Ferro­electric materials have a variety of technological applications, as transducers, capacitors, sensors, etc. Great interest in molecular ferro­electrics has emerged because of their structural flexibility, tunability, and homochirality. However, the discoveries of molecular ferro­electrics are not abundant. The lack of chemical design is the main challenge in realizing new molecular ferro­electrics. Consequently, chemical design approaches, including the ideas of introducing quasi-spherical theory, homochirality, and H/F substitution, have been developed recently. Through these advanced methodologies, a wide range of ferro­electrics were successfully synthesized, changing the blind search into a targeted chemical design. In this Perspective, we aim to provide insight into the fundamental chemistry and physics of molecular ferro­electrics and propose the concept of “ferro­electro­chemistry”, concerned with the targeted design and performance optimization of molecular ferro­electrics from the chemical point of view. We start with the basic theories used in the modification of chemical structures for new molecular ferro­electrics, such as the quasi-spherical theory. After that, we focus on the fundamentals of homochirality from the perspective of chemistry and advantages of introducing a homochiral molecule within the scope of ferro­electrics. Further, we explore another design strategy, H/F substitution, as an analogue of the H/D isotope effect. The introduction of a F atom usually does not change the polar point group but may induce a minor structural disruption that enhances physical properties such as Curie temperature and spontaneous polarization. We hope our comprehensive studies on the targeted design and performance optimization strategies for molecular ferro­electrics may build up and enrich the content of ferro­electro­chemistry.

Spelling is an important application of brain-computer interfaces (BCIs). Previous BCI spellers were not suited for widespread use due to their low information transfer rate (ITR). In this study, we constructed a high-ITR BCI speller based on the steady-state visual evoked potential (SSVEP). A 45-target BCI speller was implemented with a frequency resolution of 0.2 Hz. A sampled sinusoidal stimulation method was used to present visual stimuli on a conventional LCD screen. The online results revealed that the proposed BCI speller had a good performance, reaching a high average accuracy (84.1% for 2 s stimulation time; 90.2% for 3 s stimulation time) and the corresponding high ITR (105 bits/min for 2 s stimulation time, 82 bits/min for 3 s stimulation time) during the low-frequency stimuli, while 88.7% and 61 bits/ min were achieved for a 4 s time window during the high-frequency stimuli.

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Schizophrenia is a severe mental disorder characterized by impaired perception, delusions, thought disorder, abnormal emotion regulation, altered motor function, and impaired drive. The default mode network (DMN), since it was first proposed in 2001, has become a central research theme in neuropsychiatric disorders, including schizophrenia. In this review, first we define the DMN and describe its functional activity, functional and anatomical connectivity, heritability, and inverse correlation with the task positive network. Second, we review empirical studies of the anatomical and functional DMN, and anti-correlation between DMN and the task positive network in schizophrenia. Finally, we review preliminary evidence about the relationship between antipsychotic medications and regulation of the DMN, review the role of DMN as a treatment biomarker for this disease, and consider the DMN effects of individualized therapies for schizophrenia.

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