摘要：We investigated the variation of current density–voltage (
J–V) characteristics of an organic solar cell (OSC) in the dark and at 9 different light intensities ranging from 0.01 to 1 sun of the AM1.5G spectrum. All three conventional parameters, short-circuit currents (
J
sc), open-circuit voltage (
V
oc), and Fill factor (FF), representing OSC performance evolved systematically in response to light intensity increase. Unlike
J
sc that showed quasi-linear monotonic increase,
V
oc and FF showed distinctive non-monotonic variations. To elucidate the origin of such variations, we performed extensive simulation studies including Shockley–Read–Hall (SRH) recombination losses. Simulation results were sensitive to defect densities, and simultaneous agreement to 10 measured
J–V curves was possible only with the defect density of
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