Appu Kumar Singh

@iiserb.ac.in

Post Doctoral Fellow, Electrical Engineering and Computer Science
Indian Institute of Science Education and Research Bhopal

Appu Kumar Singh


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https://researchid.co/appusingh94242

EDUCATION

PhD, Indian Institute of Technology Kharagpur, India

RESEARCH, TEACHING, or OTHER INTERESTS

Electronic, Optical and Magnetic Materials, Materials Chemistry, Mechanical Engineering, Surfaces, Coatings and Films
16

Scopus Publications

211

Scholar Citations

8

Scholar h-index

7

Scholar i10-index

Scopus Publications

  • Pressure-driven semiconductor-metal transition in two-dimensional InSiTe3: a DFT study of thermoelectric and optoelectronic properties
    Appu Kumar Singh, Dhiman Banik, PR Sreeram, Chandra Sekhar Tiwary, Tarun Kumar Kundu
    Computational Materials Science, 2025
  • Enhanced thermoelectric performance of sustainable earth-abundant two-dimensional Galena (PbS)
    Appu Kumar Singh, R. Karthik, Sreeram Punathil Raman, Tarun Kumar Kundu, Chanda Sekhar Tiwary
    Journal of Materials Science, 2025
  • Enhanced Thermoelectric Performance of Nanostructured 2D Tin Telluride
    Appu Kumar Singh, Rajeev Karthik, Punathil Raman Sreeram, Tarun Kumar Kundu, Chandra Sekhar Tiwary
    Small, 2024
    A lot of experimental studies are conducted on theoretically predicted thermoelectric 2D materials. Such materials can pave the way for charging ultra‐thin electronic devices, self‐charging wearable devices, and medical implants. This study systematically explores the thermoelectric attributes of bulk and 2D nanostructured Tin Telluride (SnTe), employing experimental investigations and theoretical analyses based on semiclassical Boltzmann transport theory. The bulk SnTe is synthesized through flame melting, while the 2D SnTe is produced via liquid phase exfoliation. The comprehensive assessment of thermoelectric properties integrated experimental measurements utilizing a Physical Property Measurement System and theoretical calculations from the BoltzTraP code. Experimental thermoelectric studies show a high ZT of 0.17 for 2D SnTe when compared to bulk (0.005) at room temperature. This rise in ZT is due to the high Seebeck coefficient and low thermal conductivity of nanostructured 2D SnTe. Density functional theory (DFT) studies reveal the contribution of the density of states (DOS) and energy bandgap in enhancing the Seebeck coefficient and lowering thermal conductivity by interface scattering.
  • Sachharomyces Cerevisae Dry Powder-Mediated Exfoliation of Graphite Chunks into Functionalized Few-Layer Graphene
    Reddhy Mahle, Swathi Suran, Appu Singh, Partha Kumbhakar, Douglas S. Galvao, Venkata Ravi Sankar Cheela, Brajesh Dubey, Rahul R. Nair, Chandra S. Tiwary, Rintu Banerjee
    ACS Sustainable Chemistry and Engineering, 2024
    Owing to the active production of metabolites during reproduction and growth, microbial cells have been incessantly explored for their potential in the fabrication and functionalization of inorganic materials. Yeast cells, which are nonpathogenic microbes, exhibit biotransformation reactions and the potential to modify functional groups when grown under fermentative conditions. Here, we attempted to delay graphite chunks into graphene flakes by incubating them with dry Sachharomyces cerevisae powder. The evident delamination/thinning of graphene layers was demonstrated using microscopic and spectroscopic analyses which confirmed the exfoliation of graphite to few-layer graphene (FLG). The gate-to-gate life cycle assessment (LCA) of the developed process established the sustainability and environmental hotspots for the approach. Our study demonstrates the facile, green, and sustainable exfoliation of graphite using off-the-shelf materials in laboratories or kitchens and can be scaled up to industry levels. Yeast cells were also explored for the exfoliation of another 2D material, MoS2, and showed the potential to flake off the bulk structure into few MoS2 sheets.
