Sigma Xi Competition

1. Achieving the Photon Upconversion
Process with Biomolecules
Miguel Martinez
The Bronx High School of Science

2. The Upconversion Process
• Upconversion is a process in which photons
are converted to those of a higher
wavelength.
• Upconversion was first proposed by Nicolaas
Bloembergen, who suggested that the photon
counting abilities of rare earth metals
• Upconversion has diverse applications in
many technologies, including energy
conversion and medicine.

3. Upconversion Mechanisms
• Excited State Absorption (ESA): Two low energy photons excite an
ion into a higher energy level and a single, high energy photon is
emitted when the ion transitions to the ground state
• Energy Transfer Upconversion (ETU): An energy transfer between
two rare earth ions, culminating in the release of high energy
photons
• Photon Avalanche (PA): A combination of the previous two
mechanisms culminating in the release of several high energy
photons
Figure created
by Joubert
(2010)

4. The Problem with Rare Earth
Metals
• It is widely believed that rare earth materials
are required for this process.
• There is currently an impending shortage of
rare earth materials due to several factors,
including geopolitical tension, widespread
use, and environmental regulations.
• It has been shown that rare earth mines have
adverse environmental and health impacts
for neighboring communities.

5. A Novel Mechanism
• My new approach to the upconversion
process seeks to work around the use of
rare earths by working backwards from a
light-energy conversion process
methodology.
• This would create a molecular tetrad with
an applied voltage created with
biosynthetic materials.

6. Great Implications for Energy
and Medicine
• These devices could be used to increase
the efficiency of solar cells by several
factors through an upconverting glass.
• This device could be used as an
Upconversion Nanoparticle, which
provides greater precision for in vivo
sensing, which is needed for the treatment
of cancer.

7. Procedure
• My methodology involves finding and solving
the master equation for four molecules in a
molecular tetrad connected to two leads with
an applied voltage in a steady state. Matlab
was used for the computational procedure.
• This novel methodology uses a combination
of Quantum Electron Transport Theory and
Marcus Theory of electron transfer reactions
that has been previously established by
Smirnov et. Al (2009).

8. Diagram of Tetrad

9. Governing Equations of the
System

10. Figure 1. Relation between Current and Voltage Separation.

11. Figure 2. Relation between Emitted Photon Energy and
Voltage Separation.

12. Figure 3. Relation between Photon Energy and Emitted
Energy.

13. Viability of the Upconversion
System
• The system achieved a particle current of
about 2.9e+6 particles per millisecond and
emitted photon energy of 9 meV per second
under optimized parameters.
• This model presents a viable tunable model
for upconversion using reasonable
parameters.
• Biosynthetic molecules are being rapidly
developed, allowing for better cost and
efficiency.

14. Limitations
• The parameters of this model are only
applicable to solar cell applications. As a
result, the use of specific biosynthetic
molecules was not explored.
• The nature of the matrix-solving method
leads to an odd fluctuation in the signs of
values. These fluctuations are consistent
across all the different processes, yet are
most likely a mathematical artifact.

15. Future Inquiry
• The use of specific biosynthetic molecules
ought to be explored to see how specific
properties impact the model.
• Different conversion frequencies should
be explored for use in different
applications.

16. Major References
• 1. M. Klare. Our Fossil-Fueled Future: World Energy in 2040. Ecowatch. September 2013. Retrieved from
http://ecowatch.com/2013/09/10/fossil-fueled-future-world-energy-in-2040/
• 3. D. Jolly. China Export Restrictions on Metals Violate Global Trade Law, Panel Finds. The New York Times. March 27, 2014.
Print.
• 6. J. Chen and J. Z. Zhao. Upconversion Nanomaterials: Synthesis, Mechanism, and Applications in Sensing. Sensors 12, 2414-
2435, 2012
• 7. T. Trupke, M. A. Green, P. Würfel, Improving solar cell efficiencies by up-conversion of sub-bandgap light. J. Appl. Phys. 92, pp.
4117-4122, 2002
• 9. C. Yuan et al. Use of colloidal upconversion nanocrystals for energy relay solar cell light harvesting in the near-infrared region. J.
Mater. Chem. 22, pp. 16709-16713, 2012
• 11. A.Yu. Smirnov, L.G. Mourokh, P.K. Ghosh, F. Nori. High-efficiency energy conversion in a molecular triad connected to
conducting leads. J. Phys. Chem. C. 113, 21218, 2009
• 12. Risk, W. P., T. R. Gosnell, and A. V. Nurmikko. "Upconversion lasers", Compact Blue-Green Lasers. 1st ed. Cambridge:
Cambridge University Press, 2003. 385-467. Cambridge Books Online.
• 13. Marie-France Joubert, Photon avalanche upconversion in rare earth laser materials, Optical Materials, Volume 11, Issues 2–3,
January 1999, Pages 181-203, ISSN 0925-3467
• 14. X. Zhu and N. Peyghambarian, High-Power ZBLAN Glass Fiber Lasers: Review and Prospect.Advances in OptoElectronics
(2010)
• 15. L. D Sun, Y. F. Wang, and C.H. Yan. Paradigms and Challenges for Bioapplication of Rare Earth Upconversion Luminescent
Nanoparticles: Small Size and Tunable Emission/Excitation Spectra. Accounts of chemical research. 2014