1 Fall, 2013 Instructor: J.-W. John Cheng Mech. Engr. Dept., Nat ’ l Chung Cheng Univ. Interfacial Physics and Thin-Film Processing Ch 1 Intro. to Flexible Electronics and Printing Technology

JCheng Outline 1.1 Prospects and Fabrication Challenge of Flexible Electronics 1.2 Overview of Printing Technologies Flexography, gravure printing, screen printing Inkjet printing, micro-contact printing References

3 1.1 Prospect and Fabrication Challenge of Flexible Electronics

JCheng What Is Flexible Electronics? Flexible electronics Electronics “ can be bent, flexed *, conformed or rolled without losing functionality ” Closely related names Organic electronics Electronics made of organic materials, non-silicon Printed electronics Electronics fabricated using printing method * flex = bend repeatedly

JCheng OE-A Roadmap for Organic and Printed Electronics Applications Source: Organic and Printed Electronics, 4th ed., OE-A (Organic Electronics Association), 2011

JCheng Applications – Flexible Displays Samsung full-color flexible display screen-folding,12929.html Sony full-color flexible display 2007 ( organic-el-display/)

JCheng Applications – Flexible Photovoltaics Organic solar bag by Neuber 2010 ( gress-with-flexible-photovoltaics asp?sessionid=1)

JCheng Applications – Flexible Lighting Prototype OLED lamps by China’s Visionox (

JCheng Applications – Flexible RFID Flexible RFID by Kovio 2010 with inkjet printed nanosilicon transistors on stainless steel foil ( 10_ asp) The bottom line The bad news is that, highest volume RFID is all about tag cost, not multiple benefits from printing such as tightly rollable, invisible, stretchable or edible. The good news is that fully printed RFID can be one tenth or less of the cost of the conventional silicon chip based tag # of proj on RFID China: 267

JCheng A Turning Point of Flexible Electronics First commercial success – AMOLED AMOLED was adopted by Samsung Galaxy series smart phones 4/2009 – Galaxy (3.2 ”, 320x480 pixel) 3/2010 – Galaxy S (4 ”, 480x800) 2/2011 – Galaxy S II (4.3 ”, 480x800) 5/2012 – Galaxy S III (4.8 ”, 1280x720) 4/2013 – Galaxy S IV (5 ”, 1920x1080) Samsung became world leading smart phone providers in Q3, 2011 Sources: ~58x58  m 2 /pixel Samsung Galaxy S4

JCheng Samsung 2011 Success Heralding Arrival of Flexible Electronics From plenary speech of Prof. Karl Leo at LOPE-C 2012

JCheng What Is Next and When? Time Roof top grid connected Organic Backplane E-ink display RFID ， OTFT… General lighting (flexible)technology Rollable OLED TVs From Prof. Karl Leo 2011

JCheng Future Market Size of Flexible Electronics 依據 IdTechex 研究預測 2027 年全球產值約 3,300 億美元 比較重要產品市場為 - 邏輯記憶體 - OLED 顯示器 - 太陽能電池 Semiconductor industry revenue in 2012: USD $312.8 billions Endure-Slow-Growth-in-2012.aspx

JCheng Vacuum-Based vs. Printing-Based Suitable for large-area roll-to-roll fabrication Source: Nikkei Electronics Asia Complex processes and equipment Inconvenient for large-area fabrication Simplified manufacturing processes and equipment

JCheng Expectation of Printing-Based Fab Comprising only coating and printing steps Reliable large-scale processing *Vacuum deposition is not applicable to polymers; printing is the only possibility [Kre2009] Krebs, Solar Energy Materials & Solar Cells, 93 (2009) 394– “ If large-scale processing proves to be problematic or impossible, the concept of polymer solar cells would become a scientific curiosity …. ” * [Kre2009]

JCheng Challenge: < 10  m Resolution Time Roof top grid connected Organic Backplane E-ink display RFID ， OTFT… General lighting (flexible)technology Rollable OLED TVs From Prof. Karl Leo 2011 ~5  m resolution ~20  m resolution Resolution spec’s based on Galaxy S4 requirements 58 x 58  m 2 /pixel, PenTile RGBG guessing ~66% light output PenTile RGBG OLED subpixel OTFT