Lai, H.; Luo, J.; Zwirner, Y.; Olthof, S.; Wieczorek, A.; Ye, F.; Jeangros, Q.; Yin, X.; Akhundova, F.; Ma, T.; He, R.; Kothandaraman, R.K.; Chin, X.; Gilshtein, E.; Müller, A.; Wang, C.; Thiesbrummel, J.; Siol, S.; Prieto, J.M.; Unold, T.; Stolterfoht, M.; Chen, C.; Tiwari, A.N.; Zhao, D.; Fu, F.: High-Performance Flexible All-Perovskite Tandem Solar Cells with Reduced Voc-Deficit in Wide-Bandgap Subcell. Advanced Energy Materials 12 (2022), p. 2108132/1-12
10.1002/aenm.202202438
Open Access Version
Abstract:
Among various types of perovskite-based tandem solar cells (TSCs), all-perovskite TSCs are of particular attractiveness for building- and vehicle-integrated photovoltaics, or space energy areas as they can be fabricated on flexible and lightweight substrates with a very high power-to-weight ratio. However, the efficiency of flexible all-perovskite tandems is lagging far behind their rigid counterparts primarily due to the challenges in developing efficient wide-bandgap (WBG) perovskite solar cells on the flexible substrates as well as their low open-circuit voltage (VOC). Here, it is reported that the use of self-assembled monolayers as hole-selective contact effectively suppresses the interfacial recombination and allows the subsequent uniform growth of a 1.77 eV WBG perovskite with superior optoelectronic quality. In addition, a postdeposition treatment with 2-thiopheneethylammonium chloride is employed to further suppress the bulk and interfacial recombination, boosting the VOC of the WBG top cell to 1.29 V. Based on this, the first proof-of-concept four-terminal all-perovskite flexible TSC with a power conversion efficiency of 22.6% is presented. When integrating into two-terminal flexible tandems, 23.8% flexible all-perovskite TSCs with a superior VOC of 2.1 V is achieved, which is on par with the VOC reported on the 28% all-perovskite tandems grown on the rigid substrate.