1. Current through electronic device

2. Dynamics of electronic carriers J = nev d = ne 2 F  /m* J =  F (lei de Ohm)  = ne 2  /m* = ne  v d =  F  = e  /m*  = e(ne  e + np  p )

3. NON-LINEAR EFFECTS ON THE MOBILITY Space-charge limited current J  (9/8)  V 2 /l 3 ********************************************** Poole-Frenkel effect J = ne  (E)E with

4. Capacitor – Electric Field

5. Dielectrics - Polarization

6. Dipole Moment  = 2a

7. DEVICE 3: OTFTs Organic Thin-Film Transistors DEVICE 2: OLEDs Organic Light-Emitting Diodes DEVICE 1: OPVs Organic Photovoltaics

8. DEVICE 1: OPV Organic Photovoltaics

9. Generations of Solar Cells First: PV p-n junction diode of crystalline silicon (market) Second: PV thin films of non-monocrystalline semiconductors (amorphous silicon, poly-crystalline silicon, cadmium telluride films, copper indium selenide/sulfide,...) (market) Third: Organic photovoltaic cells, photoelectrochemical cells, dye-sensitized Solar cells,...) (research) Fourth: Biomolecular cells (prevision) - Mimicking the nature.

10. MARKET

11. Sun: Total power Organic material Absorption

12. Equivalent circuit and characteristic curve I sc..... Short-circuit current V oc.... Open-circuit voltage I mp.... Current at maximum power V mp.... Voltage at maximum power Fill Factor FF = (V mp x I mp )/(V oc x I sc ) Current source Diode R c (contact + bulk) resistances R s shunt resistance

13. EFFICIENCY

14. Efficiency Quantum efficiency: ratio of the number of collected charge carriers to the number of incident photons (EQE or IPCE). Power Conversion Energy (PCE):ratio between the solar power produced by the cell by the power of the incidente flux of light

16. First generation: pn JUNCTION

17. Thickness  100  m

18. Second generation: Inorganic Heterojunction Thickness  5  m

19. Third generation: Organics

20. ELECTRONIC DEFECTS Poly(p-phenylene) - PPP Charge spin exciton singlet 0 0 Negative polaron - e 1/2 Positive polaron e 1/2 Negative bipolaron - 2e 0 Positive bipolaron 2e 0

21. In organic semiconductor the generation of carriers is a secondary process. Excitons (bound electron-hole pairs) are created by absorption of light, and should be dissociated, and then the carriers collected by electrodes) HETEROJUNCTION Thickness < 100 nm

22. 2.5 % Efficient Organic Plastic Solar Cells S. E. Shaheen et al, Appl. Phys. Lett 78, 841 (2001) First High Efficiency

23. Dispersed electronegative species

24. Poly(disilanyleneoligothienylene) + C 60

25. Onsager effect T = 300 K  = 3 r  20 nm An electric field of the order of 10 5 V/cm already stimulates the dissociation mechanism

26. High Efficiency Cell (4.2 %) 4.2 % Efficient Organic PV Cells Wtih Low Series Resistances J. Xue et al, Appl. Phys. Lett. 84, 3013 (2004) Double heterostructure 20 nm donor-like layer-CuPc 40 nm acceptor-like layer-C 60 10 nm exciton-blocking layer of bathocuproine (BCP)

27. High efficiency cell (4.6 %) Poly(ethylenedioxythiophene):polystyrenesulfonate Poly(3-hexylthiophene-2,5-diyl):[6,6]-phenil-C61-butyric acid methyl ester Copper phthalocyanine:fullerene High efficient organic tandem solar cells using na improved connecting architecture A.G. F. Janseen et al, Appl. Phys. Lett. 91, 073519 (2007)

28. Donor-acceptor mixture

29. Important characteristics Characteristics of OPV: High absorption coefficient (10 -5 cm -1 ) Short penetration depth Thin films (10 – 1000 nm) Important limitation for organic PV is the short diffusion length of the exciton

30. To mention Electrochemical Solar Cell

31. Summary

32. OPV End

33. DEVICE 2: OLEDs Organic Ligth-Emittng Diodes

34. Polymers and Small Molecules PLEDs and SMOLEDs

35. Most important luminescent polymers Poly(p-phenylene vinylene) Polyfluorene

36. Most important luminescent small molecules ALq3 Pentacene derivatives

37. Most important electrical and optical characteristics

38. IV curves ITO/PPV/Al ITO/MH-PPV/Al

39. Current vs Luminescence

40. JABLONSKI DIAGRAM

41. Absorption and Emission (molecules) Frank-Condon Efeect

42. Absorption and Emission of PPV

43. Photo and Electroluminescent emission

44. Detecteur 0º0º 180º 90º Analisateur P 1 (//) S-Film P1()P1() Laser Optical system to detect polarized photoluminescence

45. Disordered PPV Film Stretched PPV Film

46. Stretched PPV

47. Electronic Model and Distribution of conjugation lenght PPV

48. TECHNOLOGY

50. PLEDs – Blue and White

51. Ink Jet Printing Process Ink-Jet Printer Heads PLEDs are solution processable, and can be applied using ink jet printing processes

52. Printers

53. Technological Advances of OLEDs

54. Future? No, present!

55. Comparison OLED-LCD Light Diffuser Prism Sheet Polarizer Film Common Electrode Protective Film Glass Substrate Waveguide Plate Back Light Reflector Polarizer Film Black Matrix Color Filter Capacitor Alignment Film Liquid Crystal Spacer Sealant 7mm Typical TFT-LCD Potentially, up to 50% of the display cost is eliminated P-OLED devices can reduce costs significantly: No backlight unit No liquid crystal light valve No color filter Simpler bill of materials Simpler production method Display Electrode Glass Substrate 2mm Typical Cathode Anode (ITO) Glass Substrate P-OLED Glass Substrate Polarizer Film Emissive Layer Interlayer Hole Conducting Polymer 200nm

56. White OLED (Organic Lighting)