Finding New Precursors for Light Harvesting Materials: A Computational Study of the Fluorescence Potential of Benzanthrone Dyes

Due to their unique excited state dynamics, acenes play a dominant role in optoelectronic and light-harvesting applications. Their optical and electronic properties are typically tailored by side-group engineering, which often...

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REKAYASA STRUKTUR AKSEPTOR PADA ZAT WARNA ORGANIK TIPE D- π -A DENGAN KERANGKA TIOFEN

Journal of Research and Education Chemistry ◽

10.25299/jrec.2020.vol2(1).4857 ◽

2020 ◽

Vol 2 (1) ◽

pp. 30

Author(s):

Imelda Imelda

Keyword(s):

Dipole Moment ◽

Band Gap ◽

Calculation Method ◽

Research Study ◽

Light Harvesting ◽

Organic Dyes ◽

Computational Study ◽

Harvesting Efficiency ◽

Light Harvesting Efficiency

This research study about tiofen based organic dyes with D-π-A type as sensitizer on DSSC. The dyes were varied with the acceptor chain and were given names of dyes 1 to 10. The dye with the smallest band gap was added with the electron withdrawing and donating groups. The computational study used the hyperchem package with the AM1 calculation method. The result showed that dye 8 has the smallest band gap is 4,9 eV and dipole moment is 9,3 D. The effect of adding Cl as an electron withrawing group (EWG) can reduce the band gap value to 4,7 eV. The conclusions are that dye 8 is more potential as sensitizer on DSSC and the addition of Cl as EWG can improve the light harvesting efficiency.

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High-Resolution electron crystallography of the light-harvesting chlorophyll-a/b protein complex from chloroplast membranes

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100181816 ◽

1990 ◽

Vol 48 (1) ◽

pp. 610-610

Author(s):

Werner Kühlbrandt ◽

Da Neng Wang ◽

K.H. Downing

Keyword(s):

High Resolution ◽

Electron Diffraction ◽

Chlorophyll A ◽

Protein Complex ◽

Structural Integrity ◽

Light Harvesting ◽

Lhc Ii ◽

Diffraction Patterns ◽

Difference Fourier ◽

2D Crystals

The light-harvesting chlorophyll-a/b protein complex (LHC-II) is the most abundant membrane protein in the chloroplasts of green plants where it functions as a molecular antenna of solar energy for photosynthesis. We have grown two-dimensional (2d) crystals of the purified, detergent-solubilized LHC-II . The crystals which measured 5 to 10 μm in diameter were stabilized for electron microscopy by washing with a 0.5% solution of tannin. Electron diffraction patterns of untilted 2d crystals cooled to 130 K showed sharp spots to 3.1 Å resolution. Spot-scan images of 2d crystals were recorded at 160 K with the Berkeley microscope . Images of untilted crystals were processed, using the unbending procedure by Henderson et al . A projection map of the complex at 3.7Å resolution was generated from electron diffraction amplitudes and high-resolution phases obtained by image processing .A difference Fourier analysis with the same image phases and electron diffraction amplitudes recorded of frozen, hydrated specimens showed no significant differences in the 3.7Å projection map. Our tannin treatment therefore does not affect the structural integrity of the complex.

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Macroorganisation and flexibility of thylakoid membranes

Biochemical Journal ◽

10.1042/bcj20190080 ◽

2019 ◽

Vol 476 (20) ◽

pp. 2981-3018 ◽

Cited By ~ 8

Author(s):

Petar H. Lambrev ◽

Parveen Akhtar

Keyword(s):

Light Harvesting ◽

Current Knowledge ◽

Three Dimensional ◽

Photosynthetic Apparatus ◽

Dynamic Responses ◽

State Transitions ◽

Photochemical Quenching ◽

Light Harvesting Complex ◽

Complex Ii ◽

Light Harvesting Complex Ii

Abstract The light reactions of photosynthesis are hosted and regulated by the chloroplast thylakoid membrane (TM) — the central structural component of the photosynthetic apparatus of plants and algae. The two-dimensional and three-dimensional arrangement of the lipid–protein assemblies, aka macroorganisation, and its dynamic responses to the fluctuating physiological environment, aka flexibility, are the subject of this review. An emphasis is given on the information obtainable by spectroscopic approaches, especially circular dichroism (CD). We briefly summarise the current knowledge of the composition and three-dimensional architecture of the granal TMs in plants and the supramolecular organisation of Photosystem II and light-harvesting complex II therein. We next acquaint the non-specialist reader with the fundamentals of CD spectroscopy, recent advances such as anisotropic CD, and applications for studying the structure and macroorganisation of photosynthetic complexes and membranes. Special attention is given to the structural and functional flexibility of light-harvesting complex II in vitro as revealed by CD and fluorescence spectroscopy. We give an account of the dynamic changes in membrane macroorganisation associated with the light-adaptation of the photosynthetic apparatus and the regulation of the excitation energy flow by state transitions and non-photochemical quenching.

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