High-efficiency QLED structures
A light-emitting layer structure that maximizes constructive interference for light emission by varying a phase shift introduced by reflective electrodes. The light-emitting layer structure includes a first and second optical cavity including a first and second reflective electrode; a first and second partially transparent electrode; and a first and second emissive layer (EML) disposed between the first and second reflective electrodes and the first and second partially transparent electrodes, wherein the first EML emits light having a first wavelength; wherein the first reflective electrode introduces a first phase shift, depending on the first wavelength, on reflection of light emitted by the first EML; and wherein the second EML emits light having a second wavelength and the second reflective electrode introduces a second phase shift, depending on the second wavelength, on reflection of light emitted by the second EML, and the first phase shift is different from the second phase shift.
1. A light-emitting layer structure comprising:
a first optical cavity comprising:
a first reflective electrode;
a first partially transparent electrode; and
a first emissive layer (EML) disposed between the first reflective electrode and the first partially transparent electrode, wherein the first EML is configured to emit light having a first wavelength;
wherein the first reflective electrode is configured to introduce a first phase shift, depending on the first wavelength, on reflection of light emitted by the first EML; and
a second optical cavity comprising:
a second reflective electrode;
a second partially transparent electrode; and
a second EML disposed between the second reflective electrode and the second partially transparent electrode, wherein the second EML is configured to emit light having a second wavelength;
wherein the second reflective electrode is configured to introduce a second phase shift, depending on the second wavelength, on reflection of light emitted by the second EML, and the first phase shift is different from the second phase shift;
where each of the first reflecting electrode and the second reflecting electrode comprises a base layer and at least one emitting side layer located on an emitting side of the base layer, wherein the at least one emitting side layer has a thickness less than a thickness of the base layer;
wherein the at least one emitting side layer comprises a first emitting side layer and a second emitting side layer located on an emitting side of the first emitting side layer, wherein a combined thickness of the first emitting side layer and the second emitting side layer is less than the thickness of the base layer.
2. The light-emitting layer structure of claim 1 , wherein the at least one emitting side layer has a thickness from 0.5 nm to 12 nm.
3. The light-emitting layer structure of claim 1 , wherein the at least one emitting side layer has a real component of refractive index that is higher than a real component of refractive index of the base layer.
4. The light-emitting layer structure of claim 1 , wherein the at least one emitting side layer includes aluminum and the base layer includes silver.
5. The light emitting-layer structure of claim 1 , wherein the combined thickness of the first emitting side layer and the second emitting side layer is from 0.5 nm to 12 nm.
6. The light emitting-layer structure of claim 1 , wherein the second emitting side layer has a real component of refractive index that is higher than a real component of refractive index of the first emitting side layer, and the first emitting side layer has a real component of refractive index that is higher than a real component of refractive index of the base layer.
7. The light-emitting layer structure of claim 1 , wherein the base layer has a thickness of 80-100 nm.
8. The light-emitting layer structure of claim 1 , wherein the first phase shift is configured to cause light having the first wavelength to propagate in the first optical cavity at a first mode and the second phase shift is configured to cause light having the second wavelength to propagate in the second optical cavity at a second mode.
9. The light-emitting layer structure of claim 1 , wherein the first reflective electrode includes a first material for introducing the first phase shift and the second reflective electrode includes a second material for introducing the second phase shift.
10. The light-emitting layer structure of claim 1 , wherein the first emissive layer and/or the second emissive layer includes quantum dots for light emission.