Just as biological synapses provide basic functions for the nervous system, artificial synaptic devices serve as the fundamental building blocks of neuromorphic networks; thus, developing novel artificial synapses is essential for neuromorphic computing. By exploiting the band alignment between 2D inorganic and organic semiconductors, the first multi-functional synaptic transistor based on a molybdenum disulfide (MoS 2 )/perylene-3,4,9,10-tetracarboxylic dianhydride (PTCDA) hybrid heterojunction, with remarkable short-term plasticity (STP) and longterm plasticity (LTP), is reported. Owing to the elaborate design of the energy band structure, both robust electrical and optical modulation are achieved through carriers transfer at the interface of the heterostructure, which is still a challenging task to this day. In electrical modulation, synaptic inhibition and excitation can be achieved simultaneously in the same device by gate voltage tuning. Notably, a minimum inhibition of 3% and maximum facilitation of 500% can be obtained by increasing the electrical number, and the response to different frequency signals indicates a dynamic filtering characteristic. It exhibits flexible tunability of both STP and LTP and synaptic weight changes of up to 60, far superior to previous work in optical modulation. The fully 2D MoS 2 /PTCDA hybrid heterojunction artificial synapse opens up a whole new path for the urgent need for neuromorphic computation devices.

Two flexible and colorless polymers are synthesized based on a phosphorus-containing derivative of a bio-based aromatic aldehyde (4-hydroxybenzaldehyde) by a thiol-ene reaction. Thanks to the high polarizability of phosphorus and sulfur atoms, two polymers display refractive index (n) values of 1.721 and 1.698 at 546 nm, respectively. These data are much higher than those of polyphosphonates (below 1.65) and are comparable to those of polyphosphazenes with undesirable halogens (1.664–1.755). Moreover, both the polymers (TVP-TH1 and TVP-TH2) exhibit a transmittance of above 88% in the wavelength range from 550 to 2000 nm and a transmittance of about 0% in the UV region, indicating their potential application as transparent coatings for hindering the ultraviolet ray and infrared transmitting materials. In particular, these phosphorous-sulfide polymers display good thermostability with a glass transition temperature (T g) of above 130 °C and 5% weight loss temperature (T 5d) of over 310 °C. These results imply that new phosphorous-sulfide polymers are very suitable as encapsulation resins for light-emitting diodes (LEDs) and optical materials and as antireflective coatings and microlenses for the image sensors of complementary metal oxide semiconductors (CMOSs).

Siloxane-based polymer films obtained by the sol−gel process are often porous and exhibit low refractive indices. To address this issue, we have prepared two intrinsic high refractive index siloxane− sulfide polymer networks via the Piers−Rubinsztajn reaction and thiol− ene click chemistry based on readily available tetraethoxysilane (TEOS). Our siloxane−sulfide polymers consisting of aromatic groups and sulfur display enhanced thermostability with high T g (>120 °C) and T 5d (>320 °C) as compared to related materials. Such good thermal properties significantly expand their application as high thermostable optical materials. Besides, both flexible and colorless polymer films P1 and P2 exhibit high refractive indices of 1.625 and 1.665 at 546 nm, respectively. P2 also shows high refractive index of 1.648 at 1000 nm. Moreover, both siloxane−sulfide polymer films are uniform and homogeneous with high optical transmittance of 90% for wavelength ranging from 400 to 2000 nm. These data indicate that the new siloxane−sulfide polymers have potential application as optical materials such as antireflective coatings, encapsulation resin for the fabrication of LED, and the infrared transmitting materials.

Perfluorocyclobutyl (PFCB)-based polymers exhibit attractive properties, including good thermal and chemical stability, high hydrophobicity and transparency, as well as good insulating properties.