Steady-state device characteristics of P3HT:F8TBT devices. (a) Spectral response of EQE of an optimized 70 nm thick device (solid) and of a 220 nm thick device (dashed) measured at an intensity of ; (b) corresponding current voltage curves under simulated sunlight ( AM1.5G); (c) intensity dependence of short-circuit current under monochromatic illumination at 525 nm. In part (c) the symbols represent the data while the straight lines are power law fits of the form (squares: 70 nm thick device, ; circles: 220 nm thick device, ).
Transient short-circuit photocurrent of a 220 nm thick P3HT:F8TBT device in response to a square light pulse with wavelength of 525 nm for various intensities. (a) Absolute photocurrent response. (b) Photocurrent response normalized to the photocurrent at . Inset: Normalized decay kinetics plotted on a log-linear scale.
Plot of extracted charge vs light intensity calculated from the data of Fig. 2. The straight solid line provides a guide to the eye to judge the nonlinearity of the trend on this log-log plot.
(a) Influence of a constant background illumination on photocurrent dynamics with a constant background illumination of for different intensities of pulsed light. (b) Plot of normalized photocurrent transients comparing fall dynamics with (solid, constant background photocurrent subtracted) and without (dashed) a background illumination of for different pulse intensities.
(a) Influence of background light intensity on photocurrent dynamics for a constant pulse intensity of . (b) Comparison of curves in part (a) with constant photocurrent baseline subtracted. The insert highlights changes in fall dynamics with changing background intensity.
Dependence of transient photocurrent on applied electric field for a pulse width of 500 ns. (a) Absolute photocurrent response. (b) Normalized photocurrent response.
Short-circuit photocurrent dynamics in response to a 500 ns pulse for various pulse intensities [(a)–(c)] and for different intensities of constant background illumination [(d)–(f)]. (a) Absolute photocurrent response to 500 ns pulses of various intensities; (b) Normalized photocurrent response to 500 ns pulses of various intensities; (c) Plot of peak current (i.e., current at 500 ns) vs pulse intensity. The squares represent the data while the solid line is a power law fit with exponent of . (d) Absolute photocurrent response to a constant pulse illumination for different background illumination intensities; (e) Change in photocurrent with constant pulse illumination for different background illumination intensities (constant photocurrent background subtracted); (f) normalized photocurrent transients for a constant pulse illumination but different background illumination intensities (multiple curves overlap).
(a) Photocurrent transients at different pulse intensities calculated using the time-dependent drift-diffusion model. The inset displays the curves normalized to the photocurrent at . (b) Comparison of experimental (squares) and calculated (line) photocurrent transients at a pulse intensity of . The inset displays these curves on a log-linear plot highlighting the deviation between experiment and model at low photocurrent densities after turn off.
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