The effects of different local crystalline structures of two-dimensional (2D) MoS2sheets on the performance of organic solar cells (OSCs) are studied, providing new insights towards high-performance devices.

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ABC triblock copolymers in which a block with stimulus-dependent solvophilicity resides between solvophilic and solvophobic end blocks can undergo reversible transitions between different thermodynamically stable assemblies in the presence or absence of stimulus. As a new example of such a copolymer system, thermoresponsive poly(ethylene oxide)-b-poly(ethylene oxide-stat-butylene oxide)-b-poly(isoprene) (E-BE-I) triblock copolymers with narrow molecular weight distributions (M(w)/M(n): 1.05-1.18) were prepared by sequential living anionic and nitroxide-mediated radical polymerizations. The specific copolymers examined (9.0 ≤ M(n) ≤ 14.4 kg/mol, 14% ≤ wt % isoprene ≤35%) form near-spherical aggregates with narrow size distributions at 25 °C. The thermoresponsive behavior of these polymers was studied by applying cloud point, DLS, and TEM measurements to a representative polymer, E(2.3)BE(5.3)I(2.3). The transformation of polymer aggregates from spherical micelles to vesicles (polymersomes) at elevated temperatures was detected by DLS and TEM studies, both with and without cross-linking of polymer assemblies. The rate of transformation with E-BE-I systems is more rapid than that observed for poly(ethylene oxide)-b-poly(N-isopropylacrylamide)-b-poly(isoprene) assemblies, suggesting that interchain hydrogen bonding of responsive blocks after dehydration plays an important role in the kinetics of aggregate rearrangement.

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We propose and demonstrate an all-fiber passively mode-locked laser with a figure-8 cavity, which generates pulsed cylindrical vector beam output based on a mode selective coupler (MSC). The MSC made of a two mode fiber and a standard single mode fiber is used as both the intracavity transverse mode converter and mode splitter with a low insertion loss of about 0.65 dB. The slope efficiency of the fiber laser is > 3%. Through adjusting the polarization state in the laser cavity, both radially and azimuthally polarized beams have been obtained with high mode purity which are measured to be > 94%. The laser operates at 1556.3 nm with a spectral bandwidth of 3.2 nm. The mode-locked pulses have duration of 17 ns and a repetition rate of 0.66 MHz.

The limited intrinsic conductivity of two-dimensional (2D) MoS₂ nanosheets compromises its high electrocatalytic performance. In this work, we develop a facile method of simply dispersing MoS₂ nanosheets into a water-isopropanol solution of high-conducting single-walled carbon nanotubes (SWCNTs) for preparation of MoS₂/SWCNT composites. The SWCNTs in the hybrid system serve as effective electron transport channels among 2D MoS₂ nanosheets and facilitate charge transfer at the catalyst-electrolyte interface. We investigated the influence of SWCNTs ratios on the catalytic activities and obtained a high-performance hybrid catalyst with a low Tafel slope of 40.82 mV/decade and prominent electrochemical durability. The demonstration of our hybrid electrocatalytic system, with its scalable capacity for facile preparation, provides a new pathway to enhance HER activity.

Cubic In 2 O 3 (bcc-In 2 O 3 ) was transformed into a mixture of bcc-In 2 O 3 and rhombohedral In 2 O 3 (rh-In 2 O 3 ) by Zn doping. The Zn-doped flower-like In 2 O 3 structures consisted of many thin sheets with a length of 0.4-1 mm, and cubes with a length of 200 nm, while the size of the microflowers was 1-3.5 mm. The Zn doping concentration significantly affected the phase transformation and the overall morphology of In 2 O 3 . Furthermore, the analysis of N 2 adsorption-desorption measurements showed that the Zn-doped flower-like In 2 O 3 structures (sample S5) adsorbed the largest amount of N 2 and had the biggest surface area (46.41 m 2 g À1 ), which contributed to an improvement in gas sensing performance. Finally, sensors based on the mixture of bcc-and rh-In 2 O 3 structures exhibited a much higher response to NO 2 than the pure bcc-In 2 O 3 (sample S1), and the Zn-doped flower-like In 2 O 3 structures (sample S5) exhibited the highest response of 27.4 AE 2.5 for 5 ppm NO 2 . Thus, the gas sensing performance of In 2 O 3 was enhanced significantly by the phase transformation.

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