Pathway for recovery of photo-degraded polymer solar cells by post degradation thermal anneal

Abstract

The photo-degradation of polymer solar cells is a critical challenge preventing its commercial deployment. We experimentally fabricate organic solar cells and characterize their degradation under solar simulators in an environmental chamber under nitrogen flow, without exposure to oxygen and moisture. We have developed a thermally stable inverted organic solar cell architecture in which light induced degradation of device characteristics can be reversibly annealed to the pristine values. The stable inverted cells utilized MoO x layers that are thermally treated immediately after their deposition on the organic layer, and before metal cathode deposition. Organic solar cells that are photo-degraded in the presence of oxygen, however show irreversible degradation that cannot be thermally recovered. The decrease of organic solar cell characteristics correlates with increases in mid-gap electronic states, measured using capacitance spectroscopy and dark current. It is likely the photo-induced defect states caused by local H motion from the alkyl chains to the aromatic backbone, can be reversibly annealed at elevated temperatures after photo-degradation. Our results provide a pathway for improving the stability of organic photovoltaics.

Thermal Activation of PEDOT:PSS/PM6:Y7 Based Films Leads to Unprecedent High Short‐Circuit Current Density in Nonfullerene Organic Photovoltaics

“…Where, the Pre-TT devices demonstrated higher energy by one order of magnitude than the pristine ones, reflecting less localized interfacial induced defects compared to the pristine devices. [24,102,107,109,110] This behavior was interestingly matched with the suppressing of recombination behavior in Figure 5 which explains the higher J SC obtained for the treated devices through the Pre-TT approach.…”

Effect of Additives and Annealing on the Performance of Nonfullerene‐Based Binary and Ternary Organic Photovoltaics

“…This behavior can be explained by Equation ( 3), assuming that this small shift of E O or higher DOS values might result from the decrease in the βN value, which means higher obtained energy because of less-localized shallow trap sites created due to the addition of 2% CN to the blend film. [75,81,82,84,85] The details regarding the calculation of the energy shifting values are explained in the Supplementary Information. By comparing the energy shift values of the 0% CN devices (A and C) and the 2% CN ones (B and D), as shown in Figure S9a,b, Supporting Information, we obtained that the 0% CN devices exhibited almost double trapping sites more than the 2% CN-treated ones.…”

Analysis of application status and development prospect of environmental chambers: A review

“…When studying the performance of batteries, especially automotive batteries, small environmental chambers are often used to simulate extreme environments. [108][109][110][111][112][113] The cooling performance, thermal insulation performance and startup performance in extreme environments are important indexes that could affect the safety and durability of batteries. Therefore, the application of environmental chamber to study the battery performance not only ensures the safety but also improves the utilization efficiency of resources.…”