ORGANIC LIGHT EMITTING DIODE (OLED)
Organic light-emitting diodes (OLEDs) are solid-state devices made up of thin films of organic molecules that produce light with the application of electricity.
Like a LED, an OLED is a solid-state semiconductor device made up of 100 to 500 nm thick.
The organic light-emitting diode (OLED) consists of a film of organic compounds.
The layer usually combines a polymer substance which allows the suitable organic compound to be deposited. They can emit light of different colours.
Principle:
An electron moves from the cathode to the emissive layer and the hole moves from the anode to the conductive layer and they recombine to produce photons. This is the principle used in OLED.
Construction:
The OLED consists of a cathode and an anode, in between Which there are two organic layers viz.
1. Emissive layer and
2. A conductive layer made up of organic material of different conductivities.
All the layers are grown over a transparent substrate through which the light has to be emitted.
Necessary biasing in given for the OLED, by connecting the anode to positive and the cathode to negative
Working:
1. The forward bias voltage is applied across the OLED.
2. By the applied voltage, the cathode gives an electron to the emissive layer.
3. The anode gets an electron from the conductive layer and produces a hole in the conductive layer.
4. Thus, the emissive layer becomes rich in negatively charged particles [electrons] and the conductive layer becomes rich in positively charged particles [holes].
5. Now, due to the electrostatic forces between these electrons and holes, they come closer and recombine with each other.
6. The recombination of electrons and holes occurs closer to the emissive layer. Inorganic semiconductors, holes move faster than electrons.
7. This recombination produces light and it is emitted through the transparent substrate
Advantages:
Applications
Organic light-emitting diodes (OLEDs) are solid-state devices made up of thin films of organic molecules that produce light with the application of electricity.
Like a LED, an OLED is a solid-state semiconductor device made up of 100 to 500 nm thick.
The organic light-emitting diode (OLED) consists of a film of organic compounds.
The layer usually combines a polymer substance which allows the suitable organic compound to be deposited. They can emit light of different colours.
Principle:
An electron moves from the cathode to the emissive layer and the hole moves from the anode to the conductive layer and they recombine to produce photons. This is the principle used in OLED.
Construction:
The OLED consists of a cathode and an anode, in between Which there are two organic layers viz.
1. Emissive layer and
2. A conductive layer made up of organic material of different conductivities.
All the layers are grown over a transparent substrate through which the light has to be emitted.
Necessary biasing in given for the OLED, by connecting the anode to positive and the cathode to negative
Working:
1. The forward bias voltage is applied across the OLED.
2. By the applied voltage, the cathode gives an electron to the emissive layer.
3. The anode gets an electron from the conductive layer and produces a hole in the conductive layer.
4. Thus, the emissive layer becomes rich in negatively charged particles [electrons] and the conductive layer becomes rich in positively charged particles [holes].
5. Now, due to the electrostatic forces between these electrons and holes, they come closer and recombine with each other.
6. The recombination of electrons and holes occurs closer to the emissive layer. Inorganic semiconductors, holes move faster than electrons.
7. This recombination produces light and it is emitted through the transparent substrate
Advantages:
- Robust Design - OLED’s are tough enough to use in portable devices such as cellular phones, digital video cameras, DVD players, car audio equipment etc.,
- viewing Angles - Can be viewed up to 160 degrees.
- High. Resolution. High information applications including videos and graphics (Active-matrix)
- Electronic Paper - OLEDs are paper-thin.
- Video Capabilities - They hold the ability to handle streamlined video, which could revolutionize the display and cellular phone market.
- Power Usage - Takes less power.
- The limited lifetime of the organic materials Is The biggest technical problem for OLEDs.
- The intrusion of water into displays can damage or destroy organic materials.
- Color The reliability of the OLED is still not up to the mark.
- After a month of use, the screen becomes non-uniform.
Applications
- Commercial applications such as small screens for mobile phones and portable digital audio players (MP3 players), car radios Where OLED technology is used.
- They can be used in television scream, computer displays. advertising. information and indication.
- OLEDs can also be used in light sources for general space illumination and large area hight-emitting elements.
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