Designing Contact Layers and Surface Treatments to Overcome Performance Challenges for Perovskite Tandems
Rebecca Belisle a, James Raiford b, Kevin Bush c, Luca Bertoluzzi c, Aryeh Gold-Parker d f, Axel Palmstrom b, Rohit Prasanna e, Michael Toney f, Stacey Bent b, Michael McGehee e
a Department of Physics, Wellesley College
b Department of Chemical Engineering, Stanford University
c Department of Materials Science and Engineering, Stanford University, 476 Lomita Mall, McCullough Building, Stanford, United States
d Department of Chemistry, Stanford University, Stanford, 94305, United States
e Department of Chemical and Biological Engineering, University of Colorado Boulder
f Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory Menlo Park, 94025, United States
Proceedings of International Conference on Hybrid and Organic Photovoltaics (HOPV19)
Roma, Italy, 2019 May 12th - 15th
Organizers: Prashant Kamat, Filippo De Angelis and Aldo Di Carlo
Oral, Rebecca Belisle, presentation 187
Publication date: 11th February 2019

Perovskite tandems have come to the fore as highly promising photovoltaic technologies. However, in order for these solar cells to reach their high-efficiency potential, some significant performance challenges must first be overcome. Namely, we must reduce the parasitic absorption in contact-layers that substantially reduces the short-circuit current of perovskite tandems, and we must understand and prevent the photo-induced phase segregation in high-bandgap perovskites that limits the open-circuit voltage of these devices. In this talk, we will share our results addressing these two challenges through the design and characterization of contact layers and surface treatments for perovskite tandems.

To mitigate losses in short-circuit current, we have developed a novel hole transport bilayer for improved photocurrent and stability in N-I-P architecture perovskite solar cells for 2-terminal tandems. By combining a thin, undoped organic small molecule and a novel air-stable vanadium oxide buffer layer deposited via atomic layer deposition (ALD), we are able to fabricate stable semi-transparent perovskite solar cells with low parasitic absorption. This reduced absorption manifests in an 2.3 mA/cm2 increase in device photocurrent when compared to controls made with the spiro-OMeTAD, and creates a pathway towards higher efficiency perovskite tandems.

However, to fully realize the potential of perovskite tandems requires improvement in the photovoltage in addition to the photocurrent, and to address present limits we again look to improvements in contact materials and surface treatments.  By varying selective-contact materials and surface chemistry we demonstrate a substantial reduction in non-radiative recombination and suppression of photo-induced halide segregation. Based on these observations, we have developed a model of phase segregation linked to electron trapping at surface states, and in light of this model we suggest a pathway towards optically-stable high bandgap perovskites. Overall, this work highlights the importance of and opportunities for the development of novel contact and interfacial layers for high efficiency perovskite tandems.  

This research was supported by NSF EAGER Award Number 1664669, the U.S. Department of Energy (DOE) PVRD2 program under Award No. DE-EE0008154, the Swiss National Science Foundation “Postdoc Mobility” Fellowship Number P400P2_180780, NSF GRFP Award Number DGE-1147470, and the Hybrid Perovskite Solar Cell program of the National Center for Photovoltaics, funded by the U.S. Department of Energy Office of Energy Efficiency and Renewable Energy. Use of the Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, is supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences under Contract No. DE-AC02-76SF00515.

© Fundació Scito
We use our own and third party cookies for analysing and measuring usage of our website to improve our services. If you continue browsing, we consider accepting its use. You can check our Cookies Policy in which you will also find how to configure your web browser for the use of cookies. More info