Surface Plasmon Enhanced Organic Photoelectronic Conversion Devices

Abstract

Surface plasmon resonance (SPR) phenomena have attracted considerable attention since many years because of the extremely strong enhancement and confinement of electric fields near metal surfaces. Recently, we have studied grating-coupled surface plasmon-based multiple plasmonic structures for electric-field enhanced organic device applications such as biosensors and photo-electric conversion devices [1, 2]. In this presentation, we will introduce our recent progress on surface plasmon enhanced photo-electric conversion systems. The cooperative multiple plasmonic effect exhibits advantages, including broader light absorption enhancement, enhanced exciton generation rate and dissociation efficiency, and increased charge carrier density and lifetime. Figure shows an example of our plasmonic device, i.e. surface plasmon enhanced photoelectrochemical sensor, which was constructed by electro-depositing nanocomposite film of poly(3,4−ethylene dioxythiophene):poly (styrene sulfonate) (PEDOT:PSS) and gold nanoparticles (AuNPs) onto ITO coated glass substrate (ITO/PEDOT:PSS/AuNPs) and this platform was used as a working electrode for the quantification of glucose. UV-vis spectra of nanocomposite film obviously revealed an absorption enhancement in the visible region, indicating the surface plasmon resonance absorption of AuNPs at approximately 550 nm (Figure 1A). Current responses of the ITO/PEDOT:PSS/AuNPs were proportional to the concentration of glucose. Also, the photocurrents were significantly enhanced under irradiation of the solar light, exhibiting satisfactory results with a wide linear range from 2.4 to 22.0 mM and a sensitivity of 0.047 µA mM-1, and a low detection limit of 1.23 mM (Figure 1B). The photocurrent enhancements represent the potential of the localized surface plasmon resonance excitation of AuNPs, which generates hot photocarriers, approach to improve the efficiency of glucose detection.