Optical Oxygen Pressure Sensing Based on Triplet-Triplet Quenching of Fullerene-Polystyrene Film Using Laser Flash Photolysis: Soccerballene C_(60) Versus Rugbyballene C_(70)

摘要

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-AS 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~(-10 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 = 0.02). These results show that C_(60)-and C_(70)-AS films are highly sensitive for oxygen in the total oxygen pressure region and in the low oxygen pressure region, respectively.