GeTe-based alloys have attracted considerable attention as promising mid-temperature thermoelectric materials owing to their excellent performance. In this study, a series of Ge_0.8-xMn_0.1Pb_0.1Bi_xTe alloys were synthesized by vacuum melting followed by hot-press sintering. The results demonstrate that Bi incorporation significantly enhances the Seebeck coefficient. With increasing Bi content, the crystal structure gradually evolves from a rhombohedral to a cubic phase. Simultaneously, Bi-induced lattice distortion intensifies phonon scattering, leading to a marked reduction in lattice thermal conductivity, while the electronic thermal conductivity also decreases as a result of reduced electrical conductivity. At 773 K, the total thermal conductivity of Ge_0.8-xMn_0.1Pb_0.1Bi_0.02Te reaches a low value of 1.34 W/(m·K). Consequently, the alloys exhibit enhanced thermoelectric figure of merit (Z_T) values in the low-to-mid temperature range while maintaining high Z_Tat elevated temperatures, yielding a high average thermoelectric figure of merit (Z_T,avg) of 0.80.

Potassium tantalate niobate (KTN)-based ferroelectric single crystals with a perovskite structure have been extensively studied over the past few decades due to their advantages such as high piezoelectric constants, high phase transition temperatures, and nontoxic chemical compositions. With a deeper understanding of crystal growth processes and post-growth treatments, researchers have improved crystal quality and continuously increased crystal sizes using the top-seeded solution growth method. Recent studies have reported a piezoelectric constant exceeding 505 pC/N and an electromechanical coupling factor of 0.75 for tetragonal KTN single crystals. A high unipolar strain of 0.32% was achieved under an electric field of 15 kV/cm. This paper systematically reviews the research progress of piezoelectric properties of KTN-based ferroelectric single crystals, encompassing their growth techniques and approaches for enhancing electromechanical properties, such as ion doping and domain structures. Key technical approaches such as domain engineering and those for reducing growth defects and enhancing electromechanical performance are discussed. In addition, the current research challenges are identified, and future development prospects are outlined.

Ferroelectric optoelectronic artificial synapses, as an emerging class of intelligent devices, are regarded as ideal candidates for constructing neuromorphic visual systems owing to their advantages, such as ultrafast read-write speed and ultra-low energy consumption. This Perspective systematically reviews recent research progress in ferroelectric optoelectronic artificial synaptic devices. First, the operating mechanisms of two types of devices—namely photoconductive and photovoltaic devices—and their simulation of basic synaptic functions are discussed. Subsequently, the applications of these devices in neuromorphic visual systems are reviewed, including the simulation of learning and memory functions in biological visual systems, image information preprocessing and recognition, the detection and processing of dynamic visual information, and applications in multimodal interaction systems. Finally, the main challenges in the development of this class of devices are summarized from the perspectives of material preparation, device fabrication processes, and system architecture, and future development prospects are also presented. This Perspective not only provides a structured knowledge framework for experts in the field but also offers valuable reference information and directional guidance for advancing the development of novel low-power intelligent visual hardware.