Surface plasmonic controllable enhanced emission from the intrachain and interchain excitons of a conjugated polymer

Abstract

We demonstrate selectively enhanced emission by controlling the intrachain and interchain excitons of a conjugated polymer through adjusting surface plasmons. Enhanced light emission from the intrachain excitons was observed by coupling the localized surface plasmon resonance with the intrachain band of the conjugated polymer using Ag nanoparticles. Light emission from the interchain excitons was enhanced by exploiting both the increased strength of the interchain dipole due to the image dipole and the coupling between excitons and surface plasmon polaritons (SPPs). As the Ag nanostructures become complete films, light emission from the interchain excitons increased.

Review paper: Semiconductor nanoparticles with surface passivation and surface plasmon

“…[56][57][58][59][60][61][62][63][64][65][66][67][68][69][70][71] Surface-plasmon resonance induced by the oscillation of the charge density of conduction electrons, and its corresponding electromagnetic field can strongly affect the optical properties of any semiconductor nanoparticles nearby.…”

Surface plasmon-enhanced electroluminescence in organic light-emitting diodes incorporating Au nanoparticles

“…[4][5][6] However, the poor light extraction efficiency of $20% in a conventional OLED limits the external quantum efficiency due to the total internal reflection (TIR) at the glass substrate/air and indium-tinoxide (ITO)/substrate interfaces, the waveguide (WG) mode at the organic/ITO anode interface, and the surface plasmon (SP) losses at the metallic cathode/organic interface. [7][8][9][10] Various methods have been proposed to enhance light out-coupling in OLEDs, including surface microstructures on ITO anode to reduce the WG mode loss, 11,12 photonic crystals or microlens arrays attached on the glass substrate for the reduction of TIR, 13,14 corrugated cathode to reduce SP losses, [15][16][17][18] optical microcavity structures, 19 and so on. Recently, the localized SP effect excited by metallic nanostructures is becoming one of the most attractive approaches for light emission enhancement in OLEDs through the coupling with localized SP resonance and the emission energy.…”

“…Recently, the localized SP effect excited by metallic nanostructures is becoming one of the most attractive approaches for light emission enhancement in OLEDs through the coupling with localized SP resonance and the emission energy. [15][16][17][18]20,21 For example, Koo et al have demonstrated the enhancement of light extraction efficiency in OLEDs by a quasi-periodic buckling structure without introducing spectral changes and directionality. 15 The roughness on the cathode side induced by lithography process 16 or template transform 15 can match the momentum of SPs and radiated light, leading to the SP enhancement.…”

“…26 It has been reported that the coupling process between SPs and radiated light is much faster than spontaneous recombination of excitons, and the exciton lifetime in SP-enhanced devices should be much decreased. 17,27 Here, time-resolved PL spectra of a 50 nm-thick Alq 3 layer on PEDOT:PSS coated ITO glass substrates with and without Au NPs were measured as shown in Fig. 3.…”

Photoexcitations From Intrachain and Interchain Excitons of Surface Plasmon Mediated Conjugated Polymers for PLED

“…Notably, the photophysics of interchain and intrachain interactions can be applied to polymer Thin-film field-effect transistors (TFTs), because mobility is limited by interchain rather than intrachain transport [18]. In a previous paper, we reported the achievement of selectively enhanced emission by controlling the intrachain and interchain excitons of MEH-PPV films through adjustment of surface plasmons [19]. In this paper, we present the results of picosecond TR-PL spectroscopy studies on SP mediated MEH-PPV films.…”