. The influence of the phase transformation linked to the synthesis temperature, and the inclusion of an electric double-layer AC material into the nanofibers clearly demonstrates an enhancement in their energy-storage capability. Furthermore, the Fe-based nanofibers exhibited excellent cycling stability with good capacity retention of 73% and 99.8%, respectively, after 2000 cycles at a high 30 A g−1 gravimetric current as well as low resistance obtained by impedance spectroscopy analysis. The implication of the results depicts the potential of adopting these γ-Fe2O3 nanorods as suitable material electrodes in electrochemical energy-storage devices.

For the future development of environmentally friendly and sustainable electrode materials, herein, novel orthorhombic vanadium pentoxide@carbon composites (V2O5@C–WHS, V2O5@C–R1HS and V2O5@C–R2HS) were synthesized via a green solvothermal process.

In this work, a birnessite-type MnO2/carbon composite with hierarchical nanostructures was synthesized using KMnO4 solution and spent printing carbon grains. A hybrid electrochemical supercapacitor device was fabricated based on the birnessite-type MnO2–carbon composite electrode and carbonized iron-polyaniline/nickel graphene foam as positive and negative electrodes, respectively. At the lowest specific current of 1.0 A g−1 and cell potential of 2.2 V in 2.5M KNO3 electrolyte, the device displayed a high energy and power density of 34.6 W h kg−1 and 1100.0 W kg−1, respectively. The device further displayed long-term cycling stability with a capacitance retention of 98% over 10 000 galvanostatic charge–discharge cycles at 10 A g−1. This device displays the overall excellent electrochemical performance.

A simple low-cost electrochemical deposition technique has been used to grow molybdenum oxide (MoO 3 ) and vanadium oxide (V 2 O 5 ) nanostructures separately on cobalt oxide (Co x O y ) thin film to form two different bilayer films. The samples were characterized by some surface probing techniques. Morphological and crystal structural studies revealed that the deposited α-MoO 3 and V 2 O 5 layers completely laminated the underlying cubic Co x O y film to form compact structures without any significant lattice distortion. The average particle sizes were estimated to be between 34 nm and 41 nm. Optical studies revealed the presence of two energy band transitions in the spinel Co x O y structure which can be attributed to the occurrence of ligand-to-metal charge transfer (LMCT). The electrical studies showed a trap-filled limit voltage ( V TFL ) in the Co x O y layer which was explained on the basis of space charge limited current (SCLC) behavior of porous film, and it was corrected with lamination by the overlayer. This study also reaffirmed the role of transition metal oxides as a recipe for window and buffer layers capable of minimizing photon absorption loss and recombination of charge carriers between absorber and the contact electrodes in optoelectronic devices.

The nitrogen-doped, n-type 4H-SiC with 6 mu m thick epitaxial layer was irradiated at the perpendicular incidence and room temperature by 167 MeV Xe+26 ions to a fluence of 5 x 10(12) cm(-2). The Monte Carlo simulation code, Stopping and Range of Ions in Matter (SRIM) was used to simulate the Xe26+ ions irradiated in SiC. The Rutherford backscattering spectrometry (RBS) analysis with 3.5 MeV He+ + ions which have a projected range of similar to 9 mu m in SiC (SRIM prediction) did not detect implanted Xe. Raman spectroscopy and imaging depth profiles clearly showed three distinct parts of the swift heavy ion (SHI)-irradiated 4H-SiC, i.e. 5.6 mu m irradiated epitaxial layer, 6.9 mu m damaged irradiated layer and non-irradiated 4H-SiC bulk. Raman spectroscopy showed new broad bands of crystalline Si-Si and distorted Si-C in the damaged irradiated layer. The new Si-Si bands were attributed to the ordering in the Si-Si homonuclear bonds without crystal amorphization. The scanning near-field optical microscopy (SNOM) results of the SHI-irradiated 4H-SiC sample displayed a very low signal counts (transmission) compared to the virgin sample, and this difference in the optical absorption could be correlated with the defects energy levels created within the bandgap of the sample upon irradiation.

