We report on the temperature-dependent Schottky barrier in organic solar cells based on PTB7:PC 71 BM. The ideality factor is found to increase with temperature decreasing, which is explained by a model in which the solar cell is taken as Schottky barrier diode. Accordingly, the dark current in the device originates from the thermally emitted electrons across the Schottky barrier. The fittings obtained with the thermal emission theory are systematically studied at different temperatures. It is concluded that the blend/Ca/Al interface presents great inhomogeneity, which can be described by 2 sets of Gaussian distributions with large zero bias standard deviations. With the decrease of temperature, electrons favor going across the Schottky barrier patches with lower barrier height and as a consequence the ideally factor significantly increases at low temperature.

中文翻译：

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PTB7：PC 71 BM基有机太阳能电池中与温度相关的势垒高度不均匀性

我们报道了基于PTB7：PC 71 BM的有机太阳能电池中温度相关的肖特基势垒。发现理想因子随温度降低而增加，这可以通过将太阳能电池用作肖特基势垒二极管的模型来解释。因此，器件中的暗电流源自跨过肖特基势垒的热发射电子。通过热发射理论获得的配件在不同温度下得到了系统的研究。结论是，共混物/ Ca / Al界面存在很大的不均匀性，这可以用两组具有高零偏标准偏差的高斯分布来描述。随着温度的降低