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Prof. S. Ravi P. Silva
Advanced Technology Institute, University of Surrey, Guildford GU2 7XH, UK

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0 Nanotechnology
0 Solar Cells
0 energy materials
0 water technology
0 Nano-biotechnology

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Paper
Published: 09 July 2021 in Materials Advances
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Ruddlesden–Popper phase (RPP) perovskites of the form A1n−1A22BnX3n+1 show great promise in stable photovoltaic (PV) devices or as light emitting diodes (LEDs), by allowing for the mixing of 2D materials and tuning of the band gap over a large energy range.

ACS Style

Cameron C. L. Underwood; J. David Carey; S. Ravi P. Silva. Influence of A site cation on nonlinear band gap dependence of 2D Ruddlesden–Popper A2Pb1−xSnxI4 perovskites. Materials Advances 2021, 1 .

AMA Style

Cameron C. L. Underwood, J. David Carey, S. Ravi P. Silva. Influence of A site cation on nonlinear band gap dependence of 2D Ruddlesden–Popper A2Pb1−xSnxI4 perovskites. Materials Advances. 2021; ():1.

Chicago/Turabian Style

Cameron C. L. Underwood; J. David Carey; S. Ravi P. Silva. 2021. "Influence of A site cation on nonlinear band gap dependence of 2D Ruddlesden–Popper A2Pb1−xSnxI4 perovskites." Materials Advances , no. : 1.

Research article
Published: 01 July 2021 in ENERGY & ENVIRONMENTAL MATERIALS
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Understanding the fundamental properties of metal halide perovskite materials is driving the development of novel optoelectronic applications. Here, we report the observation of a recoverable laser-induced fluorescence quenching phenomenon in perovskite films with a microscopic grain-scale restriction, accompanied by spectral variations. This fluorescence quenching depends on the laser intensity and the dwell time under Auger recombination dominated conditions. These features indicate that the perovskite lattice deformation may take the main responsibility for the transient, show a new aspect to understand halide perovskite photo-stability. We further modulate this phenomenon by adjusting the charge carrier recombination and extraction, revealing that efficient carrier transfer can improve the bleaching resistance of perovskite grains. Our results provide future opportunities to attain high-performance devices by tuning the perovskite lattice disorder and harvesting the energetic carriers.

ACS Style

Yuren Xiang; Yameng Cao; Wenqiang Yang; Rui Hu; Sebastian Wood; Bowei Li; Qin Hu; Fan Zhang; Jujie He; Mozhgan Yavari; Jinlai Zhao; Yunlong Zhao; Jun Song; Junle Qu; Thomas P. Russell; S. Ravi P. Silva; Wei Zhang. Laser‐induced recoverable fluorescence quenching of perovskite films at a microscopic grain‐scale. ENERGY & ENVIRONMENTAL MATERIALS 2021, 1 .

AMA Style

Yuren Xiang, Yameng Cao, Wenqiang Yang, Rui Hu, Sebastian Wood, Bowei Li, Qin Hu, Fan Zhang, Jujie He, Mozhgan Yavari, Jinlai Zhao, Yunlong Zhao, Jun Song, Junle Qu, Thomas P. Russell, S. Ravi P. Silva, Wei Zhang. Laser‐induced recoverable fluorescence quenching of perovskite films at a microscopic grain‐scale. ENERGY & ENVIRONMENTAL MATERIALS. 2021; ():1.

Chicago/Turabian Style

Yuren Xiang; Yameng Cao; Wenqiang Yang; Rui Hu; Sebastian Wood; Bowei Li; Qin Hu; Fan Zhang; Jujie He; Mozhgan Yavari; Jinlai Zhao; Yunlong Zhao; Jun Song; Junle Qu; Thomas P. Russell; S. Ravi P. Silva; Wei Zhang. 2021. "Laser‐induced recoverable fluorescence quenching of perovskite films at a microscopic grain‐scale." ENERGY & ENVIRONMENTAL MATERIALS , no. : 1.

Research article
Published: 27 June 2021 in Advanced Functional Materials
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The unprecedented advancement in power conversion efficiencies (PCEs) of perovskite solar cells (PSCs) has rendered them a promising game-changer in photovoltaics. However, unsatisfactory environmental stability and high manufacturing cost of window electrodes are bottlenecks impeding their commercialization. Here, a strategy is introduced to address these bottlenecks by replacing the costly indium tin oxide (ITO) window electrodes via a simple transfer technique with single-walled carbon nanotubes (SWCNTs) films, which are made of earth-abundant elements with superior chemical and environmental stability. The resultant devices exhibit PCEs of ≈19% on rigid substrates, which is the highest value reported to date for ITO-free PSCs. The facile approach for SWCNTs also enables application in flexible PSCs (f-PSCs), delivering a PCE of ≈18% with superior mechanical robustness over their ITO-based counterparts due to the excellent mechanical properties of SWCNTs. The SWCNT-based PSCs also deliver satisfactory performances on large-area (1 cm2 active area in this work). Furthermore, these SWCNT-based PSCs can retain over 80% of original PCEs after exposure to air over 700 h while ITO-based devices only sustain ≈60% of initial PCEs. This work paves a promising way to accelerate the commercialization of ITO-free PSCs with reduced material cost and prolonged lifetimes.

