1. • Organic electronics are devices such as
Solar Cells, TV’s, and cell phone screens
that utilize organic materials. The use of
Organic materials offer many exciting
advantages including mechanical
flexibility and low cost of materials and
manufacturing.
Introduction
• Photoswitching molecules change
conformation when irradiated with
discrete wavelengths of light. Doping the
organic semiconductors of OFETs with
photoswitchable molecules can enable
multifunctional transistors [3].
• Using optical analysis we aim to study
the dependence of switching of a pyrrole
substituted aurone (Py, fig. 1) on the
surrounding environment to determine
the viability of this molecule for use in
light-switchable OFETs.
• Our long term goal is to examine the
photoswitching of Py in an organic
semiconductor and the effects of this
switching on transistor properties.
• Py studied in thick and thin
Py/PMMA polymer films (.04785%
Py by weight)
• Created predominantly E isomer
samples by irradiating molecules
with 405nm light for 120s
• Created Predominantly Z Isomers
by irradiating molecules with
469nm light for 300s
Methods
Results
Conclusion
• Py can be photoisomerized in thick and
thin polymer films
• Py’s conversion from Z to E occurs
much faster relative to the E to Z
conversion
References
[1] Flexible Organic Solar Modules. N.d. Photograph. Idw-
online.de Karin Schneider. Web.
[2]Organic Field Effect Transistor N.d. Photograph. bo.ismn.cnr.it/
Web.
[3] Emanuele Orgiu, et al. “Optically switchable transistor via
energy-level phototuning in a bicomponent organic
semiconductor.” Nature Chemistry vol. 4 (2012)
[4] Loew, Maura. “CHARACTERIZATION OF AN AURONE
BEARING A PYRROLE SUBSTITUENT” Ch. 4 Ph.D Thesis
Acknowledgements
1. Department of Physics - Binghamton University – State University of New York
James Duffy1, Tong Yang1, Maura Loew2, Susan Bane2, Jeffrey Mativetsky1
Optically Switching Organic Field Effect Transistors
0
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Intensity(CPS)
Wavelength (nm)
Thick Film Z Isomer Fluorescence
(405nm Excitation)
Irradiated @ 405 nm
Irradiated @ 469 nm
Predominantly E
Predominantly Z
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Intensity(CPS)
Wavelength (nm)
Thick Film E Isomer Fluorescence
(469nm Excitation)
Irradiated @ 405nm
Irradiated @ 469nm
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Fluorescence(CPS)
Time Irradiated (s)
Fluorescence Decay of Z Isomer
during Z to E switching
0
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0 10000 20000 30000 40000 50000 60000
Intensity(CPS)
Time Irradiated (s)
Fluorescence Decay of E Isomer during
E to Z switching
1000 2000 3000 4000 5000 6000
• Photoswitching of Py in
thin polymer films
examined in real time
by collecting the
intensity of each
isomer’s emission peak
while irradiating for
conformational change.
Thin Film Kinetics
Irradiating at 469nm, collecting emission at 497nmIrradiating at 405nm, collecting Emmision at 446nm
0
2000
4000
6000
8000
10000
12000
14000
400 450 500 550 600 650
Intensity(CPS)
Wavelength (nm)
Thin Film Z Isomer Fluorescence
(405nm Excitation)
Irradiated @ 405nm
Irradiated @ 469nm
0
5000
10000
15000
20000
25000
30000
35000
450 470 490 510 530 550 570 590 610 630 650
Emmission(CPS)
Wavelength (nm)
Thin Film E Isomer Fluorescence
(469nm Excitation)
Irradiated @ 405 nm
Irradiated @ 469 nm
[1]
• A key device in Organic Electronics is the
Organic Field Effect Transistor (OFET).
Thick Film Emission
[2]
Thin Film Emission
• After irradiation the
samples exhibited
distinct emission spectra
indicative of good
photoswitching.
• The photoswitching of
Py is maintained in thin
films.
Future Goals
• Study optical properties of Py in TIPS-
Pentacene organic semiconductor
• Examine photoswitching effects of Py on
OFET with Py doped organic
semiconductor
λ
λ=405nm
Excitation
Emission
λ=469nm
Excitation
Emission
Z Isomer E Isomer
Photoisomerization of Py[4]
Fig. 1
Predominantly E
Predominantly Z
Predominantly E
Predominantly Z
Predominantly E
Predominantly Z
• Dr. Scott Handy - Supplier of Py
• Takian Chio
• Alexander Haruk
Goals
2. Department of Chemistry – Binghamton University – State University of New York