Recycling Procedure of Perovskite Minimodules

As perovskite and perovskite-silicon tandem modules are already on the market, time is come to think about their recycling. For the year 2034 it is estimated that perovskite-silicon tandems will have 10% global market share[1] which will correspond to ~100 GW [2]. On one hand, perovskite and perovskite-silicon tandem modules contain critical materials[3] like indium in the transparent contact layers, cesium in the perovskite absorber layer or silver in the interconnection with electrically conductive adhesives (ECAs) in case for Perovskite-silicon tandem modules or they could contain silver in the back contact in case of perovskite single modules. On the other hand, approximately one third of the molecular weight of the perovskite absorber is lead. Regarding the whole module stack, the perovskite layer is only 300-600nm thick which corresponds to approximately 1 g Pb per m2 [4]. Lead is not critical in terms of abundance, but it is toxic and therefore landfill of perovskite modules must be strictly avoided to ensure that lead leakage to the environment and to the food chain is prevented.
The first publication about recycling of fully encapsulated perovskite modules was published by Chen et al. [5], but they used high temperature (250 °C). In our study, we developed an industrial-scale recycling process at 140-160°C for perovskite modules that allows >96% of the perovskite material to be recovered and reused in the manufacture of modules within the DBU funded project PeroCycle.
In addition, we could recover the indium containing TCO-coated glasses selectively and undamaged so that no intermixing with the encapsulation glass occurs and recoating after cleaning is possible. In recycling processes where solar modules are shredded, the glass fractions of substrate and encapsulation glass are mixed and crushed, resulting in downcycling. In contrast, in our study, the perovskite modules are thermo-mechanically separated in one piece, allowing the carrier glass to be reused after purification. This saves energy and material.
With our developed recycling procedure, mini-modules processed with recycled substrates and recycled PbI2 achieved >90% of the efficiency of minimodules made from fresh ITO substrates and fresh PbI2.

[1] International Technology Roadmap for Photovoltaics (ITRPV), 2023 Results, 15th Edition, May 2024.
[2] W. Hemetsberger, M. Schmela, S. Dunlop, SolarPower Europe (2024): Global Market Outlook for Solar Power 2024-2028, June 2024, ISBN: 9789464669169.
[3] Wagner et al., The resource demands of multi-terawatt-scale perovskite tandem photovoltaics, Joule (2024)
[4] Hailegnaw, B., et al., Rain on Methylammonium Lead Iodide Based Perovskites: Possible Environmental Effects of Perovskite Solar Cells. The Journal of Physical Chemistry Letters, 2015. 6(9): p. 1543-1547.
[5] B. Chen, C. Fei, S. Chen, H. Gu, X. Xiao, J. Huang, Recycling lead and transparent conductors from perovskite solar modules, Nat. Commun. 12 (1) (2021) 5859, https://doi.org/10.1038/s41467-021-26121-1.