Amina Zafar

Amina Zafar
PINSTECH

Doctor of Philosophy

About

27
Publications
4,640
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332
Citations

Publications

Publications (27)
Article
The detection of cholesterol is very crucial in clinical diagnosis for rapid and accurate monitoring of multiple disease-biomarkers. There is a great need for construction of a highly reliable and stable electrocatalyst for the efficient detection of cholesterol. In this work, mesoporous NiCo2S4nanoflakes of enhanced electrochemical properties are...
Article
Nanomaterial synergy in a hybrid system offers an unprecedented opportunity for the development of high-performance energy storage devices. In this work, to intrinsically boost the lithium storage properties of layered structure V2O5, hybrid systems involving V2O5/MWCNTs are synthesized and investigated as cathode materials for lithium-ion batterie...
Article
The development of a reliable non-enzymatic multi-analyte biosensor is remained a great challenge for biomedical and industrial applications. In this prospective, rationally designed electrode materials having voltage switchable electrocatalytic properties are highly promising. Here, we report vanadium doped ZnO engineered nanostructures (Zn1-xVxO...
Article
The synthesis of one-dimensional heterostructures having high dielectric constant and low dielectric loss has remained a great challenge. Until now, the dielectric performance of ZnO-ZnS heterostructures was scarcely investigated. In this work, large-scale ZnO-ZnS heterostructures were synthesized by employing the chemical vapor deposition method....
Article
Full-text available
The thinnest light disk is demonstrated at the atomic level by developing an erasable method to directly write encrypted information onto WS2 monolayers. The write‐in is realized by precise control of photoluminescence emission by means of ozone functionalization and scanning focused laser beam. The visual decryption and reading‐out of information...
Article
Full-text available
Thinnest Light Disk In article number 2103140, Hongwei Liu, Junpeng Lu, Yunfei Chen, Zhenhua Ni, and co-workers present the thinnest light disk with an encryption functionality based on WS2 monolayers. The writing-in and reading-out of information are enabled by directly controlling the fluorescence contrast of the WS2 monolayers. The writing speed...
Article
Full-text available
This paper presents the fluorescence manipulation of Rhodamine-6G (R6G) due to Au nanoparticles (Au-NPs) covered by pristine graphene and hydrogen-terminated graphene. By taking florescence signals of R6G on a quartz substrate as the standard reference, we observe an ∼fourfold increase in fluorescence intensity of R6G on bare Au-NPs deposited on th...
Article
Multiaxial molecular ferroelectrics (MFe) attain great attention due to their number of equivalent ferroelectric axes, an essential characteristic for many applications of these polar polycrystalline materials. Here we report a systematic approach to reveal the temperature‐dependent Raman spectroscopic investigation of the vibrational properties of...
Article
We present a simple, but rapid and accurate approach to identify the layer number of graphene oxide (GO) by using its thermally enhanced optical contrast via vacuum heating. As expected, changes have been observed both in the thicknesses and chemical structures of the material upon the thermal treatment, which can be attributed to the reduction of...
Article
van der Waals (vdW) heterostructures constructed by stacking different two dimensional layered materials are extensively utilized in designing novel optoelectronic devices, such as photodetectors and light-emitting diodes. However, the performance of vertical heterostructures is impeded by challenges in effectively achieving interlayer coupling. He...
Article
Ferroelectric thin films are extensively attractive as next-generation non-volatile memories. Recently molecular ferroelectrics (MFe), as an emerging new class, have been a new research focus due to their desirable characteristics such as good solution processability, tunable chemical properties and bio-friendly compositions. However, traditional u...
Article
Full-text available
Defect‐induced trap states are essential in determining the performance of semiconductor photodetectors. The de‐trap time of carriers from a deep trap can be prolonged by several orders of magnitude as compared to shallow traps, resulting in additional decay/response time of the device. Here, it is demonstrated that the trap states in 2D ReS2 can b...
Preprint
Defect induced trap states are essential in determining the performance of semiconductor photodetectors. The de-trap time of carriers from a deep trap could be prolonged by several orders of magnitude as compared to shallow trap, resulting in additional decay/response time of the device. Here, we demonstrate that the trap states in two-dimensional...
