Excited state dynamics for visible-light sensitization of a photochromic benzil-subsituted phenoxyl-imidazolyl radical

Visible-light sensitized photoswitches have been paid particular attention in the fields of life sciences and materials science because long-wavelength light reduces photodegradation, transmits deep inside of matters, and achieves the selective excitation in condensed systems. Among various photoswitch molecules, the phenoxyl-imidazolyl radical complex (PIC) is a recently developed thermally reversible photochromic molecule whose thermal back reaction can be tuned from tens of nanoseconds to tens of seconds by rational design of the molecular structure. While the wide range of tunability of the switching speed of PIC opened up various potential applications, no photosensitivity to visible light limits its applications. In this study, we synthesized a visible-light sensitized PIC derivative conjugated with a benzil unit. Femtosecond transient absorption spectroscopy revealed that the benzil unit acts as a singlet photosensitizer for PIC by the Dexter-type energy transfer. Visible-light sensitized photochromic reactions of PIC are important for expanding the versatility of potential applications to life sciences and materials science.

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Excited State Dynamics for Visible Light Sensitization of Fast Photochromic Phenoxyl-Imidazolyl Radical Complex with Aryl Ketone

10.3762/bxiv.2019.46.v1 ◽

2019 ◽

Author(s):

Yoichi Kobayashi ◽

Yukie Mamiya ◽

Katsuya Mutoh ◽

Hikaru Sotome ◽

Masafumi Koga ◽

...

Keyword(s):

Visible Light ◽

Life Science ◽

Materials Science ◽

Transient Absorption ◽

Transient Absorption Spectroscopy ◽

Back Reaction ◽

Switching Speed ◽

Radical Complex ◽

Wide Range ◽

Potential Applications

Visible light sensitized photoswitches have been paid particular attention in the fields of life science and materials science because long-wavelength light reduces photodegradation, transmits deep inside of matters, and achieves the selective excitation in condensed systems.Among various photoswitch molecules, phenoxyl-imidazolyl radical complex (PIC) is a recently developed thermally-reversible photochromic molecule whose thermal back reaction can be tuned from tens of nanoseconds to tens of seconds by rational designs of the molecular structure. While the wide range of tunability of the switching speed of PIC opened up various potential applications, no photosensitivity to visible light limits its applications. In this study, we synthesized a visible light sensitized PIC derivative conjugated with a benzil unit. Femtosecond transient absorption spectroscopy revealed that the benzil unit acts as a singlet photosensitizer for PIC by the Dexter-type energy transfer. Visible light sensitized photochromic reactions of PIC are important for expanding the versatility of potential applications to life science and material science.

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Nanosecond photochromic molecular switching of a biphenyl-bridged imidazole dimer revealed by wide range transient absorption spectroscopy

Chemical Communications ◽

10.1039/c4cc06001f ◽

2015 ◽

Vol 51 (7) ◽

pp. 1375-1378 ◽

Cited By ~ 12

Author(s):

Tetsuo Yamaguchi ◽

Michiel F. Hilbers ◽

Paul P. Reinders ◽

Yoichi Kobayashi ◽

Albert M. Brouwer ◽

...

Keyword(s):

Time Constant ◽

Absorption Spectroscopy ◽

Recovery Time ◽

Transient Absorption ◽

Thermal Recovery ◽

Transient Absorption Spectroscopy ◽

Back Reaction ◽

Molecular Switching ◽

Wide Range

We demonstrate that a biphenyl-bridged imidazole dimer exhibits fast photochromism with a thermal recovery time constant of ∼100 ns, which is the fastest thermal back reaction in all reported imidazole dimers.

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SnSe Nanosheets: From Facile Synthesis to Applications in Broadband Photodetections

Nanomaterials ◽

10.3390/nano11010049 ◽

2020 ◽

Vol 11 (1) ◽

pp. 49

Author(s):

Xiangyang Li ◽

Zongpeng Song ◽

Huancheng Zhao ◽

Wenfei Zhang ◽

Zhenhua Sun ◽

...

Keyword(s):

Transient Absorption ◽

Ultrafast Optics ◽

Light Response ◽

Transient Absorption Spectroscopy ◽

Monolayer Graphene ◽

Proof Of Concept ◽

Facile Synthesis ◽

Femtosecond Transient Absorption ◽

Potential Applications ◽

Promising Area

In recent years, using two-dimensional (2D) materials to realize broadband photodetection has become a promising area in optoelectronic devices. Here, we successfully synthesized SnSe nanosheets (NSs) by a facile tip ultra-sonication method in water-ethanol solvent which was eco-friendly. The carrier dynamics of SnSe NSs was systematically investigated via a femtosecond transient absorption spectroscopy in the visible wavelength regime and three decay components were clarified with delay time of τ1 = 0.77 ps, τ2 = 8.3 ps, and τ3 = 316.5 ps, respectively, indicating their potential applications in ultrafast optics and optoelectronics. As a proof-of-concept, the photodetectors, which integrated SnSe NSs with monolayer graphene, show high photoresponsivities and excellent response speeds for different incident lasers. The maximum photo-responsivities for 405, 532, and 785 nm were 1.75 × 104 A/W, 4.63 × 103 A/W, and 1.52 × 103 A/W, respectively. The photoresponse times were ~22.6 ms, 11.6 ms, and 9.7 ms. This behavior was due to the broadband light response of SnSe NSs and fast transportation of photocarriers between the monolayer graphene and SnSe NSs.

