A method of screening for an electron transport material included in an electron transport layer of an organic light emitting device and a method of screening for a hole blocking material included in a hole blocking layer of the organic light emitting device, the method using a heterogeneous electron transfer rate constant (K) value to select the electron transport material and an electron donating rate constant k.sub.d to select the hole blocking material, thereby capable of realizing the organic light emitting device having an excellent balance between luminous efficiency and lifetime.

Provided is an organic light emitting element including: an anode; a cathode; and an organic compound layer formed between the anode and the cathode and including a hole injection layer, a hole transport layer, and an emission layer, in which: the emission layer includes a host and a dopant; the hole transport layer includes a hole transport material having multiple aromatic hydrocarbon skeletons and a single bond for linking the aromatic hydrocarbon skeletons; the hole transport material has a triplet level T.sub.1 of 1.8 eV or more; the hole transport material has a hole mobility of 1×10.sup.−5 cm.sup.2/Vs or more; and the hole transport layer and the emission layer satisfy relationships represented by the following expression (1):
|reduction potential of hole transport material|−|reduction potential of host|>0.1 V  (1)
and the following expression (2):
|HOMO level of hole transport material−HOMO level of host|<0.1 eV  (2).

A method of screening for an electron transport material included in an electron transport layer of an organic light emitting device and a method of screening for a hole blocking material included in a hole blocking layer of the organic light emitting device, the method using a heterogeneous electron transfer rate constant (K) value to select the electron transport material and an electron donating rate constant k.sub.d to select the hole blocking material, thereby capable of realizing the organic light emitting device having an excellent balance between luminous efficiency and lifetime.

A preparation method of the QD light-emitting diode includes: prepare a QD light-emitting layer on an anode, wherein the QD light-emitting layer is prepared by the QDs and the CuSCN nanoparticles; and prepare a cathode on the QD light-emitting layer, and form the QD light-emitting diode.

A quantum dot light-emitting diode and a display apparatus comprising the quantum dot light-emitting diode are provided. The quantum dot light-emitting diode comprises an anode, a hole injecting layer, a hole transporting layer, a quantum dot light-emitting layer, an electron transporting layer and a cathode from bottom to top, wherein the materials of the quantum dot light-emitting layer contain quantum dots and CuSCN nano-particles. By blending quantum dots and CuSCN nano-particles into a membrane to prepare a quantum dot light-emitting layer, a hole trap state on the surface of the quantum dots is passivated, and the transporting effect of a hole is improved, so that the injection of holes in the quantum dot light-emitting diode and that of electrons achieve balance, and thus the light-emitting efficiency and stability are improved.

This organic electroluminescent element has a structure in which, between a first electrode and a second electrode, a plurality of light-emitting units are layered with a charge generation layer 14 interposed therebetween, and comprises a red light-emitting unit and a green light-emitting unit. In the organic electroluminescent element, yellow or orange light obtained by light emission from the two light-emitting units has a peak wavelength in each of a red wavelength range of 590-640 nm and a green wavelength range of 500-560 nm, and the difference between the peak wavelength of the yellow or orange light and the dominant wavelength of the yellow or orange light is 15-25 nm.

Disclosed are a thin film transistor including a gate electrode, a semiconductor layer, a source electrode, and a drain electrode. The semiconductor layer overlaps the gate electrode. The source electrode and the drain electrode are electrically connected to the semiconductor layer. The semiconductor layer includes a first semiconductor layer including a first organic semiconductor material and a second semiconductor layer including a second organic semiconductor material. The second semiconductor layer is farther spaced apart from the gate electrode than the first semiconductor layer. A HOMO energy level of the second organic semiconductor material is different from a HOMO energy level of the first organic semiconductor material. A method of manufacturing the thin film transistor is disclosed.

This organic electroluminescent element has a structure in which, between a first electrode and a second electrode, a plurality of light-emitting units are layered with a charge generation layer 14 interposed therebetween, and comprises a red light-emitting unit and a green light-emitting unit. In the organic electroluminescent element, yellow or orange light obtained by light emission from the two light-emitting units has a peak wavelength in each of a red wavelength range of 590-640 nm and a green wavelength range of 500-560 nm, and the difference between the peak wavelength of the yellow or orange light and the dominant wavelength of the yellow or orange light is 15-25 nm.

A quantum dot light-emitting diode and a preparation method therefor, and a light-emitting module and a display apparatus. The quantum dot light-emitting diode successively comprises an anode, a hole injecting layer, a hole transporting layer, a quantum dot light-emitting layer, an electron transporting layer and a cathode from bottom to top, wherein the materials of the quantum dot light-emitting layer contain quantum dots and CuSCN nano-particles. By blending quantum dots and CuSCN nano-particles into a membrane to prepare a quantum dot light-emitting layer, a hole trap state on the surface of the quantum dots is passivated, and the transporting effect of a hole is improved, so that the injection of holes in the quantum dot light-emitting diode and that of electrons achieve balance, and thus the light-emitting efficiency and stability are improved.

An organic light-emitting diode comprises a first electrode layer, a second electrode layer, and an organic luminescent unit disposed between the first electrode layer and the second electrode layer. The organic luminescent unit has an organic electroluminescent material containing anthracene group as shown in General Formula (1):

##STR00001## wherein A is selected from the group consisting of General Formula (2), General Formula (3) and General Formula (4):

##STR00002## wherein B is selected from the group consisting of General Formula (5), General Formula (6) and General Formula (7):

##STR00003## B is General Formula (5) when A is selected from the group consisting of General Formula (2) and General Formula (3); B is selected from the group consisting of General Formula (6) and General Formula (7) when A is General Formula (4); and wherein R.sub.1 to R.sub.43 are independently selected from the group consisting of hydrogen atom, fluorine atom, cyano group, alkyl group, cycloalkyl group, alkoxy group, haloalkyl group, thioalkyl group, silyl group and alkenyl group.