Mohammad Tanvir Ahmed
@just.edu.bd
Lecturer, Department of Physics
Jashore University of Science and Technology
Mohammad Tanvir Ahmed was born in the Dhaka district of Bangladesh. He completed his SSC and HSC from Savar Cantonment Public School & College, Savar, Dhaka. He went to Jahangirnagar University, earning his Bachelor's and Master's degrees in Physics. He conducted his M.S. Thesis on Perovskite thin film for optoelectronic research. He received the NST fellowship under the Ministry of Science and Technology Bangladesh for his M.S. research. He was appointed as a lecturer of Physics at BGMEA University of Fashion & Technology from 27 March 2022 to 01 November 2022. Tanvir joined as a lecturer of Physics at Jashore University of Science and Technology on 05 November 2022.
EDUCATION
M.S. (Physics) GPA:3.99/4.00
Duration: 2018 - 2020
Jahangirnagar University
B.Sc. (Physics) CGPA:3.68/4.00
Duration: 2014 - 2018
Jahangirnagar University
H.S.C. GPA:5.00/5.00
Duration: 2011 - 2013
Savar Cantonment Public School and College
S.S.C. GPA:5.00/5.00
Duration: 2009 - 2011
Savar Cantonment Public School and College
RESEARCH, TEACHING, or OTHER INTERESTS
Materials Science, Surfaces, Coatings and Films, Condensed Matter Physics, Spectroscopy
Scopus Publications
Scholar Citations
Scholar h-index
Scholar i10-index
Scopus Publications
Mohammad Tanvir Ahmed, Abdullah Al Roman, Debashis Roy, Shariful Islam, and Farid Ahmed
Springer Science and Business Media LLC
AbstractTetragonal graphene nano-capsule (TGC), a novel stable carbon allotrope of sp2 hybridization is designed and doped with phosphorus (P) to study the O3 and SO2 gas sensitivity via density functional theory calculation. Real frequencies verified the natural existence of both TGC and P-doped TGC (PTGC). Both TGC and PTGC suffer structural deformations due to interaction with O3 and SO2 gases. The amount of charge transfer from the adsorbent to the gas molecule is significantly greater for O3 adsorption than SO2 adsorption. The adsorption energies for TGC + O3 and PTGC + O3 complexes are − 3.46 and − 4.34 eV respectively, whereas for TGC + SO2 and PTGC + SO2 complexes the value decreased to − 0.29 and − 0.30 eV respectively. The dissociation of O3 is observed via interaction with PTGC. A significant variation in electronic energy gap and conductivity results from gas adsorption which can provide efficient electrical responses via gas adsorption. The blue/red shift in the optical response proved to be a way of detecting the types of adsorbed gases. The adsorption of O3 is exothermic and spontaneous whereas the adsorption of SO2 is endothermic and non-spontaneous. The negative change in entropy verifies the thermodynamic stability of all the complexes. QTAIM analysis reveals strong covalent or partial covalent interactions between absorbent and adsorbate. The significant variation in electrical and optical response with optimal adsorbent-gas interaction strength makes both TGC and PTGC promising candidates for O3 and SO2 sensing.
Ishrat Jahan Tonny, Mim Khatun, Debashis Roy, Abdullah Al Roman, and Mohammad Tanvir Ahmed
AIP Publishing
We conducted theoretical calculations to examine the energetic stability of pristine aluminum nitride (AlN) and N-defected AlN nanosheets, along with their structural, electronic, and optical properties, utilizing density functional theory. Furthermore, we explored the adsorption properties of BF3 and ClF3 toxic gases on both pristine AlN and N-defected AlN nanosheets. Our findings reveal that the N-defect on the AlN nanosheet enhances the gas adsorption energies (−1.354 and −13.263 eV) compared to the pristine AlN nanosheet. Additionally, the absolute value of the bandgap for the N-defected AlN nanosheet increases to 3.032 eV, exceeding the 2.997 eV value of the pristine AlN nanosheet. The gas molecules suffer significant deformation due to their interaction with adsorbents. Upon BF3 gas adsorption, the bandgap of the N-defected AlN nanosheet diminishes to zero. Moreover, the recovery time after gas adsorption on the N-defected AlN nanosheet surpasses that of the pristine AlN nanosheet. Both adsorbents showed a high absorption coefficient of over 104 cm−1 in the UV region. Significant peak shifting in the optical spectra of the N-defected AlN nanosheet was observed due to gas adsorption. The pronounced changes in structural, electronic, and optical properties following toxic gas adsorption suggest that N-defected AlN nanosheets are suitable for the adsorption (dissociation) of BF3 (ClF3) gases.
