Plasmon-enhanced polymer photovoltaic cells based on large aspect ratio gold nanorods and the related working mechanism

Two types of Au nanorods (NRs) possessing longitudinal/transverse axes of 55/11 (NR₁₁) and 90/18 nm (NR₁₈) are, respectively, incorporated into the hole extraction layer to improve optical-to-electrical conversion performances in polymer photovoltaic cells. Totally different improvement factors in short-circuit current and power conversion efficiency occur in the NR₁₁- and NR₁₈-doped cells. Optical simulations, electrical analysis, and morphology alteration accompanying with the incorporation of NRs were proceeded to investigate the reason, and analysis demonstrates that a slower damping of field around NRs₁₈ (results in a field and absorption enhancement around the active layer) and one order higher scattering cross section in the NR₁₈-incorporated cell are key factors contributed to the improvement of cell performances.