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Potential-Induced Degradation in Perovskite Devices: From Novel Stress Testing to Effective Avoidance
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Potential-Induced Degradation in Perovskite Devices: From Novel Stress Testing to Effective Avoidance
No full textNot availabl
GABA, Glx, and GSH in the cerebellum: their role in motor performance and learning across age groups
No full textIntroduction The cerebellum is essential for motor control and learning, relying on structural and functional integrity. Age-related atrophy leads to Purkinje cell loss, but subtle neurochemical changes in GABA, Glx (glutamate + glutamine), and glutathione (GSH) may precede degeneration and contribute to motor decline.Methods 25 younger (YA) and 25 older adults (OA) were included in this study. Magnetic resonance spectroscopy (MRS), using the MEGA-PRESS sequence, was used to investigate how age affects GABA, Glx and GSH levels in the right cerebellar hemisphere, and their relationship with motor performance, measured using a visuomotor bimanual tracking task (BTT).Results In line with previous work YA outperformed OA on both the simple and complex task variants of the BTT. Furthermore, YA demonstrated faster short-term motor learning as compared to OA. On the metabolic level, no significant age group differences in cerebellar GABA, Glx or GSH levels, nor any task-related modulation of GABA or Glx were observed. Additionally, neither baseline neurometabolite levels nor their modulation predicted motor performance or learning.Discussion These results align with previous research suggesting that neurometabolic aging is region-specific, with the cerebellum potentially being more resilient due to its slower aging process. Since neither baseline nor task-related modulation of GABA, Glx, or GSH predicted motor performance or learning, cerebellar neurometabolite concentrations may not directly underlie age-related behavioral changes. Instead, volumetric decline and changes in structural and functional connectivity in the aging cerebellum may play a more significant role in motor decline as compared to neurochemical alterations. Nonetheless, it is important to consider that motor performance and learning rely on distributed brain networks-including cortical and subcortical structures-which also undergo age-related changes and may contribute to observed behavioral declines. While our findings do not support a direct role of cerebellar neurometabolite levels in age-related motor performance differences, they underscore the complexity of neurochemical aging.The author(s) declare that financial support was received for the research and/or publication of this article. This work was supported by the Research Foundation Flanders grant (G039821N). SVM (11L9322N), MH (11F6921N), and RB (1SD8323N) were funded by a grant from the Research Foundation Flanders. SVM (BOF21INCENT15) was supported by the UHasselt Special Research Fund grant. MH was supported by the KU Leuven Special Research
Fund (PDMT2/24/077)
On The Susceptibility of PID in Perovskite Modules: A Comparison of ITO and Cu Contacts
No full textOrganic-inorganic perovskite lead halide solar cells (PSCs) have received increasing interest in the last decade. PSCs already achieve record efficiencies above 25%. However, long-term stability is still a problem, especially when transitioning from cells to modules.
One of the described long-term stability problems at the module level is Potential-induced degradation (PID), caused by the voltage build-up by modules connected in series.
PID is extensively investigated within crystalline silicon PV, while very little is known for perovskites. Carolus et al. reported nearly complete efficiency losses within 18 hours of a PID stress test, indicating their high susceptibility to PID[1]. In order to tackle PID-related stability issues and make commercialization a reality, it is crucial to retrieve insights into the physics of the PID mechanism.
This study investigates and compares the PID mechanism within p-i-n CsFAPbIBr perovskite modules with either a copper (Cu) or an indium tin oxide (ITO) rear contact. Several soda-lime glass-glass configured 5.5 x 5.5 cm² mini-modules were PID stressed from the p-side at 40⁰C and 1000 V for 192 hours using the foil method. Intermediate current-voltage measurements (IV) and electroluminescence (EL) images were taken to investigate the PID progress.
The ITO contacted perovskite modules illustrate an incubation period of about 100 hours. A slight drop in short-circuit current (Isc) and a modest increase in series resistance can be observed within this incubation period.
Subsequently, a significant drop in Isc and increase in series resistance are noticeable. Evidently, after 192 hours, an additional decrease in shunt resistance is noticeable, resulting in a total relative loss of efficiency of almost 80%. The EL images illustrate no significant differences in the incubation period, although the formation of inhomogeneities can be observed further in the degradation process[2].
