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Russell J, Holt J, Chandrasekar R. The 'Wirral Wedge': an aid to position arm safely in upper limb surgery. Ann R Coll Surg Engl 2025; 107:74-75. [PMID: 38563059 PMCID: PMC11658884 DOI: 10.1308/rcsann.2023.0103] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/09/2023] [Indexed: 04/04/2024] Open
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Rohullah M, Chosenyah M, Kumar AV, Chandrasekar R. Cornu-Spiral-Like Organic Crystal Waveguide Providing Discriminatory Optical Pathway for Smart Organic Photonic Circuit. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2024:e2407498. [PMID: 39487632 DOI: 10.1002/smll.202407498] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/25/2024] [Revised: 10/17/2024] [Indexed: 11/04/2024]
Abstract
In the era of artificial intelligence, developing advanced and intelligent photonic circuits has become essential. In this work, the fabrication of a smart organic photonic circuit (OPC), is illustrated which utilizes a Cornu-spiral-like waveguide (CSW) to produce discriminating optical pathways in the circuit. The mechanical flexibility of Schiff base, (E)-1-(((5-iodopyridin-2-yl)imino)methyl)naphthalen-2-ol (IPyIN) facilitates the fabrication of a first-of-its-kind, two-ring-based CSW via the atomic force microscopy cantilever tip-assisted mechanophotonics approach. The photonic studies suggest that the CSW structure routes optical signals in discriminating trajectories. To capitalize on the discriminatory properties of the CSW, two linear waveguides onto both rings of the CSW are integrated to create a smart OPC. This smart OPC can selectively route optical signals either partially or fully in the circuit, depending on the pathways determined by the CSW, thus enabling the circuit to switch ON or OFF. Such intelligent photonic circuits are essential for advancing smart technologies.
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Vinod Kumar A, Pattanayak P, Khapre A, Nandi A, Purkayastha P, Chandrasekar R. Capturing the Interplay Between TADF and RTP Through Mechanically Flexible Polymorphic Optical Waveguides. Angew Chem Int Ed Engl 2024; 63:e202411054. [PMID: 38924274 DOI: 10.1002/anie.202411054] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2024] [Accepted: 06/24/2024] [Indexed: 06/28/2024]
Abstract
Polymorphism plays a pivotal role in generating a range of crystalline materials with diverse photophysical and mechanical attributes, all originating from the same molecule. Here, we showcase two distinct polymorphs: green (GY) emissive and orange (OR) emissive crystals of 5'-(4-(diphenylamino)phenyl)-[2,2'-bithiophene]-5-carbaldehyde (TPA-CHO). These polymorphs display differing optical characteristics, with GY exhibiting thermally activated delayed fluorescence (TADF) and OR showing room temperature phosphorescence (RTP). Additionally, both polymorphic crystals display mechanical flexibility and optical waveguiding capabilities. Leveraging the AFM-tip-based mechanophotonics technique, we position the GY optical waveguide at varying lengths perpendicular to the OR waveguide. This approach facilitates the exploration of the interplay between TADF and RTP phenomena by judiciously controlling the optical path length of crystal waveguides. Essentially, our approach provides a clear pathway for understanding and controlling the photophysical processes in organic molecular crystals, paving the way for advancements in polymorphic crystal-based photonic circuit technologies.
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Ranjan S, Kumar AV, Chandrasekar R, Takamizawa S. Spatially controllable and mechanically switchable isomorphous organoferroeleastic crystal optical waveguides and networks. Nat Commun 2024; 15:7478. [PMID: 39209836 PMCID: PMC11362157 DOI: 10.1038/s41467-024-51504-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2024] [Accepted: 08/09/2024] [Indexed: 09/04/2024] Open
Abstract
The precise, reversible, and diffusionless shape-switching ability of organic ferroelastic crystals, while maintaining their structural integrity, positions them as promising materials for next-generation hybrid photonic devices. Herein, we present versatile bi-directional ferroelasticity and optical waveguide properties of three isomorphous, halogen-based, Schiff base organic crystals. These crystals exhibit sharp bending at multiple interfaces driven by molecular movement around the CH = N bond and subsequent 180° rotational twinning, offering controlled light path manipulation. The ferroelastic nature of these crystals allowed the construction of robust hybrid photonic structures, including Z-shaped configurations, closed-loop networks, and staircase-like hybrid optical waveguides. This study highlights the potential of shape-switchable organoferroelastic crystals as waveguides for applications in programmable photonic devices.