ACS Style

Jing Zhang; Xiangang Hu; Hui Li; Kangyu Ji; Bowei Li; Xueping Liu; Yuren Xiang; Pengxiang Hou; Chang Liu; Zhiheng Wu; Yonglong Shen; Samuel D. Stranks; S. Ravi P. Silva; Hui‐Ming Cheng; Wei Zhang. High‐Performance ITO‐Free Perovskite Solar Cells Enabled by Single‐Walled Carbon Nanotube Films. Advanced Functional Materials 2021, 2104396 .

AMA Style

Jing Zhang, Xiangang Hu, Hui Li, Kangyu Ji, Bowei Li, Xueping Liu, Yuren Xiang, Pengxiang Hou, Chang Liu, Zhiheng Wu, Yonglong Shen, Samuel D. Stranks, S. Ravi P. Silva, Hui‐Ming Cheng, Wei Zhang. High‐Performance ITO‐Free Perovskite Solar Cells Enabled by Single‐Walled Carbon Nanotube Films. Advanced Functional Materials. 2021; ():2104396.

Chicago/Turabian Style

Jing Zhang; Xiangang Hu; Hui Li; Kangyu Ji; Bowei Li; Xueping Liu; Yuren Xiang; Pengxiang Hou; Chang Liu; Zhiheng Wu; Yonglong Shen; Samuel D. Stranks; S. Ravi P. Silva; Hui‐Ming Cheng; Wei Zhang. 2021. "High‐Performance ITO‐Free Perovskite Solar Cells Enabled by Single‐Walled Carbon Nanotube Films." Advanced Functional Materials , no. : 2104396.

Editorial
Published: 19 June 2021 in ENERGY & ENVIRONMENTAL MATERIALS
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Our world has witnessed an unprecedented time in the last twelve months, with many activities coming to a standstill because of the Covid-19 pandemic. In all walks of life, the world will not be the same as it struggles for normality at present, with many sectors shut for extended periods of time and some businesses shutdown for good. Yet, with all this upheaval, there are still challenges ahead that can make the last 12 months seem insignificant, with the potential of becoming an existential crisis for the human race. This is none other than Climate Change.

ACS Style

S. Ravi P. Silva. EDITORIAL: Now is the time for energy materials research to save the planet. ENERGY & ENVIRONMENTAL MATERIALS 2021, 1 .

AMA Style

S. Ravi P. Silva. EDITORIAL: Now is the time for energy materials research to save the planet. ENERGY & ENVIRONMENTAL MATERIALS. 2021; ():1.

Chicago/Turabian Style

S. Ravi P. Silva. 2021. "EDITORIAL: Now is the time for energy materials research to save the planet." ENERGY & ENVIRONMENTAL MATERIALS , no. : 1.

Research article
Published: 03 June 2021 in ENERGY & ENVIRONMENTAL MATERIALS
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Despite the long-established rocking-chair theory of lithium-ion batteries (LIBs), developing novel characterisation methodology with higher spatiotemporal resolution facilitate better understanding of the solid-electrolyte interphase studies to shape the reaction mechanisms. In this work, we develop a Xenon ion plasma focused ion beam (Xe+ PFIB)-based characterisation technique to probe the cross-sectional interface of both ternary cathode and graphite anode electrodes, with the focus on revealing the chemical composition and distribution underneath the electrode surface by in-depth analysis of secondary ions. Particularly, the lithium fluoride is detected in the pristine cathode prior to contact with the electrolyte, reflecting that the electrode degradation is in the form of the loss of lithium inventory during electrode preparation. This degradation is related to the hydrolysis of the cathode material and the decomposition of the PVDF binder. Through the quantitative analysis of the transition-metal degradation products, manganese is found to be the dominant element in the newly formed inactive fluoride deposition on the cathode, while no transition metal signal can be found inside the anode electrode. These insights at high resolution implemented via a PFIB-based characterisation technique not only enrich the understanding of the degradation mechanism in the LIBs but also identify and enable a high-sensitivity methodology to obtain the chemical survey at the subsurface, which will help remove the capacity-fade observed in most LIBs.

ACS Style

Xuhui Yao; Tomáš Šamořil; Jiří Dluhoš; John F. Watts; Zhijia Du; Bohang Song; S. Ravi P. Silva; Tan Sui; Yunlong Zhao. Degradation Diagnostics from the Subsurface of Lithium‐Ion Battery Electrodes. ENERGY & ENVIRONMENTAL MATERIALS 2021, 1 .

AMA Style

Xuhui Yao, Tomáš Šamořil, Jiří Dluhoš, John F. Watts, Zhijia Du, Bohang Song, S. Ravi P. Silva, Tan Sui, Yunlong Zhao. Degradation Diagnostics from the Subsurface of Lithium‐Ion Battery Electrodes. ENERGY & ENVIRONMENTAL MATERIALS. 2021; ():1.

Chicago/Turabian Style

Xuhui Yao; Tomáš Šamořil; Jiří Dluhoš; John F. Watts; Zhijia Du; Bohang Song; S. Ravi P. Silva; Tan Sui; Yunlong Zhao. 2021. "Degradation Diagnostics from the Subsurface of Lithium‐Ion Battery Electrodes." ENERGY & ENVIRONMENTAL MATERIALS , no. : 1.

