Tailoring the electronic properties of the SnO2 nanoparticle layer for n-i-p perovskite solar cells by Ti3C2TX MXene

• Published in: Materials today communications Vol. 36; p. 106700
• Main Authors: Din, Muhammad Faraz Ud, Sousani, Shima, Kotlar, Mario, Ullah, Sami, Gregor, Maros, Scepka, Tomas, Soyka, Yaryna, Stepura, Anastasiia, Shaji, Ashin, Igbari, Femi, Vegso, Karol, Nadazdy, Vojtech, Siffalovic, Peter, Jergel, Matej, Omastova, Maria, Majkova, Eva
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.08.2023
• Subjects: Electron transport layers; Electronic properties; in situ GIWAXS; Perovskite solar cells; Power conversion efficiency; Ti3C2Tx MXene; in situ GIWAXS; Electronic properties; Electron transport layers; Ti3C2Tx MXene; Power conversion efficiency; Perovskite solar cells
• ISSN: 2352-4928; 2352-4928
• DOI: 10.1016/j.mtcomm.2023.106700

The effect of the Ti3C2Tx MXene modification of the SnO2 electron transport layer (ETL) was studied for the concentration range 0–7.4 wt% MXene. The electronic properties of the MXene-modified ETL were studied by the electrical conductivity measurements, density of states mapping by the energy-resolved electrochemical impedance spectroscopy, ultraviolet photoelectron spectroscopy, and photoluminescence. The structure and morphology of the MXene-modified ETL and the top perovskite layer were analyzed by the scanning electron microscopy (SEM), scanning transmission electron microscopy, grazing-incidence X-ray diffraction and in situ grazing-incidence wide-angle X-ray scattering (GIWAXS). The increased electrical conductivity and electron selectivity for the MXene-modified SnO2 ETL was confirmed up to 1 wt% MXene. For 7.4 wt% MXene, significant suppression of the hole blocking property of the ETL was found. The in situ GIWAXS was performed during the post-deposition annealing of the perovskite layer. The increased perovskite grain size on the SnO2 ETL modified by MXene compared to the pure SnO2 ETL visible by SEM was confirmed. The uniaxial texture of the perovskite crystals was revealed in both cases with an increased misorientation angle for the MXene-modified ETL. The grain size and misorientation angle do not exhibit any systematic temporal changes during the post-deposition annealing. The increasing number of the grains during the annealing was observed. These results are explained using the nucleation and growth model. The increased power conversion efficiency from 17.4% to 18.3% of the archetypal methylammonium-lead-iodide perovskite solar cell after the modification of the SnO2 ETL with 0.1 wt% MXene is the effect of two contributions - increased electrical conductivity of the ETL and improved crystallinity and larger grain size compared to the pure SnO2 ETL, which lowers the total boundary area and charge recombination at trap states typically formed at grain boundaries. [Display omitted] •MXene modification of SnO2 enhances ETL conductivity by 60%.•Blocking nature of SnO2 layer for holes is demonstrated by density of states mapping.•MXene modified SnO2 layer promotes the perovskite grain size grown on it by 17%.•MXene-modification of SnO2 ETL does not impair the long-term stability of solar cell.