Stretchable conductors are essential components of wearable electronics. However, such materials typically sacrifice their electronic conductivity to achieve mechanical stretchability and elasticity. Here, the nanoconfinement and air/water interfacial assembly is explored to grow freestanding mechanical endurance conducting polymer nanosheets that can be stretched up to 2000% with simultaneously high electrical conductivity, inspired by kirigami. Such stretchable conductors show remarkable electronic and mechanical reversibility and reproducibility under more than 1000 cycle durability tests with 2000% deformability, which can be accurately predicted using finite element modeling. The conductivity of nanoconfined freestanding conductor nanosheets increases by three orders of magnitude from 2.2 × 10 to 4.002 S cm is shown, due to the charge-transfer complex formation between polymer chain and halogen, while the electrical conductance of the stretchable kirigami nanosheets can be maintained over the entire strain regime. The nanoconfined polymer nanosheets can also act as a sensor capable of sensing the pressure with high durability and real-time monitoring.

Single-phase “greener” phosphor with broadband emission made of colloidal quantum dots (QDs) is most desirable for use as color convertors in white light-emitting diodes (WLEDs). Here, we demonstrate a single “cadmium-free” component system consisting of Cu-doped InP core/ZnS barrier/InP quantum well/ZnS shell QDs, which exhibits two emission peaks by controlling the barrier thickness under single-excitation wavelength, one of which being attributed to Cu-doped InP, and the other resulting from InP quantum well. The dual emissive peaks were successfully tuned in a range from visible to near-infrared by simple control of the core size and the well thickness, respectively. Using optimal structures as color converters, we successfully obtained WLED with a color rending index (CRI) up to 91 and CIE color coordinates of (0.338, 0.330) by combination with blue LED chip, indicating this single-phase phosphor with great promise for use in solid-state lighting due to flexibly tunable dual emission peak position in the entire visible region.

Although layered transition metal dichalcogenide (TMD) nanosheets have attracted great attention due to their unique properties, it still remains challenge to develop a facile strategy for the precise control of the lateral sizes and layer numbers of TMD nanosheets. In this study, we demonstrate a solution-phase synthetic protocol to prepare colloidal MS2 (M = Mo, W) nanosheets which possess extremely small lateral dimensions from 15 to 40 nm and well-controlled odd numbers of layers, such as 1, 3, and 5 layers, as characterized by transmission electron microscopy, X-ray diffraction and X-ray photoelectron spectroscopy. The size- and layer-dependence of the optical properties of colloidal MS2 (M = Mo, W) nanosheets are revealed by Raman and absorption spectra for the first time. These colloidal nanosheets, especially the single-layer ones, possess a large number of edge sites that serve as active sites for the hydrogen evolution reaction (HER). The catalysts exhibit a small HER overpotential and low Tafel slope of approximately 100 mV and 52 mV per decade for MoS2, and 80 mV and 46 mV per decade for WS2, respectively. Importantly, these products show enhanced stability after 500 potential cycles, and the current density remains almost unchanged during the test.

A pioneering work for determining the extinction coefficient of colloidal semiconductor nanocrystals (NCs) has been cited over 1500 times (W. Yu, W. Guo, X. G. Peng, Chem. Mater., 2003, 15, 2854-2860), indicating the importance of calculating NC concentration for further research and applications. In this study, the size-dependent nature of the molar extinction coefficient of "greener" CuInS(2) and ZnCuInS(3) NCs with emission covering the whole visible to near infrared (NIR) is presented. With the increase of NC size, the resulting quantitative values of the extinction coefficients of ternary CuInS(2) and quaternary ZnCuInS(3) NCs are found to follow a power function with exponents of 2.1 and 2.5, respectively. Obviously, a larger value of extinction coefficient is observed in quaternary NCs for the same size of particles. The difference of the extinction coefficient from both samples is clearly demonstrated due to incorporating ZnS with a much larger extinction coefficient into CuInS(2) NCs.