Tailored NaCl Doping of PEDOT:PSS as a Hole Transport Layer for Flexible Air-Blade-Coated Devices.

Organic photovoltaic devices hold significant promise for sustainable energy generation, due to their low manufacturing cost and benefits such as lightness, semitransparency, and flexibility. This study explores the experimental and theoretical study of the effects of sodium chloride (NaCl) doping on PEDOT:PSS, with a focus on its photovoltaic properties in inverted all air blade-coated devices. By varying NaCl concentrations, we analyze key performance metrics and annealing treatment, open-circuit voltage, short-circuit current density, fill factor, and power conversion efficiency. The results indicate that lower concentrations of NaCl substantially improve these parameters, while higher concentrations can impair the efficiency of the device. Post annealing was found to improve photovoltaic performance, especially in samples with low NaCl concentrations. Advanced characterization techniques, including atomic force microscopy, Raman spectroscopy, and scanning electron microscopy, revealed that doping with NaCl improves the molecular organization of PEDOT:PSS, leading to better light transmission and energy efficiency. Theoretical results indicate that NaCl interacts with the thiophene rings of PEDOT:PSS, modifying its electronic and structural properties. These results highlight the fundamental role of doping and processing conditions in optimizing the performance of organic solar cells, providing valuable information for the development of efficient, economical, and sustainable photovoltaic technologies.