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Suthar R, T A, Dahiya H, Singh AK, Sharma GD, Karak S. Role of Exciton Lifetime, Energetic Offsets, and Disorder in Voltage Loss of Bulk Heterojunction Organic Solar Cells. ACS Appl Mater Interfaces 2023; 15:3214-3223. [PMID: 36601721 DOI: 10.1021/acsami.2c18199] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Recently, the power conversion efficiency (PCE) of organic solar cells (OSCs) has significantly progressed with a rapid increase from 10 to 19% due to state-of-the-art research on nonfullerene acceptor molecules and various device processing strategies. However, OSCs still exhibit significant open circuit voltage loss (ΔVOC ∼ 0.6 V) due to high energetic offsets and molecular disorder. In this work, we present a systematic investigation to determine the effects of energetic offset and disorder on different recombination losses in open circuit voltage (VOC) using 13 different photoactive layers, wherein the PCE and ΔVOC vary in the ranges of 2.21-14.74% and 0.561-1.443 V, respectively. The detailed voltage loss analysis of all these devices was carried out, and voltage losses were correlated with energetic offset and disorder. This has enabled us to identify the key features for minimizing the voltage loss like: (1) a low energy offset between the donor and acceptor molecular states is essential to attain a nonradiative voltage loss (ΔVOC, nrad) as low as ∼200 meV and (2) Urbach energy, which is a measure of the materials' disorder and packing, should be low for the minimization of the radiative voltage loss (ΔVOC, rad). In addition, time-resolved photoluminescence spectroscopy was employed to further understand the exciton dynamics of pristine materials and donor-acceptor blends. It was observed that the absorbers with ultralong exciton lifetime (∼1000 ps) produce higher efficiencies. The current study emphasizes the importance of simultaneously testing photovoltaic performance and active layer exciton dynamics for rational device optimization and opens new prospects for designing novel molecules with fine-tuning of energetic offset and disorder with longer exciton lifetime which is the effective strategy to boost the efficiency of OSCs to their modified Shockley-Queisser (SQ) limit by minimizing radiative and nonradiative voltage losses.
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Affiliation(s)
- Rakesh Suthar
- Organic and Hybrid Electronic Device Laboratory, Department of Energy Science and Engineering, Indian Institute of Technology Delhi, New Delhi110016, India
| | - Abhijith T
- Organic and Hybrid Electronic Device Laboratory, Department of Energy Science and Engineering, Indian Institute of Technology Delhi, New Delhi110016, India
| | - Hemraj Dahiya
- Department of Physics, The LNM Institute of Information Technology, Jaipur, Rajasthan302031, India
| | - Abhishek Kumar Singh
- Department of Electronics Engineering, Rajiv Gandhi Institute of Petroleum Technology, Amethi, Uttar Pradesh229304, India
| | - Ganesh D Sharma
- Department of Physics, The LNM Institute of Information Technology, Jaipur, Rajasthan302031, India
| | - Supravat Karak
- Organic and Hybrid Electronic Device Laboratory, Department of Energy Science and Engineering, Indian Institute of Technology Delhi, New Delhi110016, India
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Abhijith T, E S, Suthar R, Sharma P, Thomas S, Karak S. Understanding the linear and nonlinear optical responses of few-layer exfoliated MoS 2and WS 2nanoflakes: experimental and simulation studies. Nanotechnology 2022; 33:435702. [PMID: 35850090 DOI: 10.1088/1361-6528/ac81d7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/20/2022] [Accepted: 07/17/2022] [Indexed: 06/15/2023]
Abstract
Understanding the linear and nonlinear optical (NLO) responses of two-dimensional nanomaterials is essential to effectively utilize them in various optoelectronic applications. Here, few-layer MoS2and WS2nanoflakes with lateral size less than 200 nm were prepared by liquid-phase exfoliation, and their linear and NLO responses were studied simultaneously using experimental measurements and theoretical simulations. Finite-difference time-domain (FDTD) simulations confirmed the redshift in the excitonic transitions when the thickness was increased above 10 nm indicating the layer-number dependent bandgap of nanoflakes. WS2nanoflakes exhibited around 5 times higher absorption to scattering cross-section ratio than MoS2nanoflakes at various wavelengths. Open aperture Z scan analysis of both the MoS2and WS2nanoflakes using 532 nm nanosecond laser pulses reveals strong nonlinear absorption activity with effective nonlinear absorption coefficient (βeff) of 120 cm GW-1and 180 cm GW-1, respectively, which was attributed to the combined contributions of ground, singlet excited and triplet excited state absorption. FDTD simulation results also showed the signature of strong absorption density of few layer nanoflakes which may be account for their excellent NLO characteristics. Optical limiting threshold values of MoS2and WS2nanoflakes were obtained as ∼1.96 J cm-2and 0.88 J cm-2, respectively, which are better than many of the reported values. Intensity dependent switching from saturable absorption (SA) to reverse SA was also observed for MoS2nanoflakes when the laser intensity increased from 0.14 to 0.27 GW cm-2. The present study provides valuable information to improve the selection of two-dimensional nanomaterials for the design of highly efficient linear and nonlinear optoelectronic devices.
