State Key Laboratory of Digital Manufacturing Equipment and Technology

Sb2Se3 is a very promising photovoltaic material because of its attractive material, optical and electrical properties. Very recently, we reported a superstrate CdS/Sb2Se3 solar cell with 5.6% certified efficiency. In this letter, we focused on the optical properties of amorphous and polycrystalline Sb2Se3 thin films prepared by thermal evaporation. Using temperature dependent transmission spectrum and temperature dependent photoluminescence, the indirect optical transition nature and bandgap values as functions of temperature were acquired. Using ellipsometry measurements and Swanepoel's envelope method, the refractive indices as well as the dielectric constant in a wide wavelength range of 193–2615 nm were obtained. These works would lay the foundation for the further development of Sb2Se3 thin film solar cells.

Assembling multifunctional thin devices onto arbitrary curvilinear surfaces allows widespread and innovative applications in artificial intelligence and advanced healthcare industries.

The encapsulation of carbon counter electrode based perovskite solar cells with PDMS is studied. The solar cells demonstrate a 54% enhancement over those without encapsulation and an impressive stability over 3000 h.

Hybrid flow shop scheduling problem (HFSP) has been extensively discussed and the main objectives are related to completion time. The reduction of energy consumption should be considered fully in HFSP in the era of green manufacturing. In this study, biobjective energy-efficient HFSP is considered, which is made up of three subproblems including scheduling, machine assignment, and speed selection. A three-string coding method is used to indicate solutions of three subproblems. A new teachers' teaching-learning-based optimization (TTLBO) is proposed to minimize total energy consumption and total tardiness. Total tardiness is regarded as a key objective and a lexicographical method is adopted to compare solutions. TTLBO generates new solutions using a new optimization mechanism and is made up of the self-learning, interactive learning, and teaching of teachers. The learning phase of students are deleted from the algorithm. Multiple neighborhood searches are used to implement the self-learning of teachers and global search based on crossover is chosen to imitate other tivities of teachers. A number of experiments are conducted to test the impact of the new optimization meachanism on the performance of TTLBO and compare TTLBO with other algorithms from the literature. The computational results show that TTLBO is a competitive algorithm for the considered HFSP.

We demonstrate the application of a low-temperature carbon counter electrode with good flexibility and high conductivity in fabricating perovskite solar cells. A modified two-step method was used for the deposition of nanocrystalline CH3NH3PbI3 under high relative humidity. The carbon counter electrode was printed on a perovskite layer directly, with different sizes of graphite powder being employed. The interfacial charge transfer and transport in solar cells were investigated through photoluminescence and impedance measurements. We find that the existence of nano-graphite powder in the electrode has a noticeable influence on the back contact and cell performance. The prepared devices of hole-conductor-free perovskite heterojunction solar cells without encapsulation exhibit advantageous stability in air in the dark, with the optimal power conversion efficiency reaching 6.88%. This carbon counter electrode has the features of low-cost and low-temperature preparation, giving it potential for application in the large-scale flexible fabrication of perovskite solar cells in the future.

The hierarchical ZnO-NAs sensor shows highly sensitive, repeatable on–off cycles and temperature dependent response to NO₂. The optimal process parameters of the MES-CHSM are presented to achieve optimal morphology, enlarge gas response and measuring range.

This note addresses a leader-follower consensus control problem for second-order multi-agent systems in a complicated scenario where the agent states are partially measurable and the agent dynamics are intrinsically nonlinear. More specifically, when the states of an agent are not fully measurable, a measurement output is thus defined. As a typical example, the measurement output is defined as the position of an agent while its velocity is unmeasurable. We propose a measurement output feedback controller with a dynamic observer for the unmeasurable states. Moreover, the proposed controller with sufficiently large but explicitly designed gains is able to deal with system nonlinearities when the region of attraction is semi-globally specified.

Low-temperature printable carbon based planar-heterojunction perovskite solar cells with efficiencies exceeding 15% were demonstrated by using a TiO₂/SnO₂bilayer as ETL together with CuPc as HTL.

This paper describes the design and characterization of microfluidic serpentine antennas with reversible stretchability and designed mechanical frequency modulation (FM). The microfluidic antennas are designed based on the Poisson's ratio of the elastomer in which the liquid alloy antenna is embedded, to controllably decrease, stabilize or increase its resonance frequency when being stretched. Finite element modelling was used in combination with experimental verification to investigate the effects of substrate dimensions and antenna aspect ratios on the FM sensitivity to uniaxial stretching. It could be designed within the range of -1.2 to 0.6 GHz per 100% stretch. When the aspect ratio of the serpentine antenna is between 1.0 and 1.5, the resonance frequency is stable under stretching, bending, and twisting. The presented microfluidic serpentine antenna design could be utilized in the field of wireless mobile communication for the design of wearable electronics, with a stable resonance frequency under dynamic applied strain up to 50%.

Accurate pattern transfer in wafer scanners necessitates the wafer stage and the reticle stage executing a coordinated motion with the synchronization error in terms of nanometers. In an attempt to cope with this challenging issue, a cross-coupling iterative learning control (ILC) with two inputs and two outputs is proposed and then decomposed into two ILC with the same convergence condition, a master–slave ILC for the reticle stage and an independent ILC for the wafer stage. To handle the inevitable stochastic disturbance, which inhibits the achievable ILC performance, an adaptive gain is involved in the proposed method for the sake of accelerated convergence as well as enhanced robustness. It remains constant or is decreased adaptively along the iteration axis, depending on the proportion that the stochastic term accounts for in the error signal. Moreover, a phase leader is chosen as the learning filter and tuned along with the initial learning gain by a frequency-domain approach. Experimental comparisons with existing close yet distinctive approaches highlight the effectiveness and superiority of the proposed method.

