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BETA
Jafri, Syed Hassan MujtabaORCID iD iconorcid.org/0000-0003-4713-7146
Alternative names
Publications (10 of 66) Show all publications
Wani, I. H., Jafri, S. H., Wärnå, J., Hayat, A., Li, H., Shukla, V. A., . . . Leifer, K. (2019). A sub 20 nm metal-conjugated molecule junction acting as a nitrogen dioxide sensor. Nanoscale, 11(14), 6571-6575
Open this publication in new window or tab >>A sub 20 nm metal-conjugated molecule junction acting as a nitrogen dioxide sensor
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2019 (English)In: Nanoscale, ISSN 2040-3364, E-ISSN 2040-3372, Vol. 11, no 14, p. 6571-6575Article in journal (Refereed) Published
Abstract [en]

The interaction of a gas molecule with a sensing material causes the highest change in the electronic structure of the latter, when this material consists of only a few atoms. If the sensing material consists of a short, conductive molecule, the sensing action can be furthermore probed by connecting such molecules to nanoelectrodes. Here, we report that NO2 molecules that adhere to 4,4'-biphenyldithiol (BPDT) bound to Au surfaces lead to a change of the electrical transmission of the BPDT. The related device shows reproducible, stable measurements and is so far the smallest (<20 nm) gas sensor. It demonstrates modulation of charge transport through molecules upon exposure to nitrogen dioxide down to concentrations of 55 ppb. We have evaluated several devices and exposure conditions and obtained a close to linear dependence of the sensor response on the gas concentration.

National Category
Nano Technology
Identifiers
urn:nbn:se:uu:diva-381056 (URN)10.1039/c8nr08417c (DOI)000464454400007 ()30916070 (PubMedID)
Funder
Swedish Research CouncilKnut and Alice Wallenberg FoundationGöran Gustafsson Foundation for Research in Natural Sciences and MedicineCarl Tryggers foundation Swedish Energy AgencySwedish Foundation for Strategic Research
Available from: 2019-04-03 Created: 2019-04-03 Last updated: 2019-05-03Bibliographically approved
Han, Y., Li, H., Jafri, S. H., Ossipov, D. A., Hilborn, J. & LEIFER, K. (2019). Graphene Based Mechanical Biosensor by Employing Non-covalent Stacking Functionalization.
Open this publication in new window or tab >>Graphene Based Mechanical Biosensor by Employing Non-covalent Stacking Functionalization
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2019 (English)In: Article in journal, News item (Other academic) Submitted
Abstract [en]

Herein we demonstrate a novel methodology to achieve mechanical biosensor by employing the distinguished interaction forces between the atomic force microscope (AFM) probe and sensor surfaces as the response signal. This mechanical biosensor is fabricated by utilizing the non-covalent π-π stacking of pyrene-maltose onto graphene surfaces with Concanavalin A (Con A) as a target protein. The atomic resolution scanning tunneling microscopy (STM) images indicate the successful formation of the self-assembled and densely packed pyrene-maltose layer on the sensor surface, which gives distinct atomic lattice structure as compared to pristine graphene. This mechanical biosensor exhibits detection of Con A with the sensitivity down to nanomolar level. Therefore, this proposed mechanical biosensor has the potential to be employed in a variety of bio-sensing applications.

National Category
Nano Technology Analytical Chemistry
Identifiers
urn:nbn:se:uu:diva-378559 (URN)
Available from: 2019-03-06 Created: 2019-03-06 Last updated: 2019-04-24
Ghajeri, F., Topalian, Z., Tasca, A., Jafri, S. H., Leifer, K., Norberg, P. & Sjöström, C. (2018). Case Study of a Green Nanoporous Material from Synthesis to Commercialisation: Quartzene®. Current Opinion in Green and Sustainable Chemistry, 12, 101-109
Open this publication in new window or tab >>Case Study of a Green Nanoporous Material from Synthesis to Commercialisation: Quartzene®
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2018 (English)In: Current Opinion in Green and Sustainable Chemistry, ISSN 2452-2236, Vol. 12, p. 101-109Article in journal (Refereed) Published
Abstract [en]

