Choi Hwa Seob, Li Shunning, Park In-Hyeok, Liew Weng Heng, Zhu Ziyu, Kwon Ki Chang, Wang Lin, Oh In-Hwan, Zheng Shisheng, Su Chenliang, Xu Qing-Hua, Yao Kui, Pan Feng, Loh Kian Ping
SZU-NUS Collaborative Innovation Center for Optoelectronic Science & Technology, International Collaborative Laboratory of 2D Materials for Optoelectronics Science and Technology of Ministry of Education, Institute of Microscale Optoelectronics, Shenzhen University, 518060, Shenzhen, P.R. China.
School of Advanced Materials, Peking University Shenzhen Graduate School, 518055, Shenzhen, P.R. China.
Nat Commun. 2022 Feb 10;13(1):794. doi: 10.1038/s41467-022-28314-8.
The miniaturization of ferroelectric devices in non-volatile memories requires the device to maintain stable switching behavior as the thickness scales down to nanometer scale, which requires the coercive field to be sufficiently large. Recently discovered metal-free perovskites exhibit advantages such as structural tunability and solution-processability, but they are disadvantaged by a lower coercive field compared to inorganic perovskites. Herein, we demonstrate that the coercive field (110 kV/cm) in metal-free ferroelectric perovskite MDABCO-NH-(PF) (MDABCO = N-methyl-N'-diazabicyclo[2.2.2]octonium) is one order larger than MDABCO-NH-I (12 kV/cm) owing to the stronger intermolecular hydrogen bonding in the former. Using isotope experiments, the ferroelectric-to-paraelectric phase transition temperature and coercive field are verified to be strongly influenced by hydrogen bonds. Our work highlights that the coercive field of organic ferroelectrics can be tailored by tuning the strength of hydrogen bonding.
非易失性存储器中铁电器件的小型化要求器件在厚度缩小至纳米尺度时仍能保持稳定的开关行为，这就需要矫顽场足够大。最近发现的无金属钙钛矿具有结构可调和溶液可加工性等优点，但与无机钙钛矿相比，其矫顽场较低。在此，我们证明无金属铁电钙钛矿MDABCO-NH-(PF)（MDABCO = N-甲基-N'-二氮杂双环[2.2.2]辛鎓）中的矫顽场（110 kV/cm）比MDABCO-NH-I（12 kV/cm）大一个数量级，这是由于前者中分子间氢键更强。通过同位素实验，验证了铁电-顺电相变温度和矫顽场受氢键的强烈影响。我们的工作强调，有机铁电体的矫顽场可以通过调节氢键强度来调整。
