Ferroelectric materials with reversible spontaneous polarization have been extensively investigated as active media for non-volatile memories. However, most of the ferroelectric materials known suffer from high internal resistances, large bandgap, and poor carrier transportation, which hindered their further applications.

The family of hybrid perovskite ferroelectrics combining polarization and semiconducting properties presents itself as a promising alternative. Particularly, taking the excellent semiconducting and fatigue-free potential into consideration, the researchers could expect that the layered hybrid perovskite ferroelectrics could reformate the field of photovoltaic non-volatile memories. 

In a study published in Angew. Chem. Int. Ed., the research team led by Prof. LUO Junhua and Dr. LIU Xitao from Fujian Institute of Research on the Structure of Matter (FJIRSM) of the Chinese Academy of Sciences (CAS) reported a fatigue-free layered hybrid perovskite ferroelectric, (C₆H₅CH₂NH₃)₂CsPb₂Br₇ (BCPB), which is demonstrated for exploration of photovoltaic non-volatile memories.

Through unit-transmutation from the fatigue-free bismuth-layered ferroelectrics, the researchers developed a novel 2D layered hybrid perovskite ferroelectric BCPB with ferroelectric properties including high Curie temperature of 425 K and fatigue-free spontaneous polarization (P_s) of 6.5 μC/cm². Such superior ferroelectric features are reminiscent of an avenue to its bulk photovoltaic effects.

Furthermore, the unique structure of BCPB with self-regulated net electrical charged layers gives rise to a fatigue-free feature. As expected, BCPB displays excellent bulk photovoltaic effect (BPVE) properties with noticeable zero-bias photocurrent density (3.5 μA/cm²), and a high on/off switching ratio of current (over 3×10⁵), superior to those of the most active ferroelectric semiconductor BiFeO₃.

Particularly, the researchers found that the value of spontaneous polarization and zero-bias photocurrent show no significant attenuation after 10⁸ polarity switching cycles, promoting the potential applications of BCPB in photovoltaic non-volatile memories.

This study throws light on the explorations for fatigue-free semiconducting ferroelectrics and excavates their potentials in next-generation electronic devices.

A fatigue-free layered hybrid perovskite ferroelectric for the exploration of photovoltaic non-volatile memories (Image by Prof. LUO's group)