In the study of structure–property relationships for rational materials design, hollow multishell structures (HoMSs) have attracted tremendous attention owing to the optimal balance between mass transfer and surface exposure. Considering the shell structure can significantly affect the properties of HoMSs, in this paper, we provide a novel one‐step strategy to continually regulate the shell structures of HoMSs. Through a simple phosphorization process, we can effectively modify the shell from solid to bubble‐like and even duplicate the shells with a narrow spacing. Benefitting from the structure merits, the fabricated CoP HoMSs with close duplicated shells can promote gas release owing to the unbalanced Laplace pressure, while accelerating liquid transfer for enhanced capillary force. It can provide effective channels for water and gas and thus exhibits a superior electrocatalytic performance in the hydrogen and oxygen evolution reaction.

Overcoming the issue of the stability of tin‐based perovskites is a major challenge for the commercial development of lead‐free perovskite solar cells. To attack this problem, a new organic cation, azetidinium (AZ), is incorporated into the crystal structure of formamidinium tin triiodide (FASnI3) to form the mixed‐cation perovskite AZxFA1‐xSnI3. As AZ has a similar size to FA but a larger dipole moment, hybrid AZxFA1‐xSnI3 films exhibit variation in optical and electronic properties on increasing the proportion of AZ. Trifluoromethylbenzene (CF3C6H5) serves as antisolvent to fabricate smooth and uniform perovskite films for the devices with an inverted planar heterojunction structure. The device performance is optimized to produce the greatest efficiency at x=0.15 (AZ15), for which a power conversion efficiency of 9.6 % is obtained when the unencapsulated AZ15 device is stored in air for 100 h. Moreover, the device retains 90 % of its initial efficiency for over 15 days. The significant performance and stability of this device reveal that the concept of mixed cations is a promising approach to stabilize tin‐based perovskite solar cells for future commercialization.

We report a facile BiBr3(DMSO)2 adduct process to produce high-quality Cs2AgBiBr6 films with large grains for the first time, which leads to an enhancement of over 40% on the PCE of Cs2AgBiBr6-based solar cells compared to that of the control sample.

In the study of structure–property relationships for rational materials design, hollow multishell structures (HoMSs) have attracted tremendous attention owing to the optimal balance between mass transfer and surface exposure. Considering the shell structure can significantly affect the properties of HoMSs, in this paper, we provide a novel one‐step strategy to continually regulate the shell structures of HoMSs. Through a simple phosphorization process, we can effectively modify the shell from solid to bubble‐like and even duplicate the shells with a narrow spacing. Benefitting from the structure merits, the fabricated CoP HoMSs with close duplicated shells can promote gas release owing to the unbalanced Laplace pressure, while accelerating liquid transfer for enhanced capillary force. It can provide effective channels for water and gas and thus exhibits a superior electrocatalytic performance in the hydrogen and oxygen evolution reaction.