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In this paper, we report a fiber curvature sensor based on a seven-core fiber Mach-Zender interferometer (t-SCF-MZI), which is realized by tapered welding. The experimental results show that the curvature response of t-SCF-MZI is significantly enhanced due to the change in the cone diameter. In a series of experiments, when the diameter of the seven-core fiber lumbar spine is 41.44 μm, the curvature sensitivity is increased by about 200%, and the maximum value reaches -30.647 nm/m −1 . In order to facilitate the test, after the sensor is packaged, the photoelectric converter and data acquisition card are introduced into the sensing system. The sensor output light signal is converted into a computer-recognizable electrical signal, curvature human application detection, such as finger curvature test has high practicability and prospect.

In organic photovoltaics, morphological control of donor and acceptor domains on the nanoscale is the key for enabling efficient exciton diffusion and dissociation, carrier transport and suppression of recombination losses. To realize this, here, we demonstrated a double-fibril network based on a ternary donor–acceptor morphology with multi-length scales constructed by combining ancillary conjugated polymer crystallizers and a non-fullerene acceptor filament assembly. Using this approach, we achieved an average power conversion efficiency of 19.3% (certified 19.2%). The success lies in the good match between the photoelectric parameters and the morphological characteristic lengths, which utilizes the excitons and free charges efficiently. This strategy leads to an enhanced exciton diffusion length and a reduced recombination rate, hence minimizing photon-to-electron losses in the ternary devices as compared to their binary counterparts. The double-fibril network morphology strategy minimizes losses and maximizes the power output, offering the possibility of 20% power conversion efficiencies in single-junction organic photovoltaics. The morphology of donor–acceptor blends in organic photovoltaics dictates the efficiency of the exciton dissociation and charge diffusion, and thus the final device performance. Here, the authors show that filament assembly helps to maximize the output, further enabling a power conversion efficiency greater than 19%.

This article built the model of concentrated photovoltaic and thermal (CPV/T) systems under the double-axis tracking mode in the east, west, south, and north directions, as well as the single-axis tracking mode in the north and south directions. According to this model, the function of the CPV/T system could be researched. The article established 3D models of large-scale CPV/T systems in different tracking modes and used this model to study the occlusion problem of CPV/T systems. Taking into account cosine loss, edge loss, and occlusion, this paper established energy reception models for different trace modes of the CPV/T system. The energy reception model calculated that the annual energy reception rate of the CPV/T system in the single-axis tracking mode was not a patch on the double-axis tracking CPV/T system. Subsequently, a scaled CPV/T total energy mathematical model was established under these two tracking mods in the article. Combined with the non-steady energy model, the annual total photoelectricity and photothermal output of the CPV/T systems in the single-axis tracking mode and the double-axis tracking mode with an area of 1600 m 2 in Xi’an were calculated. The photoelectricity and photothermal outputs of the double-axis tracking mode were 169216 kW·h and 856183 kW·h, respectively. The single-axis tracking node had an annual output of 126898 kW·h for photoelectricity and 637490 kW·h for photothermal.

Minimizing energy loss is of critical importance in the pursuit of attaining high-performance organic solar cells. Interestingly, reorganization energy plays a crucial role in photoelectric conversion processes. However, the understanding of the relationship between reorganization energy and energy losses has rarely been studied. Here, two acceptors, Qx-1 and Qx-2, were developed. The reorganization energies of these two acceptors during photoelectric conversion processes are substantially smaller than the conventional Y6 acceptor, which is beneficial for improving the exciton lifetime and diffusion length, promoting charge transport, and reducing the energy loss originating from exciton dissociation and non-radiative recombination. So, a high efficiency of 18.2% with high open circuit voltage above 0.93 V in the PM6:Qx-2 blend, accompanies a significantly reduced energy loss of 0.48 eV. This work underlines the importance of the reorganization energy in achieving small energy losses and paves a way to obtain high-performance organic solar cells. Minimising energy loss is important for achieving high-performance organic solar cells. Here, the authors design and synthesise two acceptors with small reorganisation energies and reveal the relationship between reorganisation energy and energy losses.

This paper designs a measuring and detecting device for medical centrifuges. The device integrates the measurement of rotational speed, temperature, and time. The photoelectric tachometer was transformed into a laser speed detection module to adapt to the rotational speed measurement of the closed centrifuge and a wireless temperature detection module could be inserted into the slot of the centrifuge tube to measure the temperature of the tube position when the centrifuge rotates at a high speed. This method achieved reliable and accurate measurement of the speed, temperature, and time of various centrifuges with low costs.