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Rohullah M, Pradeep VV, Singh S, Chandrasekar R. Mechanically controlled multifaceted dynamic transformations in twisted organic crystal waveguides. Nat Commun 2024; 15:4040. [PMID: 38740755 DOI: 10.1038/s41467-024-47924-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2023] [Accepted: 04/16/2024] [Indexed: 05/16/2024] Open
Abstract
This study introduces mechanically induced phenomena such as standing, leaning, stacking, and interlocking behaviors in naturally twisted optical waveguiding microcrystals on a substrate. The microscale twisted crystal self-assembled from 2,4-dibromo-6-(((2-bromo-5-fluorophenyl)imino)methyl)phenol is flexible and emits orange fluorescence. Mechanistic analysis reveals the strain generated by the intergrowing orientationally mismatched nanocrystallites is responsible for the twisted crystal growth. The crystal's mechanical flexibility in the perpendicular direction to (001) and (010) planes can be attributed to intermolecular Br···Br, F···Br, and π···π stacking interactions. Through a systematic process involving step-by-step bending and subsequent optical waveguiding experiments at each bent position, a linear relationship between optical loss and mechanical strain is established. Additionally, the vertical standing and leaning of these crystals at different angles on a flat surface and the vertical stacking of multiple crystals reveal the three-dimensional aspects of organic crystal waveguides, introducing light trajectories in a 3D space. Furthermore, the integration of two axially interlocked twisted crystals enables the coupling of polarization rotation along their long axis. These crystal dynamics expand the horizons of crystal behavior and have the potential to revolutionize various applications, rendering these crystals invaluable in the realm of crystal-related science and technology.
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Barman D, Annadhasan M, Bidkar AP, Rajamalli P, Barman D, Ghosh SS, Chandrasekar R, Iyer PK. Highly efficient color-tunable organic co-crystals unveiling polymorphism, isomerism, delayed fluorescence for optical waveguides and cell-imaging. Nat Commun 2023; 14:6648. [PMID: 37863932 PMCID: PMC10589249 DOI: 10.1038/s41467-023-42017-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2023] [Accepted: 09/27/2023] [Indexed: 10/22/2023] Open
Abstract
Photofunctional co-crystal engineering strategies based on donor-acceptor π-conjugated system facilitates expedient molecular packing, consistent morphology, and switchable optical properties, conferring synergic 'structure-property relationship' for optoelectronic and biological functions. In this work, a series of organic co-crystals were formulated using a twisted aromatic hydrocarbon (TAH) donor and three diverse planar acceptors, resulting in color-tunable solid and aggregated state emission via variable packing and through-space charge-transfer interactions. While, adjusting the strength of acceptors, a structural transformation into hybrid stacking modes ultimately results in color-specific polymorphs, a configurational cis-isomer with very high photoluminescence quantum yield. The cis-isomeric co-crystal exhibits triplet-harvesting thermally activated delayed fluorescence (TADF) characteristics, presenting a key discovery in hydrocarbon-based multicomponent systems. Further, 1D-microrod-shaped co-crystal acts as an efficient photon-transducing optical waveguides, and their excellent dispersibility in water endows efficient cellular internalization with bright cell imaging performances. These salient approaches may open more avenues for the design and applications of TAH based co-crystals.