  • Giant Stark effect assisted radio frequency energy harvesting using atomically thin earth-abundant iron sulphide (FeS2)
    Karthik R., Appu Kumar Singh, Shreyasi Das, Suman Sarkar, Tarun Kumar Kundu, Swastik Kar, P. R. Sreeram, Chandra Sekhar Tiwary
    Journal of Materials Chemistry A, 2024
    2D FeS2 has the potential to convert ambient radiofrequency electromagnetic radiation signals into usable energy, which can be utilized to power portable and wearable electronic devices.
  • Energy Harvesting Using High-Strength and Flexible 3D-Printed Cellulose/Hexagonal Boron Nitride Nanosheet Composites
    Anjali Jayakumar, Rushikesh S. Ambekar, Preeti Lata Mahapatra, Appu Kumar Singh, Tarun Kumar Kundu, Sreeram P R, Rahul R. Nair, Chandra Sekhar Tiwary
    ACS Applied Nano Materials, 2023
    As a natural polymer, cellulose is abundant, low-cost, robust, and biodegradable and can be chemically modified. This work explores the enhancement of mechanical, thermal, and flexoelectric properties of three-dimensional (3D)-printed carboxymethyl cellulose (CMC) due to the addition of mechanically exfoliated hexagonal boron nitride (hBN). hBN was observed to act as a rheology modifier, and CMC reinforced with 2% hBN exhibited the maximum apparent viscosity of 12.24 Pa·s at a shear rate of 100 s–1. The 0.5% hBN/CMC film exhibited the highest mechanical and thermal stability. A flexoelectric energy harvester was fabricated out of 3D-printed hBN/CMC composites to test the effectiveness of strain-induced charge production. By varying the load resistance and applied pressure, we were able to measure the voltage and current flowing through the device. We found that a load resistance of 180 kΩ connected across a 2% hBN/CMC device resulted in the highest power delivery of 5.5 nW. When mechanical strain is applied, a charge state fluctuation and spontaneous polarization in the hBN/CMC matrix are seen. This phenomenon can be explained based on the flexoelectric energy-harvesting mechanism, supported by density functional theory (DFT) calculations.
  • Energy harvesting using two-dimensional magnesiochromite (MgCr2O4)
    P.L. Mahapatra, A.K. Singh, R. Tromer, P. Kumbhakar, S.K. Sinha, B. Lahiri, T.K. Kundu, D.S. Galvao, C.S. Tiwary
    Materials Today Nano, 2023
  • Highly Sensitive Pyroelectric Detector Using Atomically Thin Nanoscale Silicon Ditelluride
    Karthik R, Sreeram P R, Appu Kumar Singh, M. R. Anantharaman, Shan Abraham Sam, Suman Sarkar, Tarun Kumar Kundu, Chandra Sekhar Tiwary
    ACS Applied Nano Materials, 2023