Article
Ultrathin indium selenide (InSe), as a newly emerging two-dimensional material with high carrier mobility and broadband optical absorption, is considered as a promising candidate for electronic and optoelectronic devices. It has been a challenge to produce air-stable mono- or few-layer InSe nanosheets because they degrade rapidly in an ambient envi...
Article
Full-text available
Two-dimensional (2D) InSe is an attractive semiconductor because of its bandgap in the near infrared region, high carrier mobility and chemical stability. Here, we present systematic investigations on the layer-dependent optical properties of few-layer InSe (2–6 layers). We develop a quantitative calibration map using optical images and Raman and p...
Article
Monolayer transition metal dichalcogenides (TMDs) such as MoS2 and WS2 have been considered as promising candidate materials in nanophotonic applications. However, the structure stability of TMDs based optoelectronic devices is highly sensitive to the working environment. Here we present a successive photoluminescence study of the thermal stability...
Article
Electron–phonon coupling enhancement in metal-doped single-layer graphene has been investigated. Different metal adatoms were deposited on chemical vapor deposition (CVD) graphene and annealed at high temperature under vacuum. The interaction between these metals and graphene was studied by Raman spectroscopy. A significant variation in peak width...
Article
Full-text available
In this letter, a high-performance graphene-based electrostatic field sensor is demonstrated. Combining the ultrahigh mobility of graphene and the long lifetime of carriers in SiO 2 /lightly doped Si substrate, our device achieves a fast response of ~2 μs and detection limit of electrostatic potential as low as ~5 V, which is improved by an order o...
Article
Two-dimensional (2D) molybdenum disulfide (MoS2) is considered as a promising candidate for electronic and optoelectronic devices. However, structural defects in MoS2 are widely reported and can greatly degrade its electrical and optical properties. In this work, we investigate the structural defects in MoS2 by low temperature photoluminescence (PL...
Article
The optical emission efficiency of two dimensional layered transition metal dichalcogenides (TMDs) is one of the most important parameter that affects their optoelectronic performance. Optimization of growth parameters of chemical vapor deposition (CVD) to achieve optoelectronics-grade quality TMDs is therefore highly desirable. Here, we present a...
Article
The two-dimensional structure and unique properties make graphene an efficient candidate to strengthen the electrical and mechanical characteristics of polymer composites. The effectiveness for improving the electrical property of composites strongly depends on the size, electrical conductivity and dispersion of graphene fillers in polymer matrix....
Article
We report on the manipulation of the fluorescence quenching of Rhodamine 6G (R6G) on graphene by defect engineering via hydrogen and Ar+ plasma treatments. The amount and nature of defects in graphene were estimated on the basis of the Raman intensity ratios I(D)/I(G) and I(D)/I(D') of graphene. Results showed that the quenching factor (QF) gradual...
Article
Full-text available
Three-dimensional (3D) carbon nano-materials, e.g. a graphene sponge (GS) are promising candidates for the removal of pollutants and the separation of oil and water. A systematic study on how oils or organic solvents disperse in the porous structures of 3D carbon nano-materials, and the factors affecting their sorption process, would be beneficial...
Article
We investigated electrical properties of nanostructured La1−x Srx FeO3 (0 ≤ x ≤ 1) from 300 K–400 K. The nanostructured La1−x Srx FeO3 (0 ≤ x ≤ 1) was synthesized by citrate gel method requiring no pH control. X-ray diffraction pattern showed that single phase LaFeO3 with an orthorhombic structure was formed. The structure changed into rhombohedral...
Article
The gamma radiation-induced degradation of environmental pollutant methoxychlor in water was investigated. A Co-60 gamma radiation source with a dose rate of 372 Gy h(-1) was used for gamma irradiation of 1 mg L-1 and 10 mg L-1 methoxychlor in water with a varied absorbed dose of 1-5 kGy. A single step clean up and pre-concentration procedure based...
Conference Paper
Full-text available
Nanocrystelline La<sub>1-x</sub>Sr<sub>x</sub>FeO<sub>3</sub> (0≤x≤1) was prepared by sol gel citrate method. The structural characterization of the compound was carried out by XRD and SEM. X-Ray diffraction showed that single phase LaFeO<sub>3</sub> was formed with an orthorhombic structure. DC measurements of the prepared material were investigat...

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