Formation of Stable Tin Perovskites Co‐crystallized with Three Halides for Carbon‐Based Mesoscopic Lead‐Free Perovskite Solar Cells

Abstract

We synthesized and characterized methylammonium (MA) mixed tri-halide tin perovskites (MASnIBr Cl ) for carbon-based mesoscopic solar cells free of lead and hole-transporting layers. Varied SnCl /SnBr ratios yielded tin perovskites with three halides (I, Br, and Cl) co-crystallized inside the tin-perovskite. When the SnCl proportion was ≥50 % (x≥1), phase separation occurred to give MASnI Br and MASnCl Br in the stoichiometric proportions of their precursors, confirmed by XRD. A device with MASnIBr Cl (SnCl =10 %) showed the best photovoltaic performance: J =14.0 mA cm , V =380 mV, FF=0.573, and PCE=3.1 %, and long-term stability. Electrochemical impedance spectra (EIS) show superior charge recombination and dielectric relaxation properties for the MASnIBr Cl cell. Transient PL decays showed the intrinsic problem of tin-based perovskites with average lifetimes less than 100 ps.

Synergy Effect of Both 2,2,2‐Trifluoroethylamine Hydrochloride and SnF2 for Highly Stable FASnI3−xClx Perovskite Solar Cells

“…We can also observe a shift of the (001) peak located at ≈14.3°, as shown in Figure b. The shift to high degree of the peak indicates the reduction in the lattice constant, which is consistent with successful incorporation of chloride anion into the perovskite crystal lattice, as reported previously for different Cl‐containing perovskite materials …”

Lattice Modulation of Alkali Metal Cations Doped Cs1−xRxPbBr3 Halides for Inorganic Perovskite Solar Cells

“…As shown in Figure a, the cell device is composed of a multi‐layered structure of FTO/ c ‐TiO 2 / m ‐TiO 2 /Cs 1‐x R x PbBr 3 /carbon, in which the monolayer‐vertical structured perovskite grains are expected to facilitate charge transfer and suppress charge recombination. The absence of HTLs significantly reduces the production cost and simplifies fabrication processes . Figure b displays photocurrent‐voltage ( J‐V ) curves for inorganic PSCs with or without alkali metal cations doping and the corresponding photovoltaic parameters are summarized in Table .…”

Lead-free hybrid perovskites for photovoltaics

“…A combination of all three halides within a single tin-HP is a promising route to efficient and stable solar cell absorbers as shown on the example of MASnIBr 1.8 Cl 0.2 HP displaying PCEs higher than 3% in a HTL-free cell as well as a long-term operational stability [73]. …”