Session 3P4b SC2: Plasmonic Nanomaterials and Nanostrcutures for Photovoltaics and Optoelectronics in Energy 1Polymer-fullerene-based bulk heterojunction (BHJ) solar cells have many advantages
including low-cost, low-temperature fabrication, semi-transparency, and mechanical flexibility
[1, 2]. However, there is a mismatch between optical absorption length and charge transport
scale [3, 4]. These factors lead to recombination losses, higher series resistances and lower fill factors.
Attempts to optimize both the optical and electrical properties of the photoactive layer in
organic solar cells (OSCs) inevitably result in a demand to develop a device architecture that can
enable efficient optical absorption in films thinner than optical absorption length [5, 6]. Here, we
report the use of multiple metallic nanostructures to achieve the broad light absorption enhancement,
increased short-circuit circuit (Jsc) and improved fill factor (FF) simultaneously based on
a new small-bandgap polymer donor of poly {[4,8-bis-(2-ethyl-hexyl-thiophene-5-yl)-benzo[1,2-
b:4,5-b’]dithiophene-2,6-diyl]-alt-[2-(2-ethyl-hexanoyl)-thieno[3,4-b]thiophen-4,6-diyl]} (PBDTTT-C-T)
in BHJ cells [7]. The multiple metallic nanostructure consists of 2D arrays of metallic
nanograting electrode as a back reflector and metallic nanoparticles (NPs) with different geometries
embedded into the active layer. Apart from the waveguide modes and diffractions, we
simultaneously introduce hybridized surface plasmonic resonances (from Ag nanograting) and
localized plasmonic resonances (from Au and Ag NPs [8]) to successfully achieve a broadband
absorption enhancement. The detail understanding has been described with our theoretically
studies. Consequently, we improve PCE to ∼9% [9] by improving both optical and electrical
properties of single-junction OSCs through introducing dual plasmonic nanostructures which
contribute to the practical application of OSCs for photovoltaics.published_or_final_versio
