Solar energy harvesting in the epicuticle of the - NAS

Solar energy harvesting in the epicuticle of the - NAS

Solar energy harvesting in the epicuticle of the
Oriental hornet
Marian Plotkin Ph.D.
National University of Singapore
Nanoscience & Nanotechnology Initiative
The Oriental hornet worker digging activity
Correlation between worker digging activity
and UVB radiation
Brown Cuticle
Epicuticle
Exo-Endocuticle
Melanine
Hypocuticle
Yellow Cuticle
Epicuticle
Exo-Endocuticle
Hypocuticle
Xanthopterin
The development of pigments within the cuticle
1
Brown
Cuticle
Yellow
Cuticle
After removal
of yellow pigment granules
2
3
Yellow
Cuticle
Liver-like enzymatic activity within the
layer of yellow granules
Measurement of voltage between the epicuticle
and the hypocuticle
Atomic force microscopy of the epicuticle
Base (nm)
Base (nm)
The internal structure of the cuticle
Epicuticle
M
M
Reflectivity measurements
3
2
Flat surface
1
2+3
Optical modeling of reflectance of brown and yellow cuticle
A
B
C
D
Optical modeling of brown epicuticle
as a diffraction grating in transmission
Dye Sensitized Solar Cell (DSSC) with Xanthopterin
Jsc=0.858 mA/cm2
Voc= 564 mv
FF=69.2%
Conversion efficiency= 0.335%
The cuticular multilayered structure compared to a man
made antireflection coating
Discussion
1) The Oriental hornet cuticle exhibits antireflection and light trapping properties.
2) Measurements show that the complex layered structure increases the
antireflective effect. The cuticular multilayered structure may introduce a
gradual change in effective refractive index by varying the proportion of chitin
nanorods within the protein matrix or by altering the angle of the deposition of
chitin nanorods angle.
3) The Xanthopterin pigment acts as a light harvesting molecule.
4) The Oriental hornet correlates its digging activity with solar insolation.
The Oriental hornet cuticle is a photonic structure capable of harvesting sun
light. The pigment xanthopterin within the cuticle transforms sun light to
electrical energy which may serve the metabolic activity performed within the
pigment layer hence aiding in the digging activity.
Professor Jacob S. Ishay
Department of Physiology and Pharmacology, Sackler
Faculty of Medicine, Tel-Aviv University.
Professor David J. Bergman
School of Physics and Astronomy, Raymond and Beverly
Faculty of Exact Sciences, Tel-Aviv University.
Professor Arie Zaban and Idan Hod
Institute of Nanotechnology & Advanced Materials,
Department of Chemistry, Bar Ilan University.
Dmitry Galushko
Department of Physics, Technion, Israel Institute of
Technology.
Professor Darren M. Bagnall and Stuart A. Boden
Nano Research Group, Electronics and Computer
Science. University of Southampton, United Kingdom.