Upload
buikien
View
217
Download
3
Embed Size (px)
Citation preview
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 activityThe Oriental hornet worker digging activity
Correlation between worker digging activity
and UVB radiation
Brown Cuticle
Yellow Cuticle
Epicuticle
Epicuticle
Exo-Endocuticle
Exo-Endocuticle
Hypocuticle
Hypocuticle
Melanine
Xanthopterin
1 2 3
The development of pigments within the cuticle
Brown
CuticleYellow
Cuticle
Yellow
Cuticle
After removal
of yellow pigment granules
Liver-like enzymatic activity within the
layer of yellow granules
Measurement of voltage between the epicuticle
and the hypocuticle
Base (nm)
Base (nm)
Atomic force microscopy of the epicuticle
M
M
The internal structure of the cuticle
Epicuticle
Reflectivity measurements
2
1
3
2+3
Flat surface
A B
DC
Optical modeling of reflectance of brown and yellow cuticle
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. IshayDepartment of Physiology and Pharmacology, SacklerFaculty of Medicine, Tel-Aviv University.
Professor David J. BergmanSchool of Physics and Astronomy, Raymond and Beverly Faculty of Exact Sciences, Tel-Aviv University.
Professor Arie Zaban and Idan HodInstitute of Nanotechnology & Advanced Materials, Department of Chemistry, Bar Ilan University.
Dmitry GalushkoDepartment of Physics, Technion, Israel Institute of Technology.
Professor Darren M. Bagnall and Stuart A. BodenNano Research Group, Electronics and Computer Science. University of Southampton, United Kingdom.