Probing the Energy Level Alignment and the Correlation with Open-Circuit Voltage in Solution-Processed Polymeric Bulk Heterojunction Photovoltaic Devices

2016 ◽  
Vol 8 (11) ◽  
pp. 7283-7290 ◽  
Author(s):  
Qing-Dan Yang ◽  
Ho-Wa Li ◽  
Yuanhang Cheng ◽  
Zhiqiang Guan ◽  
Taili Liu ◽  
...  
Keyword(s):  
Energy Level ◽  
Open Circuit Voltage ◽  
Bulk Heterojunction ◽  
Open Circuit ◽  
Photovoltaic Devices ◽  
Solution Processed ◽  
Energy Level Alignment

Energy-level alignment and open-circuit voltage at graphene/polymer interfaces: theory and experiment

2D Materials ◽  
2016 ◽  
Vol 3 (1) ◽  
pp. 015003 ◽  
Author(s):  
Keian Noori ◽  
Dimitrios Konios ◽  
Minas M Stylianakis ◽  
Emmanuel Kymakis ◽  
Feliciano Giustino
Keyword(s):  
Energy Level ◽  
Open Circuit Voltage ◽  
Open Circuit ◽  
Polymer Interfaces ◽  
Energy Level Alignment ◽  
Theory And Experiment

Temperature dependence of HOMO-LUMO levels and open circuit voltage for P3HT:PCBM organic solar cells

2011 ◽  
Vol 1360 ◽  
Author(s):  
Yang Shen ◽  
Louis Scudiero ◽  
Mool C. Gupta
Keyword(s):  
Solar Cells ◽  
Energy Level ◽  
Temperature Dependence ◽  
Organic Solar Cells ◽  
Photoelectron Spectroscopy ◽  
Open Circuit Voltage ◽  
Bulk Heterojunction ◽  
Acid Methyl Ester ◽  
Open Circuit ◽  
Temperature Range

ABSTRACTIn this study, the open circuit voltage (VOC) of poly (3-hexylthiophene-2,5-diyl) (P3HT) and [6,6]-phenyl C61-butyric acid methyl ester (PCBM) bulk heterojunction (BHJ) organic solar cells was measured at temperatures ranging from 300 K to 400 K. The temperature dependence of the vacuum shift and of the highest occupied molecular orbital (HOMO) energy level of P3HT and PCBM were measured by ultraviolet photoelectron spectroscopy (UPS) in the same temperature range. The temperature dependence of the absorption edge was also studied in the same temperature range to obtain the temperature variation of the optical band gap energy (Eg). The measured VOC of the devices showed a clear decreasing trend with increasing operating temperature and the total decrease was found to be about 0.1 V. Although the origin of VOC is still not fully understood it is generally believed that the energy level offset between the HOMO of the donor and the LUMO of the acceptor minus the exciton binding energy (0.3 eV) directly determines the value of VOC. However, by utilizing the measured values of the HOMO for the P3HT (donor) and of the LUMO for the PCBM (acceptor), we have found that the calculated values of VOC and its temperature dependence do not agree with the measured VOC values. This indicates that factors other than the offset between the HOMO of the donor and the LUMO of the acceptor materials are impacting VOC.

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