Light and dark characteristics for a P3HT/PCBM (1:1) device spin coated at 600 rpm from 30 mg/ml concentrated solution in chlorobenzene: (a) A typical J-V curve of a device where the voltage dependence of J is obvious (Voc = 560 mV, Jsc = 10.3 mA, FF = 45%, and PCE = 2.7%). (b)Determination of the shunt conductance from dJ/dV.
(a) Plot of the derivative, dV/dJ vs 1/J from the dark J-V data to determine R from the intercept and A from the slope. Inset shows the same plot as the main figure for J-V under illumination (light), (b) ln(J + Jsc-GV) plotted against the internal junction voltage V-JR where intercept on the ordinate gives Jo and slope A.
(a) Temperature dependence of the open circuit voltage, Voc, for various devices spin coated from different blend ratios of P3HT and PCBM. (b)X-ray diffraction data of pristine P3HT film (annealed) and P3HT/PCBM blend (1:2) film. The detrimental effects of PCBM addition to P3HT crystallinity are obvious.
(a) Calculated J-V behavior from the collection model described in the introduction with Lc/D = 7 and Lc/D = infinity plotted with the experimental data Jd. The FF with Lc/D = 7 is 61% whereas FF ∼80% for Lc/D = infinity (b) Fitting of the experimental data from P3HT/PCBM = 1:1, 1:2, and 1:3 devices to collection model. Lc/D = 5.5, 8.7, and 6.5, respectively. Open symbols represent the experimentally obtained data where the solid line is the fit to the data derived from JL(V).
(a) J-V curve of P3HT/PCBM solar cell showing various corrections: as measured, dark J-V shifted downward by Jsc according to the principle of superposition, corrected for R losses, corrected for collection, η(V-RJ) etc. (b) same data as in (a) plotted as power.
Plots of the photovoltaic parameters extracted from the analysis (shown in Figs. 2 and 4) of the J-V data from P3HT/PCBM (1:1) devices at various temperatures. (a) Short circuit current density, Jsc, (b) Open circuit voltage, Voc, (c) FF, and (d) PCE.
Temperature and thickness dependence of mobility-lifetime product, μτ, for P3HT/PCBM (1:1) devices.
Temperature dependence of the diode saturation current, Jo for P3HT/PCBM 1:1, 1:2, and 1:3 blend device. Solid line is the linear fit (solid line) of the ln(Jo) vs T−1 where the slope gives the activation energy over the diode ideality factor (Ea/A) and intercept the value of J′o.
(a) FF (%) versus the ratio of collection length to the device thickness, Lc/D, for P3HT/PCBM (1:1) device spin coated at 600 rpm. The ratio, Lc/D, is obtained from the J-V curves obtained from the same device but at different temperatures (b) FF (%) versus series resistance for the same device. The solid lines are guide to the eye.
Typical linear relationship of Voc and log(Jo) obtained at various temperatures for P3HT/PCBM (1:1) device spin coated at 600 rpm (b) Linear relation between Voc and the flat band potential Vfb for the same device as in (a). Inset shows the determination of Vfb from experimental data.
(a) Dark J-V curves for P3HT/PCBM (1:1) devices spin coated from solution in chlorobenzene at 600 rpm (b) J-V curves of the same sample under 1 sun illumination. The light induced parasitic effects near Voc are obvious in the light J-V curves.
(a) The derivative dV/dJ vs 1/(J + Jsc), calculated from the illuminated J-V curves obtained at various temperatures for P3HT/PCBM (1:1) device. The temperature corresponding to (i)-(ix) are: 297 K, 286 K, 277 K, 267 K, 258 K, 248 K, 238 K, 229 K, and 220 K, respectively. The inflection point indicates some blocking behavior. (b) The blocking resistance, Rb, increases as the temperature is lowered.
Temperature coefficient, dVoc/dT, and Voc at T = 0 K and 300 K extracted from Voc vs T plots for various blends and absorber thickness.
Uncorrected experimental values of the open circuit voltage, Voc, short circuit current density, Jsc and FF from the illuminated J-V data of devices. All devices are ∼150 nm.
Device parameters obtained from the fit of the measured J-V data in Table II to the collection model for P3HT/PCBM devices of blend ratio: 1:1, 1:2, and 1:3 spin coated at 600 rpm at room temperature. The Voc, Jsc, FF, and PCE values are corrected for Rs and JL(V).
Uncorrected experimental room temperature PV parameters from devices seen in Figure 7.
PV parameters obtained from analysis of J-V curves shown in Fig. 5(a).
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