研究了高真空蒸发技术制备的C60薄膜在温度自127 K至室温范围的时间分辨荧光光谱,在127 K时,C60薄膜的荧光峰处于730 nm,且其时间弛豫特性呈单指数衰减行为;当温度上升时,荧光峰红移,其弛豫特性明显偏离单指数行为。采用四能级模型处理C60激发态的弛豫行为,得到双指数衰减规律,并用双指数函数对实验结果进行了拟合,结果表明,当温度上升时,单重态至三重态T的系间交叉速率明显增大。

C60 films fabricated by high vacuum deposition technique are studied by time-resolved photoluminescence spectrscopy from 127 K to room temperature. At 127 K, the peak of the C60 PL emission is at 730 nm and its decay behaviour shows single-exponential character. With the increase of the temperature, the PL peak has a red-shift and its decay obviously deviates from the single-exponential character. Adapting a four-energy-level model, we have got double-exponential decay solution for PL emission and then used this solution to fit the experimental data. The results demonstrate that the intersystem crossing rate of the singlet excited states increases rapidly with the increase of the temperature.