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Affiliation(s)
- T Abhijith
- Organic and Hybrid Electronic Device Laboratory, Department of Energy Science and Engineering, Indian Institute of Technology Delhi, New Delhi 110016, India
| | - Shiju E
- International School of Photonics, Cochin University of Science and Technology, Cochin 682022, Kerala, India
| | - Rakesh Suthar
- Organic and Hybrid Electronic Device Laboratory, Department of Energy Science and Engineering, Indian Institute of Technology Delhi, New Delhi 110016, India
| | - Punit Sharma
- Organic and Hybrid Electronic Device Laboratory, Department of Energy Science and Engineering, Indian Institute of Technology Delhi, New Delhi 110016, India
| | - Sheenu Thomas
- International School of Photonics, Cochin University of Science and Technology, Cochin 682022, Kerala, India
| | - Supravat Karak
- Organic and Hybrid Electronic Device Laboratory, Department of Energy Science and Engineering, Indian Institute of Technology Delhi, New Delhi 110016, India
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Keshtov ML, Kuklin SA, Konstantinov IO, Khokhlov AR, Xie Z, Dou C, Koukaras EN, Suthar R, Sharma GD. Synthesis and Photovoltaic Properties of New Conjugated D‐A Polymers Based on the Same Fluoro‐Benzothiadiazole Acceptor Unit and Different Donor Units. ChemistrySelect 2020. [DOI: 10.1002/slct.201904353] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Mukhaned L Keshtov
- Institute of Organoelement Compounds of the Russian Academy of Sciences Vavilova St., 28 119991 Moscow Russian Federation
| | - Serge. A. Kuklin
- Institute of Organoelement Compounds of the Russian Academy of Sciences Vavilova St., 28 119991 Moscow Russian Federation
| | - Igor O. Konstantinov
- Institute of Organoelement Compounds of the Russian Academy of Sciences Vavilova St., 28 119991 Moscow Russian Federation
| | - Alexei R. Khokhlov
- Department of Physics of Polymers and Crystals, Faculty of Physics M.V. Lomonosov Moscow State University Leninskie Gory 1 119991 Moscow Russia
| | - Zhiyuan Xie
- Changchun Institute of Applied Chemistry Chinese Academy of Sciences Changchun 130022 China
| | - Chuandong Dou
- Changchun Institute of Applied Chemistry Chinese Academy of Sciences Changchun 130022 China
| | - Emmanuel N. Koukaras
- Laboratory of Quantum and Computational Chemistry, Department of Chemistry Aristotle University of Thessaloniki, GR- 54124 Thessaloniki Greece
| | - Rakesh Suthar
- Department of Physics The LNM Institute for Information Technology, Jamdoli, Jaipur 302031, India
| | - Ganesh D. Sharma
- Department of Physics The LNM Institute for Information Technology, Jamdoli, Jaipur 302031, India
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Padmanabha H, Suthar R, Sankhyan N. A randomized controlled trial of the ketogenic diet in refractory childhood epilepsy. Acta Neurol Scand 2018; 137:151. [PMID: 29205271 DOI: 10.1111/ane.12801] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Affiliation(s)
- H. Padmanabha
- Department of Pediatrics; Postgraduate Institute of Medical Education and Research; Chandigarh India
| | - R. Suthar
- Department of Pediatrics; Postgraduate Institute of Medical Education and Research; Chandigarh India
| | - N. Sankhyan
- Department of Pediatrics; Postgraduate Institute of Medical Education and Research; Chandigarh India
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Suthar R, Abdelfattah S, Goldman H, Garcia G, Romero-Fischmann D, Escobar M, Behrens V. Pre-eclampsia and acute pulmonary embolism-the importance of making a differential diagnosis: a case report. J Anesth 2017; 31:903-906. [PMID: 28780596 DOI: 10.1007/s00540-017-2396-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2017] [Accepted: 07/26/2017] [Indexed: 11/29/2022]
Abstract
We describe the case of a 41-year-old pregnant patient who presented at 38 weeks of gestation for an urgent cesarean section, with new onset of pre-eclampsia as the initial diagnosis. The intraoperative course was complicated by seizures and hemodynamic collapse. Initially, the presentation of seizure pointed to pre-eclampsia/eclampsia; however, with careful consideration of each event as it occurred, the correct diagnosis was later determined to be pulmonary embolism and stroke. This case illustrates the importance of considering multiple possible etiologies, even when a particular diagnosis seems obvious.
