Space Optimization for Utilization of Plasmonic Effect on a P3HT-Gold Nanoparticle Photoelectrode

Non-capped gold nanoparticles (AuNPs) with a diameter of 9–13 nm were electrochemically deposited on an ITO electrode, and poly(3-hexylthiophene-2,5-diyl) (P3HT) was spin-coated on the AuNP-deposited electrode. The degree of photocurrent enhancement exceeded unity when the coverages of AuNPs were below 14%, but were lower above 14%. The plasmonic effect was verified to be the major contribution at lower coverages, while the quenching effects became predominant at higher coverages. The spatial optimization (1–2 nm) between AuNP and P3HT was crucial and has been successful at 18%.