scholarly journals Supramolecular Bodipy Dye Architectures for Advanced Light Harvesting and Energy Transfer Applications

2021 ◽  
Author(s):  
Muhammad Yousaf
Keyword(s):  
Light Harvesting ◽  
Dye Sensitized Solar Cells ◽  
Fluorescence Emission ◽  
Emission Spectra ◽  
Photon Absorption ◽  
Quantum Yields ◽  
Reaction Centre ◽  
Two Photon Absorption ◽  
Two Photon ◽  
Sensitized Solar Cells

Shape-persistent phenylacetylene macrocycles have been explored in a number of optoelectronic and light-harvesting applications, including two-photon absorption. Likewise, BODIPY (4,4-difluoro-4-bora-3a,4a-diaza-s-indacenes) dyes have also been extensively used in material applications, owing to their tunable, intense absorption and sharp emission spectra exhibiting high quantum yields. Combining these two architectures, this thesis presents a derivative where a BODIPY is contained orthogonally within the phenylacetylene-macrocycle. This structure was inspired by photosystem II antennae complexes where energy is obsorbed by antennae complexes and funneled down to a reaction centre. Specifically, this family of molecules uses the phenylacetylene macrocycle to harvest the light and transfer it to the BODIPY core, and this has been observed by examining the fluorescence emission from the BODIPY (Figure 1). This novel dye design if coupled to a donor (D) and acceptor (A) capable of anchoring to TiO2 could be modified to become a π-spacer (i.e. D-π-A motif) for dye-sensitized solar cells resulting in panchromatic absorption, and ultimately more efficient devices.

scholarly journals Supramolecular Bodipy Dye Architectures for Advanced Light Harvesting and Energy Transfer Applications

2021 ◽  
Author(s):  
Muhammad Yousaf
Keyword(s):  
Light Harvesting ◽  
Dye Sensitized Solar Cells ◽  
Fluorescence Emission ◽  
Emission Spectra ◽  
Photon Absorption ◽  
Quantum Yields ◽  
Reaction Centre ◽  
Two Photon Absorption ◽  
Two Photon ◽  
Sensitized Solar Cells

Shape-persistent phenylacetylene macrocycles have been explored in a number of optoelectronic and light-harvesting applications, including two-photon absorption. Likewise, BODIPY (4,4-difluoro-4-bora-3a,4a-diaza-s-indacenes) dyes have also been extensively used in material applications, owing to their tunable, intense absorption and sharp emission spectra exhibiting high quantum yields. Combining these two architectures, this thesis presents a derivative where a BODIPY is contained orthogonally within the phenylacetylene-macrocycle. This structure was inspired by photosystem II antennae complexes where energy is obsorbed by antennae complexes and funneled down to a reaction centre. Specifically, this family of molecules uses the phenylacetylene macrocycle to harvest the light and transfer it to the BODIPY core, and this has been observed by examining the fluorescence emission from the BODIPY (Figure 1). This novel dye design if coupled to a donor (D) and acceptor (A) capable of anchoring to TiO2 could be modified to become a π-spacer (i.e. D-π-A motif) for dye-sensitized solar cells resulting in panchromatic absorption, and ultimately more efficient devices.

scholarly journals Photolysis of SiH4 by the Third Harmonic of a Nd:YAG Laser at 355 NM

1996 ◽  
Vol 16 (4) ◽  
pp. 245-253
Author(s):  
K. Sentrayan ◽  
E. Haque ◽  
A. Michael ◽  
V. S. Kushawaha
Keyword(s):  
Laser Energy ◽  
Emission Spectra ◽  
Photon Absorption ◽  
Absorption Process ◽  
Third Harmonic ◽  
Two Photon Absorption ◽  
Two Photon ◽  
The Third ◽  
Atomic Lines ◽  
White Deposit

The photolysis of silane (SiH4) was carried out using the third harmonic of a Nd: YAG laser at 355 nm, at a fixed SiH4 pressure of 350 Torr, varying the laser energy fluence in the range of 30–300 Jcm-2. The emission spectra indicates that the photofragments formed are SiH2, SiH, Si, H2, and H. The (A1B1-X1A1) transitions at 552.7 nm, 525.3 nm, 505.6 nm, and 484.7 nm of SiH2 are due to a two photon absorption process. The (A2Δ-X2π) transitions of SiH at 425.9 nm, 418 nm, 414.2 nm, 412.8 nm and 395.6 nm are due to a three photon absorption process. The brownish white deposit on the cell windows indicates the presence of amorphous silicon (a:Si-H). The two atomic lines of Si(4s1P0→ 3p21D2) at 288.1 nm, and (4s3Pj→ 3P3Pj) at 251.6 nm are observed. The atomic Si transitions are due to a three photon absorption. We observed seven transitions due to molecular hydrogen at wavelengths 577.5 nm, 565.5 nm, 534.4 nm, 542.5 nm, 471 nm, 461.7 nm, and 455.4 nm. These bands are due to a four photon absorption proc6ss. In addition to the molecular bands we also observed hydrogen atomic lines Hβ, Hγ and Hδ.

