Enhancing the efficiency and stability of perovskite solar cells by incorporating MoS2 nanoparticles into the hole-transport layer

In the paper, MoS 2 nanoparticles were incorporated into HTL PEDOT:PSS of PSC. The effect of their concentration on the morphology and structure of PEDOT:PSS, optical absorption spectra and photoelectric characteristics of PEDOT:PSS in PSC was studied in detail. MoS 2 nanoparticles were synthesized by laser ablation of MoS 2 in isopropanol. Comprehensive analysis of AFM and optical absorption showed that the addition of MoS 2 nanoparticles to HTL leads to an increase in the values of the root-mean-square deviation Sq and the optical band gap. Impedance spectroscopy was used to determine the role of MoS 2 nanoparticles in the charge transfer mechanism in HTL. The measurement results showed that the recombination resistance, which determines the charge recombination rate at the interface boundaries, increases, reaching a maximum value at a MoS 2 concentration of 6 wt%. A further increase in concentration leads to a decrease in the recombination resistance. Measurements of the current-voltage characteristics of PSC show that increasing the concentration of MoS 2 to 6 wt% leads to an increase in the light energy conversion efficiency to 19.19 %. It is explained that the improvement in the photovoltaic characteristics of the devices is associated with an improvement in the transport efficiency in HTL and charge separation at the HTL/perovskite interface, while their deterioration is associated with the release of nanoparticles to the HTL surface, which results in increased charge recombination at the interface boundaries. In addition, MoS 2 nanoparticles in PEDOT:PSS enhance the bond strength and act as a barrier, preventing moisture penetration and, therefore, preventing perovskite degradation. • MoS 2 nanoparticles in PEDOT:PSS contribute to the increase of Sq value and the improvement of the optical band gap. • Increasing the MoS 2 concentration in PEDOT:PSS to 6 wt% leads to an increase in the PSC efficiency to 19.19 %. • MoS 2 nanoparticles fill the voids in PEDOT:PSS, preventing moisture penetration and perovskite degradation.