Abstract
By using electrical characterization and classical solid state semiconductor device theory, we demonstrate that the open circuit voltage (V oc ) in organic solar cells based on non-intentional doped semiconductors is fundamentally limited by the built-in potential (V bi ) originated at a donor-acceptor abrupt (p-n ++ ) heterojunction in case of selective contacts. Our analysis is validated using P3HT:PCBM devices fabricated in our research group. We also demonstrate that such a result can be generalized using data already reported in literature for fullerene-based solar cells. Finally, we show that the dependence of V oc on the device contacts can be understood in terms of the potential barriers formed by the Fermi level alignment of semiconductors at the heterojunction and at the Schottky junctions.
| Original language | English |
|---|---|
| Pages (from-to) | 610-619 |
| Number of pages | 10 |
| Journal | Solar Energy |
| Volume | 184 |
| Early online date | 13 Apr 2019 |
| DOIs | |
| Publication status | Published - 15 May 2019 |
Funding
J.C. Nolasco is indebted to the Alexander von Humboldt Foundation for providing the George Foster grant. A. Castro-Carranza acknowledges support from Universität Bremen/FP7-PEOPLE-2012 COFUND Marie-Curie Fellowship “BREMEN TRAC”, project no. 600411, and CONACYT Mexico. The authors also thank for the support obtained from the projects UNAM-PAPIIT IA 107517 and IA107417. J.C. Nolasco would also like to thank Dr. A Morales-Acevedo for his thoughtful discussion to make some ideas clear for this work. Appendix A
| Funders | Funder number |
|---|---|
| Alexander von Humboldt-Stiftung | |
| Seventh Framework Programme | 600411 |
Keywords
- Band bending
- Open circuit voltage
- Organic heterojunction
