Wide-Bandgap Perovskite and Perovskite/Silicon Tandem Solar Cells through Strong Hydrogen Bonding Interaction

Enhancing the crystallization quality of wide-bandgap perovskite film is vital to raise the open-circuit voltage (VOC) and performance of the device. Based on this, we present an approach involving the incorporation of 4-morpholino formamidine hydrochloride (MFC) as an additive in the antisolvent to facilitate crystal growth through the strong hydrogen bonding interactions and concurrently mitigate the deep-level defects. With this method, we can obtain increased grain size and achieve a transition toward a more n-type surface, which synergistically results in favorable carrier transport and reduced carrier recombination. Consequently, we were able to obtain an efficiency of 23.13% for 1.68 eV-inverted perovskite solar cells (PSCs) and 30.65% with a VOC of 1.951 V for the two-terminal perovskite/silicon tandem solar cells (TSCs) while maintaining long-term stability. This additive approach provides a fresh perspective in wide-bandgap PSCs and further pushes the development of perovskite/silicon TSCs.