09-03-2011, 04:41 PM
Submitted by
Deepika Jaswal
[attachment=9896]
ABSTRACT
OLEDs can have either two layers or three layers of organic material; in the latter design, the third layer helps transport electrons from the cathode to the emissive layer. A number of materials have been developed and improved in order to fulfill the requirements of this application. The materials differ from one another by their structure but also by the mechanism involved in the electroluminescence produced (fluorescence versus phosphorescence).
When properly stacked, these materials result in a device that can achieve the required high efficiency and long lifetime. Such red, green and blue devices can then be combined in matrices to become the core of a display. Building up these structures onto a display backplane is one of the challenges facing the industry.
1.0 INTRODUCTION
Since the breakthrough by Kodak in 1987, organic light-emitting diodes (OLEDs) have been seen as one of the most promising technologies for future displays. Like an LED, an OLED is a solid-state semiconductor device that is 100 to 500 nanometers thick or about 200 times smaller than a human hair.
OLEDs can have either two layers or three layers of organic material; in the latter design, the third layer helps transport electrons from the cathode to the emissive layer. A number of materials have been developed and improved in order to fulfill the requirements of this application. The materials differ from one another by their structure but also by the mechanism involved in the electroluminescence produced (fluorescence versus phosphorescence).
When properly stacked, these materials result in a device that can achieve the required high efficiency and long lifetime. Such red, green and blue devices can then be combined in matrices to become the core of a display. Building up these structures onto a display backplane is one of the challenges facing the industry. The circuitry for driving the pixels can be adapted to the OLED, sometimes at the expense of the simplicity of the display, but bearing in mind that the fabrication process must remain industrially viable.
The utility of a mobile computer, such as a laptop, is largely constrained by battery life. The display stands out as a major consumer of battery energy, so reducing that consumption is desirable. Through a detailed characterization of display usage patterns, it is show that screen usage of a typical user is primarily associated with content that could be displayed in smaller and simpler displays with significantly lower energy use.
The utility of a mobile computer, such as a laptop, is largely constrained by battery life. The display stands out as a major consumer of battery energy, so reducing that consumption is desirable. Through a detailed characterization of display usage patterns, it is show that screen usage of a typical user is primarily associated with content that could be displayed in smaller and simpler displays with significantly lower energy use.
Emerging organic light emitting diode (OLED) based displays obviate external lighting; and consume drastically different power when displaying different colors, due to their emissive nature. This creates a pressing need for OLED display power models for system energy management, optimization as well as energy efficient GUI design, given the display content or even the graphical user interface (GUI) code.
2.0 HISTORY
These were first developed in the early 1950’s in France by applying a high-voltage alternating current field to crystalline thin films of acridine orange and quinacrine. The first diode device with organic materials was invented at Eastman Kodak in the 1980’s by Dr. Ching Tang and Steven Van Slyke.
Today OLED is used in television screens, computer displays, portable system screens, advertising, information and indication. It is also used in light sources for general space illumination, and large-area light-emitting elements.
3.0 BASIC OF ORGANIC SEMICONDUCTORS:
(STRUCTURE AND GRAPHS)
In the figures below , figure a and b show Locus electrical curves of the OLET in n-polarization in figure (a)while (b) shows p-polarization.
During the n-polarization the electroluminescence output power (magenta) is also collected. Figure c shows the transfer characteristic curves, the source–drain current (IDS) is measured keeping the drain–source potential constant at 90 V, while sweeping the gate-source potential from 0 to 90 V.
In figure d, AFM image of a 7-nm-thick DFH-4T film grown on glass/ITO/PMMA substrate.
e, AFM image of a 40-nm-thick film of Alq3
3%)DCM blend grown on top of the DFH-4T thin film reported in d. f, AFM image of a 15-nm-thick DH-4T film grown on top of the Alq33%)DCM film reported in e. For ease of comparison the same z-axis colour scale is used for both images e and
Deepika Jaswal
[attachment=9896]
ABSTRACT
OLEDs can have either two layers or three layers of organic material; in the latter design, the third layer helps transport electrons from the cathode to the emissive layer. A number of materials have been developed and improved in order to fulfill the requirements of this application. The materials differ from one another by their structure but also by the mechanism involved in the electroluminescence produced (fluorescence versus phosphorescence).
When properly stacked, these materials result in a device that can achieve the required high efficiency and long lifetime. Such red, green and blue devices can then be combined in matrices to become the core of a display. Building up these structures onto a display backplane is one of the challenges facing the industry.
1.0 INTRODUCTION
Since the breakthrough by Kodak in 1987, organic light-emitting diodes (OLEDs) have been seen as one of the most promising technologies for future displays. Like an LED, an OLED is a solid-state semiconductor device that is 100 to 500 nanometers thick or about 200 times smaller than a human hair.
OLEDs can have either two layers or three layers of organic material; in the latter design, the third layer helps transport electrons from the cathode to the emissive layer. A number of materials have been developed and improved in order to fulfill the requirements of this application. The materials differ from one another by their structure but also by the mechanism involved in the electroluminescence produced (fluorescence versus phosphorescence).
When properly stacked, these materials result in a device that can achieve the required high efficiency and long lifetime. Such red, green and blue devices can then be combined in matrices to become the core of a display. Building up these structures onto a display backplane is one of the challenges facing the industry. The circuitry for driving the pixels can be adapted to the OLED, sometimes at the expense of the simplicity of the display, but bearing in mind that the fabrication process must remain industrially viable.
The utility of a mobile computer, such as a laptop, is largely constrained by battery life. The display stands out as a major consumer of battery energy, so reducing that consumption is desirable. Through a detailed characterization of display usage patterns, it is show that screen usage of a typical user is primarily associated with content that could be displayed in smaller and simpler displays with significantly lower energy use.
The utility of a mobile computer, such as a laptop, is largely constrained by battery life. The display stands out as a major consumer of battery energy, so reducing that consumption is desirable. Through a detailed characterization of display usage patterns, it is show that screen usage of a typical user is primarily associated with content that could be displayed in smaller and simpler displays with significantly lower energy use.
Emerging organic light emitting diode (OLED) based displays obviate external lighting; and consume drastically different power when displaying different colors, due to their emissive nature. This creates a pressing need for OLED display power models for system energy management, optimization as well as energy efficient GUI design, given the display content or even the graphical user interface (GUI) code.
2.0 HISTORY
These were first developed in the early 1950’s in France by applying a high-voltage alternating current field to crystalline thin films of acridine orange and quinacrine. The first diode device with organic materials was invented at Eastman Kodak in the 1980’s by Dr. Ching Tang and Steven Van Slyke.
Today OLED is used in television screens, computer displays, portable system screens, advertising, information and indication. It is also used in light sources for general space illumination, and large-area light-emitting elements.
3.0 BASIC OF ORGANIC SEMICONDUCTORS:
(STRUCTURE AND GRAPHS)
In the figures below , figure a and b show Locus electrical curves of the OLET in n-polarization in figure (a)while (b) shows p-polarization.
During the n-polarization the electroluminescence output power (magenta) is also collected. Figure c shows the transfer characteristic curves, the source–drain current (IDS) is measured keeping the drain–source potential constant at 90 V, while sweeping the gate-source potential from 0 to 90 V.
In figure d, AFM image of a 7-nm-thick DFH-4T film grown on glass/ITO/PMMA substrate.
e, AFM image of a 40-nm-thick film of Alq3
3%)DCM blend grown on top of the DFH-4T thin film reported in d. f, AFM image of a 15-nm-thick DH-4T film grown on top of the Alq33%)DCM film reported in e. For ease of comparison the same z-axis colour scale is used for both images e and
