Proceedings of Asia-Pacific International Conference on Perovskite, Organic Photovoltaics and Optoelectronics (IPEROP23)
DOI: https://doi.org/10.29363/nanoge.iperop.2023.023
Publication date: 21st November 2022
Perovskite solar cells (PSCs) are suitable candidates as sub cells for tandem solar cell technologies thanks to their bandgap tunability and high efficiency. For an all-thin film tandem solar cell, high-bandgap PSCs can be matched with low-bandgap CIGS. State-of-the-art high-bandgap PSCs last for thousands of hours at standard operating conditions[1], but the required operational stability for the commercialization of such applications is more than 20 years. Therefore, there is the need to optimize the devices for stability under accelerated ageing conditions.
In this study, we tested encapsulated perovskite solar cells of various compositions with bandgaps higher than 1.6eV and an efficiency of up to 20%. The stressing experiments were carried out at different temperatures from 25°C up to 85°C at MPP conditions in air with 1-sun equivalent illumination intensity (ISOS-L1 conditions) using the benchtop instrument Litos. Additionally, by performing in-situ JV scans every 60 minutes, we could follow the evolution of the PV parameters in parallel with stressing. The MPP decay can be fitted with a bi-exponential function, where the first exponent is attributed to a burn-in effect from which the burn-in time is derived. This allows to determine the effective operative lifetime of the device. The decay of the MPP correlates with the short-circuit current decay, thus indicating the development of charge generation and collection issues with ageing. We performed additional characterization techniques before and after the stressing experiments using the Paios measurement platform to gain further insight into the degradation mechanisms. The aged devices present slower current rise and decay dynamics as observed in transient photocurrent (TPC) compared to the pristine devices confirming the appearance of charge transport issues. Following the optimization of the device stability on glass substrates, the ageing tests will be performed for PSCs deposited on flexible substrate.
References:
[1] X. Zhao et al., “Accelerated aging of all-inorganic, interface-stabilized perovskite solar cells,” Science, vol. 377, no. 6603, pp. 307–310, Jul. 2022, doi: 10.1126/science.abn5679.