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Clocking the buildup dynamics of light-induced states through attosecond transient absorption spectrum

Journal of Physics B Atomic Molecular and Optical Physics ◽

10.1088/1361-6455/ac3847 ◽

2021 ◽

Author(s):

Xiaoxia Wu ◽

Shaofeng Zhang ◽

Difa Ye

Keyword(s):

Floquet Theory ◽

Transient Absorption ◽

Scaling Law ◽

Time Lag ◽

Time Dependent ◽

Transient Absorption Spectroscopy ◽

Transient Absorption Spectrum ◽

Wide Range ◽

Maximal Shift ◽

Buildup Time

Abstract The buildup processes of the light-induced states (LISs) in attosecond transient absorption spectroscopy are studied by solving the time-dependent Schrödinger equation and compared with the quasistatic Floquet theory, revealing a time lag of the maximal shift and strongest absorbance of the LIS with respect to the zero delay that is referred to as the buildup time. We analytically derive a scaling law for the buildup time that conﬁrms the numerical results over a wide range of detunings. Our theory veriﬁes the commonly accepted scenario of nearly instantaneous response of matter to light if the pump ﬁeld is blue-detuned, but some differences are found in the near-resonant and red-detuning cases. Implications of the buildup time in petahertz optoelectronics are discussed.

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Preparation of Succinoglycan Hydrogel Coordinated With Fe3+ Ions for Controlled Drug Delivery

Polymers ◽

10.3390/polym12040977 ◽

2020 ◽

Vol 12 (4) ◽

pp. 977 ◽

Cited By ~ 1

Author(s):

Yiluo Hu ◽

Daham Jeong ◽

Yohan Kim ◽

Seonmok Kim ◽

Seunho Jung

Keyword(s):

Drug Delivery ◽

Visible Light ◽

Sinorhizobium Meliloti ◽

Environmental Changes ◽

Controlled Drug Delivery ◽

Attenuated Total Reflection ◽

Extracellular Polysaccharides ◽

Rheological Analysis ◽

Wide Range ◽

Potential Applications

Hydrogel materials with a gel-sol conversion due to external environmental changes have potential applications in a wide range of fields, including controlled drug delivery. Succinoglycans are anionic extracellular polysaccharides produced by various bacteria, including Sinorhizobium species, which have diverse applications. In this study, the rheological analysis confirmed that succinoglycan produced by Sinorhizobium meliloti Rm 1021 binds weakly to various metal ions, including Fe2+ cations, to maintain a sol form, and binds strongly to Fe3+ cations to maintain a gel form. The Fe3+-coordinated succinoglycan (Fe3+-SG) hydrogel was analyzed by attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy, circular dichroism (CD), and field-emission scanning electron microscopy (FE-SEM). Our results revealed that the Fe3+ cations that coordinated with succinoglycan were converted to Fe2+ by a reducing agent and visible light, promoting a gel-sol conversion. The Fe3+-SG hydrogel was then successfully used for controlled drug delivery based on gel-sol conversion in the presence of reducing agents and visible light. As succinoglycan is nontoxic, it is a potential material for controlled drug delivery.

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Interfacial charge separation in Cu2O/RuOx as a visible light driven CO2 reduction catalyst

Physical Chemistry Chemical Physics ◽

10.1039/c4cp00102h ◽

2014 ◽

Vol 16 (13) ◽

pp. 5922-5926 ◽

Cited By ~ 36

Author(s):

Ernest Pastor ◽

Federico M. Pesci ◽

Anna Reynal ◽

Albertus D. Handoko ◽

Mingjia Guo ◽

...

Keyword(s):

Visible Light ◽

Absorption Spectroscopy ◽

Charge Separation ◽

Transient Absorption ◽

Co2 Reduction ◽

Charge Carriers ◽

Transient Absorption Spectroscopy ◽

Visible Light Driven ◽

Interfacial Charge

Transient absorption spectroscopy as a tool to monitor charge carriers in Cu2O–RuOx photocathodes for CO2 reduction.