Mohammad Tanvir Ahmed, Debashis Roy, Abdullah Al Roman, Shariful Islam, and Farid Ahmed
Royal Society of Chemistry (RSC)
The sensitivity of a RbSnCl3 perovskite 2D layer toward NH3, SO2, and NO toxic gases has been studied via DFT analysis.
Mohammad Tanvir Ahmed, Shariful Islam, and Farid Ahmed
Wiley
AbstractOrganometallic perovskites have become one of the most common multifunctional materials in optoelectronic research fields. This research studies density functional theory calculation on orthorhombic hydrazinium lead iodide (N2H5PbI3) perovskite by replacing A‐site cation with a borane ammonium (BH2NH3+) ion. The perovskite showed a significant structural deformation and an orthorhombic to triclinic phase transition due to A‐site ion replacement. The N2H5PbI3 perovskite has a band gap of 1.64 eV, suitable for the solar cell absorber layer. The band gap has increased to 2.12 eV after complete A‐site ion replacement. All structures showed a high absorption coefficient over 104 cm−1 in the low wavelength region and an increase in refractive index from 2.5 to 2.75 due to ion replacement. All the structures showed high optical conductivity of 1015 s−1 order in the blue wavelength region. These new perovskite structures hold the potential to provide a revolution in optoelectronic research.
Md. Maruf Chand, Shariful Islam, Mohammad Tanvir Ahmed, Muhammad Shahriar Bashar, and Farid Ahmed
AIP Publishing
The non-toxic nature and remarkable optoelectronic properties of kesterite (Cu2ZnSnS4 and CZTS) make CZTS a potential candidate for solar cell absorber layer material. Since alkali metal doping has shown a performance boost of active layers of solar cells, this work investigates the effects of significant lithium doping on sol-gel-produced CZTS thin films. CZTS- and lithium (Li)-doped CZTS thin films were prepared using the spin coating technique. The variation of structural, morphological, and optical properties of CZTS due to Li-doping has been studied by x-ray diffraction, scanning electron microscopy, and UV–visible spectroscopy techniques. All the synthesized LixCu2−xZnSnS4 (x = 0, 0.2, 0.4, 0.6) films showed fine crystallinity with average crystallite sizes of 4.745, 6.013, 6.255, and 6.404 nm, respectively. The average grain size decreases from 0.336 to 0.310 µm via increasing Li concentration. The inclusion of Li increased the bandgap energy ranges from 1.5 to 1.808 eV. The Li0.6Cu1.4ZnSnS4 thin showed the highest absorption coefficient of 3.505 × 104 cm−1 among all the prepared thin films. A high optical conductivity over 1014 s−1 was observed for CZTS, which further increased with an increased Li concentration. The synthesized structures showed enhanced characteristics suitable for solar cell application.
Mohammad Tanvir Ahmed, Debashis Roy, Abdullah Al Roman, Shariful Islam, and Farid Ahmed
Royal Society of Chemistry (RSC)
Chromium metal removal from polluted environments using C8 and B4N4 nanocages.
