Department of Physics
Effect of ZnO Electron Extraction Layer on Charge Recombination and Collection Properties in Organic Solar Cells
The effect of zinc oxide (ZnO) electron extraction layer (EEL) on charge recombination and collection properties in bulk-heterojunction (BHJ) organic solar cells (OSCs), based on poly[[4,8-bis[(2-ethylhexyl)oxy] benzo [1,2-b:4,5-b'] dithiophene-2,6- diyl] [3-fluoro-2-[(2- ethylhexyl)carbonyl] thieno [3,4-b] thiophenediyl]] (PTB7):3'H-Cyclopropa[8,25] [5,6]fullerene-C70-D5h(6)-3'- butanoicacid, 3'-phenyl-, methyl ester (PC70BM) blend system, has been analyzed using the transient photo-current (TPC) and photo-induced charge extraction by linearly increasing voltage (photo-CELIV) measurements. The TPC and photo-CELIV results indicate that the trap-limited bimolecular recombination can be strongly suppressed by interposing a 20 nm thick ZnO EEL between the BHJ and cathode, leading to a 9.4% increase in power conversion efficiency. The presence of ZnO EEL is beneficial in efficient operation of OSCs in two ways: (1) suppressing trap-limited bimolecular recombination and (2) enhancing the charge collection at the organic/cathode interface.
Source Publication Title
ACS Applied Energy Materials
American Chemical Society
Link to Publisher's Edition
Lan, W., Liu, Y., Department of Physics, Research Centre of Excellence for Organic Electronics, and Institute of Advanced Materials, Hong Kong Baptist University, Hong Kong., Xu, B., Pu, H., Wei, B., Tian, W., & Zhu, F. (2019). Effect of ZnO Electron Extraction Layer on Charge Recombination and Collection Properties in Organic Solar Cells. ACS Applied Energy Materials. https://doi.org/10.1021/acsaem.9b01383