Synthetic amorphous silicas with high porosity (94–97%) are introduced and various pathways for their synthesis are presented. The materials have structures with high surface area (300–750 m2/g) and are commercialised under the name of Quartzene®. Low cost silica sources and ambient pressure drying enable production in large scale with approximately 70% cost reduction as compared to conventional method silica aerogels. The structure is analysed, properties are reported as low density (0.04–0.15 g/ml), low thermal conductivity (24–26 mW/m·K), etc. Formaldehyde gas adsorption tests reveal that the uptake level of samples made by Quartzene® is significantly increased as compared to commercially available adsorbents. Thermal conductivity at elevated temperatures for mixtures of Quartzene® and stone wool shows a 23% reduction at 650 °C as compared to pure stone wool. Scaling up process for this green material meeting environmental sustainability demands in industrial manufacturing is discussed and challenges/current developments are presented.

Place, publisher, year, edition, pages
Elsevier, 2018
Keywords
green nanoporous materials, green chemistry, silica based materials
National Category
Materials Chemistry Engineering and Technology
Research subject
Engineering Science with specialization in Materials Science; Engineering Science with specialization in Materials Analysis
Identifiers
urn:nbn:se:uu:diva-359840 (URN)10.1016/j.cogsc.2018.07.003 (DOI)000445965000017 ()
Funder
EU, Horizon 2020, 718823
Note

Highlights

•Water based chemistry and ambient pressure drying technique is used for synthesis of a silica based nanoporous material.

•Properties are characterized as: 94–97% Porosity, High surface area (300–750 m2/g), Low density (0.04–0.15 g/ml), etc.

•The material is cost-efficient and supports industrial application areas with benign environmental effects.

Available from: 2018-09-06 Created: 2018-09-06 Last updated: 2019-05-13Bibliographically approved
Li, H., Papadakis, R., Jafri, S. H., Thersleff, T., Michler, J., Ottosson, H. & Leifer, K. (2018). Superior adhesion of graphene nanoscrolls. Communications Physics, 1, Article ID 44.
Open this publication in new window or tab >>Superior adhesion of graphene nanoscrolls
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2018 (English)In: Communications Physics, E-ISSN 2399-3650, Vol. 1, article id 44Article in journal (Refereed) Published
Abstract [en]

An emerging material in the carbon family, a graphene nanoscroll (GNS) is composed of tubularly scrolled monolayer graphene and has shown superlubricity and large current sustainability, surpassing the properties of monolayer graphene itself. Here we report on the superior adhesion of GNS prepared with a high yield synthesis method that allows for mass production of high quality GNSs. Raman spectra indicate that the GNS still maintains the signature of monolayer graphene, implying the lacking of pi-stacking between adjacent layers. Importantly, adhesion measurements using atomic force microscopy reveal these GNSs with height range of 120-130 nm show a 2.5-fold stronger adhesion force than pristine graphene. This result potentially indicates that the GNS has higher adhesion than monolayer graphene and even higher than the liquid-solid and hydrogen-bonding enhanced interfaces which are essential types of adhesions involved in the field of physical adhesions and thus, GNS could be a new candidate for super-strong and lightweight devices.

Place, publisher, year, edition, pages
NATURE PUBLISHING GROUP, 2018
National Category
Materials Chemistry Engineering and Technology
Identifiers
urn:nbn:se:uu:diva-362689 (URN)10.1038/s42005-018-0043-2 (DOI)000442027400001 ()
Funder
Knut and Alice Wallenberg FoundationWenner-Gren Foundations
Available from: 2018-11-09 Created: 2018-11-09 Last updated: 2019-05-06Bibliographically approved
Ali, H., Eriksson, J., Li, H., Jafri, S. H., Kumar, M. S., Ögren, J., . . . Leifer, K. (2017). An electron energy loss spectrometer based streak camera for time resolved TEM measurements. Ultramicroscopy, 176, 5-10
Open this publication in new window or tab >>An electron energy loss spectrometer based streak camera for time resolved TEM measurements
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2017 (English)In: Ultramicroscopy, ISSN 0304-3991, E-ISSN 1879-2723, Vol. 176, p. 5-10Article in journal (Refereed) Published
Abstract [en]

We propose an experimental setup based on a streak camera approach inside an energy filter to measure time resolved properties of materials in the transmission electron microscope (TEM). In order to put in place the streak camera, a beam sweeper was built inside an energy filter. After exciting the TEM sample, the beam is swept across the CCD camera of the filter. We describe different parts of the setup at the example of a magnetic measurement. This setup is capable to acquire time resolved diffraction patterns, electron energy loss spectra (EELS) and images with total streaking times in the range between 100 ns and 10 μs.