    Two-dimensional (2D) materials are increasingly being used as detectors and are gaining popularity due to the advantage of tunability of their electrical and thermal properties. Certain non-centrosymmetric materials exhibit a property known as pyroelectricity, which can be utilized to detect infrared (IR) radiation. On the other hand, the pyroelectric effect can be induced in centrosymmetric materials by making them react to external stimuli that break up their symmetry. Here, we report the pyroelectric behavior of a centrosymmetric 2D SiTe2 by inducing interface polarization in a Schottky junction. For this bulk, SiTe2 was synthesized via induction melting and its 2D counterpart via liquid-phase exfoliation. A pyroelectric photodetector in Au/p-SiTe2/ITO configuration was fabricated. The electrical studies confirm the formation of a Schottky junction. The 2D SiTe2-based pyroelectric detector exhibited a high pyroelectric coefficient of 3.73 mC/m2 K and a good responsivity of 3.9 × 105 Jones. The obtained pyroelectric coefficient using 2D SiTe2 was remarkably superior to that of conventional bulk materials. This enhanced property arises from the combined effect of the two-dimensional nature of the material and the induced interface polarization in the device. We employed density functional theory to support our experimental observations. The performance results suggest that 2D SiTe2 could be a benchmark candidate for ultrafast pyroelectric detectors.
  • Energy harvesting from radio waves using few-layer 2D galena (galenene)
    Karthik R, Appu Kumar Singh, P R Sreeram, Preeti Lata Mahapatra, Douglas S. Galvao, Chandra Sekhar Tiwary
    Nanoscale, 2023
    Radiofrequency (RF) energy harvesting is receiving increased attention in today's digital era due to its potential to replace or improve the longevity of energy storage devices in low-power IoT devices.
  • Energy harvesting using two-dimensional (2D) d-silicates from abundant natural minerals
    Preeti Lata Mahapatra, Appu Kumar Singh, Raphael Tromer, Karthik R., Ambresha M., Gelu Costin, Basudev Lahiri, Tarun Kumar Kundu, P. M. Ajayan, Eric I. Altman, Douglas S. Galvao, Chandra Sekhar Tiwary
    Journal of Materials Chemistry C, 2023
    This paper demonstrates the exfoliation of naturally occurring silicates into two-dimensional structures. Moving the d-silicate device repeatedly in a vertical direction causes it to react robotically and generate up to ∼400 mV of voltage.
  • Anaerobe Syntrophic Co-culture-Mediated Green Synthesis of Ultrathin Niobium Carbide (NbC) Sheets for Flexoelectricity Generation
    Reddhy Mahle, Preeti Lata Mahapatra, Appu Kumar Singh, Partha Kumbhakar, Manas Paliwal, Chandra Sekhar Tiwary, Rintu Banerjee
    ACS Sustainable Chemistry and Engineering, 2022
  • Energy Harvesting Using Cotton Fabric Embedded with 2D Hexagonal Boron Nitride
    Preeti L. Mahapatra, Appu K. Singh, Basudev Lahiri, Tarun K. Kundu, Ajit K. Roy, Partha Kumbhakar, Chandra S. Tiwary
    ACS Applied Materials and Interfaces, 2022
  • Review of strategies toward the development of alloy two-dimensional (2D) transition metal dichalcogenides
    Appu Kumar Singh, Partha Kumbhakar, Aravind Krishnamoorthy, Aiichiro Nakano, Kishor Kumar Sadasivuni, Priya Vashishta, Ajit K. Roy, Vidya Kochat, Chandra Sekhar Tiwary
    Iscience, 2021
  • Thermoelectric performance of nanostructured PbSnTeSe high entropy thermoelectric alloy synthesized via spark plasma sintering
    Arun Raphel, Appu Kumar Singh, P. Vivekanandhan, S. Kumaran
    Physica B Condensed Matter, 2021
  • High entropy stabilization and band engineering driven high figure of merit in nanostructured PbSn0.875TeSeBi0.125 alloy
    Arun Raphel, Vivekanandhan P, Appu Kumar Singh, Kumaran S
    Journal of Solid State Chemistry, 2021
  • Exhaust manifold waste heat recovery system of a single cylinder engine
    Neha Tiwari, Appu Kumar Singh, Tejas Vishwakarma, Harshal Sharma, Mohammed Suhail
    Applied Mechanics and Materials, 2014

