Flexible Organic Optoelectronic Devices On Silk Fibroin

Organic optoelectronic devices have gained wide attentions due to their flexibility, lightness, large-scale roll-to-roll processes and cost-effective potential. With the development of optoelectronic and biological technology, the researches of optoelectronic devices with good biocompatibility, eco-friendly, human non-irritability, human affinity and degradation in optoelectronic and biological fields have acquired more and more attentions. Up to now, organic optoelectronic devices are mainly based on rigid glass or synthetic polymer substrates, which do not meet the requirements of flexibility, human affinity and degradation. So, flexible substrates would be essential precondition for organic optoelectronic devices if they are integrated into human daily life. Silk fibroin(SF), as a natural protein, would be an excellent candidate material because of its good biodegradability, human affinity, biocompatibility and mechanical properties. Here, SF films were used as substrates in place of glass or synthetic polymers. And silver nanowires(Ag NWs) were embedded into SF film as a conductive layer. We fabricated flexible SF-Ag NWs(SF-Ag) substrates with excellent transmittance and conductivity. Finally, organic solar cells(OSCs) and organic light emitting diodes(OLEDs) were fabricated on SF-Ag substrates. The whole thesis included the following parts:Firstly, we presented the composition, structure and application of SF. And we summarized the materials, structures, principle and development of OSCs and OLEDs.Secondly, we presented the fabrication processes and properties of SF-Ag substrate. SF films were used as substrates and Ag NWs were embedded into SF as a conductive layer for SF-Ag substrates. The conductivity, transmittance and atomic force microscopy analysis of the substrate shown that the resistance(11.0 ?/sq) and visible light transmittance(80%) of SF-Ag substrates were as similar as commercial indium tin oxide(ITO) glass substrates and superior than ITO on polymer substrates. The root-mean-square(RMS) roughness value of the SF-Ag substrates was 1.50 nm, which was much smaller than the values of ITO substrates. Besides, SF-Ag substrates retained their resistance lower than 20 ?/sq after being folded in 500 times.Thirdly, we presented the structures, fabrication and properties of OSCs and OLEDs. An OSCs based on the structure of SF-Ag/PFN/PTB7:PC71BM/Mo O3/Ag that achieved an open circuit voltage of 0.70 V, a short circuit current density of 15.92 m A/cm2, a fill factor of 65%, power conversion efficiency(PCE)of 7.29% and specific weight in units of 1.71 W/g. And also the device yielded a PCE of 6.50%, when was bent with an angle of 120 o. OLED were fabricated by evaporating HAT-CN, TAPC, CBP:Irppy2(acac), TPBi, Liq and Al, respectively. And OLED based on SF-Ag substrate achieved a current efficiency of 19 cd/A.Finally, we presented a summarization of the whole thesis and an outlook of organic optoelectronic devices on SF.