Abstract
Achieving long-term stability in organic solar cells is a remaining bottleneck for the commercialization of this otherwise highly appealing technology. In this work, we study the performance and stability differences in standard and inverted DBP/C70 based organic solar cells. Differences in the charge-transfer state properties of inverted and standard configuration DBP/C70 solar cells are revealed by sensitive external quantum efficiency measurements, leading to differences in the open-circuit voltages of the devices. The degradation of standard and inverted solar cell configurations at ISOS aging test conditions (ISOS-D-3 and ISOS-T-3) was investigated and compared. The results indicate that the performance drop in the small molecule bilayer solar cells is less related to changes at the D-A interface, suggesting also a pronounced morphological stability, and instead, in the case of inverted cells, dominated by degradation at the electron transport layer (ETL) bathocuproine (BCP). Photoluminescence measurements, electron-only-device characteristics, and stability measurements show improved exciton blocking, electron transport properties and a higher stability for BCP/Ag ETL stacks, giving rise to inverted devices with enhanced performance and device stability.
Highlights
During the past years, organic solar cells (OSCs) have received a great deal of attention as they offer unique advantages such as low fabrication cost, semi-transparency and lightweight modules
We investigate the differences in VOC of the devices through the sensitive external quantum efficiency (sEQE) measurements and CT state characteristics
Based on the electron transfer theory developed by Marcus[44,45], energy of the CT state (ECT), the reorganization energy (λ), and the amplitude of the CT absorption band (f) are determined by fitting the low energy part of the EQE spectrum with a Gaussian, using the method outlined in reference[15]
Summary
Organic solar cells (OSCs) have received a great deal of attention as they offer unique advantages such as low fabrication cost, semi-transparency and lightweight modules. We investigate degradation pathways in Tetraphenyldibenzoperiflanthen (DBP) and Fullerene (C70) based organic solar cells, having standard and inverted device architectures. We use sensitive external quantum efficiency (sEQE) measurements to detect morphological differences between standard and inverted device configurations, and to detect potential degradation at the DBP/C70 interface after aging the devices at ISOS-D-3 (darkness, 80 °C, 85% relative humidity (RH)) and ISOS-T-3 (darkness, −40 °C, ambient humidity) aging conditions.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
