Solution-processed PEDOT: PSS/MoS₂ nanocomposites as efficient hole-transporting layers for organic solar cells

An efficient hole-transporting layer (HTL) based on functionalized two-dimensional (2D) MoS₂-poly(3,4-ethylenedioxythiophene): poly(styrenesulfonate) (PEDOT: PSS) composites has been developed for use in organic solar cells (OSCs). Few-layer, oleylamine-functionalized MoS₂ (FMoS₂) nanosheets were prepared via a simple and cost-effective solution-phase exfoliation method; then, they were blended into PEDOT: PSS, a conducting conjugated polymer, and the resulting hybrid film (PEDOT: PSS/FMoS₂) was tested as an HTL for poly(3-hexylthiophene):[6,6]-phenyl-C₆₁-butyric acid methyl ester (P3HT: PCBM) OSCs. The devices using this hybrid film HTL showed power conversion efficiencies up to 3.74%, which is 15.08% higher than that of the reference ones having PEDOT: PSS as HTL. Atomic force microscopy and contact angle measurements confirmed the compatibility of the PEDOT: PSS/FMoS₂ surface for active layer deposition on it. The electrical impedance spectroscopy analysis revealed that their use minimized the charge-transfer resistance of the OSCs, consequently improving their performance compared with the reference cells. Thus, the proposed fabrication of such HTLs incorporating 2D nanomaterials could be further expanded as a universal protocol for various high-performance optoelectronic devices.