Space charge distribution at the interface of organic materials with metals and metal oxides

Author(s)

Carlos Vinicius Santos Batista

• Document type: Master's Dissertation
• Press: Bauru. 2021-06-07.
• Institution: Universidade Estadual Paulista (Unesp). Faculdade de Ciências. Bauru
• Defense date: 2021-04-07
• Advisor: Carlos César Bof Bufon

Abstract

An obstacle for the development and improvement of devices based on organic materials is related to the complexity of the interface formed between such materials and substrates of different natures. Electronic devices based on π-conjugated molecules have been on the focus of several research efforts in the last decade. Among them, a class of molecules that stands out is phthalocyanine (Pc), due to the ability to control its properties.At nanoscale, the hybrid organic/inorganic interfaces of systems based on π-conjugated molecules rise up as their most fundamental components. They are responsible for various functions, properties or issues – previously architected or advertently avoided. Here we combine atomic force microscopy and Kelvin-probe force microscopy to investigate the surface potential of hybrid metal/organic and metal-oxide/organic interfaces – i.e., a-few-nanometer-thick copper phthalocyanine (CuPc) films grown on different metal electrodes (Au, Ni, Ag, Cr, and Ti). As result, we estimate the molecular orientation, quantify the thin- and ultrathin-CuPc-film’s work function, their substrate-dependent interface dipoles, and their space-charge regions. The KPFM results served as basis to choice electrodes for the development of organic-thin-films rectifiers. Considering that CuPc ultrathin films are model nanomaterials employed in several state-of-the-art studies, our experimental findings provide a consistent roadmap for further developments on hybrid organic/inorganic functional devices. (AU)

• FAPESP's process: 19/10188-3 - Space-charge distributions at interfaces of metal/insulator and metal/organics applied to hybrid capacitors based on nanomembranes
• Grantee: Carlos Vinicius Santos Batista
• Support Opportunities: Scholarships in Brazil - Master