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CH. 3 Solar Cell Basic III: Principle. Organic Materials for Electronics and Photonics II. Light. LED. Electric energy. Light Emitting Diodes. Electric energy to light energy Materials for LED. C. B. C. B. E F. E F. V. B. V. B. Mechanism of p-n Junction. Energy.
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CH. 3 Solar Cell Basic III: Principle Organic Materials for Electronics and Photonics II
Light LED Electric energy Light Emitting Diodes • Electric energy to light energy • Materials for LED
C. B. C. B. EF EF V. B. V. B. Mechanism of p-n Junction Energy
Mechanism of p-n Junction Depletion Layer Energy
Mechanism of p-n Junction • Forward bias + - Energy h
LED Small Molecules (SMOLED) Polymer (PLED) Inorganic Organic (OLED) PLED PLED (Polymer Light Emitting Diode) - LED used polymer not only as the semiconductor material in LEDs but also as the composition of LED (substrate, active layer, electrode, etc.). • Advantages of PLED • low cost - low operating voltage • fast response time - full color emission • large area, flat, flexible display - easy fabrication
ITO Sputtering ITO Patterning - Photolithography ITO glass cleaning HTL coating (PEDOT:PSS) - Spin coating Emitting layer coating - Spin coating Aluminum evaporation Structure of PLED
Aluminum polymer ITO Glass + - Polymer cathode Anode h Mechanism of PLED
CRT LCD PDP Organic EL Flexible display Evolution of Display
Requirement for Flexible Display Flexible packaging material Substrate⇒ Flexible !! (Glass → Plastic) Electrode ⇒ Flexible electrode Emitting layer ⇒ Flexible Semiconducting polymer
ITO as Flexible Electrode Require a ‘genuine’ flexible & transparent electrode!!
Requirements for Flexible Electrode 1. Flexibility 2. Conductivity 3. Transparency Plastic Electrode using Conducting Polymer
Reduction of Molecular Scale Disorder σdc≥ 1,000 S/cm “Recent Invention of New Metallic Polyaniline” K. Lee & S.H. Lee Nature 441 (2006) 65.
Metallic PANI Electrode K. Lee et al. Nature 441 (2006) 65. Reduction of Molecular Scale Disorder σdc≥ 1,000 S/cm
New PANI Electrode Flexible Electrode using Metallic PANI Flexible LED Flexible Solar Cell