Electrical and Optical Properties of La1–x A x Fe1–y B y O3−δ Perovskite Films (with A = Sr and Ca, and B= Co, Ga, Ti): Toward Interlayers for Optoelectronic Applications

This paper shows that perovskite oxides can be used as p-type interfacial layers of optoelectronic devices thanks to their optical and electrical properties, morphologies, and work functions. La1–x A x Fe1–y B y O3−δ perovskite films (with A = Sr, Ca and B = Co,Ga,Ti) have been synthesized by pulsed layer deposition (PLD). The impacts of A-site and B-site cation substitutions as well as of oxygen stoichiometry in the perovskite structure on their optical and electrical properties have been studied. The oxygen stoichiometry has a large impact on the electrical conductivity and the absorption spectra of the perovskite films, enabling us to finely tune the material composition or annealing to match most of the requirements associated with their use as selective contact in optoelectronic devices. Finally, we suggest La0.8Sr0.2Fe0.7Ga0.3O3−δ and CaTi0.8Fe0.2O3−δ perovskite films as relevant candidates as p-type interlayers for third generation solar cells or organic and hybrid light-emitting devices. Using an annealing of 500 °C, CaTi0.8Fe0.2O3−δ was successfully integrated in a working perovskite light emitting diode (PeLED) based on the methylamonnium lead bromide (CH3NH3PbBr3) hybride perovskite, showing comparable performance to a reference devices based on a conventional PEDOT:PSS layer.