Tuning open-circuit voltage in organic solar cells by magnesium modified Alq3
Journal
Journal of Applied Physics
Journal Volume
110
Journal Issue
8
Date Issued
2011
Author(s)
Chou, C.-T.
Lin, C.-H.
Wu, M.-H.
Cheng, T.-W.
Lee, J.-H.
Liu, C.-H.J.
Tai, Y.
Chattopadhyay, S.
Chen, K.-H.
Abstract
The low molecular weight tris-(8-hydroxyquinoline) aluminum (Alq 3) has been incorporated with magnesium (Mg) that altered the nature of its opto-electronic characteristics. The lowering of the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) in Mg:Alq3, compared to pure Alq3, creates a stronger field (exceeding the exciton binding energy) at the donor-acceptor junction to dissociate the photo-generated exciton and also provides a low barrier for electron transport across the device. In an electron-only device (described in the text), a current enhancement in excess of 103+, with respect to pure Alq3, could be observed at 10 V applied bias. Optimized Mg:Alq3 layer, when introduced in the photovoltaic device, improves the power conversion efficiencies significantly to 0.15 compared to the pure Alq3 device. The improvement in the photovoltaic performance has been attributed to the superior exciton dissociation and carrier transport. © 2011 American Institute of Physics.
SDGs
Other Subjects
Applied bias; Current enhancement; Donor-acceptors; Electron transport; Exciton dissociation; Exciton-binding energy; Highest occupied molecular orbital; Low molecular weight; Lowest unoccupied molecular orbital; Organic solar cell; Photovoltaic devices; Photovoltaic performance; Power conversion efficiencies; Tris(8-hydroxyquinoline)aluminum; Binding energy; Conversion efficiency; Excitons; Molecular modeling; Molecular orbitals; Open circuit voltage; Photovoltaic effects; Magnesium
Publisher
American Institute of Physics
Type
journal article