title: Self-Functionalization Behind a Solution-Processed NiOxFilm Used As Hole Transporting Layer for Efficient Perovskite Solar Cells.
abstract: Fabrication of solution-processed perovskite solar cells (PSCs) requires the deposition of high quality films from precursor inks. Frequently, buffer layers of PSCs are formed from dispersions of metal oxide nanoparticles (NPs). Therefore, the development of trustable methods for the preparation of stable colloidal NPs dispersions is crucial. In this work, a novel approach to form very compact semiconducting buffer layers with suitable optoelectronic properties is presented through a self-functionalization process of the nanocrystalline particles by their own amorphous phase and without adding any other inorganic or organic functionalization component or surfactant. Such interconnecting amorphous phase composed by residual nitrate, hydroxide, and sodium ions, proved to be fundamental to reach stable colloidal dispersions and contribute to assemble the separate crystalline nickel oxide NPs in the final film, resulting in a very homogeneous and compact layer. A proposed mechanism behind the great stabilization of the nanoparticles is exposed. At the end, the self-functionalized nickel oxide layer exhibited high optoelectronic properties enabling perovskite p-i-n solar cells as efficient as 16.6% demonstrating the pertinence of the presented strategy to obtain high quality buffer layers processed in solution at room temperature.
authors.affiliation: Centro de Investigación, Innovación y Desarrollo de Materiales-CIDEMAT, Facultad de Ingeniería, Universidad de Antioquia (UdeA) , Calle 70 52-21, Medellín, Colombia.
authors.forename: John
authors.identifier: http://orcid.org/0000-0002-3895-5596
authors.initials: J
authors.lastname: Ciro
authors.affiliation: Centro de Investigación, Innovación y Desarrollo de Materiales-CIDEMAT, Facultad de Ingeniería, Universidad de Antioquia (UdeA) , Calle 70 52-21, Medellín, Colombia.
authors.forename: Daniel
authors.initials: D
authors.lastname: Ramírez
authors.affiliation: Centro de Investigación, Innovación y Desarrollo de Materiales-CIDEMAT, Facultad de Ingeniería, Universidad de Antioquia (UdeA) , Calle 70 52-21, Medellín, Colombia.
authors.forename: Mario Alejandro
authors.identifier: http://orcid.org/0000-0001-7093-7964
authors.initials: MA
authors.lastname: Mejía Escobar
authors.affiliation: Centro de Investigación, Innovación y Desarrollo de Materiales-CIDEMAT, Facultad de Ingeniería, Universidad de Antioquia (UdeA) , Calle 70 52-21, Medellín, Colombia.
authors.forename: Juan Felipe
authors.identifier: http://orcid.org/0000-0002-6236-8922
authors.initials: JF
authors.lastname: Montoya
authors.affiliation: Centro de Investigación, Innovación y Desarrollo de Materiales-CIDEMAT, Facultad de Ingeniería, Universidad de Antioquia (UdeA) , Calle 70 52-21, Medellín, Colombia.
authors.forename: Santiago
authors.initials: S
authors.lastname: Mesa
authors.affiliation: Centro de Investigación, Innovación y Desarrollo de Materiales-CIDEMAT, Facultad de Ingeniería, Universidad de Antioquia (UdeA) , Calle 70 52-21, Medellín, Colombia.
authors.forename: Rafael
authors.identifier: http://orcid.org/0000-0001-6392-0419
authors.initials: R
authors.lastname: Betancur
authors.affiliation: Centro de Investigación, Innovación y Desarrollo de Materiales-CIDEMAT, Facultad de Ingeniería, Universidad de Antioquia (UdeA) , Calle 70 52-21, Medellín, Colombia.
authors.forename: Franklin
authors.identifier: http://orcid.org/0000-0003-1722-5487
authors.initials: F
authors.lastname: Jaramillo
keywords: PIN perovskite solar cell; colloidal nanoparticles stability; hole transport layer; nickel oxide; self-functionalization