Supramolecular Architecture and Electrical Properties of a Perylene Derivative in Physical Vapor Deposited Films

Materials Research

José Diego Fernandes¹  Pedro Henrique Benites Aoki¹  Ricardo Flavio Aroca¹  Wagner Dias Macedo Junior¹  Agda Eunice De Souza¹  Silvio Rainho Teixeira¹  Maria Luiza Braunger¹  Clarissa De Almeida Olivati¹  Carlos José Leopoldo Constantino¹ 

关键词: supramolecular structure;    thin films;    perylene derivative;    electrical measurements;   

DOI  :  10.1590/1516-1439.349614

来源: SciELO

【 摘 要 】

The supramolecular structure of organic thin films is a key factor in their optical and electrical properties and, consequently, in the technological applications involving organic electronic. Here, thin films of a perylene derivative, the bis butylimido perylene (BuPTCD), were produced by vacuum thermal evaporation (PVD, physical vapor deposition). The main objective is to investigate the supramolecular structure of the BuPTCD in these PVD films, which implies to control their thickness at nanometer scale and to determine their molecular organization, morphology at micro and nanometer scales and crystallinity. The ultraviolet-visible absorption reveals a uniform growth of the PVD films. The optical and atomic force microscopy images show a homogeneous surface of the film at micro and nanometer scales, respectively. The X-ray diffraction indicates that both powder and PVD film are in the crystalline form. Complementary, a preferential head-on orientation of the molecules in the PVD films is determined via infrared absorption spectroscopy. Besides, the annealing process (200oC) did not affect the molecular organization of the PVD films, revealing a thermal stability of the BuPTCD molecules within the PVD films. Through DC electrical measurements, an electrical conductivity of 7.45x10-10 S/m was determined for BuPTCD PVD films onto Au interdigitated electrodes (IDE-structured devices), which can be enhanced, under illumination, by two orders of magnitude (photoconductivity effect). As proof-of-concept, the IDE-structured devices are tested as gas sensor for trifluoroacetic acid.

【 授权许可】

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