Two‐step deposition method has been widely exploited to fabricate FA1‐xCsxPbI3 perovskite solar cells. However, in previous studies, CsI is mainly added into the PbI2 precursor with DMF/DMSO as ...solvent. Here in this study, a novel method to fabricate FA1‐xCsxPbI3 perovskite has been proposed. The CsI is simultaneously added into the PbI2 precursor and the organic FAI/MACl salts solution in our modified two‐step deposition process. The resulting FA1‐xCsxPbI3 film exhibits larger perovskite crystals and suppressed defect density (4.05×1015 cm−3) compared with the reference perovskite film (9.23×1015 cm−3) without CsI. Therefore, the obtained FA1‐xCsxPbI3 perovskite solar cells have demonstrated superior power conversion efficiencies (PCE=21.96 %) together with better long‐term device stability.
CsI is simultaneously added into PbI2 precursor and organic FAI solution in the two‐step deposition method to promote the film quality of FA1‐xCsxPbI3 film. Therefore, our modified two‐step deposition method could contribute to perovskite solar cells with superior performance.
Full text
Available for:
FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
This study aims to improve the performance and generalization capability of end-to-end autonomous driving with scene understanding leveraging deep learning and multimodal sensor fusion techniques. ...The designed end-to-end deep neural network takes as input the visual image and associated depth information in an early fusion level and outputs the pixel-wise semantic segmentation as scene understanding and vehicle control commands concurrently. The end-to-end deep learning-based autonomous driving model is tested in high-fidelity simulated urban driving conditions and compared with the benchmark of CoRL2017 and NoCrash. The testing results show that the proposed approach is of better performance and generalization ability, achieving a 100% success rate in static navigation tasks in both training and unobserved situations, as well as better success rates in other tasks than the prior models. A further ablation study shows that the model with the removal of multimodal sensor fusion or scene understanding pales in the new environment because of the false perception. The results verify that the performance of our model is improved by the synergy of multimodal sensor fusion with scene understanding subtask, demonstrating the feasibility and effectiveness of the developed deep neural network with multimodal sensor fusion.
The surface Fermi level pinning effect promotes the formation of metal‐independent Ohmic contacts for the high‐speed GaSb nanowires (NWs) electronic devices, however, it limits next‐generation ...optoelectronic devices. In this work, lead‐free all‐inorganic perovskites with broad bandgaps and low work functions are adopted to decorate the surfaces of GaSb NWs, demonstrating the success in the construction of Schottky‐contacts by surface engineering. Benefiting from the expected Schottky barrier, the dark current is reduced to 2 pA, the Ilight/Idark ratio is improved to 103 and the response time is reduced by more than 15 times. Furthermore, a Schottky‐contacted parallel array GaSb NWs photodetector is also fabricated by the contact printing technology, showing a higher photocurrent and a low dark current of 15 pA, along with the good infrared photodetection ability for a concealed target. All results guide the construction of Schottky‐contacts by surface decorations for next‐generation high‐performance III–V NWs optoelectronics devices.
Schottky‐contacted high‐performance GaSb nanowires photodetectors are achieved by the surface decoration of lead‐free all‐inorganic perovskites. Benefiting from the expected Schottky barrier, the dark current is reduced to 2 pA, the Ilight/Idark ratio is improved to 103 and the response time is reduced by more than 15 times under the illumination of a 1550 nm laser.
Full text
Available for:
BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
We report the isolation and characterization of a novel bat coronavirus which is much closer to the severe acute respiratory syndrome coronavirus (SARS-CoV) in genomic sequence than others previously ...reported, particularly in its S gene. Cell entry and susceptibility studies indicated that this virus can use ACE2 as a receptor and infect animal and human cell lines. Our results provide further evidence of the bat origin of the SARS-CoV and highlight the likelihood of future bat coronavirus emergence in humans.
Measurement-device-independent quantum key distribution (MDI-QKD), based on two-photon interference, is immune to all attacks against the detection system and allows a QKD network with untrusted ...relays. Since the MDI-QKD protocol was proposed, fiber-based implementations aimed at longer distance, higher key rates, and network verification have been rapidly developed. However, owing to the effect of atmospheric turbulence, MDI-QKD over a free-space channel remains experimentally challenging. Herein, by developing a robust adaptive optics system, high-precision time synchronization and frequency locking between independent photon sources located far apart, we realized the first free-space MDI-QKD over a 19.2-km urban atmospheric channel, which well exceeds the effective atmospheric thickness. Our experiment takes the first step toward satellite-based MDI-QKD. