Dissertation > Excellent graduate degree dissertation topics show

Analysis of Light Out-coupling Efficiency in Polymer Light-emitting Devices

Author: GuiYuChang
Tutor: WenShangSheng
School: South China University of Technology
Course: Materials Physics and Chemistry
Keywords: Polymer light-emitting diode Light out-coupling efficiency Transfermatrix method distributed Bragg reflector
CLC: TN383.1
Type: Master's thesis
Year: 2012
Downloads: 63
Quote: 1
Read: Download Dissertation

Abstract


Because of the advantages such as ultra thin, light weight, low cost, low energyconsumption, active illuminating, wide viewing angle and fast response speed and soon, organic light emitting diodes(OLEDs) have a great potential application prospectin display and lighting area. It has been paid great attentions attention in both theacademic and industrial circles. Also it is expected to become the next generation offlat panel display and light source. Over the years, the luminous efficiency improvingis thought to be the key factor of improving the performance of OLEDs. There for, thedevelopment of new materials has been widely concerned and studied. On the otherhand, the device structure optimizing is another way to improve the deviceperformance. In recent years, there is more and more research work on light outputprocess of the OLEDs. How to reduce the total reflection effects in the OLEDs, andhow to improve optical coupling efficiency have become the key problems whichmust be solved.Generally, the traditional structure of OLEDs has been used in most occasion.But when it’s applied in thin film transistor(TFT) active driver display screen, there iscompetition between the display area and driving circuit of the light pixels. Thedriving circuits cover30%-50%light area of OLEDs. Applying the top emittingstructure of OLEDs can make up for traditional OLEDs’lower aperture opening ratio,and greatly improve the optical coupling efficiency.The light out-coupling efficiency of polymer light-emitting devices（PLED）wassimulated based on transfer matrix method by using MATLAB software. Theinfluence of emitting layer, PEDOT layer, ITO layer on the performance of thePLED’s out-coupling efficiency was studied. The influence of three different microshapes on glass surface such as hemispherical shape, conical shape are simulated byusing TRACEPRO software. The results show that the light out-coupling efficiency isthe largest and the uniformity of diodes light output is the best when the conical shapeon the glass surface is employed. To overcome the deficiency of the traditional OLED device structure, the lightout-coupling efficiency of top-emitting polymer light-emitting devices（TEPLED）based on MEH-PPV was simulated by applying the transfer matrix method andsoftware MATLAB. The influence of anode materials, cathode materials, cappinglayers and observing angle on the performance of the TEPLED’s out-couplingefficiency was studied. Compared with Ag film anode device, the one based ondistributed Bragg reflector（DBR）presented higher out-coupling efficiency andreached47.43%. To decrease the light absorption and reflection by sub-transparentmetal, transparent materials cathode was designed so that the light-coupling efficiencyraised about10%compared with Ag anode devices which reached67.11%. Theinfluence of DBR on the observe angles of total TEPLED was studied. The resultsshow that it has little effect on light-coupling efficiency of TEPLED by DBR whenthe observe angle changes in a narrow range(30°). It was bigger when the observeangle with more than30°. The research of OLED structures and the application ofDBR provided a theoretical basis for the optimization of out-coupling efficiency ofTEPLED.

Related Dissertations

  1. Theoretical and Experimental Study of Monolithic White Light LED Based on DBR,TN312.8
  2. The Study on Characteristics of Tunable Integrated Devices Based on the SGDBR Laser,TN248.4
  3. DBR fiber lasers based on self-mixing effect of,TN248
  4. Reaserch on Novel Photodetectors with Flat-Top and Steep-Edge Response for WDM Systerm,TN929.11
  5. GaN-based light-emitting diode light extraction analysis and simulation,TN312.8
  6. Study of Thermal of Polymer Organic Light-Emitting Devices from ANSYS,TN312.8
  7. Enhanced Light Extraction Efficiency of LEDs by Using Photonic Crystal and Omni-directional Reflector,TN312.8
  8. Theoretical Reaserch on the Application of DBRs in UV-LED,TN312.8
  9. Resonant cavity enhanced GaInAsSb infrared photodetector research,TN215
  10. Design, Processing and Characteristics Analysis of 850nm Vertical-Cavity Surface-Emitting Lasers,TN248
  11. A Study on AlxGa1-xN/GaN Distributed Bragg Reflectors and Active-Passive Coupled-Double-Microring Silicon Resonators,TN303
  12. Research on the Integrated Demulitiplexing and Receiving Technology of WDM Systems,TN36
  13. Study of Efficient White Polymer Light-emitting Devices from Blends,TN383.1
  14. Study on the Fabrication and Characteristics of Vertical-Cavity Surface-Emitting Lasers,TN248
  15. Designs and Syntheses of Novel Polyphenylvinylene(PPV) Derivatives and Their Applications in Light-emitting Diode and Solar Cells,TN304
  16. Quantum Efficiency Evolution in a Hole-injection Layer Inserted within a Polymer Light-emitting Diode,TN312.8
  17. Research on Wavelength-Selective Photodetectors for Dense Wavelength Division Mutiplexing (DWDM) Systerm,TN929.11
  18. Fabrication of High Power GaN-based LED Chip,TN312.8
  19. Novel ( Lv north ) of the polyimide light emitting diode,TN312.8
  20. The Reaserch on Si-Based Integrated De-Multiplexing Receiver for Optical Communication,TN929.1
  21. Band Gaps of Periodic Piezoelectric Beams,TU352.1

CLC: > Industrial Technology > Radio electronics, telecommunications technology > Semiconductor technology > Light-emitting devices >
© 2012 www.DissertationTopic.Net  Mobile