Synthesis, DNA photocleavage, singlet oxygen photogeneration and two photon absorption properties of ruthenium-phenanthroline porphyrins

2015 ◽  
Vol 19 (09) ◽  
pp. 1046-1052 ◽  
Author(s):  
Ze-Bin Xu ◽  
Fa-Quan Yu ◽  
Fengshou Wu ◽  
Heng Zhang ◽  
Kai Wang ◽  
...  
Keyword(s):  
Singlet Oxygen ◽  
Cross Section ◽  
Therapeutic Agents ◽  
Photon Absorption ◽  
Quantum Yields ◽  
Absorption Properties ◽  
Dna Photocleavage ◽  
Two Photon Absorption ◽  
Two Photon ◽  
Photochemical Properties

Through a new synthetic route, three ruthenium-phenanthroline porphyrins (RPP1, RPP2 and RPP3) were prepared. Their photophysical and photochemical properties, such as DNA photocleavage activity, singlet-oxygen photogeneration and two-photon absorption (2PA) were evaluated. These porphyrins 1–3 had substantial photocleavage activities, with 71%, 74% and 38% observed at 20 μM. The porphyrins with different substituents on phenathroline group had similar singlet oxygen quantum yields, with ΦΔ values at 0.52, 0.47 and 0.41, respectively. The 2PA cross-section (σ(2)) values of RPP 1–3, measured by the Z-scan method, were calculated to be 152, 172 and 135 GM, respectively, which were around 5-fold higher than that of H2TPP . Thus, these porphyrins, with their good photocleavage activities, 1 O 2 quantum yields and high 2PA cross section, suggest great potential as photodynamic therapeutic agents.

Preparation and Photophysical Properties of All-trans Acceptor–π-Donor (Acceptor) Compounds Possessing Obvious Solvatochromic Effects

2017 ◽  
Vol 70 (9) ◽  
pp. 1048
Author(s):  
Yu-Lu Pan ◽  
Zhi-Bin Cai ◽  
Li Bai ◽  
Sheng-Li Li ◽  
Yu-Peng Tian
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Photophysical Properties ◽  
Emission Spectra ◽  
Photon Absorption ◽  
Linear Absorption ◽  
Functional Theory ◽  
Two Photon Absorption ◽  
Two Photon ◽  
Donor Acceptor

A series of all-trans acceptor–π-donor (acceptor) compounds (BAQ, SFQ, BLQ, and XJQ) were conveniently synthesised and characterised by infrared, nuclear magnetic resonance, mass spectrometry, and elemental analysis. Their photophysical properties, including linear absorption, one-photon excited fluorescence, two-photon absorption, and two-photon excited fluorescence, were systematically investigated. All the compounds show obvious solvatochromic effects, such as significant bathochromic shifts of the emission spectra and larger Stokes shifts in more polar solvents. Under excitation from a femtosecond Ti : sapphire laser with a pulse width of 140 fs, they all exhibit strong two-photon excited fluorescence, and the two-photon absorption cross-sections in THF are 851 (BAQ), 216 (SFQ), 561 (BLQ), and 447 (XJQ) GM respectively. A combination of density functional theory (DFT) and time-dependent density functional theory (TDDFT) approaches was used to investigate the relationships between the structures and the photophysical properties of these compounds. The results show that they may have a potential application as polarity-sensitive two-photon fluorescent probes.

scholarly journals Prospects for More Efficient Multi-Photon Absorption Photosensitizers Exhibiting Both Reactive Oxygen Species Generation and Luminescence

Molecules ◽  
2021 ◽  
Vol 26 (20) ◽  
pp. 6323
Author(s):  
Emma Robbins ◽  
Stéphanie Leroy-Lhez ◽  
Nicolas Villandier ◽  
Marek Samoć ◽  
Katarzyna Matczyszyn
Keyword(s):  
Reactive Oxygen Species ◽  
Reactive Oxygen Species Generation ◽  
Reactive Oxygen ◽  
Inorganic Nanoparticles ◽  
Photon Absorption ◽  
Quantum Yields ◽  
Oxygen Species ◽  
Microscopy Imaging ◽  
Two Photon Absorption ◽  
Two Photon

