| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 79623 | Solar Energy Materials and Solar Cells | 2011 | 5 Pages |
Organic photovoltaic devices using an electrode of indium tin oxide (ITO) coated with a buffer layer of poly(3,4-ethylenedioxythiophene):poly(4-styrenesulfonate) (PEDOT:PSS) exposed to controlled humidity during fabrication showed a 65–75% decrease in efficiency and displayed S-shaped J–V curves, changes, which are attributed to different levels of indium and tin migration into the PEDOT:PSS film. A distinct shift in the secondary electron cut-off in the UV Photoelectron spectra (UPS) of ITO/PEDOT:PSS samples exposed to controlled humidity indicate an increase of the dipole at the ITO/PEDOT:PSS interface, which could explain the appearance of S-shaped J–V curves. Additionally, the electron density at low binding energies is reduced for the humidity exposed PEDOT:PSS suggesting a second mechanism for decreased device performance.
Graphical abstract.Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► The efficiency of OPVs reduces significantly upon exposure to humidity. ► Humidity exposure of the ITO/PEDOT:PSS interface in OPVs leads to S-shaped J–V curves. ► S-shaped J–V curves indicate reduced charge transport over an interface.► Electron spectroscopy shows changes in the interfacial properties.