The Cu-contacted perovskite modules are significantly more prone to PID than their ITO counterpart. Similarly, the drop in Isc and increase in series resistance can be observed; however, no incubation period is present.
Analogous to crystalline silicon, it is hypothesized that positively charged sodium ions migrate out of the cover glass towards the PV cell. Hence, the ions can alter the conductivity of the contacts or migrate deeper into the stack and form inhomogeneities in the perovskite material[3]. However, additional PID stress tests are ongoing to validate the hypothesized findings. Furthermore, microstructural analysis is necessary to designate this degradation mechanism's root cause and retrieve more insights into its physical behavior and kinetics
PET-based perovskite solar cells to avoid potential-induced degradation
No full textInterest in perovskite solar cells (PSCs) has grown, with advances in stability and scalability for commercialization. However, in real-world conditions, PSCs can encounter potential-induced degradation (PID), primarily due to sodium ion (Na+) migration from conventional soda-lime glass (SLG) substrates. This study investigates whether PID can be completely avoided using Na+-free substrates such as polyethylene terephthalate (PET). PET and SLG-based PSCs were subjected to -1000 V PID stress. The test was conducted in an inert environment to exclude other degradation factors. After 300 h, PET-based PSCs demonstrated only a 0.11% efficiency loss, staying well below the 5% stability threshold, compared to a 15% loss in SLG-based PSCs. The results confirm that using Na+-free substrates effectively prevents PID, and that Na+ migration is the primary cause of degradation during PID stress. These findings support further research to develop PID-resistant PSCs.This work was supported by “Fonds Wetenschappelijk Onderzoek” and the FWO SB PhD fellowship funding under Project No. 1SD8323N. Furthermore, the authors would like to sincerely thank Shanti Van Malderen for her contributions and insightful guidance throughout this research
Mitigation of potential-induced degradation in perovskite solar cells using overnight voltage recovery
No full textPotential-induced degradation (PID) poses a critical threat to the long-term stability of perovskite solar cells (PSCs), driven by sodium ion (Na+) migration from soda-lime glass substrates to the active layer. This study examines the effect of periodically interspersing PID stress with overnight voltage recovery or shelf storage on 48 PSCs during a 500-h experimental protocol comprising 150 h of accumulated PID stress and 350 h of accumulated recovery or storage. Overnight shelf-stored devices degraded to 79% normalized efficiency, while those subjected to overnight voltage recovery maintained 94 percent. These results highlight overnight voltage recovery as an effective PID mitigation strategy, preserving PSC performance and advancing their stability for practical applications.Funding
This work was supported by “Fonds Wetenschappelijk Onderzoek” and the FWO SB PhD fellowship funding under Project No. 1SD8323N.
Acknowledgments
The authors gratefully acknowledge “Fonds Wetenschappelijk Onderzoek” and the FWO SB PhD fellowship funding under Project No. 1SD8323N
On The Susceptibility of PID in Perovskite Modules: A Comparison of ITO and Cu Contacts
No full textOrganic-inorganic perovskite lead halide solar cells (PSCs) have received increasing interest in the last decade. PSCs already achieve record efficiencies above 25%. However, long-term stability is still a problem, especially when transitioning from cells to modules.
One of the described long-term stability problems at the module level is Potential-induced degradation (PID), caused by the voltage build-up by modules connected in series.
PID is extensively investigated within crystalline silicon PV, while very little is known for perovskites. Carolus et al. reported nearly complete efficiency losses within 18 hours of a PID stress test, indicating their high susceptibility to PID[1]. In order to tackle PID-related stability issues and make commercialization a reality, it is crucial to retrieve insights into the physics of the PID mechanism.
This study investigates and compares the PID mechanism within p-i-n CsFAPbIBr perovskite modules with either a copper (Cu) or an indium tin oxide (ITO) rear contact. Several soda-lime glass-glass configured 5.5 x 5.5 cm² mini-modules were PID stressed from the p-side at 40⁰C and 1000 V for 192 hours using the foil method. Intermediate current-voltage measurements (IV) and electroluminescence (EL) images were taken to investigate the PID progress.