The photocurrent generation in photovoltaics relies essentially on the interface of p-n junction or Schottky barrier with the photoelectric efficiency constrained by the Shockley-Queisser limit. The recent progress has shown a promising route to surpass this limit via the bulk photovoltaic effect for crystals without inversion symmetry. Here we report the bulk photovoltaic effect in two-dimensional ferroelectric CuInP 2 S 6 with enhanced photocurrent density by two orders of magnitude higher than conventional bulk ferroelectric perovskite oxides. The bulk photovoltaic effect is inherently associated to the room-temperature polar ordering in two-dimensional CuInP 2 S 6 . We also demonstrate a crossover from two-dimensional to three-dimensional bulk photovoltaic effect with the observation of a dramatic decrease in photocurrent density when the thickness of the two-dimensional material exceeds the free path length at around 40 nm. This work spotlights the potential application of ultrathin two-dimensional ferroelectric materials for the third-generation photovoltaic cells. While magnetism, hyperferroelectricity, and topological phases in the two-dimensional limit have been widely explored, the direct experimental study on bulk photovoltaic effect in 2D materials remains unimplemented. Here, the authors find bulk photovoltaic effect in 2D ferroelectric CuInP 2 S 6 .

Aiming at the absolute photoelectric encoder used in the stable platform, a FPGA-based scheme which can read encoder data and measure velocity is proposed. The scheme uses the nonlinear tracking differentiator theory to design the speed measurement of the stable platform, which can avoid the error amplification caused by the conventional differential speed measurement. And this solution can implement in engineering easily because it does not require additional hardware circuitry. Numerical simulation analysis and experimental results show that the scheme can accurately read the encoder signal and estimate the encoder's angular rate based on the position signal. The experiment proves that the method is accurate and effective.

For organic solar cells to be competitive, the light-absorbing molecules should simultaneously satisfy multiple key requirements, including weak-absorption charge transfer state, high dielectric constant, suitable surface energy, proper crystallinity, etc. However, the systematic design rule in molecules to achieve the abovementioned goals is rarely studied. In this work, guided by theoretical calculation, we present a rational design of non-fullerene acceptor o-BTP-eC9, with distinct photoelectric properties compared to benchmark BTP-eC9. o-BTP-eC9 based device has uplifted charge transfer state, therefore significantly reducing the energy loss by 41 meV and showing excellent power conversion efficiency of 18.7%. Moreover, the new guest acceptor o-BTP-eC9 has excellent miscibility, crystallinity, and energy level compatibility with BTP-eC9, which enables an efficiency of 19.9% (19.5% certified) in PM6:BTP-C9:o-BTP-eC9 based ternary system with enhanced operational stability. A systematic design of light-absorbing molecules is challenging for them to satisfy multiple key requirements for efficient solar cell application. Here, the authors optimize halogen substitution position in terminal groups of acceptors for realizing ternary cells with efficiency approaching 20%.

Development of lead-free inorganic perovskite material, such as Cs 2 AgBiBr 6 , is of great importance to solve the toxicity and stability issues of traditional lead halide perovskite solar cells. However, due to a wide bandgap of Cs 2 AgBiBr 6 film, its light absorption ability is largely limited and the photoelectronic conversion efficiency is normally lower than 4.23%. In this text, by using a hydrogenation method, the bandgap of Cs 2 AgBiBr 6 films could be tunable from 2.18 eV to 1.64 eV. At the same time, the highest photoelectric conversion efficiency of hydrogenated Cs 2 AgBiBr 6 perovskite solar cell has been improved up to 6.37% with good environmental stability. Further investigations confirmed that the interstitial doping of atomic hydrogen in Cs 2 AgBiBr 6 lattice could not only adjust its valence and conduction band energy levels, but also optimize the carrier mobility and carrier lifetime. All these works provide an insightful strategy to fabricate high performance lead-free inorganic perovskite solar cells. Though inorganic perovskites are an attractive, non-toxic and stable alternative to organic-inorganic halide perovskite solar cells, realizing efficient devices remains a challenge. Here, the authors report hydrogenated lead-free inorganic perovskite solar cells with enhanced power conversion efficiency.

Until about a decade ago, laser-induced ionization was considered instantaneous. Since then, applications of attosecond laser pulses have shown multiple subtle and complex factors that influence the precise timing of electron ejection from atoms and surfaces. Vos et al. measured the corresponding attosecond dynamics of dissociative photoionization in a diatomic molecule, carbon monoxide. By imaging the charged fragments, the timing could be correlated with the specific spatial portion of the molecule from which the electron wave packet emerged. Science , this issue p. 1326 The precise timing of ionization in CO varies with respect to the portion of the molecule from which the electron emerges. Attosecond metrology of atoms has accessed the time scale of the most fundamental processes in quantum mechanics. Transferring the time-resolved photoelectric effect from atoms to molecules considerably increases experimental and theoretical challenges. Here we show that orientation- and energy-resolved measurements characterize the molecular stereo Wigner time delay. This observable provides direct information on the localization of the excited electron wave packet within the molecular potential. Furthermore, we demonstrate that photoelectrons resulting from the dissociative ionization process of the CO molecule are preferentially emitted from the carbon end for dissociative 2 Σ states and from the center and oxygen end for the 2 Π states of the molecular ion. Supported by comprehensive theoretical calculations, this work constitutes a complete spatially and temporally resolved reconstruction of the molecular photoelectric effect.