| Pacific Rim Symposium on Surfaces, Coatings and Interfaces (PacSurf 2016) | |
| Energy Harvesting & Storage | Wednesday Sessions |
| Session EH-WeP |
| Session: | Energy Harvesting & Storage Poster Session |
| Presenter: | Philip Schulz, NREL, USA |
| Authors: | P. Schulz, NREL, USA M. Yang, NREL, USA R. Ihly, NREL, USA K. Zhu, NREL, USA J.L. Blackburn, NREL, USA J.J. Berry, NREL, USA |
| Correspondent: | Click to Email |
The ongoing development of hybrid organic inorganic perovskite photovoltaics has revealed that the numerous interfaces in perovskite solar cells (PSC) play crucial roles for device efficiency and stability. Importantly, many critical interfacial properties are still poorly understood, a deficiency that often limits efforts to improve device performance. Carbon nanotubes have been identified as viable transport layer components in high efficient PSC with enhanced cell characteristics. In this talk I will present our most recent results exploring the mechanisms by which carbon nanotubes enable advantageous charge carrier extraction from the absorber layer and how carbon nanotube interlayers can ideally be embedded in the device geometry.
First, we demonstrated in a detailed photoemission spectroscopy study of semiconducting single-walled carbon nanotubes (s-SWCNT) on top of methlyammonium lead iodide (MAPbI3) absorber films that the formation of an interfacial dipole leads to beneficial band bending in the s-SWCNT film. This observed alignment allows for rapid hole extraction at this interface from the absorber onto the s-SWCNT transport layer as seen from the clear spectroscopic signatures of both phases (MAPbI3 and s-SWCNT) in transient absorption spectroscopy.1 Subsequently, we were able to show that this enhanced hole extraction process impacts the kinetics of charge transfer at multiple interfaces within the device stack by unambiguously tracking charge carrier dynamics with a combination of time resolved photoluminescence, transient absorbance and time resolve microwave conductivity measurements.2 Eventually, we showed that integrating a thin s-SWCNT interlayer between the MAPbI3 absorber and a conventional organic hole transport layer leads to a significant improvement of device characteristics and cell performance. In my outlook I will sketch how the ensemble of these studies opens up an avenue to tailor-made charge carrier extraction interlayers for the next generation of transport layers in PSC.
[1] P. Schulz, Anne-Marie Dowgiallo, Mengjin Yang, Kai Zhu, Jeffrey L. Blackburn, Joseph J. Berry. J. Phys. Chem. Lett.2016, 7, 418–425
[2] R. Ihly, Anne-Marie Dowgiallo, Mengjin Yang, Philip Schulz, Noah Stanton, Obadiah G. Reid, Andrew. J. Ferguson, Kai Zhu, Joseph J. Berry, Jeffrey L. Blackburn. Energy & Environ. Sci.2016, 9, 1439–1449