Transcript OLED Fabrication

• OLEDs are light emitting devices
that have a thin film of organic
compounds as its emissive
electroluminescent layer.
Physical Vapor Deposition
 Screen Printing
 Ink Jet Printing
 In-line Fabrication

Thermal vapor evaporation of small
molecules occurs in environment of 10e(6) Torr or higher
 It is usually carried out on glass substrate
 Multicolor displays are made using
properly matched shadow masks for
depositing RGB emitting materials

Thickness can be easily controlled
 2-dimensional combinatorial arrays of
OLEDs can be easily fabricated in a
single deposition procedure
 PVD uses the generally available
vacuum equipment that exists in the
semiconductor industry

Expensive
 Not flexible
 Has no control to direct the materials to
deposit on the desired areas
 Inefficient use of materials

Used in low information content displays
such as logos and signs
 Thin films achieved
 Elements of screen printing: screen,
stencil, squeegee, ink, press bed, and
substrate
 Mesh materials can vary from polyester
to stainless steel

1.
2.
3.
4.
5.
The mesh material is stretched across a
frame
Hole transport layer prepared using a
solution of diamine, polycarbonate, and
rubrene.
Squeegee is used to wipe solution through
the open mesh
Resulting film covers entire surface of ITO
Electron transport layer (ETL) and cathode
are deposited by PVD
• For patterned hole transport layer (HTL)
devices: cathode is deposited in a block larger
than the HTL pattern
• For non-patterned HTL: cathode is deposited
through a mask to create emitting regions of
known area for device output measurement
Simple
 Lower cost
 Great reduction in materials usage
because materials are only directed to
the printed areas
 Faster than inkjet printing
 More versatile

OLEDs are sprayed onto substrates like
ink sprayed on paper during printing
 Advantages:

- Reduced cost
- Allows OLEDs to be printed on very large
films
Ink jet printing to define and pattern RGB emitting subpixels
Mass production
technique
• Vertical in-line tool
operates with
continuous substrate
flow
• Linear sources of
depositing organic
and metallic
materials
•
•
•
•
•
•
•
•
Cheaper mass production technique
Excellent thickness homogeneity
Excellent deposition stability
Complicated stack structures possible
High deposition rates/high throughput
High material usage
Large substrate handling






Ghassan E. Jabbour et al., Screen Printing for the Fabrication of Organic
Light-Emitting Devices, IEEE 7:5, 2001
Joseph Shinar, Organic Light-emitting Devices.
http://www.ewh.ieee.org/soc/cpmt/presentations/cpmt0401a.pdf
http://www.opera2015.org/deliverables/MONA_CDROM/4_Symposium%20Presentations/04-scholles2752.pdf
Muhamad Mat Salleh, et.al., Fabrication of Organic Light Emitting
Diodes.
http://optics.org/cws/article/research/24299