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Pradeep VV, Chosenyah M, Mamonov E, Chandrasekar R. Crystal photonics foundry: geometrical shaping of molecular single crystals into next generation optical cavities. NANOSCALE 2023. [PMID: 37427664 DOI: 10.1039/d3nr02229c] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/11/2023]
Abstract
The advancements in organic photonics have reached new heights in the recent past with the demonstration of diverse organic crystal optical components and circuits. However, the development of industrially viable manufacturing of organic optical components is the need of the hour for finding an alternative to silicon-based photonics. Here, we demonstrate focused ion beam (FIB) milling as a tool to shape organic single crystals into optical cavities of diverse geometries and dimensions. The generality of FIB milling was tested on perylene and coumarin-153 microcrystals. The microcrystals obtained by self-assembly of perylene and sublimation of coumarin-153 were carved into desired disc-, ring- and rectangular shapes. These shaped crystals act as cavities exhibiting sharp resonance modes in the fluorescence spectrum, confirming optical interference. The FDTD numerical calculations support the light electric field distribution in these optical cavities. This unprecedented single crystal processing technique enables industrial-scale production of optical components and circuits and acts as a foundry for crystal photonics.
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Awad WM, Davies DW, Kitagawa D, Mahmoud Halabi J, Al-Handawi MB, Tahir I, Tong F, Campillo-Alvarado G, Shtukenberg AG, Alkhidir T, Hagiwara Y, Almehairbi M, Lan L, Hasebe S, Karothu DP, Mohamed S, Koshima H, Kobatake S, Diao Y, Chandrasekar R, Zhang H, Sun CC, Bardeen C, Al-Kaysi RO, Kahr B, Naumov P. Mechanical properties and peculiarities of molecular crystals. Chem Soc Rev 2023; 52:3098-3169. [PMID: 37070570 DOI: 10.1039/d2cs00481j] [Citation(s) in RCA: 64] [Impact Index Per Article: 32.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/19/2023]
Abstract
In the last century, molecular crystals functioned predominantly as a means for determining the molecular structures via X-ray diffraction, albeit as the century came to a close the response of molecular crystals to electric, magnetic, and light fields revealed that the physical properties of molecular crystals were as rich as the diversity of molecules themselves. In this century, the mechanical properties of molecular crystals have continued to enhance our understanding of the colligative responses of weakly bound molecules to internal frustration and applied forces. Here, the authors review the main themes of research that have developed in recent decades, prefaced by an overview of the particular considerations that distinguish molecular crystals from traditional materials such as metals and ceramics. Many molecular crystals will deform themselves as they grow under some conditions. Whether they respond to intrinsic stress or external forces or interactions among the fields of growing crystals remains an open question. Photoreactivity in single crystals has been a leading theme in organic solid-state chemistry; however, the focus of research has been traditionally on reaction stereo- and regio-specificity. However, as light-induced chemistry builds stress in crystals anisotropically, all types of motions can be actuated. The correlation between photochemistry and the responses of single crystals-jumping, twisting, fracturing, delaminating, rocking, and rolling-has become a well-defined field of research in its own right: photomechanics. The advancement of our understanding requires theoretical and high-performance computations. Computational crystallography not only supports interpretations of mechanical responses, but predicts the responses itself. This requires the engagement of classical force-field based molecular dynamics simulations, density functional theory-based approaches, and the use of machine learning to divine patterns to which algorithms can be better suited than people. The integration of mechanics with the transport of electrons and photons is considered for practical applications in flexible organic electronics and photonics. Dynamic crystals that respond rapidly and reversibly to heat and light can function as switches and actuators. Progress in identifying efficient shape-shifting crystals is also discussed. Finally, the importance of mechanical properties to milling and tableting of pharmaceuticals in an industry still dominated by active ingredients composed of small molecule crystals is reviewed. A dearth of data on the strength, hardness, Young's modulus, and fracture toughness of molecular crystals underscores the need for refinement of measurement techniques and conceptual tools. The need for benchmark data is emphasized throughout.
