§motivation(1) Viewgraphs by J D White Paper Thin Lighting for a Wall

§motivation(2) Viewgraphs by J D White RRR Displays: The Polymer Vision -- Rollable, Rugged, Roaming

§motivation(3) Viewgraphs by J D White Solar Curtains (Karnarka) 太陽電

§motivation(4) Viewgraphs by J D White Displays: The Polymer Advantage Flexible Bright No directionality  > light bulb  > LCD displays  Low power consumption Cheap Ref. IEEE Spectrum August 2000

§motivation(5) Viewgraphs by J D White Solar Cells? 太陽電如何？ What's Important? –Efficiency? –Carrier Mobility? –Size? –Scalability? YES, but… Ultimately, only 1 thing really matters… $/Watt Electricity output

§motivation(6) Viewgraphs by J D White Solar Cells: The Polymer Advantage Semiconductor properties with polymer processing –CHEAP Chemical modification to the basic polymer chain is relatively simple –Optimize emission/absorption wavelength, –Optimize basic physical properties

§motivation(7) Viewgraphs by J D White Old Predictions within 10 years, the square footage of organic circuitry might exceed that of silicon electronics (IEEE Spectrum 2000) The technology of conjugated polymers is a disruptive technology. Just as the transistor wiped out companies making the vacuum tube, so will organic electronics wipe out those relying on silicon (Alan Heeger, 2000 Nobel prize Laurite)

§motivation(8) Viewgraphs by J D White Seven Year Old Headline News “Flexible future in store for flat-panel displays ” PCWORLD (30th September 2004) “Flexible flat-panel displays coming soon” Computer Weekly (2nd August 2004)

§motivation(9) Viewgraphs by J D White Why not? Device Life Time: A factor of 10 shorter than needed for computer displays Believed due to quenching of the light emitting/absorbing sites due to interaction with Oxygen. Underlying photo-physics not understood Light 光 O2O2 + = Death 死

§motivation(10) Viewgraphs by J D White How to find a solution? Device Approach Basic Physics

§motivation(11) Viewgraphs by J D White Review: Operation of an PLED Ref. IEEE Spectrum August 2000 OPV

§motivation(12) Viewgraphs by J D White Device Approach Design device to stop oxygen from reaching active area –Difficult: Plastics are permeable gases Design electrodes to minimize metal ion migration –Difficult: Efficient hole injectors (I.e. Ca + ) also like to move

§motivation(13) Viewgraphs by J D White Basic Physics Goal: Seek to understand energy transfer between and within polymers Goal: Seek to understand the quenching process itself Then can design around the problem…

§motivation(14) Viewgraphs by J D White Not a Simple System…. Single polymer effects –Intra-chain emission –Aggregate emission Multiple polymer effects –Inter-chain –Dimers, trimers, excimers Basic Physics is masked Fluorescence Spectrum of DOO-PPV

§motivation(15) Viewgraphs by J D White A way forward… Clearly we would like to separate out these effects and study them individually (Physicists like simple problems…:) Thus one turns to single molecule detection (SMD) and single molecule spectroscopy (SMS)