Improving interface quality for 1-cm² all-perovskite tandem solar cells

R He and WH Wang and ZJ Yi and F Lang and C Chen and JC Luo and JW Zhu and J Thiesbrummel and S Shah and K Wei and Y Luo and CL Wang and HG Lai and H Huang and J Zhou and BS Zou and XX Yin and SQ Ren and X Hao and LL Wu and JQ Zhang and JB Zhang and M Stolterfoht and F Fu and WH Tang and DW Zhao, NATURE, 618, 80-+ (2023).

DOI: 10.1038/s41586-023-05992-y

All-perovskite tandem solar cells provide high power conversion efficiency at a low cost(1-4). Rapid efficiency improvement in small- area (<0.1 cm(2)) tandem solar cells has been primarily driven by advances in low-bandgap (approximately 1.25 eV) perovskite bottom subcells(5-7). However, unsolved issues remain for wide-bandgap (> 1.75 eV) perovskite top subcells(8), which at present have large voltage and fill factor losses, particularly for large-area (>1 cm(2)) tandem solar cells. Here we develop a self-assembled monolayer of (4-(7H-dibenzoc,gcarbazol-7-yl)butyl)phosphonic acid as a hole- selective layer for wide-bandgap perovskite solar cells, which facilitates subsequent growth of high-quality wide-bandgap perovskite over a large area with suppressed interfacial non-radiative recombination, enabling efficient hole extraction. By integrating (4-(7H-dibenzoc,gcarbazol-7-yl)butyl)phosphonic acid in devices, we demonstrate a high open-circuit voltage (V-OC) of 1.31 V in a 1.77-eV perovskite solar cell, corresponding to a very low V-OC deficit of 0.46 V (with respect to the bandgap). With these wide-bandgap perovskite subcells, we report 27.0% (26.4% certified stabilized) monolithic all- perovskite tandem solar cells with an aperture area of 1.044 cm(2). The certified tandem cell shows an outstanding combination of a high V-OC of 2.12 V and a fill factor of 82.6%. Our demonstration of the large-area tandem solar cells with high certified efficiency is a key step towards scaling up all-perovskite tandem photovoltaic technology.

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