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Annadhasan M, Vinod Kumar A, Giri P, Nandy S, K Panda M, Jovan Jose KV, Chandrasekar R. Dimension Engineering of Stimuli-Responsive 1D Molecular Crystals into Unusual 2D and 3D Zigzag Waveguides. Angew Chem Int Ed Engl 2023:e202302929. [PMID: 36975093 DOI: 10.1002/anie.202302929] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2023] [Revised: 03/26/2023] [Accepted: 03/27/2023] [Indexed: 03/29/2023]
Abstract
We demonstrate an innovative technique to achieve organic 2D and 3D waveguides with peculiar shapes from an acicular, light-stimulus-responsive molecular crystal, (2Z,2'Z)-3,3'-(anthracene-9,10-diyl)bis(2-(3,5-bis(trifluoromethyl)phenylacrylonitrile), Ant-CF3. The greenish-yellow fluorescent (FL) Ant-CF3 molecular crystals exhibit laser power-dependent permanent mechanical bending in 2D and 3D. Investigation of a single-crystal using spatially-resolved Raman/FL/electron microscopy, and theoretical calculations revealed photothermal (Z,E)/(E,E) isomerization-assisted transition from crystalline to amorphous phase at the laser-exposed regions. This phenomenon facilitates the dimension engineering of a 1D crystal waveguide into a 2D waveguide on a substrate or a 3D waveguide in free space. The presented technique has broader implications in organic photonics and other crystal-related technologies at large.
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Annadhasan M, Vinod Kumar A, Giri P, Nandy S, K. Panda M, Jovan Jose KV, Chandrasekar R. Dimension Engineering of Stimuli‐Responsive 1D Molecular Crystals into Unusual 2D and 3D Zigzag Waveguides. Angew Chem Int Ed Engl 2023. [DOI: 10.1002/ange.202302929] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/30/2023]
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Vinod Kumar A, Rohullah M, Chosenyah M, ravi J, Venkataramudu U, Chandrasekar R. Amphibian‐like Flexible Organic Crystal Optical Fibers for Underwater/Air Micro‐Precision Lighting and Sensing. Angew Chem Int Ed Engl 2023. [DOI: 10.1002/ange.202300046] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/12/2023]
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Vinod Kumar A, Rohullah M, Chosenyah M, Ravi J, Venkataramudu U, Chandrasekar R. Amphibian-like Flexible Organic Crystal Optical Fibers for Underwater/Air Micro-Precision Lighting and Sensing. Angew Chem Int Ed Engl 2023; 62:e202300046. [PMID: 36762607 DOI: 10.1002/anie.202300046] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2023] [Revised: 01/23/2023] [Accepted: 02/08/2023] [Indexed: 02/11/2023]
Abstract
Visible light guiding optical fibers with underwater operational capability are highly desired for subaquatic communication and sensing technologies. Herein, we present mechanically flexible, blue-violet fluorescent (4,4'-bis(2,6-di(1H-pyrazol-1-yl)pyridin-4-yl)biphenyl) (BPP) crystal waveguides with high-aspect ratio. These milli-meter-long BPP crystals guide light actively and passively in ambient and underwater conditions demonstrating their amphibian-like character. Due to the crystal's high flexibility, the optical fiber's output light direction in submerged and ambient states can be altered mechanically for high-precision lighting and sensing applications. The development of such multi-environment-compatible and mechanically flexible organic optical fibers acting as sensing materials possess enormous potential for short-range underwater photonic technologies.
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Vinod Kumar A, Godumala M, Ravi J, Chandrasekar R. A Broadband, Multiplexed‐Visible‐Light‐Transport in Composite Flexible‐Organic‐Crystal Waveguide. Angew Chem Int Ed Engl 2022. [DOI: 10.1002/ange.202212382] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Vinod Kumar A, Godumala M, Ravi J, Chandrasekar R. A Broadband, Multiplexed‐Visible‐Light‐Transport in Composite Flexible‐Organic‐Crystal Waveguide. Angew Chem Int Ed Engl 2022; 61:e202212382. [DOI: 10.1002/anie.202212382] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2022] [Indexed: 11/07/2022]
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Chinnasamy R, Ravi J, Vinay Pradeep V, Manoharan D, Emmerling F, Bhattacharya B, Ghosh S, Chandrasekar R. Adaptable Optical Microwaveguides From Mechanically Flexible Crystalline Materials. Chemistry 2022; 28:e202200905. [DOI: 10.1002/chem.202200905] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2022] [Indexed: 11/07/2022]
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Rohullah M, Pradeep VV, Ravi J, Kumar AV, Chandrasekar R. Micromechanically-Powered Rolling Locomotion of a Twisted-Crystal Optical-Waveguide Cavity as a Mobile Light Polarization Rotor. Angew Chem Int Ed Engl 2022; 61:e202202114. [PMID: 35278020 DOI: 10.1002/anie.202202114] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2022] [Indexed: 11/06/2022]
Abstract
We demonstrate mechanically-powered rolling locomotion of a twisted-microcrystal optical-waveguide cavity on the substrate, rotating the output signal's linear-polarization. Self-assembly of (E)-2-bromo-6-(((4-methoxyphenyl)imino)methyl)-4-nitrophenol produces naturally twisted microcrystals. The strain between several intergrowing, orientationally mismatched nanocrystalline fibres dictates the pitch lengths of the twisted crystals. The crystals are flexible, perpendicular to twisted (001) and (010) planes due to π⋅⋅⋅π stacking, C-H⋅⋅⋅Br, N-H⋅⋅⋅O and C-H⋅⋅⋅O interactions. The twisted crystals in their straight and bent geometries guide fluorescence along their body axes and display optical modes. Depending upon the degree of mechanical rolling locomotion, the crystal-waveguide cavity correspondingly rotates the output signal polarization. The presented twisted-crystal cavity with a combination of mechanical locomotion and photonic attributes unfolds a new dimension in mechanophotonics.
