Light-emitting element, light-emitting device, authentication device, and electronic apparatus
A light-emitting element includes an anode, a cathode, a light-emitting layer which is provided between the anode and the cathode and emits light in a wavelength range of 700 nm or more by conducting electricity between the anode and the cathode, and an electron transport layer which is provided between the light-emitting layer and the cathode, and includes a first electron transport layer located on the cathode side and a second electron transport layer located on the light-emitting layer side, wherein organic materials contained in the light-emitting layer, a hole injection layer, the first electron transport layer, and the second electron transport layer have a glass transition temperature Tg of 135° C. or higher or do not have a glass transition temperature.
1. A light-emitting element, comprising:
an anode;
a cathode;
a light-emitting layer which is provided between the anode and the cathode and emits light in a wavelength range of 700 nm or more by conducting electricity between the anode and the cathode;
a hole injection layer which is provided between the light-emitting layer and the anode; and
an electron transport layer which is provided between the light-emitting layer and the cathode, and includes a first electron transport layer located on the cathode side and a second electron transport layer located on the light-emitting layer side, wherein
organic materials contained in the light-emitting layer, the hole injection layer, the first electron transport layer, and the second electron transport layer have a glass transition temperature Tg of 135° C. or higher or do not have a glass transition temperature,
wherein the hole injection layer comprises a HIL-B compound or a HIL-C compound, the HIL-B compound having the following general formula:
where R 1 -R 4 are selected from a hydrogen atom, an arylamino group, a carbazolyl group, and combinations thereof; and
the HIL-C compound having the following general formula:
where R 5 -R 6 are selected from an arylamino group, a carbazolyl group, and combinations thereof;
wherein the light emitting layer comprises a thiadiazole-based compound (IRD1) having the following general formula:
where R is selected from an aryl group, an arylamino group, a triarylamino group, and derivatives thereof;
wherein the first electron transport layer comprises a first anthracene-based compound having an anthracene skeleton and a nitrogen-containing heterocyclic skeleton, the anthracene skeleton having the following general formula:
where R 1 -R 7 are selected from a hydrogen atom, an alkyl group, an aryl group, an aryl group with substituent, an arylamino group, and combinations thereof; and
wherein the second electron transport layer comprises a second anthracene-based compound lacking a heterocyclic skeleton and having the general formula:
where R 1 and R 2 are selected from a hydrogen atom, an alkyl group, an aryl group, an aryl group with substituent, an arylamino group, an arylamino group with substituent, and combinations thereof.
2. The light-emitting element according to claim 1 , wherein the second anthracene-based compound has a glass transition temperature Tg of 145° C. or higher or does not have a glass transition temperature.
3. A light-emitting device, comprising the light-emitting element according to claim 2 .
4. An authentication device, comprising the light-emitting element according to claim 2 .
5. An electronic apparatus, comprising the light-emitting element according to claim 2 .
6. The light-emitting element according to claim 1 , wherein
the glass transition temperature (T g ) of the light-emitting layer is represented by Tg(Host),
the glass transition temperature (T g ) of the hole injection layer is represented by Tg(HIL), and
the glass transition temperature (T g ) of the second electron transport layer is represented by Tg(ETL2), and
wherein the glass transition temperature (Tg) of the light-emitting layer Tg(Host), the glass transition temperature (Tg) of the hole injection layer Tg(HIL), and the glass transition temperature (Tg) of the second anthracene-based compound Tg(ETL2) satisfy the following relational formula (I):
Tg ( HIL )> Tg (Host) and Tg ( ETL 2)> Tg (Host) (I).
7. The light-emitting element according to claim 6 , wherein further Tg(HIL) and Tg(ETL2) satisfy the following relational formula (II):
Tg ( HIL )> Tg ( ETL 2) (II).
8. A light-emitting device, comprising the light-emitting element according to claim 6 .
9. The light-emitting element according to claim 1 , wherein the light-emitting element is configured to conduct electricity between the anode and the cathode at a current density of 0.5 A/cm 2 or more and 2.0 A/cm 2 or less.
10. A light-emitting device, comprising the light-emitting element according to claim 1 .
11. An authentication device, comprising the light-emitting element according to claim 1 .
12. An electronic apparatus, comprising the light-emitting element according to claim 1 .