Influence of the interface material layers and semiconductor energetic disorder on the open circuit voltage in polymer solar cells. Issue 10 (21st February 2015)

• Record Type: Journal Article
• Authors: Zampetti, Andrea; Fallahpour, Amir Hossein; Dianetti, Martina; Salamandra, Luigi; Santoni, Francesco; Gagliardi, Alessio; Auf der Maur, Matthias; Brunetti, Francesca; Reale, Andrea; Brown, Thomas M.; Di Carlo, Aldo
• Is Part Of: Journal of polymer science. Volume 53:Issue 10(2015:May 15)
• Page Start: 690
• Page End: 699
• Publication Date: 2015-02-21
• Subjects: 547
• DOI: 10.1002/polb.23685
• Languages: English
• ISSNs: 0887-6266

Abstract

<abstract abstract-type="main"> <title>ABSTRACT</title> <p>Material layers at electrode/semiconductor interfaces are fundamental for the photovoltaic properties of polymer solar cells. The relationship between open‐circuit voltage (<bold><italic>V</italic><sub>OC</sub></bold>) and the work function (<bold><italic>φ</italic></bold>) of these interface layers is still a matter of debate. Simulations, together with experiments on over more than 20 cell architectures based on P3HT:PC<sub>60</sub>BM, enabled us to <bold>analyze</bold> the physical dependence of <italic>V</italic><sub>OC</sub> on <bold><italic>φ</italic></bold>. In particular, when the work function of the contacts is well inside the gap we observe that performance depends strongly on even small variations of <bold><italic>φ</italic></bold>. On the other hand, when it approaches the energy levels of the semiconducting polymers, device operation becomes the most efficient and less sensitive to variations in <bold><italic>φ</italic></bold>. Furthermore, by varying the Gaussian density of states (DOS) of the active blend we were able to show that <bold><italic>V</italic><sub>OC</sub></bold> performance depends significantly also on the DOS. Our study based on the simultaneous variation of transport layers represents a promising method to optimize the design and performance of polymer solar cells. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. <bold>2015</bold>, <italic>53</italic>, 690–699</p> </abstract>