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Rohullah M, Pradeep VV, Ravi J, Kumar AV, Chandrasekar R. Micromechanically‐Powered Rolling Locomotion of Twisted‐Crystal Optical‐Waveguide‐Cavity as a Mobile Light Polarization Rotor. Angew Chem Int Ed Engl 2022. [DOI: 10.1002/ange.202202114] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Chandrasekar R. Mechanophotonics - a guide to integrating microcrystals toward monolithic and hybrid all-organic photonic circuits. Chem Commun (Camb) 2022; 58:3415-3428. [PMID: 35229866 DOI: 10.1039/d2cc00044j] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Molecular crystals are emerging as a non-silicon alternative for the construction of all-organic photonic integrated circuits (OPICs). The advent of flexible molecular crystals and the development of atomic force microscopy tip-based mechanical micromanipulation (mechanophotonics) techniques facilitate the construction of many proof-of-principle OPICs. This article validates the reason for using organic crystals as alternate non-silicon materials for OPIC fabrication. It also guides the readers by introducing several crystal-based photonic modules and OPIC prototypes, their passive and active light transduction potentials, and the possibility of implementing well-known photo-physical concepts viz. optical energy transfer and reabsorbance mechanisms. There is also an urgent need to develop a suitable technique for creating geometrically and dimensionally well-defined organic crystals displaying photonic attributes. Finally, the goal should be to build a library of selected optical crystals to facilitate the construction of OPICs with a pick-and-place approach.
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Barman D, Annadhasan M, Chandrasekar R, Iyer PK. Hot-exciton harvesting via through-space single-molecule based white-light emission and optical waveguides. Chem Sci 2022; 13:9004-9015. [PMID: 36091201 PMCID: PMC9365089 DOI: 10.1039/d2sc02172b] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2022] [Accepted: 07/02/2022] [Indexed: 11/21/2022] Open
Abstract
Through-space donor–alkyl bridge–acceptor (D–σ–A) luminogens are developed as new organic single-molecule white light emitters (OSMWLEs) involving multiple higher lying singlet (Sn) and triplet (Tm) states (hot-excitons). Experimental and theoretical results confirm the origin of white light emission due to the co-existence of prompt fluorescence from locally excited states, thermally activated delayed fluorescence (TADF), and fast/slow dual phosphorescence color mixing simultaneously. Notably, the fast phosphorescence was observed due to trace amounts of isomeric impurities from commercial carbazole, while H-/J-aggregation resulted in slow phosphorescence. Crystal structure-packing-property analysis revealed that the alkyl chain length induced supramolecular self-assembly greatly influenced the solid-state optical properties. Remarkably, the 1D-microrod crystals of OSMWLEs demonstrated the first examples of triplet harvesting waveguides by self-guiding the generated phosphorescence through light propagation along their longitudinal axis. This work thus highlights an uncommon design strategy to achieve multi-functional OSMWLEs with in-depth mechanistic insights and optical waveguiding applications making them a potentially new class of white emissive materials. Through-space donor–alkyl bridge–acceptor multifunctional organic single molecules that simultaneously displayed white light emission, thermally activated delayed fluorescence, room temperature dual phosphorescence and optical wave-guiding properties.![]()
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Chandrasekar R, Sivagami B, Eswarisai M, Nandini P, Pallavi Y, Sai Dikshitha P, Shirisha V, Yamini Y. Analytical method validation for related substances in sodium valproate oral solution by gas chromatography. FUTURE JOURNAL OF PHARMACEUTICAL SCIENCES 2021. [DOI: 10.1186/s43094-021-00344-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
Abstract
Background
