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Transparent, flexible surface-enhanced Raman scattering (SERS) substrates were fabricated by metalization of structured polyethylene terephthalate (PET) sheets. The resultant Ag-coated structured PET SERS substrates were revealed to be highly sensitive with good reproducibility and stability, an enhancement factor of 3 × 10 6 was acquired, which can be attributed mainly to the presence of plentiful multiple-type hot spots within the quasi-three-dimensional surface of the structured PET obtained by oxygen plasma etching. In addition, detections of model molecules on fruit skin were also carried out, demonstrating the great potential of the Ag-coated structured PET in in-situ detection of analyte on irregular objects. Importantly, the technique used for the preparation of such substrate is completely compatible with well-established silicon device technologies, and large-area fabrication with low cost can be readily realized. [ABSTRACT FROM AUTHOR]

Abstract: Large-area, well-separated, and vertically aligned silicon nanowire (SiNW) arrays with excellent antireflection properties were fabricated through a combination of anodic aluminum oxide template and metal-assisted chemical etching, followed by supercritical drying. Less than 1% reflectance was achieved over the wavelength range of 200–600nm, and 23% reduction in average reflectance was observed over the 200–1000nm range, compared with the conical-frustum structure array by natural drying. Furthermore, the well-separated SiNW arrays considerably facilitated the conformal coating of the plasma-enhanced chemical vapor deposited amorphous silicon layer on the SiNW surface, which could result in effective passivation of surface states. Therefore, such well-separated and vertically aligned SiNW arrays are highly promising for solar cell application. [Copyright &y& Elsevier]

Abstract: Microcrystalline silicon (μc-Si) films were deposited at a high rate and low temperature using jet-type inductively coupled plasma chemical vapor deposition (jet-ICPCVD), and the deposition rate, microstructure and electrical properties of the deposited films were investigated. It was demonstrated that a high deposition rate of over 20 nm/s can be achieved while maintaining high crystallinity and low dark conductivity. The deposition rate is well controlled by regulating the generation rate and transport of growth precursors. High crystallinity of the films results principally from hydrogen-induced chemical annealing. Furthermore, the excellent electrical properties benefit from the low oxygen content and/or low deposition temperature. [Copyright &y& Elsevier]

Recent literature shows that automated vehicle (AV) significantly impacts traffic flow stability. However, as a widely used longitudinal AV technology, the Adaptive Cruise Control (ACC) system still has several unknown features that lack field data for modeling. We ran a series of novel tests with two ACC vehicles to simulate the behavior of the AV platoon in the field experiment. We designed a linear car-following controller in the upper layer system and tested the string stability of the ACC vehicle platoon. Data is collected through the vehicle's GPS sensor and upper controller. These data can help us estimate the feedback delay in the upper layer and parasitic lag in the lower layer. The data analysis results specify the range of different time delays and further optimize the dynamic response model in the lower layer. Then we propose an improved longitudinal model based on a first-order inertia system with a pure time delay in the dynamic response process. The experimental results show that the improved longitudinal model is twenty percent more accurate than the traditional first-order inertia model. Finally, we analyze the string stability of the improved longitudinal model. The results indicate that the improved longitudinal model has more strict stability conditions than the traditional model. Although the current feedback delay can satisfy the string stability criterion, the parasitic lag in the dynamics response process cannot satisfy the stability criterion. In this study, a customized ACC car-following controller is implemented in the field experiments, and thus all hypotheses and analysis results are validated by field data. [ABSTRACT FROM AUTHOR]

[Display omitted] • The gradient mixed-cation perovskite is constructed in air with a relative humidity of 50 ± 5%. • Gradient distribution of FA cations optimizes the device energy level alignment. • The Hole Transport layer is Dopant-Free P3HT material. • The as-optimized device gains a champion PCE of 16.26% for air-processed P3HT based device. Poly(3-hexylthiophene) (P3HT) based devices possess potential toward low-cost and easy fabrication for high-performance perovskite solar cells (PSCs). However, these devices currently suffer from stability and relative low performance. Herein, a gradient mixed-cation perovskite is obtained by a facile strategy of tailoring MAPbI 3-x Cl x , in which MAFAPbI 3-x Cl x were constructed in ambient air by directly spin-coating FAI onto perovskite intermediate phase. The pristine device shows an inferior power conversion efficiency (PCE) of 13.71%, whereas the as-optimized device achieves a PCE of 16.26%. A gradient distribution of FA cation is revealed by crystal unit parameters and energy dispersive spectrometer (EDS). The lifted valence band edge matches better with the HOMO of P3HT, thus resulting in the faster charge extraction. In addition, the reduced trap states lead to the enhanced crystallinity and the mitigation of perovskite/P3HT interface, and then the stability is significantly enhanced. Our work provides a facile way to improve the performance of P3HT based air-processed PSCs, which can bring these devices closer to low-cost commercial applications. [ABSTRACT FROM AUTHOR]

NiO x -based inverted structure perovskite devices possess advantages in the application of single junction and tandem solar cells. However, energy loss and instability originating from interface defects commonly result in inferior device performance. Herein, Potassium Bromide (KBr), as a buffer layer, was inserted between the perovskite and NiO x hole transport layer to modify the interface. The valence band maximum of NiO x improved to −5.37 eV which matches better with perovskite. The lifetime of hot carriers and intrinsic charge recombination revealed by Femtosecond transient absorption spectroscopy (fs-TAS) confirm that KBr modification can facilitate charge separation. Benefiting from the improvement of perovskite quality which results from K+ diffusion and enhanced charge transport, the power conversion efficiency (PCE) of the modified device reaches up to 19.21%, whereas the pristine is 17.56%. Meanwhile, the air stability of the unencapsulated device also improved dramatically, which maintains 80% of its initial PCE after 1100 h high humidity storage. This work unambiguous reveals the mechanism of perovskite/NiO x interface modification and provides a facile and effective strategy for interface optimization. • KBr buffer layer was inserted to modify the interface between NiO x HTL and perovskite film. • KBr modification can facilitates charge separation and optimizes the energy level alignment. • The as-optimized device gains a champion PCE of 19.21% for inverted perovskite solar cells. • Unencapsulated device maintain 80% of its initial PCE after 1100 h high humidity storage. [ABSTRACT FROM AUTHOR]