We report an atomic scale controllable synthesis of Pd/Pt core shell nanoparticles (NPs) via area-selective atomic layer deposition (ALD) on a modified surface. The method involves utilizing octadecyltrichlorosilane (ODTS) self-assembled monolayers (SAMs) to modify the surface. Take the usage of pinholes on SAMs as active sites for the initial core nucleation, and subsequent selective deposition of the second metal as the shell layer. Since new nucleation sites can be effectively blocked by surface ODTS SAMs in the second deposition stage, we demonstrate the successful growth of Pd/Pt and Pt/Pd NPs with uniform core shell structures and narrow size distribution. The size, shell thickness and composition of the NPs can be controlled precisely by varying the ALD cycles. Such core shell structures can be realized by using regular ALD recipes without special adjustment. This SAMs assisted area-selective ALD method of core shell structure fabrication greatly expands the applicability of ALD in fabricating novel structures and can be readily applied to the growth of NPs with other compositions.

The structural, electronic, electrochemical as well as diffusion properties of Na doped phosphorene have been investigated based on first-principles calculations. The strong binding energy between Na and phosphorene indicates that Na could be stabilized on the surface of phosphorene without clustering. By comparing the adsorption of Na atoms on one side and on both sides of phosphorene, it has been found that Na-Na exhibits strong repulsion at the Na-Na distance of less than 4.35 Å. The Na intercalation capacity is estimated to be 324 mA h g(-1) and the calculated discharge curve indicates quite a low Na(+)/Na voltage of phosphorene. Moreover, the diffusion energy barrier of Na atoms on the phosphorene surface at both low and high Na concentrations is as low as 40-63 meV, which implies the high mobility of Na during the charge/discharge process.

Abstract Effective performance of modern manufacturing systems requires integrating process planning and scheduling more tightly, which is consistently challenged by the intrinsic interrelation and intractability of these two problems. Traditionally, these two problems are treated sequentially or separately. Integration of process planning and scheduling (IPPS) provides a valuable approach to improve system performance. However, IPPS is more complex than job shop scheduling or process planning. IPPS is strongly NP-hard in that, compared to an NP-hard job shop scheduling problem with a determined process plan, the process plan for each job in IPPS is also to be optimised. So, an imperialist competitive algorithm (ICA) is proposed to address the IPPS problem with an objective of makespan minimisation. An extended operation-based representation scheme is presented to include information on various flexibilities of process planning with respect to determined job shop scheduling. The main steps of the proposed ICA, including empires construction, assimilation, imperialistic competition, revolution and elimination, are elaborated using an illustrative example. Performance of the proposed ICA was evaluated on four sets of experiments taken from the literature. Computational results of the ICA were compared with that of some existing algorithms developed for IPPS, which validates the efficiency and effectiveness of the ICA in solving the IPPS problem. Keywords: imperialist competitive algorithmintegrated process planning and schedulingscheduling Acknowledgements The authors thank the anonymous referees whose comments helped to much improve this paper. This research work is supported by the National High-Tech Research and Development Program of China 863 Program (grant no. 2007AA04Z107) and the State Key Program of National Natural Science of China (grant no. 51035001).

Ultrafast and self-powered photodetectors based on high-quality evaporated CsPbBr₃ perovskites for applications in optical communication are demonstrated. The photodetectors achieve an ultrafast response time of 3.8 μs and on/off ratio of 3.5 × 10⁴.

Efficient PbS quantum-dot solar cells were achieved through SnO₂–Cl interface passivation.

at these CPs exhibits a valley-like shape versus the layer number, and the bottom appears at 3-layers. This non-monotonic evolution is explained as a competition between the layer-dependent decrease of the exciton effect and the layer-dependent increase of the joint density of states.

One-step synthesis of a nickel phosphide nanowire array on nickel foam, which can be used as a bifunctional catalyst for water splitting and shows an excellent electrocatalytic activity for the hydrogen and oxygen evolution reaction.

A series of La_xSm_1−xMn₂O_δ (<italic>x</italic> = 0, 0.1, 0.3, 0.5) catalysts were synthesized through a co-precipitation method. The catalytic activity for NO oxidation was enhanced with La substitution, and the maximum activity was achieved at <italic>x</italic> = 0.3.

Flexible capacitive pressure sensors have many important applications but usually exhibit a highly non-linear response as the sensitivity drops dramatically towards high pressure. Herein, we propose a novel strategy to achieve high linearity over a broad sensing range by using percolative composites as the dielectric layer. The linear response is attributed to the fast increase in dielectric constant that can compensate for the sensitivity drop caused by the decreased compressibility during compression. An analytical model is established to predict the linearity by coupling the percolation theory and Mooney-Rivlin equation. Based on the model, a capacitive pressure sensor using a spiky nickel/polydimethyl siloxane composite as the dielectric layer is fabricated as a demonstration and exhibits excellent linearity (R2 = 0.999) up to 1.7 MPa. In addition, owing to the nature of the polymer composite, its dispersion can be conformally coated on surfaces with complex shapes or be molded into films with surface microstructures to achieve a unique combination of high sensitivity and linear response over a wide pressure sensing range.

A series of mullite SmMn₂O₅ oxides were prepared by citric acid (CA), hydrothermal (HT) and co-precipitation (CP) and combustion of ethylene glycol and methanol solutions (EG&amp;M) methods, and tested for NO_x-assisted soot combustion.