Sodium Valproate is the sodium salt of valproic acid (VPA). Valproic acid is mainly used for the treatment of epilepsy. The specific aim of the study is to develop and validate an optimized method for the determination of six related substances such as N,N-dimethyl valpronamide, valeric acid, 2-methyl valeric acid, 2-ethyl valeric acid, 2-isopropyl valeric acid and 2-n-butyl valeric acid in Sodium Valproate Oral Solution by Gas Chromatography. Chromatographic separations of these six related substances were achieved on DB-FFAP fused silica capillary column (30 m × 0.53 mm) bonded with a 0.5-µm layer of macrogol 20,000 2-nitroterephthalate materials used as stationary phase. The six related impurities were extracted using heptane and monitored by Gas Chromatography coupled with flame ionization detector. The performance of the developed method was assessed by evaluating system suitability, method precision, specificity, linearity and range, ruggedness, accuracy, robustness.
Results
The correlation coefficient was within the acceptance criteria in the range of 0.9998. The evaluated concentrations for Sodium Valproate were in the ranges of 5.05–25.27 ppm. The average recovery values were in the range of 92.4–100.4%. Solution Stability experiments were performed to evaluate the degradation behavior of SVS.
Conclusion
A novel, precise and sensitive GC method was developed, validated and optimized for the determination of six related substances in sodium Valproate oral solution. The results obtained from the validation experiments demonstrated that the method is accurate, precise, linear, specific, sensitive and robust. Hence, the proposed method can be an alternative method, for the determination of related substances in sodium valproate oral solution drug substance.
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Tardío C, Pradeep VV, Martín R, Rodríguez AM, de la Hoz A, Jada R, Annadhasan M, Prieto P, Chandrasekar R. Polarised Optical Emission from Organic Anisotropic Microoptical Waveguides Grown by Ambient Pressure Vapour-deposition. Chem Asian J 2021; 16:3476-3480. [PMID: 34468084 DOI: 10.1002/asia.202100910] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2021] [Revised: 08/31/2021] [Indexed: 11/06/2022]
Abstract
Ambient pressure chemical vapour deposition of 5,5'-bis((2-(trifluoromethyl)phenyl)ethynyl)-2,2'-bithiophene provides ultrapure needle-shaped crystals. The crystal's supramolecular structure consists of an array of hydrogen bonds and π-π interactions leading to anisotropic arrangements. The cyan emitting crystals exhibit an optical waveguiding tendency with guided polarised optical emissions due to anisotropic molecular arrangements.
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Chandrasekar R. Mechanophotonics-Mechanical Micromanipulation of Single-Crystals toward Organic Photonic Integrated Circuits. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2021; 17:e2100277. [PMID: 33938127 DOI: 10.1002/smll.202100277] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/15/2021] [Revised: 02/22/2021] [Indexed: 06/12/2023]
Abstract
The advent of molecular crystals as "smart" nanophotonic components namely, organic waveguides, resonators, lasers, and modulators are drawing wider attention of solid-state materials scientists and microspectroscopists. Crystals are usually rigid, and undeniably developing next-level crystalline organic photonic circuits of complex geometries demands using mechanically flexible crystals. The mechanical shaping of flexible crystals necessitates applying challenging micromanipulation methods. The rise of atomic force microscopy as a mechanical micromanipulation tool has increased the scope of mechanophotonics and subsequently, crystal-based microscale organic photonic integrated circuits (OPICs). The unusual higher adhesive energy of the flexible crystals to the surface than that of crystal shape regaining energy enables carving intricate crystal geometries using micromanipulation. This perspective reviews the progress made in a key research area developed by my research group, namely mechanophotonics-a discipline that uses mechanical micromanipulation of single-crystal optical components, to advance nanophotonics. The precise fabrication of photonic components and OPICs from both rigid and flexible microcrystal via AFM mechanical operations namely, moving, lifting, cutting, slicing, bending, and transferring of crystals are presented. The ability of OPICs to guide, split, couple, and modulate visible electromagnetic radiation using passive, active, and energy transfer mechanism are discussed as well with recent literature examples.
