We report the initial results of GaAs and GaInP solar cells grown by all solid-state molecular-beam-epitaxy (MBE) technique. For GaAs single-junction solar cell, with the application of AlInP as the window layer and GaInP as the back surface field layer, the photovoltaic conversion efficiency of 26% at one sun concentration and air mass 1.5 global (AM1.5G) is realized. The efficiency of 16.4% is also reached for GaInP solar cell. Our results demonstrate that the MBE-grown phosphide-contained III-V compound semiconductor solar cell can be quite comparable to the metal-organic-chemical-vapor-deposition-grown high-efficiency solar cell.

In-plane anisotropy induced by a low-symmetric lattice structure in two-dimensional (2D) van der Waals (vdWs) materials has significantly promoted their applications in optoelectronic devices, especially in polarization photodetection. Given the mature preparation technology of transition metal dichalcogenides (TMDCs), introducing artificial anisotropy into symmetric TMDCs becomes a promising way to trigger more excellent functionalities beyond their intrinsic properties. Herein, monolayer MoS2 in the MoS2/Ta2NiSe5 vdWs heterostructure presents obvious anisotropic optical properties confirmed by polarized Raman and photoluminescence spectra, which is mainly ascribed to the uniaxial strain via strong interlayer couplings. Moreover, the MoS2/Ta2NiSe5 heterojunction endows unique orientation-selected polarized absorbance. In the visible region, the dominant polarized orientation is along the armchair axis while rotated to the perpendicular direction in the near-infrared spectrum, which is mainly ascribed to the intrinsic linear dichroism of Ta2NiSe5. The results suggest that the MoS2/Ta2NiSe5 heterostructure provides a promising platform for artificial regulation of the optoelectronic properties of symmetric MoS2 and integrated optical applications in the polarization-sensitive photodetection.

In this work, ZIF-8-derived Co₃O₄@ZnO microspheres were prepared by a liquid-phase concentration-controlled nucleation strategy. The results of the material characterization showed that Co₃O₄@ZnO microspheres were obtained, and the surface structure could be controlled with the concentration of the ligand. Compared with pure Co₃O₄ microspheres, the operating temperature of optimized Co₃O₄@ZnO microspheres increased by 90 °C after the gas-sensing test. The response to 50 ppm acetone of Co₃O₄@ZnO microspheres was 4.5 times higher than that of pure Co₃O₄, and the detection limit reached 0.5 ppm. Meanwhile, Co₃O₄@ZnO microspheres showed a shorter response-recovery time and better selectivity. The enhanced-sensing mechanism of the ZIF-8-derived Co₃O₄@ZnO microspheres was also analyzed.

Electroplating copper is widely used in the fabrication of flexible III-V multijunction solar cell because of its excellent characteristics of lightness, flexibility and conductivity of thin Cu, which can be directly applied as the flexible support and the external electrode. In this letter, we studied the diffusion effect of copper in the flexible GaInP/GaAs solar cells under high temperature annealing, which plays an essential role in achieving a promising ohmic contact between contact layer and metal. However, the degradation in the performance of flexible cell was observed when the annealing procedure was employed at the last step of the device fabricating process. The secondary ion mass spectrometry and electroluminescence results have indicated that the degradation of the solar cell performance after high-temperature annealing is attributed to the excess copper diffusion into active region of the solar cell. High temperature diffusion of copper can be solved by prior-annealing to form ohmic contact.

In the case of the fabrication of flexible solar cells based on the inverted metamorphic multijunction (IMM) structure, the conventional high-temperature annealing will result in the thin-film epitaxial layer warp or even crack, which could seriously affect the yield of flexible solar cells. The poor device fabrication processing compatibility arises from the large difference in thermal expansion coefficients between the ultrathin epitaxial layer and the flexible substrate. In this work, we developed the PdGe electrode to achieve the specific contact resistivity of 3.4 $\times$ 10 $^{-\text{6}}$ $\Omega \cdot$ cm $^{\text{2}}$ with low-temperature annealing. Thermal cycle tests have demonstrated the ultrahigh stability of the ohmic contact performance. By the employment of the designed electrode, the flexible large-sized GaInP/GaAs/InGaAs solar cells were successfully fabricated with a conversion efficiency of 35.37% under the AM1.5G illumination. The encapsulated flexible solar cells can remain above 98% of initial performance under the circumstance of 85 $^{\circ}$ C and 85% relative humidity. The stable and reliable electrode based on low-temperature annealing technology will greatly improve the production yield in the preparation of flexible electronic devices.

In the field of fiber-optic sensing, effectively reducing the noise of sensing spectra and achieving a high signal-to-noise ratio (SNR) has consistently been a focal point of research. This study proposes a deep-learning-based denoising method for fiber-optic sensors, which involves pre-processing the sensor spectrum into a 2D image and training with a cycle-consistent generative adversarial network (Cycle-GAN) model. The pre-trained algorithm demonstrates the ability to effectively denoise various spectrum types and noise profiles. This study evaluates the denoising performance of simulated spectra obtained from four different types of fiber-optic sensors: fiber Fabry–Perot interferometer (FPI), regular fiber Bragg grating (FBG), chirped FBG, and FBG pair. Compared to traditional denoising algorithms such as wavelet transform (WT) and empirical mode decomposition (EMD), the proposed method achieves an SNR improvement of up to $13.71 \mathrm{dB}$, an RMSE that is up to three times smaller, and a minimum correlation coefficient ($R^2$) of no less than 99.70% with the original high-SNR signals. Additionally, the proposed algorithm was tested for multimode noise reduction, demonstrating an excellent linearity in temperature response with a $R^2$ of 99.95% for its linear fitting and $99.74\%$ for the temperature response obtained from single-mode fiber sensors. The proposed denoising approach effectively reduces the impact of various noises from the sensing system, enhancing the practicality of fiber-optic sensing, especially for specialized fiber applications in research and industrial domains.