Keywords
Time resolved; TEM; Energy filter; Streak camera; Sweep
National Category
Physical Sciences Engineering and Technology
Identifiers
urn:nbn:se:uu:diva-329982 (URN)10.1016/j.ultramic.2016.11.026 (DOI)000403992200003 ()
Available from: 2017-09-25 Created: 2017-09-25 Last updated: 2017-11-20Bibliographically approved
Calard, F., Wani, I. H., Hayat, A., Jarrosson, T., Lere-Porte, J.-P., Jafri, S. H., . . . Orthaber, A. (2017). Designing sterically demanding thiolate coated AuNPs for electrical characterization of BPDT in a NP-molecule-nanoelectrode platform. MOLECULAR SYSTEMS DESIGN & ENGINEERING, 2(2), 133-139
Open this publication in new window or tab >>Designing sterically demanding thiolate coated AuNPs for electrical characterization of BPDT in a NP-molecule-nanoelectrode platform
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2017 (English)In: MOLECULAR SYSTEMS DESIGN & ENGINEERING, ISSN 2058-9689, Vol. 2, no 2, p. 133-139Article in journal (Refereed) Published
Abstract [en]

Molecular electronics with single or few molecules requires a stable metal-molecule nanojunction platform. Herein, we report the design and synthesis of gold nanoparticles coated with sterically demanding thiol ligands that are essential to fabricate a versatile and stable nanoelectrode-molecule-nanoparticle platform suitable for electrical characterization of small organic molecules. By combining.-tetraphenylmethane ether functionalized alkyl thioacetate and alkyl thiols, we prepared highly stable gold nanoparticles in a one-phase reaction providing simple and efficient purification. This robust preparation gives highly pure nanoparticles in very high yields (up to 90%) with long-time shelf stability. The synthesis in this work has superior reproducibility compared to previous synthesis processes that are currently being used for such molecular electronics platforms. Electron microscopy confirms the formation of uniform and small nanoparticles in the range of 5 to 7 nm. These nanoparticles with different ligand surface coverages were placed in a 20 nm nanoelectrode setup using dielectrophoretic forces. This setup was utilized to characterize the conductivity of the molecular wire 4,4'-biphenyldithiol introduced via ligand placeexchange under ambient conditions.

Place, publisher, year, edition, pages
ROYAL SOC CHEMISTRY, 2017
National Category
Engineering and Technology
Identifiers
urn:nbn:se:uu:diva-323512 (URN)10.1039/c6me00095a (DOI)000400987200003 ()
Available from: 2017-06-14 Created: 2017-06-14 Last updated: 2018-04-12Bibliographically approved
Li, H., Wani, I. H., Anumol, A., Han, Y., Jafri, S. H., Somobrata, A. & Leifer, K. (2017). Enhanced gas sensing performance of graphene/ZnS-CdS hetero-nanowires gas sensor synthesized by Langmuir-Blodgett self-assembly method. Paper presented at MME 2017 28th Micromechanics and Microsystems Europe workshop. Journal of Physics Conference Series, 922, Article ID 012023.
Open this publication in new window or tab >>Enhanced gas sensing performance of graphene/ZnS-CdS hetero-nanowires gas sensor synthesized by Langmuir-Blodgett self-assembly method
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2017 (English)In: Journal of Physics Conference Series, ISSN 1742-6588, Vol. 922, article id 012023Article in journal, Meeting abstract (Refereed) Published
Abstract [en]

Graphene is a promising material in the field of solid-state gas sensors due to the unique two-dimensional structure. Here, we have shown by fabricating graphene/ZnS-CdS hetero-nanowire structure, the gas sensor sensitivity has a two-fold increase to 20% under 15 ppm gaseous concentration compared to a 10% response in pristine graphene. Spectroscopy and microscopy analysis indicate that the semi-conducting ZnS-CdS hetero-nanowires are 2 nm wide and densely packed on top of graphene. By combining UV illumination, the device approaches a fast response/recovery and high gas sensitivity, thus has a potential to be used in a detection of wide range of gases. 