Mohammad Tanvir Ahmed, Shariful Islam, and Farid Ahmed
Elsevier BV
Mohammad Tanvir Ahmed, Sayedul Hasan, Shariful Islam, and Farid Ahmed
Elsevier BV
Mohammad Tanvir Ahmed, Shariful Islam, and Farid Ahmed
IOP Publishing
Abstract The interesting characteristics of Mobius structure inspired this research to study the effect of Boron-Nitride incorporation on Mobius Carbon (M-CX; X = 48, 44, 24, 12, 4, and 0) nanoribbon. The structural stability, vibrational, electronic, and optical properties of M-CX nanoribbons have been studied via density functional theory. The negative formation energy and real vibrational frequency verified the structural stability and natural existence of the M-CX. All the structures showed a high absorption coefficient over 104 cm−1 and a semiconductor-to-insulator transition with decreasing Carbon concentration in the M-CX structure. The M-C48 structure has the maximum reactivity whereas the M-C0 structure is chemically more stable. The observed optical and electronic studies suggest the structures are potential materials for optoelectronic research.
Sayedul Hasan, Mohammad Tanvir Ahmed, Abdullah Al Roman, Shariful Islam, and Farid Ahmed
Hindawi Limited
The electrical and optical characteristics of a ZrS2 monolayer doped with chalcogen atoms (O, Se, or Te), where dopants are introduced by substituting the S atom, are examined on the basis of the density functional theory. The semiconductors pristine ZrS2 and O, Se, and Te-doped ZrS2 monolayers possessed indirect band gaps of 1.187 eV, 1.227 eV, 1.146 eV, and 0.922 eV, respectively. According to the formation energy, the O-doped ZrS2 monolayer is more stable compared to Se-doped and Te-doped ZrS2 monolayers. The optical properties are very similar for both the undoped and doped ZrS2 monolayers. The absorption coefficient and optical conductivity are the highest in the ultraviolet energy region. The designed materials are potentially suitable for UV photodetection and UV filtering applications.
Mohammad Tanvir Ahmed, Shariful Islam, and Farid Ahmed
AIP Publishing
The interesting characteristics of graphyne structure inspired this research to study the effect of oxygen incorporation and boron nitride doping on γ-graphyne. The structural stability, vibrational, and electronic properties of γ-graphyne, γ-graphyne oxide, and boron nitride doped γ-graphyne have been studied via density functional theory. The negative formation energy verified the structural stability of all the structures. Both γ-graphyne oxide and boron nitride doped γ-graphyne showed a significantly deformed geometry compared to pure γ-graphyne. The energy gap of pure γ-graphyne was obtained to be 2.604 eV, which tuned to 3.059 eV and 3.51 eV through oxygen addition and boron nitride doping, respectively. Boron nitride doped γ-graphyne revealed better structural stability, whereas high reactivity was observed for pure γ-graphyne.
Mohammad Tanvir Ahmed, Shariful Islam, and Farid Ahmed
The Royal Society
The interesting properties of Mobius structure and boron-carbon-nitride (BCN) inspired this research to study different characteristics of Mobius BCN (MBCN) nanoribbon. The structural stability and vibrational, electrical and optical properties are analysed using the density functional theory. The gas-sensing ability of the modelled MBCN structure was also studied for methane, hydrogen sulfide, ammonia, phosgene and methanol gases. The negative adsorption energy and alteration of electronic bandgap verified that MBCN is very sensitive toward the selected gases. The complex structures showed a high absorption coefficient with strong chemical potential and 7 ps–0.3 ms recovery time. The negative change in entropy signifies that all the complex structures were thermodynamically stable. Among the selected gases, the MBCN showed the strongest interaction with methanol gas.
M.T. Ahmed, S. Islam, and F. Ahmed
Wiley
Organic‐inorganic perovskites have become widely studied materials for their superior optoelectronic applications. This research reports the synthesis of CH3NH3PbI3 perovskite microrods via one‐step deposition for optoelectronic applications. Crystalline and morphological structure, bond information, optical, and electrical characteristics have been studied. The perovskite microrods showed fine crystalinity with 90 nm–300 nm rod diameter with a high absorption coefficient over 104 cm−1. A very lesser refractive index (1.85–2.00) was observed in the visible region. A comparison among different bandgap measuring techniques has also been demonstrated and up to 5.5 % deviation in measured bandgap was observed.
