Enhancing efficiency with fluorinated interlayers in small molecule organic solar cells
Journal
Journal of Materials Chemistry
Journal Volume
22
Journal Issue
43
Pages
22899-22905
Date Issued
2012
Author(s)
Han, H.-C.
Tseng, C.-A.
Du, C.-Y.
Ganguly, A.
Chong, C.-W.
Wang, S.-B.
Lin, C.-F.
Chang, S.-H.
Su, C.-C.
Lee, J.-H.
Chen, K.-H.
Abstract
This study presents a simple approach to improve the performance of small molecule based organic solar cells (OSCs) by inserting a fluorinated buffer layer (e.g., PFAS) at the hetero-interface of bilayer devices. As demonstrated in this work, the PFAS modification reduces the surface energy of the conventional PEDOT:PSS photoanode and results in a significant improvement in the pentacene based OSC. The passivated PEDOT:PSS surface after PFAS modification has a lower interface energy with pentacene and facilitates 3D single crystalline (dendritic-like) phase pentacene growth. Concurrently, the accumulated negative charges of the fluorinated PFAS layer result in the development of interfacial dipole moments that in turn lead to an enhanced built-in potential across the devices, and consequently enhanced hole transport efficiency. Improved performance of the modified OSCs is evident from the ∼97% enhancement in efficiency from 0.88% to 1.73%, along with the open-circuit voltage improvement from 0.29 to 0.42 V. As well as improving the photovoltaic performance, the PFAS treatment also enhances the stability of the device under high temperature annealing, which is essential in the fabrication process. © 2012 The Royal Society of Chemistry.
SDGs
Other Subjects
Bi-layer devices; Built-in potential; Fabrication process; Hetero interfaces; High-temperature annealing; Hole transports; Interface energy; Interfacial dipoles; Negative charge; Organic solar cell; PEDOT:PSS; Pentacenes; Photoanode; Photovoltaic performance; Simple approach; Single-crystalline; Small molecules; Conducting polymers; Molecules; Open circuit voltage; Solar cells
Publisher
Royal Society of Chemistry
Type
journal article