Henan Normal University

About: Henan Normal University is a education organization based out in Xinxiang, China. It is known for research contribution in the topics: Catalysis & Ionic liquid. The organization has 10863 authors who have published 11077 publications receiving 166773 citations.

Combining Energy Transfer and Optimized Morphology for Highly Efficient Ternary Polymer Solar Cells

Abstract: Aimed at achieving ideal morphology, illuminating morphology–performance relationship, and further improving the power conversion efficiency (PCE) of ternary polymer solar cells (TSCs), a ternary system is designed based on PTB7-Th:PffBT4T-2OD:PC71BM in this work. The PffBT4T-2OD owns large absorption cross section, proper energy levels, and good crystallinity, which enhances exciton generation, charge dissociation and transport and suppresses charge recombination, thus remarkably increasing the short-circuit current density (Jsc) and fill factor (FF). Finally, a notable PCE of 10.72% is obtained for the TSCs with 15% weight ratio of PffBT4T-2OD. As for the working mechanism, it confirmed the energy transfer from PffBT4T-2OD to PTB7-Th, which contributes to the improved exciton generation. And morphology characterization indicates that the devices with 15% PffBT4T-2OD possess both appropriate domain size (25 nm) and enhanced domain purity. Under this condition, it affords numerous D/A interface for exciton dissociation and good bicontinuous nanostructure for charge transport simultaneously. As a result, the device with 15% PffBT4T-2OD exhibits improved exciton generation, enhanced charge dissociation possibility, elevated hole mobility and inhibited charge recombination, leading to elevated Jsc (19.02 mA cm−2) and FF (72.62%) simultaneously. This work indicates that morphology optimization as well as energy transfer plays a significant role in improving TSC performance.

Control of PLA Stereoisomers-Based Polyurethane Elastomers as Highly Efficient Shape Memory Materials

Abstract: Poly(lactic acid) (PLA) has received increasing attention in the development of shape memory polymers (SMPs) due to its excellent physical properties and good biocompatibility. However, the intrinsically increased crystallinity of PLA at higher deformation ratios still remains a significant challenge, which remarkably restricts the chain mobility and reduces shape recovery efficiency. Being different from other types of biodegradable polymers, the diverse isomeric forms of PLA have provided great opportunities for modulation of PLA toward a favorable property by incorporating different PLA stereoisomers in one macromolecular architecture. In this paper, we report a completely amorphous PLA poly(ester urethane) elastomer that exhibits excellent shape fixity (>99%) and shape recovery (>99%) in a time frame of seconds. By means of adjusting the stereoisomeric ratios and control over architecture, the resultant poly(PLLA/PDLLA urethane)s (PLDU) elastomers show a single glass transition temperature (Tg), as th...

Enhancement of hole mobility in InSe monolayer via an InSe and black phosphorus heterostructure.

Abstract: To enhance the low hole mobility (∼40 cm2 V−1 s−1) of InSe monolayer, a novel two-dimensional (2D) van der Waals heterostructure made of InSe and black phosphorus (BP) monolayers with high hole mobility (∼103 cm2 V−1 s−1) has been constructed and its structural and electronic properties are investigated using first-principles calculations. We find that the InSe/BP heterostructure exhibits a direct band gap of 1.39 eV and type-II band alignment with electrons (holes) located in the InSe (BP) layer. The band offsets of InSe and BP are 0.78 eV for the conduction band minimum and 0.86 eV for the valence band maximum, respectively. Surprisingly, the hole mobility in the InSe/BP heterostructure exceeds 104 cm2 V−1 s−1, which is one order of magnitude larger than the hole mobility of BP and three orders larger than that of the InSe monolayer. The electron mobility is also increased to 3 × 103 cm2 V−1 s−1. The physical reason has been analyzed deeply, and a universal method is proposed to improve the carrier mobility of 2D materials by forming heterostructures with them and other 2D materials with complementary properties. The InSe/BP heterostructure can thus be widely used in nanoscale InSe-based field-effect transistors, photodetectors and photovoltaic devices due to its type-II band alignment and high carrier mobility.

Powder exfoliated MoS2 nanosheets with highly monolayer-rich structures as high-performance lithium-/sodium-ion-battery electrodes

Abstract: Due to their low yield and easy aggregation during the electrode preparation process, exfoliated MoS2 monolayers cannot fulfill the requirements of alkali-metal-ion battery tests. Hence, we have developed a facile process to fabricate powder exfoliated MoS2 nanosheets capable of large-scale production and having highly monolayer-rich structures. This process contains two steps: liquid-phase exfoliation of the edge-rich MoS2 precursor and a freeze-drying procedure. The proposed MoS2 precursors contain rich edge fractions that are easily exfoliated by this method, and the freeze-drying procedure can maintain the unique monolayer-rich structure of MoS2 in the powder phase. The electrochemical evaluations of both lithium- and sodium-ion batteries reveal that the proposed powder exfoliated monolayer-rich MoS2 electrode exhibits remarkable specific capacities and stable cyclic performances. In particular, the monolayer-rich MoS2 nanosheet electrode delivers a superior lithium-storage capacity of ∼1400 mA h g-1. The exfoliated MoS2 nanosheet electrode can withstand over 1000 cycles even at 1 A g-1. The mechanism reveals that these unique MoS2 nanosheets not only have a large surface area but also their inclusive monolayer structures exhibit much higher charge mobility than those of bulk MoS2.