The use of two-photon absorption (TPA) for such applications as microscopy, imaging, and photodynamic therapy (PDT) offers several advantages over the usual one-photon excitation. This creates a need for photosensitizers that exhibit both strong two-photon absorption and the highly efficient generation of reactive oxygen species (ROS), as well as, ideally, bright luminescence. This review focuses on different strategies utilized to improve the TPA properties of various multi-photon absorbing species that have the required photophysical properties. Along with well-known families of photosensitizers, including porphyrins, we also describe other promising organic and organometallic structures and more complex systems involving organic and inorganic nanoparticles. We concentrate on the published studies that provide two-photon absorption cross-section values and the singlet oxygen (or other ROS) and luminescence quantum yields, which are crucial for potential use within PDT and diagnostics. We hope that this review will aid in the design and modification of novel TPA photosensitizers, which can help in exploiting the features of nonlinear absorption processes.

Synthesis, characterization, photophysical and DNA photocleavage properties of amphiphilic porphyrins

2014 ◽  
Vol 18 (03) ◽  
pp. 221-230 ◽  
Author(s):  
Jie Zhang ◽  
Mingyu Teng ◽  
Dan Li
Keyword(s):  
Cross Sections ◽  
Photophysical Properties ◽  
Photon Absorption ◽  
Quantum Yields ◽  
Two Photon Absorption ◽  
Pyridinium Cation ◽  
H Nmr ◽  
Two Photon ◽  
Porphyrin Derivatives ◽  
Tof Ms

A series of amphiphilic porphyrins appended with pyridinium cation and/or polyethylene glycol have been synthesized and fully characterized by 1 H NMR, IR and MALDI-TOF-MS. Their photophysical properties were determined and the singlet oxygen (1 O 2) quantum yields of these compounds are in the range of 0.30–0.61 in CHCl 3 and 0.048–0.18 in Tris buffer. The measured two-photon absorption (TPA) cross-sections σ(2) of these porphyrin derivatives are between 110 and 240 GM. These amphiphilic porphyrins show some photocleavage activities (10%–21%) towards the anionic DNA observed at 100 μM.

Strong two-photon absorption and two-photon excited fluorescence emission of heterofluorene derivatives

2005 ◽  
Vol 27 (6) ◽  
pp. 1163-1170 ◽  
Author(s):  
Xiaomei Wang ◽  
Ping Yang ◽  
Wanli Jiang ◽  
Guibao Xu ◽  
Xiaozhi Guo
Keyword(s):  
Fluorescence Emission ◽  
Photon Absorption ◽  
Two Photon Absorption ◽  
Two Photon

scholarly journals Selective two-photon absorption in carbon dots: a piece of the photoluminescence emission puzzle

Nanoscale ◽  
2018 ◽  
Vol 10 (26) ◽  
pp. 12505-12514 ◽  
Author(s):  
Carla I. M. Santos ◽  
Inês F. A. Mariz ◽  
Sandra N. Pinto ◽  
Gil Gonçalves ◽  
Igor Bdikin ◽  
...  
Keyword(s):  
Total Energy ◽  
Carbon Dots ◽  
Emission Spectra ◽  
Photon Absorption ◽  
Carbon Nanodots ◽  
Nonlinear Excitation ◽  
Excitation Mode ◽  
Two Photon Absorption ◽  
Two Photon ◽  
Linear And Nonlinear

Optical spectroscopy of carbon nanodots reveals excitation-mode-dependent emission. Linear and nonlinear excitation at the same total energy results in different emission spectra.

Spectroscopy and Nonlinear Absorption of α, ω-dithienyi Polyenes

1997 ◽  
Vol 479 ◽  
Author(s):  
L. V. Natarajan ◽  
Laura A. Sowards ◽  
C. W. Spangler ◽  
N. Tang ◽  
P. A. Fleitz ◽  
...  
Keyword(s):  
Nonlinear Absorption ◽  
Nonlinear Optical ◽  
Photon Absorption ◽  
Quantum Yields ◽  
Two Photon Absorption ◽  
Fluorescence Quantum Yields ◽  
Two Photon ◽  
Steady State Fluorescence ◽  
Nonlinear Optical Absorption ◽  
Substituted Polyenes

AbstractThe photophysics and nonlinear absorption behaviour of a series of α, ω-dithienyl polyenes were studied in chloroform and n-octane solutions. Steady state fluorescence, fluorescence lifetime and quantum yield measurements were made. The fluorescence quantum yields were significantly lower than those of the corresponding ax,o-diphenyl polyenes. Among the dithienyl polyenes, 3,3′-substituted polyenes exhibited stronger fluorescence than those of the 2,2′-substituted. Nonlinear optical absorption experiments showed evidence of two photon absorption.

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