Fig. 4

Temperature-dependent DF dynamics. Temperature-dependent time-resolved PL decay for F8BT films of different thicknesses. Each decay curve has a fast and a slow component. a For thinnest film (~110 nm) the DF has almost remained unaffected relative to temperature, whereas for b intermediate thickness (~310 nm) and c thickest film (~560 nm) studied, the DF decay dynamics change from exponential to power-law decay at lower temperatures. Time-integrated DF intensity relative to temperature for d 110 nm e 310 nm and f 560 nm-thick films. The DF intensity has two different temperature dependence namely: thermally assisted hopping region and weakly temperature-dependent single step tunneling regions