Solvent-assisted strongly enhanced light-emitting electrochemiluminescent devices for lighting applications

Rubrene-based electrochemiluminescence (r-ECL) cells with two different solvent systems is prepared, one in a co-solvent system with a mixture of 1,2-dichlorobenzene and propylene carbonate (DCB : PC, v/v 3 : 1) and another in a single solvent system of tetrahydrofuran (THF), as the medium to form a liquid-electrolyte (L-El). By simply changing the solvent systems, from the co-solvent DCB : PC (v/v 3 : 1) to the single solvent THF, with the same amount of electrochemiluminescent rubrene (5 mM) and Li-based salt, a dramatically enhanced brightness of over 30 cd m^-2 is observed for the r-ECL cell in L-El_THF which is approximately 7-times higher than the brightness of 5 cd m^-2 observed for the r-ECL in L-El_{DCB:PC(v/v 3:1)}.