CNR ExploRA

Articolo in rivista, 2013, ENG, 10.1038/srep02581

A time-temperature integrator based on fluorescent and polymorphic compounds

Gentili, Denis; Durso, Margherita; Bettini, Cristian; Manet, Ilse; Gazzano, Massimo; Capelli, Raffaella; Muccini, Michele; Melucci, Manuela and Cavallini, Massimiliano

Melucci, M (Reprint Author), CNR, Ist Sintesi Organ & Fotoreatt, Via P Gobetti 101, I-40129 Bologna, Italy. Gentili, Denis; Gazzano, Massimo; Capelli, Raffaella; Muccini, Michele; Cavallini, Massimiliano, CNR, Ist Studio Mat Nanostrutturati, I-40129 Bologna, Italy. Durso, Margherita; Manet, Ilse; Melucci, Manuela, CNR, Ist Sintesi Organ & Fotoreatt, I-40129 Bologna, Italy. Bettini, Cristian, Lab MIST ER, I-40129 Bologna, Italy. Capelli, Raffaella; Muccini, Michele, ETC Srl, I-40129 Bologna, Italy. Cavallini, Massimiliano, SCRIBA Nanotecnol Srl, I-40129 Bologna, Italy.

Despite the variety of functional properties of molecular materials, which make them of interest for a number of technologies, their tendency to form inhomogeneous aggregates in thin films and to self-organize in polymorphs are considered drawbacks for practical applications. Here, we report on the use of polymorphic molecular fluorescent thin films as time temperature integrators, a class of devices that monitor the thermal history of a product. The device is fabricated by patterning the fluorescent model compound thieno(bis) imide-oligothiophene. The fluorescence colour of the pattern changes as a consequence of an irreversible phase variation driven by temperature, and reveals the temperature at which the pattern was exposed. The experimental results are quantitatively analysed in the range 20-200 degrees C and interpreted considering a polymorph recrystallization in the thin film. Noteworthy, the reported method is of general validity and can be extended to every compound featuring irreversible temperature-dependent change of fluorescence.

Scientific reports (Nature Publishing Group) 3 , pp. 2581–2587