National Category
Analytical Chemistry Materials Chemistry Engineering and Technology
Identifiers
urn:nbn:se:uu:diva-334517 (URN)10.1088/1742-6596/922/1/012023 (DOI)000419231200023 ()
Conference
MME 2017 28th Micromechanics and Microsystems Europe workshop
Funder
Knut and Alice Wallenberg FoundationSwedish Research Council
Available from: 2017-11-23 Created: 2017-11-23 Last updated: 2019-04-24Bibliographically approved
Ögren, J., Jafri, H., Leifer, K. & Ziemann, V. (2016). Surface Characterization and Field Emission Measurements of Copper Samples inside a Scanning Electron Microscope. In: : . Paper presented at the 7th International Particle Accelerator Conference IPAC16 in Busan, South Korea, May 2016 (pp. 2083-2085).
Open this publication in new window or tab >>Surface Characterization and Field Emission Measurements of Copper Samples inside a Scanning Electron Microscope
2016 (English)Conference paper, Published paper (Other academic)
Abstract [en]

Vacuum breakdown in normal-conducting accelerating structures is a limiting factor for high gradient acceleration.Many aspects of the physics governing the breakdown process and its onset are yet to be fully understood. At Uppsala University we address these questions with an in-situ experi-mental setup mounted in an environmental scanning electron microscope. It consists of a piezo motor driven tungsten needle and a sample surface mounted on a piezo stage, allowing for nano-meter 3D-position control. One of the piezomotors controls the needle-sample gap while the two otherscan across the surface. A DC-voltage up to 1 kV is  applied across the gap and field emission currents from a coppersurface are measured with an electrometer. Here we presentthe setup and some initial results.

National Category
Accelerator Physics and Instrumentation Engineering and Technology
Identifiers
urn:nbn:se:uu:diva-298811 (URN)
Conference
the 7th International Particle Accelerator Conference IPAC16 in Busan, South Korea, May 2016
Available from: 2016-07-08 Created: 2016-07-08 Last updated: 2019-04-24Bibliographically approved
Leifer, K., Jafri, H., Hayat, A., Orthaber, A., Fransson, J., Grigoriev, A., . . . Ottosson, H. (2015). A 10-nm sized few molecule portable platform to assess molecular electronics properties. In: : . Paper presented at Non organic polymers, Uppsala.
Open this publication in new window or tab >>A 10-nm sized few molecule portable platform to assess molecular electronics properties
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2015 (English)Conference paper, Oral presentation with published abstract (Other academic)
National Category
Natural Sciences Engineering and Technology
Identifiers
urn:nbn:se:uu:diva-285512 (URN)
Conference
Non organic polymers, Uppsala
Available from: 2016-04-19 Created: 2016-04-19 Last updated: 2019-04-24Bibliographically approved
Orthaber, A., Löfås, H., Öberg, E., Grigoriev, A., Wallner, A., Jafri, S. M., . . . Ott, S. (2015). Cooperative Gold Nanoparticle Stabilization by Acetylenic Phosphaalkenes [Letter to the editor]. Angewandte Chemie International Edition, 54(36), 10634-10638
Open this publication in new window or tab >>Cooperative Gold Nanoparticle Stabilization by Acetylenic Phosphaalkenes
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2015 (English)In: Angewandte Chemie International Edition, ISSN 1433-7851, E-ISSN 1521-3773, Vol. 54, no 36, p. 10634-10638Article in journal, Letter (Refereed) Published
National Category
Other Engineering and Technologies
Identifiers
urn:nbn:se:uu:diva-259963 (URN)10.1002/anie.201504834 (DOI)000360312800045 ()26211907 (PubMedID)
Funder
Swedish Research Council
Available from: 2015-08-13 Created: 2015-08-13 Last updated: 2019-04-24Bibliographically approved
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0003-4713-7146

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