Estudo das propriedades eletroluminescentes de células eletroquímicas emissoras de luz contendo líquidos iônicos derivados de 1,2,3-triazóis

Abstract

The Light-Emitting Electrochemical Cell (LEEC) is one of the simplest kind of electroluminescent solid-state devices. Generally, they are fabricated with only one emitting material layer (EML), so-called active emission layer, that consist of an emitter material mixed with an ionic electrolyte. Apart from the electrolyte, their structure is similar to that of a single layer organic light-emitting diode (OLED). Not only LEECs assemble most of OLEDs applications and their technological advantages, but they also bring additional ones such as (i) low dependence of the electrodes work function, (ii) low dependence to the EML thickness, (iii) low operation voltage and high brightness and finally (iv) LEECs can be printed or sprayed in large areas. In this work, it was synthesized a series of new ionic liquid (IL) based on 1,2,3-triazolium and their intermediates to investigate the performance of the ILs in LEECs. In this context, it was synthesized eight ILs with four different cations size and two anions (iodide and trifluoromethanesulfonate). These ILs were applied as electrolyte for LEECs. All devices were fabricated with a commercial poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene] (MEH-PPV) as emitter polymer. As a result, we showed that the best device performance was achieved with 4% of dohmtI and 80 nm of active layer, presenting a luminance of 3.2x104 cd/m2. Despite the use of the MEH-PPV, a polymer not so efficient when compared to the state-of-art of the novel emitter material employed nowadays, our realization showed these new ILs based on 1,2,3-triazolium have been able to provide the specific requirements of the LEEC devices.