Impact of Pb substitution by Sn²⁺ ions on the properties of CsPbBr_3-xI_x thin films

In this work is reported results of a study on optical and structural properties of thin films of cesium lead bromide iodide mixed perovskite (CsPbBr<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3-x</inf>I<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">x</inf>), synthesized by sequential evaporation of precursors (CsBr, PbBr<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf>, PbI<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf>). Special emphasis was put in evaluating the effect that the substitution of the Pb cation by Sn<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2+</sup> ions onto its optical and structural properties through transmittance, photoluminescence, Scanning Electron Microscopy (SEM) and Urbach Energy measurements. Thin films of CsPbBr<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3-x</inf>I<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">x</inf> with a high degree of reproducibility of both the molar composition and the photovoltaic properties were achieved, using an electronic system with facilities to control the growth of the samples with the help of PID and PWM algorithms.