Understanding and preventing degradation in organic photovoltaics
- Organic photovoltaics (OPVs) are an emerging photovoltaic technology with the potential for low-cost, high-throughput processing. The record laboratory efficiency for these solar cells are now at 9.2% which is approximately half of the efficiency of a traditional rooftop solar module; however, the stability of OPV needs to also reach a lifetime comparable to a 25-year traditional rooftop solar module to be competitive. Here I present the three major modes of degradation in OPV power conversion efficiency for solar cells tested at one-sun illumination in a controlled atmosphere. The first mode is a photo-induced burn-in that occurs in the first few hundred hours of operation and decreases efficiency by ~25%. This burn-in can be avoided by creating a highly aggregated blend of the polymer electron donor material and fullerene electron acceptor material. The second mode is thermal degradation that occurs above the Tg of the material. In the first portion of thermal degradation, the polymer donor material adheres to the top electrode and degrades performance by blocking the transport of electrons. This degradation can be mitigated by making the top electrode the electron withdrawing electrode. The last mode of degradation is long-term degradation and appears to be related to the amount of oxygen that the OPV device is exposed to. The three modes of degradation are shown to be general for several OPV material sets. Lastly, the talk will present rules for highly stable OPV devices and by following these rules we can produce OPVs with a lifetime in excess of 15 years and OPVs with less than half of the typical burn-in.
|Type of resource
|electronic; electronic resource; remote
|1 online resource.
|Sachs-Quintana, Isaac Tobias
|Stanford University, Department of Materials Science and Engineering.
|Statement of responsibility
|Isaac Tobias Sachs-Quintana.
|Submitted to the Department of Materials Science and Engineering.
|Thesis (Ph.D.)--Stanford University, 2014.
- © 2014 by Isaac Tobias Sachs-Quintana
- This work is licensed under a Creative Commons Attribution Non Commercial 3.0 Unported license (CC BY-NC).
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