Journal article
Published: 01 June 2021 in iScience
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Summary The endeavors to develop manufacturing methods that can enhance polymer and composite structures in spacecraft have led to much research and innovation over many decades. However, the thermal stability, intrinsic material stress, and anisotropic substrate properties pose significant challenges and inhibit the use of previously proposed solutions under extreme space environment. Here, we overcome these issues by developing a custom-designed, plasma-enhanced cross-linked poly(p-xylylene):diamond-like carbon superlattice material that enables enhanced mechanical coupling with the soft polymeric and composite materials, which in turn can be applied to large 3D engineering structures. The superlattice structure developed forms an integral part with the substrate and results in a space qualifiable carbon-fiber-reinforced polymer featuring 10–20 times greater resistance to cracking without affecting the stiffness of dimensionally stable structures. This innovation paves the way for the next generation of advanced ultra-stable composites for upcoming optical and radar instrument space programs and advanced engineering applications.

ACS Style

Michal Delkowski; Christopher T.G. Smith; José V. Anguita; S. Ravi P. Silva. Increasing the robustness and crack resistivity of high-performance carbon fiber composites for space applications. iScience 2021, 24, 102692 .

AMA Style

Michal Delkowski, Christopher T.G. Smith, José V. Anguita, S. Ravi P. Silva. Increasing the robustness and crack resistivity of high-performance carbon fiber composites for space applications. iScience. 2021; 24 (6):102692.

Chicago/Turabian Style

Michal Delkowski; Christopher T.G. Smith; José V. Anguita; S. Ravi P. Silva. 2021. "Increasing the robustness and crack resistivity of high-performance carbon fiber composites for space applications." iScience 24, no. 6: 102692.

Review
Published: 14 May 2021 in Small
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Organic–inorganic halide perovskite solar cells (PSCs) have shown a significant growth in power conversion efficiencies (PCEs) during last decade. Progress in device architecture and high‐quality perovskite film fabrication has led to an incredible efficiency over 25% in close to a decade. Developments in solution‐based thin film deposition techniques for perovskite layer preparation in PSCs provide low cost and ease of process for their manufacturing, making them a potential contender in future solar energy harvesting technologies. From small area single solar cells to large area perovskite solar modules, solvents play crucial roles in thin film quality and therefore, the device performance and stability. A comprehensive overview of solvent engineering toward achieving the highest qualities for perovskite light absorbing layers with various compositions and based on different fabrication processes is provided in this review. The mechanisms indicating the essential roles a solvent, or a solvent mixture can play to improve the crystallinity, uniformity, coverage and surface roughness of the perovskite films, are discussed. Finally, the role of solvent engineering in transferring from small area laboratory scale PSC fabrication to large area perovskite film deposition processes is explored.

ACS Style

Ehsan Rezaee; Wei Zhang; S. Ravi P. Silva. Solvent Engineering as a Vehicle for High Quality Thin Films of Perovskites and Their Device Fabrication. Small 2021, 17, 2008145 .

AMA Style

Ehsan Rezaee, Wei Zhang, S. Ravi P. Silva. Solvent Engineering as a Vehicle for High Quality Thin Films of Perovskites and Their Device Fabrication. Small. 2021; 17 (25):2008145.

Chicago/Turabian Style

Ehsan Rezaee; Wei Zhang; S. Ravi P. Silva. 2021. "Solvent Engineering as a Vehicle for High Quality Thin Films of Perovskites and Their Device Fabrication." Small 17, no. 25: 2008145.

Review
Published: 13 May 2021 in ENERGY & ENVIRONMENTAL MATERIALS
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Pb‐Sn mixed perovskites are becoming increasingly popular as narrow‐bandgap (1.2 – 1.3 eV) light absorbers in single junction perovskite solar cells (PSCs) and as bottom cells for all perovskite tandem solar cells, for high efficiency, low‐cost, light weight, roll‐to‐roll printable photovoltaic (PV) applications. From the first report of planar Pb:Sn mixed PSCs in 2014, the power conversion efficiencies (PCE) have increased from 10% to 21% by the end of 2020 with an exponential growth in research conducted in this field. Despite much effort, the performance and stability of Pb‐Sn mixed PSCs are still limited, which constrains their long‐term use in all‐perovskite tandem devices. This review highlights the avenues explored in improving different aspects of Pb‐Sn mixed PSCs and provides a comprehensive discussion of the interdependent factors affecting the device performance. This includes compositional engineering of the perovskite crystal, absorber layer fabrication and crystallisation methods, bandgap tuning, Sn4+ reduction and surface passivation of the absorber layer, as well as the selection of interlayers and electrodes of the final PSC.

ACS Style

R.M. Indrachapa Bandara; Shashini M. Silva; Cameron C.L. Underwood; K.D.G. Imalka Jayawardena; Radu A. Sporea. Progress of Pb‐Sn Mixed Perovskites for Photovoltaics: A Review. ENERGY & ENVIRONMENTAL MATERIALS 2021, 1 .