In this investigation, we report the synthesis of novel homogeneous micro–mesoporous bi-phase nanohybrids based on Ni/Zn hydroxides using a simple and low-cost free-template urea-based hydrothermal process at two different growth temperatures (120 and 180 °C) for 6 h in two cases of precursor ratios (Ni:Zn = 1:1 and Ni:Zn = 1:2). The synthesized products have been characterized with different techniques such as XRD, FT-IR, FESEM, Raman, BET and XPS analysis to identify quantitatively and qualitatively their original physico-chemical properties. The obtained structural results show the formation of bi-hydroxide-based products: α * -Ni(OH) 2 ·0.75 H 2 O with Zn 5 (CO 3 ) 2 (OH) 6 (case Ni:Zn = 1:1) or with Zn 4 (CO 3 )(OH) 6 ·H 2 O (Ni:Zn = 1:2) which are also proven by FTIR and Raman analyses. However, the obtained 3D micro–meso-nanohybrids with different pore morphology have been demonstrated through the FESEM micrographs depending on the synthesis conditions. Moreover, these porous products have been subjected to textural studies with the BET results showcasing a porous morphology with a reasonable specific surface area (SSA) and pore volume in the range (70–150 m 2 /g) and (0.19–0.85 cm 3 /g), respectively. Also, a clear improvement in the BET SSA (two times the initial value) was obtained with increasing the growth temperature in the two cases (1:1 and 1:2). Consequently, we have successfully synthesized active mesoporous materials with interesting specific surface area and porosity (pore volume and size) which make them attractive materials for electrode applications especially in energy storage and biosensing.

In this study, the synthesis of porous activated carbon nanostructures from peanut (Arachis hypogea) shell waste (PSW) was described using different porosity enhancing agents (PEA) at various mass concentrations via a two-step process. The textural properties obtained were depicted with relatively high specific surface area values of 1457 m 2 g −1 , 1625 m 2 g −1 and 2547 m 2 g −1 for KHCO 3, K 2 CO 3 and KOH respectively at a mass concentration of 1 to 4 which were complemented by the presence of a blend of micropores, mesopores and macropores. The structural analyses confirmed the successful transformation of the carbon-containing waste into an amorphous and disordered carbonaceous material. The electrochemical performance of the material electrodes was tested in a 2.5 M KNO 3 aqueous electrolyte depicted its ability to operate reversibly in both negative and positive potential ranges of 0.90 V. The activated carbon obtained from the carbonized CPSW:PEA with a mass ratio of 1:4 yielded the best electrode performance for all featured PEAs. The porous carbons obtained using KOH activation displayed a higher specific capacitance and the lower equivalent series resistance as compared to others. The remarkable performance further corroborated the findings linked to the textural and structural properties of the material. The assembled device operated in a neutral electrolyte (2.5 M KNO 3 ) at a cell potential of 1.80 V, yielded a ca. 224.3 F g −1 specific capacitance at a specific current of 1 A g −1 with a corresponding specific energy of 25.2 Wh kg −1 and 0.9 kW kg −1 of specific power. This device energy was retained at 17.7 Wh kg −1 when the specific current was quadrupled signifying an excellent supercapacitive retention with a corresponding specific power of 3.6 kW kg −1 . These results suggested that peanut shell waste derived activated carbons are promising candidates for high-performance supercapacitors.

Graphene is a carbon material with excellent properties, which makes it applicable in a myriad of applications. However, the range of the applications of graphene can be extended to the developing field of nanoelectronics and optoelectronics by doping it with heteroatoms. In this study, Be and S atoms were used to co-dope graphene. The impurity concentration was varied by increasing the size of the supercell from 2x2 through 4x4. First-principles calculations were performed to determine the dynamic stability, band structure, and optical characteristics of the system. The results of the phonon dispersion of beryllium and sulphur co-doped graphene (Be-S) show the absence of imaginary modes, suggesting that Be-S is dynamically stable. The analysis of the band structure indicates that it has a tunable indirect band-gap which increases with the impurity concentration. A band-gap magnitude is required in a graphene-based transistor. Thus, Be-S could be considered as a transistor material. As regards with the optical properties, it is observed that the optical transparency of the graphene in the ultraviolet region changes with the impurity concentration. The result shows that Be-S can be used to manipulate light waves for a device application.