Raman study of the interaction between regioregular poly(3-hexylthiophene) (P3HT) and transition-metal oxides MoO3, V2O5, and WO3 in polymer solar cells

• Published in: Chemical physics letters Vol. 644; pp. 267 - 270
• Main Authors: Yamamoto, Jun, Furukawa, Yukio
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 16.01.2016
• ISSN: 0009-2614; 1873-4448
• DOI: 10.1016/j.cplett.2015.12.012

⿢Raman spectra of ITO/P3HT/anode buffer material (MoO3, V2O5, or WO3) were obtained.⿢The Raman spectrum of ITO/MoO3/P3HT was also obtained.⿢Positive polarons were formed in a P3HT film upon MoO3, V2O5, or WO3 deposition.⿢The number of positive polarons increased in the order WO3<V2O5<MoO3.⿢Polaron electronic energy levels distribute around the Fermi level of an electrode. We measured the Raman spectra of indium-tin oxide (ITO)/poly(3-hexylthiophene) (P3HT)/metal oxide (MoO3, V2O5, or WO3) samples as an anode buffer layer. The difference Raman spectrum between ITO/P3HT/MoO3 and ITO/P3HT was similar to that of positive polarons generated by FeCl3 doping, which indicated that positive polarons were formed upon MoO3 deposition. MoO3 functioned as an oxidizing dopant. Positive polarons were also formed upon V2O5 and WO3 deposition. The polaron electronic energy levels formed near the Fermi level of an ITO, Ag, or Au electrode are associated with an improvement of charge transport through the interface.