AMA Style

R.M. Indrachapa Bandara, Shashini M. Silva, Cameron C.L. Underwood, K.D.G. Imalka Jayawardena, Radu A. Sporea. Progress of Pb‐Sn Mixed Perovskites for Photovoltaics: A Review. ENERGY & ENVIRONMENTAL MATERIALS. 2021; ():1.

Chicago/Turabian Style

R.M. Indrachapa Bandara; Shashini M. Silva; Cameron C.L. Underwood; K.D.G. Imalka Jayawardena; Radu A. Sporea. 2021. "Progress of Pb‐Sn Mixed Perovskites for Photovoltaics: A Review." ENERGY & ENVIRONMENTAL MATERIALS , no. : 1.

Research article
Published: 05 May 2021 in ACS Applied Nano Materials
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We report an in situ imaging method and use it to reveal the mechanism for the formation of extended size sheets of graphene (carpets) in few-layer graphene using the solid-state process, taking place via a layer-by-layer growth mechanism, which can result in a stack of separate individual layers of graphene. This mechanism is revealed by an imaging method that allows the use of conventional (unmodified) scanning electron microscopy to image graphene growth in situ and in real time. With this dynamic imaging, we reveal for the first time the dynamics of flake nucleation and growth and show the dynamics of flake coalescence to form extended size polycrystalline graphene carpets, allowing one to deduce a growth model. This growth method produces graphene flakes with Raman spectral characteristics that closely resemble those from exfoliated flakes obtained using the “Scotch-tape” method. The material is highly electronically intrinsic, with I2D/IG ratios as high as 5. The kinetics of electronic interconnectivity between flakes during blanket formation is imaged dynamically using a doping level contrast in an electron microscope in real time. Furthermore, the observations reveal that it is possible to maximize the time between the formation of each individual blanket, up to several minutes, thus facilitating the production of multiple decoupled graphene layers of precise thickness. This allows one to control the number of layers produced even when using catalysts of high activity and high-carbon solubility such as Fe.

ACS Style

José V. Anguita; Thomas R. Pozegic; Muhammad Ahmad; S. Ravi P. Silva. Layer-by-Layer Growth of Graphene Sheets over Selected Areas for Semiconductor Device Applications. ACS Applied Nano Materials 2021, 4, 5211 -5219.

AMA Style

José V. Anguita, Thomas R. Pozegic, Muhammad Ahmad, S. Ravi P. Silva. Layer-by-Layer Growth of Graphene Sheets over Selected Areas for Semiconductor Device Applications. ACS Applied Nano Materials. 2021; 4 (5):5211-5219.

Chicago/Turabian Style

José V. Anguita; Thomas R. Pozegic; Muhammad Ahmad; S. Ravi P. Silva. 2021. "Layer-by-Layer Growth of Graphene Sheets over Selected Areas for Semiconductor Device Applications." ACS Applied Nano Materials 4, no. 5: 5211-5219.

Review
Published: 04 May 2021 in Annals of the New York Academy of Sciences
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Many aspects of chemistry and biology are mediated by electromagnetic field (EMF) interactions. The central nervous system (CNS) is particularly sensitive to EMF stimuli. Studies have explored the direct effect of different EMFs on the electrical properties of neurons in the last two decades, particularly focusing on the role of voltage‐gated ion channels (VGCs). This work aims to systematically review published evidence in the last two decades detailing the effects of EMFs on neuronal ion channels as per the PRISM guidelines. Following a predetermined exclusion and inclusion criteria, 22 papers were included after searches on three online databases. Changes in calcium homeostasis, attributable to the voltage‐gated calcium channels, were found to be the most commonly reported result of EMF exposure. EMF effects on the neuronal landscape appear to be diverse and greatly dependent on parameters, such as the field's frequency, exposure time, and intrinsic properties of the irradiated tissue, such as the expression of VGCs. Here, we systematically clarify how neuronal ion channels are particularly affected and differentially modulated by EMFs at multiple levels, such as gating dynamics, ion conductance, concentration in the membrane, and gene and protein expression. Ion channels represent a major transducer for EMF‐related effects on the CNS.

ACS Style

Federico Bertagna; Rebecca Lewis; S. Ravi P. Silva; Johnjoe McFadden; Kamalan Jeevaratnam. Effects of electromagnetic fields on neuronal ion channels: a systematic review. Annals of the New York Academy of Sciences 2021, 1 .

AMA Style

Federico Bertagna, Rebecca Lewis, S. Ravi P. Silva, Johnjoe McFadden, Kamalan Jeevaratnam. Effects of electromagnetic fields on neuronal ion channels: a systematic review. Annals of the New York Academy of Sciences. 2021; ():1.

Chicago/Turabian Style

Federico Bertagna; Rebecca Lewis; S. Ravi P. Silva; Johnjoe McFadden; Kamalan Jeevaratnam. 2021. "Effects of electromagnetic fields on neuronal ion channels: a systematic review." Annals of the New York Academy of Sciences , no. : 1.

Paper
Published: 19 April 2021 in Physical Chemistry Chemical Physics
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Single-nanobelt gas sensor devices were nanofabricated to estimate Sn3O4 and SnO2 Debye length (L D) in presence of NO2, and gas–solid interactions between O species/NO2 and Sn2+/Sn4+ surfaces were proposed based on tin oxide sensor signals.

