Organic solar cells using plasmonics of Ag nanoprisms

We demonstrate plasmonic effects in bulk heterojunction organic solar cells (OSCs) consisting of poly(3-hexylthiophene) (P3HT) and [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) by incorporating silver (Ag) triangular shaped nanoparticles (nanoprisms; NPSs) into a poly(3,4-ethylenedioxythiophene) buffer layer. The optical absorption and geometric characteristics of the Ag NPSs were investigated in terms of their tunable in-plane dipole local surface plasmon resonance (LSPR) bands. The photovoltaic characteristics showed that the power conversion efficiency (PCE) of the plasmonic OSCs was enhanced by an increase of short circuit current (Jsc) compared to that of the reference cells without any variation in electrical properties. The enhanced Jsc is directly related to the enhancement of optical absorption efficiency by the LSPR of the Ag NPSs. We measured the photovoltaic characteristics of the plasmonic OSCs with various distances between the Ag NPSs and the P3HT:PCBM active layer, in which the PCEs of the plasmonic OSCs decreased with increasing distance. This suggests that the increase of photocurrent and optical absorption was due to near field enhancement (i.e., intensified incident light on the active layer) by the LSPR of the Ag NPSs.

The increase in the power conversion efficiency of conventional P3HT/PCBM OSCs was observed after the use of plasmonic of Ag nanoprisms. The near field enhancement by the local surface plasmon of the Ag NPSs contributed to the increase in optical absorption efficiency, resulting in an increase of photocurrent.Figure optionsDownload as PowerPoint slideHighlights
► Fabrication of plasmonic OSCs consisting of P3HT/PCBM as the active layer by incorporating PSS-coated Ag NPSs.
► Use of Ag NPSs with tunable local surface plasmon resonance (LSPR) bands to increase optical absorption.
► Enhanced PCE and photocurrent in plasmonic OSCs originated from near field enhancement.