Maximum Stability Point Tracking for Wide Bandgap Perovskite Solar Cells

Tandem approaches using wide bandgap (WBG) perovskite is of strong appeal as a way to overcome the Shockley-Queisser limit of single-junction device since the WBG perovskite can be employed as top cells in perovskite/Si or perovskite/perovskite stacks. The WBG perovskites are typically mixed I/Br halide perovskite but with considerable bromide anions for sufficient bandgap widening. However, this may be subjected to phase segregation issues that can be easily induced by light illumination under electrical biasing [1, 2]. This, therefore, negatively affects the long-term operational stability of tandem devices.
To address such issues happening in WBG perovskite-based devices, we develop a novel approach termed maximum stability point tracking (MSPT), which is a further advanced power-harvesting technique from pulsatile therapy reported by our group in 2022 [3, 4]. The new technique optimizes the operating voltage and power-harvesting conditions depending on device status by monitoring series resistance (R_s), degradation rate constants (α), and trap density (N_t), leading to more than 10% gain of total harvested energy owing to greatly improved operational stability. Suppression of phase segregation in MSPT is clearly observed as compared to standard MPPT, which has been experimentally confirmed using high resolution μ-PL mapping and deep-level capacitance profiling.
This work provides not only a comprehensive understanding of the interplay between operating conditions and degradation mechanisms in wide bandgap PSCs, but also a new power harvesting method to improve operational stability. This will help addressing a critical bottleneck in the commercialization of perovskite-based tandem solar cells.
------------------------------------------------------
[1] Ahn, N., Kwak, K., Jang, M. et al. Trapped charge-driven degradation of perovskite solar cells. Nat Commun 7, 13422 (2016). https://doi.org/10.1038/ncomms13422
[2] Byeon, J., Kim, J., Kim, J.-Y., Lee, G., Bang, K., Ahn, N., & Choi, M. Charge Transport Layer-Dependent Electronic Band Bending in Perovskite Solar Cells and Its Correlation to Light-Induced Device Degradation. ACS Energy Lett. 5(8), 2580–2589 (2020). https://doi.org/10.1021/acsenergylett.0c01022
[3] Jeong, K., Byeon, J., Jang, J. et al. Pulsatile therapy for perovskite solar cells. Joule 6, 1087–1102 (2022). https://doi.org/10.1016/j.joule.2022.04.007
[4] Ahn, N., Choi, M. Towards Long-Term Stable Perovskite Solar Cells: Degradation Mechanisms and stabilization Techniques. Adv. Sci. 11(4), 2306110 (2024). https://doi.org/10.1021/acsenergylett.0c01022