i know that the current density characteristics in oled device are as follows.
1) ohmic current region
2) charge trapping region
3) space charge limited region
and in 2) charge trapping region, the inclination is very steep . this step is the stage where the trap is filled.
but when i fabricated and measured the device, the characteristics comes out like the secon picture.
i can distinguish 1. line and 2.line
1. line is ohmic current region.
however, the boundary of 2.line and 3.line is ambiguous.
im confused that there are no 2) charge trapping region and only
3) space charge limited region or 2. line is 2) step and 3. line is 3) step.
how to interpret this J-V graph? please advise for me. thank you.
Hi, Jaehyun,
What is your OLED device structure? The energy level alignment between layers plays a crucial role to determine the JV curves. Your JV curve looks like very little traps within the injection to emitter.
Hi, Xuhua Wang
thank you for answer.
my structure is ITO/NiO/Poly-TPD/QD/ZnO/Al and spin coated.
do your mention "looks like very little traps within the injection to emitter" means
that you think 2.line is space charge limited region in second picture?
thank you.
Hi, Jaehyun,
Yes, that is right. The LED structure does have a good energy level alignment for the electron and hole injection from both sides. Therefore, there is very little charge trap in the region.
thank you so much, Xuhua Wang
a lot of questions have been solved thanks to you.
it was a great help to me.
To interpret J-V (current-voltage) according to the measurements the voltage current of a junction diode, or apply the formula gives each a value for V, finding the value of the current. Next we find the function I (V) in exponential form
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