M.T. Ahmed, S. Islam, and F. Ahmed
Elsevier BV
Mohammad Tanvir Ahmed, Shariful Islam, Muhammad Shahriar Bashar, and Farid Ahmed
Wiley
Improving device performance and reducing Pb‐toxicity is one of the fundamental issues of perovskite‐based optoelectronic technology. This research demonstrates the synthesis and characterization of pure and ZnS incorporated Cu‐based organic–inorganic perovskite via the precursor blending method. The thin films of the perovskites are deposited via one‐step spin coating method. X‐ray diffraction of all the films reveals the cubic phase where a decrease of cell volume is observed after ZnS addition. The average grain size also reduces after ZnS incorporation that is found from scanning electron microscopy analysis. The absorption coefficient of the films is of the order of 103 cm−1 in low wavelength range while a blueshifting of the absorption peak is seen due to ZnS addition. The overall resistance of the film increased with increasing ZnS concentration. An increasing bandgap from 2.3 to 2.4 eV is observed for different ZnS concentrations.
Kanij Fatema, Mohammad Tanvir Ahmed, Md. Kamal Hossain, and Farid Ahmed
Hindawi Limited
Single and mixed-halide perovskite solar cells have attracted much research attention in recent years due to the conditions of low-cost thin film solar cell technology. For this current research, perovskite materials CH3NH3PbCl3, CH3NH3PbI2Cl, CH3NH3PbICl2, and CH3NH3PbI3 have been synthesized and deposited on clean glass substrates by spin coating process. The structural and morphological properties of the prepared thin films have been studied by X-ray diffraction and Scanning electron microscopy. All the perovskite showed fine crystallinity, possessing a tetragonal phase. The average crystallite sizes of the prepared samples are obtained to be 20.77 nm, 30.18 nm, 31.11 nm, and 42.23 nm, respectively. The lattice strain decreased with increasing crystallite size. A drastic change was observed in the morphological properties of the perovskites. The perovskite grains change from microrods to microcube by substituting iodine with chlorine ions.
Mohammad Tanvir Ahmed, Shariful Islam, and Farid Ahmed
Hindawi Limited
This research demonstrates the fast synthesis of CH3NH3PbBr3 perovskite powder via antisolvent addition and further thin-film synthesis by one-step spin coating. The structural and optical properties are investigated via X-ray diffraction, Fourier-transform infrared spectroscopy, and UV–Vis spectroscopy. Crystallite sizes are compared by three different size estimation techniques, which range between 95.8 nm and 105 nm. The perovskite showed a higher absorption coefficient over 104 cm−1 and a refractive index from 3.4 to 2.3 in the visible spectrum. The bandgap was estimated via three district methods, which revealed a very slightly varied bandgap in the range of 2.29 eV–2.32 eV.
Mohammad Tanvir Ahmed, Shariful Islam, Muhammad Shahriar Bashar, Md. Abul Hossain, and Farid Ahmed
Hindawi Limited
Organometallic perovskite is one of the potential materials in the various optoelectronic research fields. This study demonstrates the synthesis of CH3NH3PbI3 : ZnS microrods via one-step spin coating for optoelectronic applications. Incorporation of ZnS in the perovskite material caused bandgap variation in the visible wavelength range. Structural and chemical properties have been observed using X-ray diffraction, scanning electron microscope, and Fourier transform infrared spectroscopy. The optical and electrical properties were studied via UV-Vis spectroscopy and impedance analyzer. The addition of ZnS caused to increase the optical absorption coefficient from ∼104 cm−1 to ∼105 cm−1. The bandgaps of the thin films were calculated using the Tauc relation and electrical method, obtained in the range 1.51 eV–1.64 eV, suitable for various optoelectronic applications.
Reshma Khatun, Mohammad Tanvir Ahmed, Shariful Islam, Md. Kamal Hossain, Md. Abul Hossain, and Farid Ahmed
Inderscience Publishers