Photophysical and Photoelectrochemical Properties of CsPbBr₃ Films Grown by Electrochemically Assisted Deposition

Abstract

Perovskite have had a great impact on the solid-state physics world in the last decade not only achieving great success in photovoltaics but, more recently, also in the implementation of other optoelectronic devices. One of the main obstacles for the adoption of Pb-based perovskite technologies are the high amounts of Pb needed in the conventional preparation methods. Here we present for the first time a detailed analysis of the photophysical and photoelectrochemical properties of CsPbBr 3 films directly grown on fluorine-doped tin oxide (FTO) coated glass through a novel technique based in the electrodeposition of PbO 2 as CsPbBr 3 precursor. This technique allows to save up to 90 % of the Pb used compared to traditional methods and can be scalable compared with the commonly used spin-coating process. The low temperature analysis of their photoluminescence spectra, performed in both steady state and time dependence, revealed a strong interaction between electrons and longitudinal optical (LO) phonons dominant at high temperatures. On the other hand, the electrochemical and photoelectrochemical analysis proves that CsPbBr 3 prepared using this new method has state-of-the-art features, showing a p-type behavior under depletion regime. This is also confirmed by photoelectrochemical measurements using p-benzoquinone as target molecule. These results prove that the proposed method can be used to produce excellent CsPbBr 3 films, saving much of the lead waste.

Origin of Photoluminescence, Exciton Binding Energy, Exciton-Phonon interaction, and Urbach Energy in γ-CsPbI3 Nanoparticles.

“…The temperature dependence of excitonic linewidths with temperature was theoretically analyzed by Segall and collaborators 80 . The authors show that exciton-phonon interactions can have three different origins 68,73,[80][81][82] i) Piezoelectric effect: In non-centrosymmetric crystals local strain can induce a local electrical polarization field thus affecting electrons.…”

“…This expression has been used extensively to account for exciton-phonon interaction in perovskites 68,79,80,82 .…”