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EMI Series Mechanistic Investigation of a Visible Light Mediated Dehalogenation/Cyclisation Reaction using Iron(III), Iridium(III) and Ruthenium(II) Photosensitizers

Catalysis Science & Technology ◽

10.1039/d1cy01771c ◽

2021 ◽

Author(s):

Akin Aydogan ◽

Rachel Bangle ◽

Simon De Kreijger ◽

John Dickenson ◽

Michael L Singleton ◽

...

Keyword(s):

Steady State ◽

Visible Light ◽

Transient Absorption ◽

Transient Absorption Spectroscopy ◽

Time Resolved ◽

Femtosecond Transient Absorption ◽

Mechanistic Investigation ◽

Femtosecond Transient Absorption Spectroscopy ◽

Visible Light Driven ◽

Time Resolved Infrared Spectroscopy

The mechanism of a visible light-driven dehalogenation/cyclization reaction was investigated using ruthenium(II), iridium(III) and iron(III) photosensitizers by means of steady-state photoluminescence, time-resolved infrared spectroscopy, and nanosecond/femtosecond transient absorption spectroscopy. The...

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Pb-Free Cs3Bi2I9 Perovskite as a Visible-Light-Active Photocatalyst for Organic Pollutant Degradation

Nanomaterials ◽

10.3390/nano10040763 ◽

2020 ◽

Vol 10 (4) ◽

pp. 763 ◽

Cited By ~ 3

Author(s):

Bianca-Maria Bresolin ◽

Carsten Günnemann ◽

Detlef W. Bahnemann ◽

Mika Sillanpää

Keyword(s):

Visible Light ◽

Transient Absorption ◽

Organic Pollutant ◽

Transient Absorption Spectroscopy ◽

Advanced Materials ◽

Organic Pollutant Degradation ◽

Metal Halide Perovskite ◽

Excellent Activity ◽

Visible Light Active ◽

Light Excitation

In our work, we employed Cs3Bi2I9 as a visible-light-active photocatalyst, synthesized with a low-temperature solvothermal method. The morphological and structural properties of the as-prepared perovskite were investigated, and the results were compared to previous studies to confirm its nature and the quality of the synthesis procedure. Transient absorption spectroscopy was applied in order to investigate the generation and lifetime of photogenerated charge carriers, revealing their formation after visible light excitation. The potential photocatalytic activity of the as-prepared metal halide perovskite was applied for the removal of Rhodamine B in aqueous solution, demonstrating an excellent activity of 93% after 180 min under visible-light irradiation. The current research aims to provide insights into the design of a new visible-light-active photocatalyst, Cs3Bi2I9, selected for its high application value in the field of advanced materials for light harvesting.

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Visible-light-induced tandem reaction of o -aminothiophenols and alcohols to benzothiazoles over Fe-based MOFs: Influence of the structure elucidated by transient absorption spectroscopy

Journal of Catalysis ◽

10.1016/j.jcat.2017.01.014 ◽

2017 ◽

Vol 349 ◽

pp. 156-162 ◽

Cited By ~ 27

Author(s):

Dengke Wang ◽

Josep Albero ◽

Hermenegildo García ◽

Zhaohui Li

Keyword(s):

Visible Light ◽

Absorption Spectroscopy ◽

Transient Absorption ◽

Transient Absorption Spectroscopy ◽

Tandem Reaction

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Photocatalyst Z-Scheme System Composed of a Linear Conjugated Polymer and BiVO4 for Overall Water Splitting Under Visible Light

10.26434/chemrxiv.12252317 ◽

2020 ◽

Author(s):

Yang Bai ◽

Keita Nakagawa ◽

Alexander Cowan ◽

Catherine Aitchison ◽

Yuichi Yamaguchi ◽

...

Keyword(s):

Visible Light ◽

Water Splitting ◽

Water Oxidation ◽

Conjugated Polymer ◽

High Throughput Screening ◽

Transient Absorption ◽

Transient Absorption Spectroscopy ◽

Proton Reduction ◽

Overall Water Splitting ◽

Multiple Components

Linear conjugated polymers have potential as photocatalysts for hydrogen production from water but so far, most studies have involved non-scalable sacrificial reagents. Z-schemes comprising more than one semiconductor are a potential solution, but it is challenging to design these systems because multiple components must work together synergistically. Here, we show that a conjugated polymer photocatalyst for proton reduction can be coupled in a Z-scheme with an inorganic water oxidation photocatalyst to promote overall water splitting without any sacrificial reagents. First, a promising combination of an organic catalyst, an inorganic catalyst, and a redox mediator was identified by using high-throughput screening of a library of components. A Z-scheme system composed of P10 (homopolymer of dibenzo[b,d]thiophene sulfone)-Fe2+/Fe3+-BiVO4 was then constructed for overall water splitting under visible light irradiation. Transient absorption spectroscopy was used to assign timescales to the various steps in the photocatalytic process. While the overall solar-to-hydrogen efficiency of this first example is low, it provides proof of concept for other hybrid organic-inorganic Z-scheme architectures in the future.

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