Harvesting Hot Holes in Plasmon-Coupled Ultrathin Photoanodes for High-Perfor...
Microfluidic oled vivek hegde
1. T. Kasahara1, J. Mizuno1, S. Hirata2, T. Edura2, S. Matsunami2, C. Adachi2, and S. Shoji1 1Waseda
University, Tokyo, JAPAN 2Kyushu University, Fukuoka, JAPAN
MEMS 2012, Paris, FRANCE, 29 January - 2 February 2012
Reporter-Vivek Hegde
2. OLED Technology
Motivation
Concept and Principle
Experimental Procedure
Design of Prototype micro-fluidic OLED
Fabrication Process
Evaluation of Fabricated micro-fluidic OLED
Result and Discussion
Conclusion
3. Micro fluidic devices have been developed for a
wide range of applications.
OLEDs containing of solid-state organic
semiconductors.
Next generation flat panel display due to their
wide viewing angle, light weight and thin
components.
Recently the optoelectronics devices based on
the liquid emitting materials such as electro-
chemiluminescence (ECL) OLEDs are also
reported.
4. The micro-channel structures are usually fabricated using
MEMS technology.
Negative photo-resist SU-8 has been suitable material for the
micro channel fabrication .
Transparent electrodes such as indium tin oxide (ITO)
facilitate the optical microscopic observation of fluidic
behaviour in the micro channels.
ITO has been widely used as an anode in OLEDs due to its
high electrical conductivity.
Here Combination of micro-fluidics and liquid OLED.
5. Different fresh liquid
organic semiconductors are
continuously injected from
the inlets to the light
emitting areas using the
syringe pumps.
6. Micro-fluidic OLED, which consists
of micro-channels and pairs of ITO
anode and cathode.
Electroluminescence is
performed in the flowed liquid
organic semiconductors by the
radiative recombination of
electron-hole pairs with DC
voltage.
7. The microchip has a 3 3 matrix of
OLED array in the SU-8 micro-
channels.
The micro-channels are sandwiched
between the ITO anodes on a glass
substrate and the polyethylene
naphthalate (PEN) film with the ITO
cathodes.
Depth is chosen about 6 µm for
enhancement of OLED performances,
widths are 1000, 1250, and 1500 µm.
8. ITO-anode patterned by conventional
photolithography and wet etching using
dilute aquarigia(a).(HCl-HNO3-H2O)
SU-8 3005 6 µm thick obtained by spun on
substrate at 4000 rpm for 20 Sec and soft
baked at 95ºC for 10 min(b).
For the surface modification of the SU-8
layer, the ITO anodes in the micro
channels were covered by sacrificial layer
of positive resist of 350 nm(c).
9. The ITO cathodes were fabricated by the
same process as the ITO anodes.
The inlet and outlet of the microchannels
were mechanically punched for injecting.
The anode and cathode substrates were
separately fabricated and were bonded to
form enclosed ITO electrodes embedded
micro-fluidic channels.
10. To incorporate oxygen
functionalities in to
SU8,PEN and ITO
Finally, the surfaces were
bonded under contact
pressure of 1.5 MPa at 140
C for 5 min to form bond
Immersed in
GOPTS-Glycidodyloxy proplyl tri
methoxysilane
APTES- Amino propyl triethoxysilane
The anode substrate was then rinsed
with acetone and IPA to remove the
sacrificial resist and any unbound
GOPTS-SAM, while the cathode
substrate was rinsed with ethanol .
11.
The inlet and OLED were were
Fabricated outlet nozzles investigated
connected to the top plate. The liquid
emitters introduced manuallymicroscope
using scanning acoustic while the
(SAM) at 175 MHz
used liquid emitters were collected from
the outlet nozzles.
TheTwo types liquid emitter was detected by:
flow of the of tests were performed
365the observation of theProper DC voltages
nm UV light irradiation. fluidic
were applied to the device with a source meter,of
behaviour and electroluminescence
and the electroluminescence was recorded with a
the liquid emitter in the micro-
digital camera. The J-V characteristics were
measured usingand the currentparameter
channels, a semiconductor density-
voltage (J-V) measurement.
analyzer
12. SAM image of the fabricated microfluidic OLED Demonstration
Electroluminescence in the microchannels of (b) 1000, (c) 1250 and (d) 1500 µm width
under applied 70 V.
13. The current density increased
with increasing applied voltage
The intensity increased
significantly larger than 30 V
J-V Characteristics of micro-fluidic OLED
14. Research proposed a combination of micro-fluidic and liquid
OLED, and fabricated a first prototype micro-fluidic OLED.
Optimized fabrication method was developed.
The electroluminescence was obtained in the flowed liquid
emitters under the appropriate applied voltage.
The current density of 2.11 mA/cm2 was measured when 60 V
was applied .
In contrast thicker emitter layer, higher driving voltage than
solid state OLED.