RECENT SCHOLAR PUBLICATIONS

  • Impact of bond angle distortions on the temperature dependent band structure and subthreshold swing behavior of UTB SOI MOSFETs
    Y Dhote, S Ghosh, NV Mishra, AK Singh, AS Medury
    Journal of Physics D: Applied Physics 59 (1), 015306 , 2026
    2026.0
  • Pressure-driven semiconductor-metal transition in two-dimensional InSiTe3: a DFT study of thermoelectric and optoelectronic properties
    AK Singh, D Banik, PR Sreeram, CS Tiwary, TK Kundu
    Computational Materials Science 258, 114113 , 2025
    2025.0
    Citations: 4
  • Enhanced thermoelectric performance of sustainable earth-abundant two-dimensional Galena (PbS)
    AK Singh, R Karthik, S Punathil Raman, TK Kundu, CS Tiwary
    Journal of Materials Science 60 (3), 1348-1360 , 2025
    2025.0
    Citations: 6
  • Enhanced thermoelectric performance of nanostructured 2D tin telluride
    AK Singh, R Karthik, PR Sreeram, TK Kundu, CS Tiwary
    Small 20 (43), 2403728 , 2024
    2024.0
    Citations: 24
  • Sachharomyces Cerevisae Dry Powder-Mediated Exfoliation of Graphite Chunks into Functionalized Few-Layer Graphene
    R Mahle, S Suran, A Singh, P Kumbhakar, DS Galvao, VRS Cheela, ...
    ACS Sustainable Chemistry & Engineering 12 (32), 11891-11900 , 2024
    2024.0
    Citations: 7
  • Understanding of potentization process of homoeopathic medicine of Aurum Metallicum and its characterisation
    P Kumbhakar, V Kumara, A Kumar
    Journal of Integrated Standardized Homoeopathy 7 (1), 4-18 , 2024
    2024.0
    Citations: 6
  • Giant Stark effect assisted radio frequency energy harvesting using atomically thin earth-abundant iron sulphide (FeS 2)
    R Karthik, AK Singh, S Das, S Sarkar, TK Kundu, S Kar, PR Sreeram, ...
    Journal of Materials Chemistry A 12 (15), 8940-8951 , 2024
    2024.0
    Citations: 7
  • Energy harvesting using two-dimensional magnesiochromite (MgCr2O4)
    PL Mahapatra, AK Singh, R Tromer, P Kumbhakar, SK Sinha, B Lahiri, ...
    Materials today nano 23, 100374 , 2023
    2023.0
    Citations: 9
  • Energy harvesting using high-strength and flexible 3D-printed cellulose/hexagonal boron nitride nanosheet composites
    A Jayakumar, RS Ambekar, PL Mahapatra, AK Singh, TK Kundu, S PR, ...
    ACS Applied Nano Materials 6 (15), 14278-14288 , 2023
    2023.0
    Citations: 18
  • Highly Sensitive Pyroelectric Detector Using Atomically Thin Nanoscale Silicon Ditelluride
    CST Karthik R, Sreeram P R*, Appu Kumar Singh, M. R. Anantharaman, Shan ...
    ACS Applied Nano Materials 6 (12), 10168–10177 , 2023
    2023.0
    Citations: 4
  • Energy harvesting from radio waves using few-layer 2D galena (galenene)
    R Karthik, AK Singh, PR Sreeram, PL Mahapatra, DS Galvao, CS Tiwary
    Nanoscale 15 (20), 9022-9030 , 2023
    2023.0
    Citations: 4
  • Energy harvesting using two-dimensional (2D) d-silicates from abundant natural minerals
    PL Mahapatra, AK Singh, R Tromer, G Costin, B Lahiri, TK Kundu, ...
    Journal of Materials Chemistry C 11 (6), 2098-2106 , 2023
    2023.0
    Citations: 21
  • Anaerobe syntrophic co-culture-mediated green synthesis of ultrathin niobium carbide (NbC) sheets for flexoelectricity generation
    R Mahle, PL Mahapatra, AK Singh, P Kumbhakar, M Paliwal, CS Tiwary, ...
    ACS Sustainable Chemistry & Engineering 10 (41), 13650-13660 , 2022
    2022.0
    Citations: 16
  • Review of strategies toward the development of alloy two-dimensional (2D) transition metal dichalcogenides
    AK Singh, P Kumbhakar, A Krishnamoorthy, A Nakano, KK Sadasivuni, ...
    Iscience 24 (12) , 2021
    2021.0
    Citations: 44
  • Thermoelectric performance of nanostructured PbSnTeSe high entropy thermoelectric alloy synthesized via spark plasma sintering
    A Raphel, AK Singh, P Vivekanandhan, S Kumaran
    Physica B: Condensed Matter 622, 413319 , 2021
    2021.0
    Citations: 26
  • High entropy stabilization and band engineering driven high figure of merit in nanostructured PbSn0. 875TeSeBi0. 125 alloy
    A Raphel, P Vivekanandhan, AK Singh, S Kumaran
    Journal of Solid State Chemistry 303, 122531 , 2021
    2021.0
    Citations: 12
  • Exhaust Manifold Waste Heat Recovery System of a Single Cylinder Engine
    N Tiwari, AK Singh, T Vishwakarma, H Sharma, M Suhail
    Applied Mechanics and Materials 592, 1534-1538 , 2014
    2014.0
    Citations: 2
  • Heat Transient in the Circular Finned Cylindrical pipe with the Application of an Off-feed Axis Solar Concentrating Collector
    AK Singh, A Singh
  • Off-feed Axis Solar Concentrating Collector with a β-configuration Stirling Engine
    AK Singh, T Vishwakarma, H Sharma, M Suhail, N Tiwari
  • Flexoelectric Energy Harvesting Using 2d Magnesiochromite (Mgcr2o4)
    PL Mahapatra, AK Singh, P Kumbhakar, R Tromer, SK Sinha, B Lahiri, ...
    Available at SSRN 4077756 , 0
    Citations: 1

