Upconversion Materials for Security Inks

• Autor(a) principal: Freire, Tomás Miguel Santos Silva
• Data de Publicação: 2018
• Tipo de documento: Dissertação
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/10362/57613
• topic: counterfeit products; security inks; microwave-assisted synthesis; Y2O3; Yb; Er; Domínio/Área Científica::Engenharia e Tecnologia::Engenharia dos Materiais

Tobacco industry generates a lot of money throughout the year, both to its producers and to governments that charge high prices for it. [1–3] Given its demand, it is enticing to forge this product and take advantage of the economy that revolves around it. [4] The fight against counterfeiting performed by the authority, contribute for the diminishing of trafficked goods, however not everything can be apprehended, wherefore is crucial to get methods that can easily identify them. The use of security inks appears as a simple alternative to this problem due to its ease of application. By using an Y2O3 doped matrix with Yttrium (Yb) and Erbium (Er), it is possible to obtain materials that exhibit the Upconversion (UC) phenomenon that can serve as markers in this type of ink. Their production through ecological processes such as microwave-assisted synthesis of water-based solutions is also an advantage. As the synthesis temperature and the amount of the reactants influence the response of these materials, by adjusting these factors it is possible to develop detectors that respond to the signature of a specific marker, which makes them interesting as security products.