An optical oxygen-sensing system based on the triplet lifetimes of fullerenes C60 and C70 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 C60 and C70 in PS film by oxygen, k(q), were estimated to be 6.6x 102 and 1.4 x 103 Torr-1 s-1, respectively (1 Torr = 133.322 Pa). The linearity of a Stern-Volmer plot of C60-PS film (r2 = 0.999) is superior to that of C70-PS film (r2 = 0.992). These results show that C60- and C70-PS films are highly sensitive for oxygen in the total oxygen pressure region and in the low oxygen pressure region, respectively.
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