Speaker
Description
Counterfeiting is a high-tech crime that increasingly menaces governments, companies, and consumers. This ever-growing phenomenon affects severely national and international security, has a major detrimental impact on commercial and industrial activities and in some cases, may also put people’s health and lives at risk [1]. Consequently, the development of anti-counterfeiting technological platforms is of fundamental importance in order to protect people from fraud and physical harm (in the case of pharmaceuticals).
The present work focus on the development of a new photoluminescent security ink composed of poly(vinylidene fluoride) (PVDF) [2] and the ionic liquid (IL) 1-butyl-3-methylimidazolium tetrakis(thenoyltrifluoroacetonato)europate(III) ([Bmim][Eu(tta)4])[3]. The material exhibits high thermal stability up to approximately 267 ºC, high chemical stability (inertness with respect to ethanol), high photostability and intense red emission when excited by long UV radiation (365 nm) with a maximum quantum yield value of 0.10±0.01 (Fig.1 a-b). As a proof of its applicability for authentication purposes, the security ink was screen-printed on a medical N95 protection mask, changing from transparent (under white light) to an intense red color emission under the irradiation of a commercial 365 nm LED as presented in Fig. 1c.
References
[1] R. Arppe et al., Nature Reviews Chemistry, 1,4 (2017).
[2] L. Ruan et al., Polymers, 10 (2018).
[3] D. M. Correia et al., Adv. Photonics Res., 2100151 (2021).
