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1,026 results on '"Singh, Surya Prakash"'

31. Spin orbit coupling and Lorentz force enhanced efficiency of TiO2 based dye sensitized solar cells

Author

Kannan, U. M., Narayana, M. Venkat, Kotnana, Ganesh, Kandhadi, Jaipal, Giribabu, L., Singh, Surya Prakash, and Jammalamadaka, S. Narayana

Subjects
Condensed Matter - Materials Science
Abstract

We report on the effect of the strong spin orbit coupling and the Lorentz force on the efficiency of TiO2 based dye sensitized solar cells. Upon inclusion of Ho2O3, due to the strong spin orbit coupling of the rare earth Ho3+ ion, we do see 13 percent enhancement in the efficiency. We attribute such an enhancement in power conversion efficiency to the increased lifetime of the photo-excited excitons. Essentially, a Ho3+ ion accelerates the phenomenon of the spin rephasing or the intersystem crossing of the excitons in a photosensitizer. Increase in the absorbance and decrease in the photoluminescence intensity suggests a decrease in the recombination rate, hinting an enhanced charge transport and is in accordance with our electrochemical impedance spectra and the J V characteristics. From the above we strongly believe that enhanced efficiency of the device is due to increased intersystem crossing which would accelerate the exciton dissociation. On top of spin orbit interaction, a configuration where the electric and magnetic fields are perpendicular to each other helped in enhancing the efficiency by 16 percent, suggesting that the Lorentz force also plays a dominant role in controlling the charge transport of the photo-generated charge carriers. We strongly believe that this simple and novel strategy of improving the efficiency may pave the way for realizing higher efficiency dye sensitized solar cells.

Published
2017
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32. Amine-Free CsPbBr3 Perovskite Nanocrystals with a Near-Unity Photoluminescence Quantum Yield for a Superfast Photodetector.

Author

Patra, Dinabandhu, Saini, Ankush, Monojit Bag, and Singh, Surya Prakash

Abstract

Herein, we have prepared halide and mixed-halide all-inorganic perovskite nanocrystals (PNCs) using an amine-free synthetic approach. Generally, monohalo-containing halide sources and their mixture have been used to prepare cesium lead halide and mixed-halide PNCs, respectively. In the current study, we made CsPbBr3 PNCs using a low concentration of 1,3-dibromopropane compared to other bromide sources in the earlier reports. The optimized sample has shown a near-unity (98.5%) relative photoluminescence quantum yield with ambient stability for over 3 months and excellent thermal stability. Rhomicuboctahedron- and dodecahedron-shaped orthorhombic CsPbBr3 PNCs were formed with average particle sizes of 25-34 nm. To show the generality of the synthesis method, we have also prepared CsPbCl3 and CsPb-(Cl, Br)3 PNCs using 1,3-dichloropropane, 1-bromo-3-chloropropane, and 1,2-dibromo-3-chloropropane. The synthesis method offers to tune the halide concentration in the mixed-halide PNCs by properly selecting multihalogen groups containing a single precursor. This amine-free CsPbBr3 PNC-based photodetector can detect ultraviolet (UV), blue, and green light. It has shown a superfast rise/fall time of 104/35 μs with a responsivity of 3.03 mA/W and a detectivity of 5.55 × 109 Jones at 40 mW/cm² under the UV light. [ABSTRACT FROM AUTHOR]

Published
2024
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39. Molecular modification of spiro[fluorene-9,9’-xanthene]-based dopant-free hole transporting materials for perovskite solar cells

Author

Kumar, Vinay, primary, Kumar, Deepak, additional, Chavan, Rohit Dinkar, additional, Kumar, Kodali Phani, additional, Yadagiri, Bommaramoni, additional, Ans, Muhammad, additional, Kruszyńska, Joanna, additional, Mahapatra, Apurba, additional, Nawrocki, Jan, additional, Nikiforow, Kostiantyn, additional, Mrkyvkova, Nada, additional, Siffalovic, Peter, additional, Yadav, Pankaj, additional, Akin, Seckin, additional, Singh, Surya Prakash, additional, and Prochowicz, Daniel, additional

Published
2024
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44. Forecasting the impact of epidemic outbreaks on the supply chain: modelling asymptomatic cases of the COVID-19 pandemic.

Author

Jha, Pradeep K., Ghorai, Suvadip, Jha, Rakhi, Datt, Rajul, Sulapu, Gowrishankar, and Singh, Surya Prakash

Subjects
COVID-19 pandemic, BASIC reproduction number, COVID-19, VIRAL transmission, EPIDEMICS, PRECISION farming
Abstract

An epidemic outbreak largely disrupts supply chains (SCs) worldwide through plummeting business confidence, especially when it becomes a pandemic; its unpredictable re-emergence and spreadability may lead to inappropriate decision-making, in turn causing severe economic shocks. In March 2020, the coronavirus disease 2019 (COVID-19) outbreak attained a pandemic level, and many millions of cases were confirmed globally. Many countries reported an increasing number of active cases and formulated long-term lockdown guidelines, which resulted in an unexpected disruption of SCs. A key challenge in this scenario is that the rising number of confirmed COVID-19 cases does not necessarily reflect the already infected or asymptomatic cases. It is thus critical to understand the impact of asymptomatic carriers on the SC, as they may be the key driver of the novel virus spread, disrupting long-term SCs. This paper generalised the susceptible-exposed-infected-recovered (S-E-I-R) approach to create a mathematical model for which the impact of a proposed asymptomatic situation on the SC is evaluated through the basic reproduction number (R0), considered the main driver of SC disruption and the equilibrium status of infection over time. This paper presents an action plan for reducing disruption in the SC based on the R0 of the model. Overall, the current study as validated through a case study suggests that the asymptomatic-situation-based model is more convenient for critically understanding as well as forecasting the outbreak’s impact on SCs. This study also highlights different perspectives of SCs for managing such types of pandemics using modelling approaches. [ABSTRACT FROM AUTHOR]

Published
2023
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