ACS Style

Mateus G. Masteghin; Ranilson A. Silva; David C. Cox; Denis R. M. Godoi; S. Ravi P. Silva; Marcelo O. Orlandi. The role of surface stoichiometry in NO2 gas sensing using single and multiple nanobelts of tin oxide. Physical Chemistry Chemical Physics 2021, 23, 9733 -9742.

AMA Style

Mateus G. Masteghin, Ranilson A. Silva, David C. Cox, Denis R. M. Godoi, S. Ravi P. Silva, Marcelo O. Orlandi. The role of surface stoichiometry in NO2 gas sensing using single and multiple nanobelts of tin oxide. Physical Chemistry Chemical Physics. 2021; 23 (16):9733-9742.

Chicago/Turabian Style

Mateus G. Masteghin; Ranilson A. Silva; David C. Cox; Denis R. M. Godoi; S. Ravi P. Silva; Marcelo O. Orlandi. 2021. "The role of surface stoichiometry in NO2 gas sensing using single and multiple nanobelts of tin oxide." Physical Chemistry Chemical Physics 23, no. 16: 9733-9742.

Correction
Published: 16 March 2021 in ACS Applied Materials & Interfaces
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ACS Style

Christopher T. G. Smith; Michal Delkowski; José V. Anguita; David C. Cox; Catherine Haas; S. Ravi P. Silva. Correction to “Complete Atomic Oxygen and UV Protection for Polymer and Composite Materials in Low Earth Orbit”. ACS Applied Materials & Interfaces 2021, 13, 13907 -13907.

AMA Style

Christopher T. G. Smith, Michal Delkowski, José V. Anguita, David C. Cox, Catherine Haas, S. Ravi P. Silva. Correction to “Complete Atomic Oxygen and UV Protection for Polymer and Composite Materials in Low Earth Orbit”. ACS Applied Materials & Interfaces. 2021; 13 (11):13907-13907.

Chicago/Turabian Style

Christopher T. G. Smith; Michal Delkowski; José V. Anguita; David C. Cox; Catherine Haas; S. Ravi P. Silva. 2021. "Correction to “Complete Atomic Oxygen and UV Protection for Polymer and Composite Materials in Low Earth Orbit”." ACS Applied Materials & Interfaces 13, no. 11: 13907-13907.

Paper
Published: 16 March 2021 in Journal of Materials Chemistry C
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Cs incorporation into perovskite film via a thin Cs2CO3 layer ETL passivation treatment.

ACS Style

Mozhgan Yavari; Xueping Liu; Thomas Webb; K. D. G. Imalka Jayawardena; Yuren Xiang; Stefanie Kern; Steven Hinder; Thomas J. Macdonald; S. Ravi P. Silva; Stephen J. Sweeney; Wei Zhang. A synergistic Cs2CO3 ETL treatment to incorporate Cs cation into perovskite solar cells via two-step scalable fabrication. Journal of Materials Chemistry C 2021, 9, 4367 -4377.

AMA Style

Mozhgan Yavari, Xueping Liu, Thomas Webb, K. D. G. Imalka Jayawardena, Yuren Xiang, Stefanie Kern, Steven Hinder, Thomas J. Macdonald, S. Ravi P. Silva, Stephen J. Sweeney, Wei Zhang. A synergistic Cs2CO3 ETL treatment to incorporate Cs cation into perovskite solar cells via two-step scalable fabrication. Journal of Materials Chemistry C. 2021; 9 (12):4367-4377.

Chicago/Turabian Style

Mozhgan Yavari; Xueping Liu; Thomas Webb; K. D. G. Imalka Jayawardena; Yuren Xiang; Stefanie Kern; Steven Hinder; Thomas J. Macdonald; S. Ravi P. Silva; Stephen J. Sweeney; Wei Zhang. 2021. "A synergistic Cs2CO3 ETL treatment to incorporate Cs cation into perovskite solar cells via two-step scalable fabrication." Journal of Materials Chemistry C 9, no. 12: 4367-4377.

Rapid communication
Published: 03 February 2021 in The Journal of Physical Chemistry Letters
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Two-dimensional (2D) Ruddlesden–Popper perovskites (RPPs) of the form PEA2Pb1–xSnxI4 can be used as the tunable active layer in photovoltaics, as the passivating layer for 3D perovskite photovoltaics or in light emitting diodes. Here, we show a nonlinear band gap behavior with Sn content in mixed phase 2D RPPs. Density functional theory calculations (with and without spin–orbit coupling) are employed to study the effects of the short-range ordering of Pb and Sn in PEA2Pb1–xSnxI4 compositions with x = 0, 0.25, 0.5, 0.75, and 1. Analysis of the partial density of states shows that the energy mismatch of the Pb 6s and Sn 5s states in the valence band maximum determines the nonlinearity of the band gap, leading to a bowing parameter of 0.35–0.38 eV. This research provides a critical insight for the design of future metal alloy 2D perovskite materials. The positions of the tunable energy band discontinuity may point to intraband transitions of interest to device engineers.

ACS Style

Cameron C. L. Underwood; J. David Carey; S. Ravi P. Silva. Nonlinear Band Gap Dependence of Mixed Pb–Sn 2D Ruddlesden–Popper PEA2Pb1–xSnxI4 Perovskites. The Journal of Physical Chemistry Letters 2021, 12, 1501 -1506.

