Optical oxygen pressure sensing based on triplet-triplet quenching of fullerene-polystyrene film using laser flash photolysis:: Soccerballene C60 versus rugbyballene C70

An optical oxygen-sensing system based on the triplet lifetimes of fullerenes C-60 and C-70 in polystyrene (PS) under different oxygen pressures was developed using laser flash photolysis. The lifetime of the photoexcited triplet state of fullerene-PS film decreases with increasing oxygen pressure. The photoexcited triplet state of fullerene-PS film was effectively quenched by oxygen. The quenching rate constant of the photoexcited triplet state of C-60 and C-70 in PS film by oxygen, k(q), were estimated to be 6.6 x 10(2) and 1.4 x 10(3) Torr(-1) s(-1), respectively (1 Torr = 133.322 Pa). The linearity of a Stern-Volmer plot of C-60-PS film (r(2) = 0.999) is superior to that of C-70-PS film (r(2) = 0.992). These results show that C-60- and C-70-PS films are highly sensitive for oxygen in the total oxygen pressure region and in the low oxygen pressure region, respectively.