At present, there have been some reports on the application of metal phase selenide (1T-MSe 2 ) in the field of energy storage. In this manuscript, a stable Sn-doped metal phase tungsten selenide (1T-WSe 2 -Sn) was elaborately fabricated in situ by a simple calcination technique. N-doping was introduced by employing chitosan as precursor and nanoreactor, the Sn-doping induces 1T phase of WSe 2 and enlarges the layer space to promote the electron/ion transport and structural stability. The optimized 1T-WSe 2 -Sn electrode delivers prominent cycling lifespan (285 mAh·g −1 at 1.0 A·g −1 after 900 cycles) along with decent rate capability when applied as an anode of sodium ion batteries (SIBs). The specific capacity was determined to be of 460 mAh·g −1 at 0.1 A·g −1 after 100 cycles. It also displays superior capacity of 183 mAh·g −1 at 0.5 A·g −1 for 200 cycles when paired with Na 3 V 2 (PO 4 ) 3 cathode. Applied as the anode for potassium ion batteries (PIBs), it exhibits a satisfactory specific capacity of 345 mAh·g −1 at 0.1 A·g −1 after 50 cycles. Graphical abstract
The development of highly efficient room-temperature ammonia (NH 3 ) sensors is crucial for industrial production and environmental monitoring. However, existing materials generally face critical challenges, including insufficient sensitivity, humidity susceptibility, and limited charge-transfer efficiency. In this study, a synergistic strategy combining electronic structure modulation with heterointerface engineering was employed to fabricate a 2D/1D heterojunction sensing material composed of S-doped WSe 2 @polyaniline (PANI). The electronic band structure was optimized by substituting S atoms into Se sites within the WSe 2 lattice, and in situ oxidative polymerization was used to achieve vertical growth of PANI nanorods on the surface of S-WSe 2 , which significantly enhanced the gas-sensing performance of the composite. The S-WSe 2 @PANI sensor exhibited a remarkable response of 505.75 % to 100 ppm NH 3 at 25 °C and 45 % relative humidity (RH), representing 7.44-fold and 5.32-fold increases compared with pure WSe 2 and PANI sensors, respectively. The sensor also demonstrated an ultra-low theoretical detection limit of 170.31 ppb and excellent moisture resistance (with a response of 857.63 % to 100 ppm NH 3 at 80 % RH). Density functional theory (DFT) calculations revealed that the S-WSe 2 @PANI heterostructure possessed stronger NH 3 adsorption capability, while the work-function difference at the PANI/S-WSe 2 interface effectively promoted charge transfer. This study integrates electronic structure regulation and morphological synergy design strategies to establish an innovative paradigm for high-performance room-temperature NH 3 sensors with substantial potential for application in complex environmental monitoring scenarios.
Metal–semiconductor contacts are crucial components in semiconductor devices. Ultrathin two-dimensional transition-metal dichalcogenide semiconductors can sustain transistor scaling for next-generation integrated circuits. However, their performance is often degraded by conventional metal deposition, which results in a high barrier due to chemical disorder and Fermi-level pinning (FLP). Although, transferring electrodes can address these issues, they are limited in achieving universal transfer of full-class metals due to strong adhesion between pre-deposited metals and substrates. Here, we propose a nanobelt-assisted transfer strategy that can avoid the adhesion limitation and enables the universal transfer of over 20 different types of electrodes. Our contacts obey the Schottky–Mott rule and exhibit a FLP of S = 0.99. Both the electron and hole contacts show record-low Schottky barriers of 4.2 and 11.2 meV, respectively. As a demonstration, we construct a doping-free WSe 2 inverter with these high-performance contacts, which exhibits a static power consumption of only 58 pW. This strategy provides a universal method of electrode preparation for building high-performance post-Moore electronic devices.
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