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Vinay Pradeep V, Tardío C, Torres-Moya I, Rodríguez AM, Vinod Kumar A, Annadhasan M, de la Hoz A, Prieto P, Chandrasekar R. Mechanical Processing of Naturally Bent Organic Crystalline Microoptical Waveguides and Junctions. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2021; 17:e2006795. [PMID: 33354900 DOI: 10.1002/smll.202006795] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2020] [Revised: 12/07/2020] [Indexed: 06/12/2023]
Abstract
Precise mechanical processing of optical microcrystals involves complex microscale operations viz. moving, bending, lifting, and cutting of crystals. Some of these mechanical operations can be implemented by applying mechanical force at specific points of the crystal to fabricate advanced crystalline optical junctions. Mechanically compliant flexible optical crystals are ideal candidates for the designing of such microoptical junctions. A vapor-phase growth of naturally bent optical waveguiding crystals of 1,4-bis(2-cyanophenylethynyl)benzene (1) on a surface forming different optical junctions is presented. In the solid-state, molecule 1 interacts with its neighbors via CH⋅⋅⋅N hydrogen bonding and π-π stacking. The microcrystals deposited at a glass surface exhibit moderate flexibility due to substantial surface adherence energy. The obtained network crystals also display mechanical compliance when cut precisely with sharp atomic force microscope cantilever tip, making them ideal candidates for building innovative T- and Δ-shaped optical junctions with multiple outputs. The presented micromechanical processing technique can also be effectively used as a tool to fabricate single-crystal integrated photonic devices and circuits on suitable substrates.
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Kumar AV, Rohullah M, Ravi J, Godumala M, Annadhasan M, Chandrasekar R. Mechanophotonic aspects of a room temperature phosphorescent flexible organic microcrystal. CrystEngComm 2021. [DOI: 10.1039/d1ce00475a] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
A novel crystal of PTX-2CF3 exhibits room temperature phosphorescence and mechanical flexibility. This flexible crystal efficiently transduces optical emission both in the straight and bent geometries.
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Annadhasan M, Kumar AV, Venkatakrishnarao D, Mamonov EA, Chandrasekar R. Mechanophotonics: precise selection, assembly and disassembly of polymer optical microcavities via mechanical manipulation for spectral engineering. NANOSCALE ADVANCES 2020; 2:5584-5590. [PMID: 36133889 PMCID: PMC9417610 DOI: 10.1039/d0na00560f] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/07/2020] [Accepted: 10/10/2020] [Indexed: 05/04/2023]
Abstract
The advancement of nanoscience and technology relies on the development and utility of innovative techniques. Precise manipulation of photonic microcavities is one of the fundamental challenges in nanophotonics. This challenge impedes the construction of optoelectronic and photonic microcircuits. As a proof-of-principle, we demonstrate here that an atomic force microscopy cantilever and confocal microscopy can be used together to mechanically micromanipulate polymer-based whispering gallery mode microcavities or microresonators into well-ordered geometries. The micromanipulation technique efficiently assembles or disassembles resonators and also produces well-ordered dimer, trimer, tetramer, and pentamer assemblies of resonators in linear and bent geometries. Interestingly, an intricate L-shaped coupled-resonator optical waveguide (CROW) comprising a pentamer assembly effectively transduces light through a 90° bend angle. The presented new research direction, which combines mechanical manipulation and nanophotonics, is also expected to open up a plethora of opportunities in nano and microstructure-based research areas including nanoelectronics and nanobiology.
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