Enhanced optical absorption of organic materials via surface plasmon resonance in gold nanoparticles

Abstract

In this paper, we described an engineered enhancement of optical absorption in an organic photovoltaic cell via the excitation of surface plasmon resonance (SPR) in spherical Au nanoparticles deposited on a device surface. We deposited gold nanoparticles with 5 nm in diameter on ITO (indium tin oxide) glass substrates and then coated poly (styrenesulfonate) / poly (2,3-dihydro-thieno-1,4-dioxin) (PEDOT) which can reduce the work function of metal atoms and poly {2-methoxy-5-(2-ethylhexyloxy)-1, 4-phenylenevinylene} (MEHPPV) with Fullerene(C₆₀) mixtures that work as p-type and n-type organic semiconductors, respectively. By using Mie theory simulation, we could predict SPR resonance peak of gold nanoparticles and we assume the enhancement in electromagnetic field absorption within a device results in increased photocurrent response in organic p-n junction diodes with gold nanoparticles. Compared with the same organic photovoltaic structures without gold nanoparticles, the proposed device shows about 40 % power efficiency improvement under halogen illumination. Experimental results agree well to the prediction of simulation, which showed SPR can be applied to enhance optical absorption of organic materials.