Lab #4 Organic LED
1
The OLED for Today
Indium-tin oxide (ITO)
(Transparent electrode)
Light&is&emi*ed&when&Ru+&and&Ru3+&combine&to&
form&two&Ru2+&complex&ions,&one&of&which&is&in&
an&excited&state.&Excited&ruthenium(II)&complex&
ions&emit&light&via&phosphorescence.&
Glass slide
Polymer film with
Ru(II) ions
Ru3+
O
Gallium-indium
eutectic alloy
Completed device
(metallic cathode on top)
Ru+
Ru3+
Ru3+
Ru3+
Ru2+
Ru2+
Ru2+
Ru2+
Ru2+
Ru2+
Ru+
Ru+
Ru+
Cathode
Anode
Deposited film (~1000 A)
hυ
Emitted light
Image by MIT OpenCourseWare.
Image by MIT OpenCourseWare.
2
Steps
IdenCfy&the&conducCng&
side&of&a&Cn&oxideE
coated&piece&of&glass&by&
using&a&mulCmeter&to&
measure&resistance.&&
ITO&
Use&a&co*on&swab&or&computer&fan&to&spread&
a&thin&layer&of&[Ru(bpy)3](BF4)2&PVA&soluCon&
on&the&glass.&keep&some&uncoated&regions&by&
taping&one&edge.&
&
[Ru(bpy) ](BF
& ) &PVA&
&
3
4 2
3
Evaporate&using&a&hot&
plate&for&several&
minutes&depending&on&
the&thickness.&
3KRWRJUDSKRIDKRWSODWHUHPRYHG
GXHWRFRS\ULJKWUHVWULFWLRQV
Steps
Prepare&a&mask&using&a&piece&of&
duct&tape&on&aluminum&foil&and&
punching&a&2/16&inch&hole.&
Use&a&co*on&swab&to&paint&
through&the&template&with&liquid&
galliumEindium&alloy&to&add&an&
acCve&metal&electrode.&
Touch&the&posiCve&lead&of&a&
4.5Evolt&power&supply&to&the&
CnEoxide&glass.&Gently&touch&
the&negaCve&lead&to&the&
galliumEindium.&
Q1:&Is&the&circuit&a&diode?&
What&happens&if&you&
reverse&the&polarity&of&the&
applied&voltage?&
V&
Q2:&Light!!!&What&is&the&
wavelength???&
&
&
&
Q3:&How&long&does&your&
OLED&last?&What&could&
cause&reducCon&of&
lifeCme?&
&
&
&
&
GaEIn&eutecCc&
&
&
&
Foil&
4
MIT OpenCourseWare
http://ocw.mit.edu
6.S079 Nanomaker
Spring 2013
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