Electrochemical and atomic force microscopy investigations of new materials from N-trifluoromethanesulfonyl-1-azahexa-1,3,5-trienes derivatives

Abstract

Filmes finos foram crescidos sobre a superfície de elétrodos de grafito pirolizado altamente orientado a partir de precursores p-doadores utilizando a técnica cíclica de voltametria cíclica e eletroquímica-microscopia de força atômica. Os resultados indicam que é possível a formação de novos compostos chamados materiais moleculares, estes são formados pelo acoplamento de espécies N-trifluormetanosulfonil-1-aza-hexa-1,3,5-trieno eletro-oxidadas e o anion [Cr(C 2 O 4 ) 3 ] 3-. Diferentes técnicas foram empregadas para caracterizar a morfologia e composição dos filmes formados. Os resultados indicam que os materiais novos exibiram uma resposta eletroquímica particular e uma textura diferente dependendo da composição química dos materiais de partida.Thin films have been created on the surface of highly oriented pyrolytic graphite electrodes from chemically synthesized -donor species by using the cyclic voltammetry technique and in situ electrochemistry-atomic force microscopy. Results indicate that it is possible to form new compounds called molecular materials from the coupling of electro-oxidized N-trifluoromethanesulfonyl-1-azahexa-1,3,5-triene species and a [Cr(C 2 O 4 ) 3 ] 3-anion. Different techniques such as AFM, SEM and EDS were employed to characterize the films morphology and composition. Results indicate that the new materials exhibited a particular electrochemical response and a different film texture depending on the chemical composition of the starting compounds. Keywords: thin films, electrodeposition, in situ AFM IntroductionOver the last few years, there have been an increasing number of reports regarding the formation of molecular materials (MMs) with electronic or opto electronic properties based on organic and organometallic derivatives.1,2 For example, it has been reported the formation of supramolecular building blocks with tailored pore structures by Plaud et al. to generate predictable and robust structures for specific applications.3 Moreover, recent research work has been oriented to the formation and characterization of molecular-material thin films. 4 For instance, the use of the chemical vapor deposition to grow thin films of molecular conductors such as (TTF)(TCNQ) (TTF= tetrathiafulvalene, TCNQ = tetracyanoquinodimethane) has been reported. [5][6][7][8] It has been observed, that a regular stacking of molecules such as those found in MMs allows the formation of semiconducting, conducting or superconducting thin films. These thin films exhibit in general preferential directions for electrical conductivity. The electrical conductivity of MMs is associated with an extensive delocalization of electrons that depends on their 317 Electrochemical and Atomic Force Microscopy Investigations of New Materials Vol. 16, No. 3A, 2005 planarity and the orbital overlap extension between their molecular units. N-Trifluoromethanesulfonyl-1-azahexa-1,3,5-trienes (TFSAT) compounds, which are highly functionalized pentametines, have been previously studied due to its interesting physical and chemical p...

Electrical and optical properties of (PPh4)2[Fe(CN)5NO] non-crystalline thin films prepared with the vacuum thermal evaporation technique

“…It may be difficult to envision a technological breakthrough while using them in their usual, single-crystalline form, but the thin-film production of such materials offers an attractive alternative [2][3][4][5][6][7]. Recent research work has been oriented to the formation and characterization of molecular-material thin films with probable photonic, optoelectronic or electronic-device applications [8,9].…”

“…A regular stacking of molecules, such as is found in molecular materials, may permit the formation of semiconducting, conducting or superconducting thin films. Therefore, in order to describe the relationship between the physical configuration and the electrical properties of the thin films, it is necessary to produce such systems with a welldefined microstructure [1][2][3][4][5][6][7][8][9].…”