Chinese Physics B, Volume. 29, Issue 9, (2020)
Temperature-dependent barrier height inhomogeneities in PTB7:PC71BM-based organic solar cells
We report on the temperature-dependent Schottky barrier in organic solar cells based on PTB7:PC71BM. 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.
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Brahim Ait Ali, Reda Moubah, Abdelkader Boulezhar, Hassan Lassri. Temperature-dependent barrier height inhomogeneities in PTB7:PC71BM-based organic solar cells[J]. Chinese Physics B, 2020, 29(9):
Received: Dec. 16, 2019
Accepted: --
Published Online: Apr. 29, 2021
The Author Email: Moubah Reda (reda.moubah@hotmail.fr)