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Affiliation(s)
- R Suthar
- Department of Anesthesiology, Mount Sinai Medical Center, Miami Beach Anesthesiology Associates, Inc., 4300 Alton Road, Miami Beach, FL, 33140, USA.
| | - S Abdelfattah
- Department of Anesthesiology, Mount Sinai Medical Center, Miami Beach Anesthesiology Associates, Inc., 4300 Alton Road, Miami Beach, FL, 33140, USA
| | - H Goldman
- Department of Anesthesiology, Mount Sinai Medical Center, Miami Beach Anesthesiology Associates, Inc., 4300 Alton Road, Miami Beach, FL, 33140, USA
| | - G Garcia
- Department of Anesthesiology, Mount Sinai Medical Center, Miami Beach Anesthesiology Associates, Inc., 4300 Alton Road, Miami Beach, FL, 33140, USA
| | - D Romero-Fischmann
- Department of Anesthesiology, Mount Sinai Medical Center, Miami Beach Anesthesiology Associates, Inc., 4300 Alton Road, Miami Beach, FL, 33140, USA
| | - M Escobar
- San Juan Bautista School of Medicine, San Juan, Puerto Rico
| | - V Behrens
- Department of Anesthesiology, Mount Sinai Medical Center, Miami Beach Anesthesiology Associates, Inc., 4300 Alton Road, Miami Beach, FL, 33140, USA
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Narayanan G, Froud T, Suthar R, Barbery K, Yrizarry J. Percutaneous irreversible electroporation (IRE) in the management of pancreatic cancer. J Vasc Interv Radiol 2014. [DOI: 10.1016/j.jvir.2013.12.083] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022] Open
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Lohiya NK, Suthar R, Khandelwal A, Goyal S, Ansari AS, Manivannan B. Sperm characteristics and teratology in rats following vas deferens occlusion with RISUG and its reversal. ACTA ACUST UNITED AC 2009; 33:e198-206. [PMID: 19811546 DOI: 10.1111/j.1365-2605.2009.00992.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The functional success of the reversal of vas occlusion by styrene maleic anhydride (RISUG), using the solvent vehicle, Dimethyl Sulphoxide (DMSO), has been investigated. Reversal with DMSO was carried out in Wistar albino rats 90 days after bilateral vas occlusion. The body weight, organ weight, sperm characteristics, fertility test and teratology, including skeletal morphology were evaluated in vas occlusion and reversal animals and in F(1) progenies to assess the functional success of the occlusion and reversal. Body weight, organ weight and the cauda epididymal sperm characteristics of vas occlusion and reversal animals and of F(1) progenies were comparable to control. Ejaculated spermatozoa in the vaginal smear showed detached head/tail, acrosomal damage, bent midpiece, bent tail and morphological aberrations in sperm head after vas occlusion, which returned to normal, 90 days after reversal. Monthly fertility test, post-injection showed 0% fertility, which improved gradually and 100% fertility was achieved 90 days after reversal. The fertility/pregnancy/implantation record and skeletal morphology of the offspring were comparable to control. The results suggest functional success and safety of vas occlusion reversal by DMSO.
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Affiliation(s)
- N K Lohiya
- Centre for Advanced Studies, Department of Zoology, University of Rajasthan, Jaipur, India.
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