MOST CITED SCHOLAR PUBLICATIONS

  • Review of strategies toward the development of alloy two-dimensional (2D) transition metal dichalcogenides
    AK Singh, P Kumbhakar, A Krishnamoorthy, A Nakano, KK Sadasivuni, ...
    Iscience 24 (12) , 2021
    2021.0
    Citations: 44
  • Thermoelectric performance of nanostructured PbSnTeSe high entropy thermoelectric alloy synthesized via spark plasma sintering
    A Raphel, AK Singh, P Vivekanandhan, S Kumaran
    Physica B: Condensed Matter 622, 413319 , 2021
    2021.0
    Citations: 26
  • Enhanced thermoelectric performance of nanostructured 2D tin telluride
    AK Singh, R Karthik, PR Sreeram, TK Kundu, CS Tiwary
    Small 20 (43), 2403728 , 2024
    2024.0
    Citations: 24
  • Energy harvesting using two-dimensional (2D) d-silicates from abundant natural minerals
    PL Mahapatra, AK Singh, R Tromer, G Costin, B Lahiri, TK Kundu, ...
    Journal of Materials Chemistry C 11 (6), 2098-2106 , 2023
    2023.0
    Citations: 21
  • Energy harvesting using high-strength and flexible 3D-printed cellulose/hexagonal boron nitride nanosheet composites
    A Jayakumar, RS Ambekar, PL Mahapatra, AK Singh, TK Kundu, S PR, ...
    ACS Applied Nano Materials 6 (15), 14278-14288 , 2023
    2023.0
    Citations: 18
  • Anaerobe syntrophic co-culture-mediated green synthesis of ultrathin niobium carbide (NbC) sheets for flexoelectricity generation
    R Mahle, PL Mahapatra, AK Singh, P Kumbhakar, M Paliwal, CS Tiwary, ...
    ACS Sustainable Chemistry & Engineering 10 (41), 13650-13660 , 2022
    2022.0
    Citations: 16
  • High entropy stabilization and band engineering driven high figure of merit in nanostructured PbSn0. 875TeSeBi0. 125 alloy
    A Raphel, P Vivekanandhan, AK Singh, S Kumaran
    Journal of Solid State Chemistry 303, 122531 , 2021
    2021.0
    Citations: 12
  • Energy harvesting using two-dimensional magnesiochromite (MgCr2O4)
    PL Mahapatra, AK Singh, R Tromer, P Kumbhakar, SK Sinha, B Lahiri, ...
    Materials today nano 23, 100374 , 2023
    2023.0
    Citations: 9
  • Sachharomyces Cerevisae Dry Powder-Mediated Exfoliation of Graphite Chunks into Functionalized Few-Layer Graphene
    R Mahle, S Suran, A Singh, P Kumbhakar, DS Galvao, VRS Cheela, ...
    ACS Sustainable Chemistry & Engineering 12 (32), 11891-11900 , 2024
    2024.0
    Citations: 7
  • Giant Stark effect assisted radio frequency energy harvesting using atomically thin earth-abundant iron sulphide (FeS 2)
