Organic light-emitting diode (OLED) display panel and manufacturing method
The present disclosure provides an OLED display panel, including a substrate and a plurality of pixel regions disposed on the substrate and emitting light in different colors. A pixel region includes a first electrode, a first auxiliary light-emitting layer, a light-emitting layer, a second auxiliary light-emitting layer, and a second electrode. A micro-cavity structure is formed between the first electrode and the second electrode. The second auxiliary light-emitting layer includes at least a first sub-auxiliary light-emitting layer. The second auxiliary light-emitting layer corresponding to the pixel regions emitting light in at least one color also includes a second sub-auxiliary light-emitting layer. At least one of the first sub-auxiliary light-emitting layer and the second sub-auxiliary light-emitting layer is made of at least a first electron-type material. The second sub-auxiliary light-emitting layer has a zero-field electron mobility greater than or equal to a pre-determined threshold.
1. An organic light-emitting diode (OLED) display panel, comprising:
a substrate; and
a plurality of pixel regions disposed on the substrate and emitting light in different colors, wherein a pixel region includes a first electrode, a first auxiliary light-emitting layer, a light-emitting layer, a second auxiliary light-emitting layer, and a second electrode, disposed in a direction far away from the substrate;
a micro-cavity structure is formed between the first electrode and the second electrode;
the second auxiliary light-emitting layer includes at least a first sub-auxiliary light-emitting layer;
the second auxiliary light-emitting layer corresponding to the pixel regions emitting light in at least one color also includes a second sub-auxiliary light-emitting layer;
at least one of the first sub-auxiliary light-emitting layer and the second sub-auxiliary light-emitting layer is made of at least a first electron-type material;
the second sub-auxiliary light-emitting layer has a zero-field electron mobility greater than or equal to a pre-determined threshold;
the first electron-type material includes a first radical group;
the first radical group is a conjugated structure containing at least three consecutive benzene rings;
at least one of the three consecutive benzene rings has a carbon atom replaced by a nitrogen atom;
the first radical group is an axially symmetric structure; and
the first radical group has a skeletal structural formula of
2. The OLED display panel according to claim 1 , wherein:
the second sub-auxiliary light-emitting layer has the zero-field electron mobility greater than or equal to 1.0×10 −4 cm 2 /V·S.
3. The OLED display panel according to claim 2 , wherein:
the first sub-auxiliary light-emitting layer has the zero-field electron mobility greater than or equal to approximately 1.0×10 −4 cm 2 /V·S.
4. The OLED display panel according to claim 3 , wherein:
the first sub-auxiliary light-emitting layer is doped with at least one of ytterbium ion, lithium ion, and cesium ion.
5. The OLED display panel according to claim 1 , wherein:
the second sub-auxiliary light-emitting layer is doped with at least one of ytterbium ion, lithium ion, and cesium ion.
6. The OLED display panel according to claim 1 , wherein:
the first sub-auxiliary light-emitting layer is made of a same material as the second sub-auxiliary light-emitting layer; and
the first sub-auxiliary light-emitting layer includes a same host material as the second sub-auxiliary light-emitting layer.
7. The OLED display panel according to claim 1 , wherein:
a cavity length of the micro-cavity structure in the pixel region is positively correlated with a wavelength of light emitted from the corresponding pixel region; and
the cavity length is an optical path distance between the first electrode and the second electrode.
8. The OLED display panel according to claim 1 , wherein:
the plurality of pixel regions includes a plurality of red pixel regions, a plurality of green pixel regions, and a plurality of blue pixel regions; and
at least in a red pixel region and a green pixel region, the second sub-auxiliary light-emitting layer is disposed between the light-emitting layer and the first sub-auxiliary light-emitting layer.
9. The OLED display panel according to claim 8 , wherein:
the second auxiliary light-emitting layer in the red pixel region has a thickness ranging approximately between 205 mn and 230 nm;
the second auxiliary light-emitting layer in the green pixel region has a thickness ranging approximately between 170 nm and 190 nm; and
the second auxiliary light-emitting layer in a blue pixel region has a thickness ranging approximately between 120 nm and 135 nm.
10. The OLED display panel according to claim 8 , wherein:
the first auxiliary light-emitting layer and the second auxiliary light-emitting layer in the red pixel region has a thickness ratio ranging approximately between 3/20 and 7/40;
the first auxiliary light-emitting layer and the second auxiliary light-emitting layer in the green pixel region has a thickness ratio ranging approximately between 7/40 and 1/5; and
the first auxiliary light-emitting layer and the second auxiliary light-emitting layer in a blue pixel region has a thickness ratio ranging approximately between 1/4 and 3/10.
11. The OLED display panel according to claim 8 , wherein:
the light-emitting layer in the red pixel region and the light-emitting layer in the green pixel region are made of a phosphorescent material; and
the light-emitting layer in a blue pixel region is made of a fluorescent material.
12. The OLED display panel according to claim 8 , wherein:
at least one of the light-emitting layer in the red pixel region and the light-emitting layer in a blue pixel region includes one or two host materials; and
the light-emitting layer in the green pixel region includes at least two host materials.
13. The OLED display panel according to claim 1 , wherein:
the first auxiliary light-emitting layer has a thickness ranging approximately between 25 nm and 45 nm; and
the first auxiliary light-emitting layer has the zero-field hole mobility ranging approximately between 1.2×10 −5 cm 2 /V·S and 9.0×10 −5 cm 2 /V·S.
14. The OLED display panel according to claim 1 , wherein:
the light-emitting layer in all pixel regions has a same thickness.
15. The OLED display panel according to claim 1 , wherein:
at least one of the light-emitting layer and the second sub-auxiliary light-emitting layer in the plurality of pixel regions has a thickness positively correlated with a wavelength of light emitted from the plurality of pixel regions.
16. The OLED display panel according to claim 1 , wherein:
at least one of the first electrode and the second electrode is disposed at a light-emitting side of the OLED display panel.
17. The OLED display panel according to claim 16 , wherein:
the second electrode is disposed at the light-emitting side of the OLED display panel; and
the first electrode includes at least a reflective electrode and at least a transparent conductive electrode.
18. The OLED display panel according to claim 17 , wherein:
the second electrode is made of at least one of MgAg alloy, Ag, AgYb alloy, and a metal alloy containing Ag and a rare earth metal;
the second electrode has light transmittance ranging approximately between 30% and 50%;
a light coupling organic layer is formed on a side of the second electrode facing away from the substrate; and
the light coupling organic layer has a refractive index greater than the refractive index of the second electrode.