The ITO contacted perovskite modules illustrate an incubation period of about 100 hours. A slight drop in short-circuit current (Isc) and a modest increase in series resistance can be observed within this incubation period.
Subsequently, a significant drop in Isc and increase in series resistance are noticeable. Evidently, after 192 hours, an additional decrease in shunt resistance is noticeable, resulting in a total relative loss of efficiency of almost 80%. The EL images illustrate no significant differences in the incubation period, although the formation of inhomogeneities can be observed further in the degradation process[2].
The Cu-contacted perovskite modules are significantly more prone to PID than their ITO counterpart. Similarly, the drop in Isc and increase in series resistance can be observed; however, no incubation period is present.
Analogous to crystalline silicon, it is hypothesized that positively charged sodium ions migrate out of the cover glass towards the PV cell. Hence, the ions can alter the conductivity of the contacts or migrate deeper into the stack and form inhomogeneities in the perovskite material[3]. However, additional PID stress tests are ongoing to validate the hypothesized findings. Furthermore, microstructural analysis is necessary to designate this degradation mechanism's root cause and retrieve more insights into its physical behavior and kinetics
Method to Study Potential-Induced Degradation of Perovskite Solar Cells and Modules in an Inert Environment
No full textThe efficiency of perovskite solar cells (PSCs) is advancing rapidly, yet their sensitivity to ambient conditions poses challenges. An additional degradation mechanism, potential-induced degradation (PID), can emerge during field operation, but the understanding of PID within perovskite devices is limited. To exclude environmental stressors, this study is conducted in an inert environment at room temperature. PSCs and mini-modules are subjected to a 324 h PID stress test at −1000 V, revealing relative efficiency losses of around 29% and 24% for the PSCs and mini-modules, respectively, exposing subtle degradation differences. These degradation rates are notably lower than reported in the literature, suggesting possible additional degradation pathways arising from suboptimal encapsulation combined with ambient conditions. Subsequently, half of the stressed samples are subject to +1000 V for 523 h and recover to a reduced efficiency loss of 15% and 7.7% for the PSCs and module, respectively. In contrast, storing the stressed samples on the shelf increased the efficiency losses to 32% (PSCs) and 41% (module). Therefore, the post-PID rates differ significantly between both groups, whereas both effects of voltage recovery and progressed degradation are more pronounced in modules compared to cells. This study contributes to a robust method for PID research.The authors gratefully acknowledge “Fonds Wetenschappelijk Onderzoek”and the FWO SB PhD fellowship funding under project no. 1SD8323
Investigation of Potential-Induced Degradation in Perovskite Solar Cells under Inert Conditions
No full textPerovskite solar cells (PSCs) have emerged as a promising photovoltaic technology due to their remarkable efficiency advancements. However, their commercialization is hindered by stability challenges, including sensitivity to environmental conditions and a critical degradation mechanism known as potential-induced degradation (PID). PID can significantly impair PSC performance within hours under operational conditions. This study investigates PID in 48 triple-cation p-i-n PSCs over 313 h in an inert environment, excluding additional stressors like moisture and oxygen. The PID-stressed devices degraded to 79% of their initial efficiency, primarily driven by losses in short-circuit current density. Time-of-flight secondary ion mass spectroscopy revealed sodium ion migration from soda-lime glass substrates into the perovskite layer. Interestingly, photoluminescence and X-ray diffraction analyses detected no measurable differences between PID-stressed and reference devices, contradicting prior literature that associates PID with perovskite segregation and decomposition. These findings challenge the conventional understanding of PID, suggesting that environmental factors such as oxygen and moisture might exacerbate degradation effects. This work provides critical insights into the intrinsic mechanisms of PID under controlled conditions and highlights the need for further research into the interplay between PID and environmental stressors to guide the development of more stable PSC technologies.The authors gratefully acknowledge the support of the “Fonds Wetenschappelijk Onderzoek” (FWO) and the FWO SB PhD fellowship under project number 1SD8323N. Special thanks are extended to Irene Dei Tos from Hasselt University for performing the XRD analysis and to Alexis Franquet from imec for conducting the ToF-SIMS measurements
Potential-induced degradation of the shunting type: on the origin of sodium in shunt paths
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