In recent years, the simplified computation of position and velocity changes in nonlinear systems using Lie groups and Lie algebra has been widely used in the study of robot localization systems. The unscented Kalman filter (UKF) can effectively deal with nonlinear systems through the unscented transformation, and in order to more accurately describe the robot localization system, the UKF method based on Lie groups has been studied successively. The computational complexity of the UKF on Lie groups is high, and in order to simplify its computation, the Lie groups are applied to the manifold, which efficiently handles the state and uncertainty and ensures that the system maintains the geometric constraints and computational simplicity during the updating process. In this paper, a multi-sensor fusion localization method based on an unscented Kalman filter on manifolds (UKF-M) is investigated. Firstly, a system model and a multi-sensor model are established based on an Autonomous Underwater Vehicle (AUV), and a corresponding UKF-M is designed for the system. Secondly, the multi-sensor fusion method is designed, and the fusion method is applied to the UKF-M. Finally, the proposed method is validated using an underwater cave dataset. The experiments demonstrate that the proposed method is suitable for underwater environments and can significantly correct the cumulative error in the trajectory estimation to achieve accurate underwater localization.

We study experimentally and theoretically the transport properties of Ag nanowire macrobundles in the presence of light irradiation. We have observed significant negative photoconductivity induced by the interaction between electrons and the excited surface plasmon polaritons (SPPs). As temperature T increases from 77 K to 304 K, the dark resistivity ρ_d without light irradiation increases linearly with T, and the resistivity change Δρ due to light irradiation decreases nonlinearly with increasing T. The current change |ΔI| due to light irradiation, which is proportional to the laser intensity, also decreases nonlinearly with increasing T. We explain well the experimental results using our proposed model with a new scattering channel due to the interaction between electrons and SPPs. Both our experimental and theoretical results reveal the novel phenomena due to the combination of photonics and electronics properties of Ag nanowires and they will be useful for scientific research, and technical applications.

The film quality of the electron transport layer (ETL) plays an important role in improving the performance of perovskite solar cells (PSCs). In order to reduce the effect of rough fluorine-doped SnO₂ (FTO)substrate on the film quality of the TiO₂ ETL, multiple cycles of spin-coating were employed to realize optimized TiO₂ film and improve the performance of PSCs with rough FTO. The results show that TiO₂ ETL was optimized most effectively using two spin-coating cycles, obtaining the best performance of PSCs with rough FTO. The carbon electrode-based PSCs were then demonstrated. Our work discusses the feasibility of low-quality rough FTO for the fabrication of PSCs and photodetectors to reduce costs.

The investigation of crystal growth is crucial for us to improve the film quality and photophysical properties of CH₃NH₃PbI₃ (MAPbI₃). In the two-step spin-coating process, the crystal structure could be modulated by controlling the growth conditions of PbI₂ and CH₃NH₃I (MAI) layers. In this paper, the PbI₂ layer was treated with annealing under different times. A liquid–liquid diffusion (LLD) mechanism is proposed to modify the deposition of MAI precursor solution and enhance the flatness of organic–inorganic hybrid perovskite film. Furthermore, the perovskite films are prepared using different concentrations of MAI. The evolution process of perovskite structure is observed by modulating the concentration of MAI. The spin-coating of moderate MAI tends to form high quality MAPbI₃ films with enhanced absorption and carrier extraction capabilities. The high concentration of MAI would cause the perovskite phase transition, which provides a novel perspective to modulate the structure of organic–inorganic hybrid perovskite in the two-step spin-coating process, although it deteriorates the device performance.

Photoelectric devices can be so widely used in various detection industries that people began to focus on its research. The research of photoelectric sensors with high performance has become an industry goal. In this paper, we prepared photodetectors using organic–inorganic hybrid semiconductor materials with narrow bandgap hexane-1,6-diammonium pentaiodobismuth (HDA-BiI₅) and investigated the detector photoresponse and time-response characteristics under a single light source. The device exhibits high photoresponsivity and fast response time. The photoresponsivity can reach 1.45 × 10⁻³ A/W and 8.5 × 10⁻⁴ A/W under laser irradiation at 375 nm and 532 nm wavelengths, and the rise and decay times are 63 ms and 62 ms, 62 ms and 64 ms, respectively. The device has excellent performance and this work can extend the application of organic–inorganic hybrid semiconductor materials in photovoltaic and photodetectors.

With the development of the semiconductor industry, research on photoelectronic devices has been emphasized. In this paper, a molecular semiconductor material with a narrow bandgap of hexane-1,6-diammonium pentaiodobismuth (HDA-BiI₅) was utilized to prepare photodetectors without electron transport layers. Using a single light source, the effects of different wavelengths and different powers on the photoresponsivity, switching ratio, specific detectivity, and external quantum efficiency of the device were investigated. It is demonstrated that this device has excellent responsivity, specific detectivity, stability, and repeatability, and this work will help expand the application of molecular semiconductor materials for photodetection.