Numerical Study on Open-Circuit Voltage of Single Layer Organic Solar Cells with Schottky Contacts: Effects of Molecular Energy Levels, Temperature and Thickness
LI Rong-Hua1, MENG Wei-Min2, PENG Ying-Quan1,2, MA Chao-Zhu1, WANG Run-Sheng1, XIE Hong-Wei1, WANG Ying1
1Laboratory of Semiconductor Devices and Engineering, Lanzhou University, Lanzhou 730000 2Key Laboratory for Magnetism and Magnetic Materials (Ministry of Education), Lanzhou University, Lanzhou 730000
Numerical Study on Open-Circuit Voltage of Single Layer Organic Solar Cells with Schottky Contacts: Effects of Molecular Energy Levels, Temperature and Thickness
LI Rong-Hua1, MENG Wei-Min2, PENG Ying-Quan1,2, MA Chao-Zhu1, WANG Run-Sheng1, XIE Hong-Wei1, WANG Ying1
1Laboratory of Semiconductor Devices and Engineering, Lanzhou University, Lanzhou 730000 2Key Laboratory for Magnetism and Magnetic Materials (Ministry of Education), Lanzhou University, Lanzhou 730000
We numerically investigate the effects of the exciton generation rate G, temperature T, the active layer thickness d and the position of LUMO level EL related to the cathode work function Wc at a given energy gap on the open-circuit voltage Voc of single layer organic solar cells with Schottky contact. It is demonstrated that open-circuit voltage increases concomitantly with the decreasing cathode work function Wc for given anode work functions and exciton generation rates. In the case of given cathode and anode work functions, the open-circuit voltage first increases with the exciton generation rate and then reaches a saturation value, which equals to the built-in voltage. Additionally, it is worth noting that a significant improvement to Voc could be made by selecting an organic material which has a relative high LUMO level (low |EL| value). However, Voc decreases as the temperature increases, and the decreasing rate reduces with the enhancement of exciton generation rate. Our study also shows that it is of no benefit to improve the open-circuit voltage by increasing the device thickness because of an enhanced charge recombination in thicker devices.
We numerically investigate the effects of the exciton generation rate G, temperature T, the active layer thickness d and the position of LUMO level EL related to the cathode work function Wc at a given energy gap on the open-circuit voltage Voc of single layer organic solar cells with Schottky contact. It is demonstrated that open-circuit voltage increases concomitantly with the decreasing cathode work function Wc for given anode work functions and exciton generation rates. In the case of given cathode and anode work functions, the open-circuit voltage first increases with the exciton generation rate and then reaches a saturation value, which equals to the built-in voltage. Additionally, it is worth noting that a significant improvement to Voc could be made by selecting an organic material which has a relative high LUMO level (low |EL| value). However, Voc decreases as the temperature increases, and the decreasing rate reduces with the enhancement of exciton generation rate. Our study also shows that it is of no benefit to improve the open-circuit voltage by increasing the device thickness because of an enhanced charge recombination in thicker devices.
LI Rong-Hua;MENG Wei-Min;PENG Ying-Quan;MA Chao-Zhu;WANG Run-Sheng;XIE Hong-Wei;WANG Ying. Numerical Study on Open-Circuit Voltage of Single Layer Organic Solar Cells with Schottky Contacts: Effects of Molecular Energy Levels, Temperature and Thickness[J]. 中国物理快报, 2010, 27(8): 88401-088401.
LI Rong-Hua, MENG Wei-Min, PENG Ying-Quan, MA Chao-Zhu, WANG Run-Sheng, XIE Hong-Wei, WANG Ying. Numerical Study on Open-Circuit Voltage of Single Layer Organic Solar Cells with Schottky Contacts: Effects of Molecular Energy Levels, Temperature and Thickness. Chin. Phys. Lett., 2010, 27(8): 88401-088401.
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