Crescimento, caracterização e aplicação de filmes finos de surface-supported metal-organic frameworks (SURMOFs) em dispositivos eletrônicos

Author(s)

Tatiana Parra Vello

• Document type: Doctoral Thesis
• Press: Campinas, SP.
• Institution: Universidade Estadual de Campinas (UNICAMP). Instituto de Química
• Defense date: 2022-05-18

Examining board members

Carlos César Bof Bufon; Antonio Riul Júnior; Neri Alves; Lucas Fugikawa Santos; Flávio Leandro de Souza

• Advisor: Carlos César Bof Bufon

Abstract

Metal-organic frameworks (MOFs) are hybrid porous materials formed by assembling organic linkers and metal clusters via coordination chemistry. Their structure exhibits unique properties, like high crystallinity, surface area, and porosity. In the last decades, the expansion of the nanotechnology field has highlighted the advantages of devices miniaturization, microfabrication, and thin film deposition. In the same direction, the interest in integrating MOFs into platforms as thin films has grown, which allows exploring their properties and applying them as functional devices. The Surface-supported Metal-Organic Frameworks (SURMOFs) have come up as a solution to apply a homogeneous, uniform film with controlled thickness. Although SURMOFs were created aiming for devices integration, there is a lack of effort in exploring them in electrical devices, especially aiming thicknesses less than 100 nm. This Ph.D. thesis focus on the integration and electrical characterization of SURMOFs on electrical devices. The HKUST-1 SURMOF was the applied structure, due to its vast information in the literature. Here, a complete study is carried out, including how substrate nature and self-assembled monolayer (SAM) chain length can influence HKUST-1 growth. To the best of our knowledge, we reported the first experimental approach to grow homogeneous SURMOF thin films anchored by SAM on an insulating surface with precise control. Moreover, the HKUST-1 SURMOF growth was controlled to match the microfabrication process and integration on nanomembrane vertical heterojunctions. We established a full parametrization of SURMOFs thin-films growth, reaching homogeneous, low-roughness films with thickness of around 10 nm. The HKUST-1 SURMOF integrated on the vertical heterojunctions were applied as templates for controlled polymerization reaction of PPy inside their pores, leading to a homogeneous and full doped film. The device performance reached an electrical conductivity of about 5.10-6 S/m under 24h of exposure to monomer vapor, showing an increment of electrical current about 7 orders of magnitude compared to pristine HKUST-1 SURMOF vertical junctions. We performed a further investigation of electrical transport mechanisms under low temperatures. The work developed during the Ph.D. has established a consolidated research field about SURMOFs on electronic devices, and the findings reported here expanded the use of MOFs/SURMOFs materials in the electronics (AU)

• FAPESP's process: 16/25346-5 - Capacitive devices for hybrid nanostructures characterization: study of electrical properties of surface metal-organic frameworks -SURMOFs- and metallophthalocyanines
• Grantee: Tatiana Parra Vello
• Support Opportunities: Scholarships in Brazil - Doctorate