    R Karthik, AK Singh, S Das, S Sarkar, TK Kundu, S Kar, PR Sreeram, ...
    Journal of Materials Chemistry A 12 (15), 8940-8951 , 2024
    2024.0
    Citations: 7
  • Enhanced thermoelectric performance of sustainable earth-abundant two-dimensional Galena (PbS)
    AK Singh, R Karthik, S Punathil Raman, TK Kundu, CS Tiwary
    Journal of Materials Science 60 (3), 1348-1360 , 2025
    2025.0
    Citations: 6
  • Understanding of potentization process of homoeopathic medicine of Aurum Metallicum and its characterisation
    P Kumbhakar, V Kumara, A Kumar
    Journal of Integrated Standardized Homoeopathy 7 (1), 4-18 , 2024
    2024.0
    Citations: 6
  • Pressure-driven semiconductor-metal transition in two-dimensional InSiTe3: a DFT study of thermoelectric and optoelectronic properties
    AK Singh, D Banik, PR Sreeram, CS Tiwary, TK Kundu
    Computational Materials Science 258, 114113 , 2025
    2025.0
    Citations: 4
  • Highly Sensitive Pyroelectric Detector Using Atomically Thin Nanoscale Silicon Ditelluride
    CST Karthik R, Sreeram P R*, Appu Kumar Singh, M. R. Anantharaman, Shan ...
    ACS Applied Nano Materials 6 (12), 10168–10177 , 2023
    2023.0
    Citations: 4
  • Energy harvesting from radio waves using few-layer 2D galena (galenene)
    R Karthik, AK Singh, PR Sreeram, PL Mahapatra, DS Galvao, CS Tiwary
    Nanoscale 15 (20), 9022-9030 , 2023
    2023.0
    Citations: 4
  • Exhaust Manifold Waste Heat Recovery System of a Single Cylinder Engine
    N Tiwari, AK Singh, T Vishwakarma, H Sharma, M Suhail
    Applied Mechanics and Materials 592, 1534-1538 , 2014
    2014.0
    Citations: 2
  • Flexoelectric Energy Harvesting Using 2d Magnesiochromite (Mgcr2o4)
    PL Mahapatra, AK Singh, P Kumbhakar, R Tromer, SK Sinha, B Lahiri, ...
    Available at SSRN 4077756 , 0
    Citations: 1
  • Impact of bond angle distortions on the temperature dependent band structure and subthreshold swing behavior of UTB SOI MOSFETs
    Y Dhote, S Ghosh, NV Mishra, AK Singh, AS Medury
    Journal of Physics D: Applied Physics 59 (1), 015306 , 2026
    2026.0
  • Heat Transient in the Circular Finned Cylindrical pipe with the Application of an Off-feed Axis Solar Concentrating Collector
    AK Singh, A Singh
  • Off-feed Axis Solar Concentrating Collector with a β-configuration Stirling Engine
    AK Singh, T Vishwakarma, H Sharma, M Suhail, N Tiwari