AMA Style

Cameron C. L. Underwood, J. David Carey, S. Ravi P. Silva. Nonlinear Band Gap Dependence of Mixed Pb–Sn 2D Ruddlesden–Popper PEA2Pb1–xSnxI4 Perovskites. The Journal of Physical Chemistry Letters. 2021; 12 (5):1501-1506.

Chicago/Turabian Style

Cameron C. L. Underwood; J. David Carey; S. Ravi P. Silva. 2021. "Nonlinear Band Gap Dependence of Mixed Pb–Sn 2D Ruddlesden–Popper PEA2Pb1–xSnxI4 Perovskites." The Journal of Physical Chemistry Letters 12, no. 5: 1501-1506.

Research article
Published: 01 February 2021 in ACS Applied Materials & Interfaces
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With the realization of larger and more complex space installations, an increase in the surface area exposed to atomic oxygen (AO) and ultraviolet (UV) effects is expected, making structural integrity of space structures essential for future development. In a low Earth orbit (LEO), the effects of AO and UV degradation can have devastating consequences for polymer and composite structures in satellites and space installations. Composite materials such as carbon fiber-reinforced polymer (CFRP) or polymer materials such as polyetherimide and polystyrene are widely used in satellite construction for various applications including structural components, thermal insulation, and importantly radio frequency (RF) assemblies. In this paper, we present a multilayered material protection solution, a multilayered protection barrier, that mitigates the effects of AO and UV without disrupting the functional performance of tested assemblies. This multilayered protection barrier deposited via a custom-built plasma-enhanced chemical vapor deposition (PECVD) system is designed so as to deposit all necessary layers without breaking vacuum to maximize the adhesion to the surface of the substrate and to ensure no pinhole erosion is present. In the multilayer solution, a moisture and outgassing barrier (MOB) is coupled with an AO and UV capping layer to provide complete protection.

ACS Style

Christopher T. G. Smith; Michal Delkowki; Jose V. Anguita; David C. Cox; Catherine Haas; S. Ravi P. Silva. Complete Atomic Oxygen and UV Protection for Polymer and Composite Materials in a Low Earth Orbit. ACS Applied Materials & Interfaces 2021, 13, 6670 -6677.

AMA Style

Christopher T. G. Smith, Michal Delkowki, Jose V. Anguita, David C. Cox, Catherine Haas, S. Ravi P. Silva. Complete Atomic Oxygen and UV Protection for Polymer and Composite Materials in a Low Earth Orbit. ACS Applied Materials & Interfaces. 2021; 13 (5):6670-6677.

Chicago/Turabian Style

Christopher T. G. Smith; Michal Delkowki; Jose V. Anguita; David C. Cox; Catherine Haas; S. Ravi P. Silva. 2021. "Complete Atomic Oxygen and UV Protection for Polymer and Composite Materials in a Low Earth Orbit." ACS Applied Materials & Interfaces 13, no. 5: 6670-6677.

Review
Published: 26 January 2021 in Quantum Reports
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Understanding the rules of life is one of the most important scientific endeavours and has revolutionised both biology and biotechnology. Remarkable advances in observation techniques allow us to investigate a broad range of complex and dynamic biological processes in which living systems could exploit quantum behaviour to enhance and regulate biological functions. Recent evidence suggests that these non-trivial quantum mechanical effects may play a crucial role in maintaining the non-equilibrium state of biomolecular systems. Quantum biology is the study of such quantum aspects of living systems. In this review, we summarise the latest progress in quantum biology, including the areas of enzyme-catalysed reactions, photosynthesis, spin-dependent reactions, DNA, fluorescent proteins, and ion channels. Many of these results are expected to be fundamental building blocks towards understanding the rules of life.

ACS Style

Youngchan Kim; Federico Bertagna; Edeline M. D’Souza; Derren J. Heyes; Linus O. Johannissen; Eveliny T. Nery; Antonio Pantelias; Alejandro Sanchez-Pedreño Jimenez; Louie Slocombe; Michael G. Spencer; Jim Al-Khalili; Gregory S. Engel; Sam Hay; Suzanne M. Hingley-Wilson; Kamalan Jeevaratnam; Alex R. Jones; Daniel R. Kattnig; Rebecca Lewis; Marco Sacchi; Nigel S. Scrutton; S. Ravi P. Silva; Johnjoe McFadden. Quantum Biology: An Update and Perspective. Quantum Reports 2021, 3, 80 -126.

AMA Style

Youngchan Kim, Federico Bertagna, Edeline M. D’Souza, Derren J. Heyes, Linus O. Johannissen, Eveliny T. Nery, Antonio Pantelias, Alejandro Sanchez-Pedreño Jimenez, Louie Slocombe, Michael G. Spencer, Jim Al-Khalili, Gregory S. Engel, Sam Hay, Suzanne M. Hingley-Wilson, Kamalan Jeevaratnam, Alex R. Jones, Daniel R. Kattnig, Rebecca Lewis, Marco Sacchi, Nigel S. Scrutton, S. Ravi P. Silva, Johnjoe McFadden. Quantum Biology: An Update and Perspective. Quantum Reports. 2021; 3 (1):80-126.

