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US 2006/0214151 A1Published application
Light-emitting element and laser apparatus using the light-emitting element
AssigneeSemiconductor Energy Laboratory Co., Ltd.
InventorsHiroko Abe, Mikio Yukawa, Ryoji Nomura
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Abstract
It is an object of the present invention to provide a light-emitting element in which an inverted distribution state can be formed by exciting an organic compound with current at low current density, and moreover to provide a laser oscillator of a current excitation type using an organic compound as a laser medium. In a light-emitting element of the present invention, a molecule existing in a ground state is not directly excited by external energy but is excited by current fed to a first layer and a second layer which are provided adjacently so that ion species are accumulated in a region of the first layer that is in contact with the second layer.
Claims66
A light-emitting element comprising a first layer and a second layer between a pair of electrodes,
- wherein the first layer and the second layer are provided adjacently so that when a hole is injected into one of the first layer and the second layer and an electron is injected into the other of the first layer and the second layer, ion species are accumulated in a region of the first layer that is in contact with the second layer.
A light-emitting element comprising a first layer and a second layer between a pair of electrodes,
- wherein the first layer and the second layer are provided adjacently so that when a hole is injected into one of the first layer and the second layer and an electron is injected into the other of the first layer and the second layer, ion species are accumulated in a region of the first layer that is in contact with the second layer, and wherein energy barriers exist between a LUMO level of the first layer and a LUMO level of the second layer and between a HOMO level of the first layer and a HOMO level of the second layer, respectively.
A light-emitting element comprising a first layer and a second layer between a pair of electrodes,
- wherein the first layer and the second layer are provided adjacently so that when a hole is injected into one of the first layer and the second layer and an electron is injected into the other of the first layer and the second layer, ion species are accumulated in a region of the first layer that is in contact with the second layer,
- wherein energy barriers exist between a LUMO level of the first layer and a LUMO level of the second layer and between a HOMO level of the first layer and a HOMO level of the second layer, respectively, and
- wherein the energy barrier between the HOMO level of the first layer and the HOMO level of the second layer is higher than the energy barrier between the LUMO level of the first layer and the LUMO level of the second layer.
A light-emitting element comprising a first layer and a second layer between a pair of electrodes,
- wherein the first layer and the second layer are provided adjacently so that when a hole is injected into one of the first layer and the second layer and an electron is injected into the other of the first layer and the second layer, ion species are accumulated in a region of the first layer that is in contact with the second layer, and
- wherein a proportion of molecules existing in a ground state in a region of the first layer that is in contact with the second layer is electrochemically decreased to make a proportion of molecules in an excited state larger than a proportion of the molecules in the ground state, thereby generating an inverted distribution state.
A light-emitting element comprising a first layer and a second layer between a pair of electrodes,
- wherein the first layer and the second layer being provided adjacently so that when a hole is injected into one of the first layer and the second layer and an electron is injected into the other of the first layer and the second layer, ion species are accumulated in a region of the first layer that is in contact with the second layer;
- a first energy barrier for blocking movement of the hole from the first layer to the second layer;
- and
- a second energy barrier for blocking movement of the electron from the second layer to the first layer.
1 more element
A light-emitting element comprising a first layer and a second layer between a pair of electrodes,
- wherein the first layer and the second layer being provided adjacently so that when a hole is injected into one of the first layer and the second layer and an electron is injected into the other of the first layer and the second layer, ion species are accumulated in a region of the first layer that is in contact with the second layer;
- a first energy barrier for blocking movement of the hole from the first layer to the second layer;
- and
- a second energy barrier for blocking movement of the electron from the second layer to the first layer;
- wherein the first energy barrier is higher than the second energy barrier.
2 more elements
A light-emitting element comprising a first layer and a second layer between a pair of electrodes,
- wherein the first layer and the second layer are provided adjacently so that when a hole is injected into one of the first layer and the second layer and an electron is injected into the other of the first layer and the second layer, ion species are accumulated in a region of the first layer that is in contact with the second layer,
- wherein polarity of a carrier to be transported preferentially is different for each of the first layer and the second layer,
- wherein a HOMO level of the first layer is higher than a HOMO level of the second layer, and
- wherein a LUMO level of the first layer is higher than a LUMO level of the second layer.
1 more element
A light-emitting element comprising a first layer and a second layer between a pair of electrodes,
- wherein the first layer and the second layer are provided adjacently so that when a hole is injected into one of the first layer and the second layer and an electron is injected into the other of the first layer and the second layer, ion species are accumulated in a region of the first layer that is in contact with the second layer,
- wherein the first layer has higher hole mobility than electron mobility,
- wherein the second layer has higher electron mobility than hole mobility,
- wherein a HOMO level of the first layer is higher than a HOMO level of the second layer, and
- wherein a LUMO level of the first layer is higher than a LUMO level of the second layer.
2 more elements
A light-emitting element comprising a first layer and a second layer between a pair of electrodes,
- wherein the first layer and the second layer are provided adjacently so that when a hole is injected into one of the first layer and the second layer and an electron is injected into the other of the first layer and the second layer, ion species are accumulated in a region of the first layer that is in contact with the second layer, and
- wherein changes of light emission spectrum intensity with respect to current density are sorted out into two linear regions with different slopes, and a region where the slope is large is on a high current density side with respect to a region where the slope is small.
A light-emitting element comprising a first layer and a second layer between a pair of electrodes,
- wherein the first layer and the second layer are provided adjacently so that when a hole is injected into one of the first layer and the second layer and an electron is injected into the other of the first layer and the second layer, ion species are accumulated in a region of the first layer that is in contact with the second layer,
- wherein energy barriers exist between a LUMO level of the first layer and a LUMO level of the second layer and between a HOMO level of the first layer and a HOMO level of the second layer, respectively, and
- wherein changes of light emission spectrum intensity with respect to current density are sorted out into two linear regions with different slopes, and a region where the slope is large is on a high current density side with respect to a region where the slope is small.
A light-emitting element comprising a first layer and a second layer between a pair of electrodes,
- wherein the first layer and the second layer are provided adjacently so that when a hole is injected into one of the first layer and the second layer and an electron is injected into the other of the first layer and the second layer, ion species are accumulated in a region of the first layer that is in contact with the second layer,
- wherein energy barriers exist between a LUMO level of the first layer and a LUMO level of the second layer and between a HOMO level of the first layer and a HOMO level of the second layer, respectively,
- wherein the energy barrier between the HOMO level of the first layer and the HOMO level of the second layer is higher than the energy barrier between the LUMO level of the first layer and the LUMO level of the second layer, and
- wherein changes of light emission spectrum intensity with respect to current density are sorted out into two linear regions with different slopes, and a region where the slope is large is on a high current density side with respect to a region where the slope is small.
1 more element
A light-emitting element comprising a first layer and a second layer between a pair of electrodes,
- wherein the first layer and the second layer are provided adjacently so that when a hole is injected into one of the first layer and the second layer and an electron is injected into the other of the first layer and the second layer, ion species are accumulated in a region of the first layer that is in contact with the second layer,
- wherein a proportion of molecules existing in a ground state in a region of the first layer that is in contact with the second layer is electrochemically decreased to make a proportion of molecules in an excited state larger than a proportion of the molecules in the ground state, thereby generating an inverted distribution state, and
- wherein changes of light emission spectrum intensity with respect to current density are sorted out into two linear regions with different slopes, and a region where the slope is large is on a high current density side with respect to a region where the slope is small.
Dependencies are inferred from the claim text.