Improved Photovoltaic Performance of GaAs/Carbon Nanotube Heterojunction Solar Cells with a Multifunctional Nafion/PEDOT:PSS Layer

Carbon nanotubes (CNTs) have gained significant interest due to their potential in enhancing the performance and cost effectiveness of photovoltaic (PV) applications. This study demonstrates the efficacy of an optimal cell configuration for InGaP/GaAs/CNT/sulfonated poly(tetrafluoroethylene) (Nafion)/PEDOT:PSS heterojunction solar cells (HJSCs). This was achieved by adjusting the thickness of the CNT film and the Al2O3 buffer layer. The facile one-step spin coating of the multifunctional Nafion/PEDOT:PSS (NP) layer on the GaAs/CNT surface contributes to hole transportation, surface passivation, and formation of antireflection and encapsulation, resulting in a high power conversion efficiency (PCE) of 14.2% with better stability over one month of light soaking. Moreover, the corresponding mechanisms of the reaction between the highly hydrophilic sulfonate group of insulating, chemically stable Nafion and PSS in PEDOT:PSS are demonstrated by analyzing the morphology, chemical component, and configuration and their photoelectric properties. This work is highly important for obtaining high-performance, cost-effective, and air-stable SCs for light-harvesting industrial development.