Chicago/Turabian Style

Youngchan Kim; Federico Bertagna; Edeline M. D’Souza; Derren J. Heyes; Linus O. Johannissen; Eveliny T. Nery; Antonio Pantelias; Alejandro Sanchez-Pedreño Jimenez; Louie Slocombe; Michael G. Spencer; Jim Al-Khalili; Gregory S. Engel; Sam Hay; Suzanne M. Hingley-Wilson; Kamalan Jeevaratnam; Alex R. Jones; Daniel R. Kattnig; Rebecca Lewis; Marco Sacchi; Nigel S. Scrutton; S. Ravi P. Silva; Johnjoe McFadden. 2021. "Quantum Biology: An Update and Perspective." Quantum Reports 3, no. 1: 80-126.

Journal article
Published: 25 January 2021 in Nano Energy
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Strategies to maximize the surface charge density across triboelectric layers while protecting it from humidity are crucial in employing triboelectric nanogenerators (TENGs) for commercial/real-time applications. Herein, for the first time, we propose the utility of crystalline silk microparticles (SMPs) to improve the surface charge density in materials like polyvinyl alcohol to realise its applicability for TENG devices. Moreover, these SMPs are extracted from discarded Bombyx mori silkworm cocoons by facile, inexpensive, and single-step alkaline-hydrolysis treatment. We examine the performance of these composites with counter-materials composed of waste PTFE plastic cups to show reuse in recycled products. The processing cost of TENG developed from recycled materials is not only low but eco-friendly. The TENG performance as a function of the concentration of SMPs is investigated and compared with the composite's work-function and surface-potentials, with the distance-dependent electric field theoretical model employed to optimize the performance. Consequently, the optimized TENG exhibits maximum output voltage, current, charge, and power density of ∼280 V, 17.3 μA, 32.5 nC, and 14.4 W·m−2, respectively, creating a highly competitive energy harvester that can conform to the rigorous needs of wearables and mobile applications. Furthermore, the fully packaged silicone rubber device protects it from humidity and enables the device utility for practical applications with a soft, comfortable, and skin-friendly interface.

ACS Style

Bhaskar Dudem; Sontyana Adonijah Graham; R.D. Ishara G. Dharmasena; S. Ravi P. Silva; Jae Su Yu. Natural silk-composite enabled versatile robust triboelectric nanogenerators for smart applications. Nano Energy 2021, 83, 105819 .

AMA Style

Bhaskar Dudem, Sontyana Adonijah Graham, R.D. Ishara G. Dharmasena, S. Ravi P. Silva, Jae Su Yu. Natural silk-composite enabled versatile robust triboelectric nanogenerators for smart applications. Nano Energy. 2021; 83 ():105819.

Chicago/Turabian Style

Bhaskar Dudem; Sontyana Adonijah Graham; R.D. Ishara G. Dharmasena; S. Ravi P. Silva; Jae Su Yu. 2021. "Natural silk-composite enabled versatile robust triboelectric nanogenerators for smart applications." Nano Energy 83, no. : 105819.

Accepted manuscript
Published: 11 January 2021 in Nanotechnology
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The allure of all carbon electronics stems from the spread in physical properties, across all its allotropes. The scheme also harbours unique challenges, like tunability of band-gap,variability of doping and defect control. Here, we explore the technique of scanning probe tip induced nanoscale reduction of graphene oxide (GO), which nucleates conducting, sp^2 rich graphitic regions on the insulating GO background. Flexibility of direct writing is supplemented with control over degree of reduction and tunability of bandgap, through macroscopic control parameters. The fabricated reduced ––GO channels and ensuing devices are investigated via spectroscopic, and temperature and bias dependent electrical transport and correlated with spatially resolved electronic properties, using surface potentiometry. Presence of carrier localisation effects, induced by the phase-separated sp^2/sp^3 domains, and large local electric field fluctuations are reflected in the non-linear transport across the channels. Together the results indicate a complex transport phenomena which may be variously dominated by tunnelling, variable range hopping or activated depending on the electronic state of the material.

ACS Style

Arijit Kayal; Harikrishnan G; Kingshuk Bandopadhyay; Amit Kumar; S Ravi P Silva; Joy Mitra. Controlling the macroscopic electrical properties of reduced graphene oxide by nanoscale writing of electronic channels. Nanotechnology 2021, 32, 175202 .

AMA Style

Arijit Kayal, Harikrishnan G, Kingshuk Bandopadhyay, Amit Kumar, S Ravi P Silva, Joy Mitra. Controlling the macroscopic electrical properties of reduced graphene oxide by nanoscale writing of electronic channels. Nanotechnology. 2021; 32 (17):175202.

Chicago/Turabian Style

Arijit Kayal; Harikrishnan G; Kingshuk Bandopadhyay; Amit Kumar; S Ravi P Silva; Joy Mitra. 2021. "Controlling the macroscopic electrical properties of reduced graphene oxide by nanoscale writing of electronic channels." Nanotechnology 32, no. 17: 175202.

Article
Published: 24 December 2020 in Physical Review B
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The electron-phonon interaction controls the intrinsic mobility of charges in metal halide perovskites, and determines the rate at which carriers lose energy. Here, the carrier mobility and cooling dynamics were directly examined using a combination of ultrafast transient absorption spectroscopy and optical pump, THz probe spectroscopy, in perovskites with different lead and tin content, and for a range of carrier densities. Significantly, the carrier mobility in the “hot phonon bottleneck” regime, where the LO phonon bath keeps carriers warm, was found to be similar to the mobility of cold carriers. A model was developed that provides a quantitative description of the experimental carrier cooling dynamics, including electron-phonon coupling, phonon-phonon coupling and the Auger mechanism. In the Pb and Sn alloy the duration of the hot carrier regime was extended as a result of the slower decay of optical phonons. The findings offer an intuitive link between macroscopic properties and the underlying microscopic energy transfer processes, and suggest new routes to control the carrier cooling process in metal halide perovskites to optimize optoelectronic devices.

ACS Style

Maurizio Monti; K. D. G. Imalka Jayawardena; Edward Butler-Caddle; Rajapakshe M. I. Bandara; Jack M. Woolley; Michael Staniforth; S. Ravi P. Silva; James Lloyd-Hughes. Hot carriers in mixed Pb-Sn halide perovskite semiconductors cool slowly while retaining their electrical mobility. Physical Review B 2020, 102, 245204 .

AMA Style

Maurizio Monti, K. D. G. Imalka Jayawardena, Edward Butler-Caddle, Rajapakshe M. I. Bandara, Jack M. Woolley, Michael Staniforth, S. Ravi P. Silva, James Lloyd-Hughes. Hot carriers in mixed Pb-Sn halide perovskite semiconductors cool slowly while retaining their electrical mobility. Physical Review B. 2020; 102 (24):245204.

Chicago/Turabian Style

Maurizio Monti; K. D. G. Imalka Jayawardena; Edward Butler-Caddle; Rajapakshe M. I. Bandara; Jack M. Woolley; Michael Staniforth; S. Ravi P. Silva; James Lloyd-Hughes. 2020. "Hot carriers in mixed Pb-Sn halide perovskite semiconductors cool slowly while retaining their electrical mobility." Physical Review B 102, no. 24: 245204.

Full paper
Published: 25 November 2020 in Advanced Functional Materials
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Organic‐inorganic hybrid semiconductors are an emerging class of materials for direct conversion X‐ray detection due to attractive characteristics such as high sensitivity and the potential to form conformal detectors. However, existing hybrid semiconductor X‐ray detectors display dark currents that are 1000–10 000× higher than industrially relevant values of 1–10 pA mm−2. Herein, ultra‐low dark currents of <10 pA mm−2, under electric fields as high as ≈4 V µm−1, for hybrid X‐ray detectors consisting of bismuth oxide nanoparticles (for enhanced X‐ray attenuation) incorporated into an organic bulk heterojunction consisting of p‐type Poly(3‐hexylthiophene‐2,5‐diyl) (P3HT) and n‐type [6,6]‐Phenyl C71 butyric acid methyl ester (PC70BM) are reported. Such ultra‐low dark currents are realized through the enrichment of the hole selective p‐type organic semiconductor near the anode contact. The resulting detectors demonstrate broadband X‐ray response including an exceptionally high sensitivity of ≈1.5 mC Gy−1 cm−2 and <6% variation in angular dependence response under 6 MV hard X‐rays. The above characteristics in combination with excellent dose linearity, dose rate linearity, and reproducibility over a broad energy range enable these detectors to be developed for medical and industrial applications.

ACS Style

M. Prabodhi A. Nanayakkara; Lidija Matjačić; Sebastian Wood; Filipe Richheimer; Fernando A. Castro; Sandra Jenatsch; Simon Züfle; Rachel Kilbride; Andrew J. Parnell; Mateus G. Masteghin; Hashini M. Thirimanne; Andrew Nisbet; K. D. G. Imalka Jayawardena; S. Ravi P. Silva. Ultra‐Low Dark Current Organic–Inorganic Hybrid X‐Ray Detectors. Advanced Functional Materials 2020, 31, 1 .

AMA Style

M. Prabodhi A. Nanayakkara, Lidija Matjačić, Sebastian Wood, Filipe Richheimer, Fernando A. Castro, Sandra Jenatsch, Simon Züfle, Rachel Kilbride, Andrew J. Parnell, Mateus G. Masteghin, Hashini M. Thirimanne, Andrew Nisbet, K. D. G. Imalka Jayawardena, S. Ravi P. Silva. Ultra‐Low Dark Current Organic–Inorganic Hybrid X‐Ray Detectors. Advanced Functional Materials. 2020; 31 (8):1.

Chicago/Turabian Style

M. Prabodhi A. Nanayakkara; Lidija Matjačić; Sebastian Wood; Filipe Richheimer; Fernando A. Castro; Sandra Jenatsch; Simon Züfle; Rachel Kilbride; Andrew J. Parnell; Mateus G. Masteghin; Hashini M. Thirimanne; Andrew Nisbet; K. D. G. Imalka Jayawardena; S. Ravi P. Silva. 2020. "Ultra‐Low Dark Current Organic–Inorganic Hybrid X‐Ray Detectors." Advanced Functional Materials 31, no. 8: 1.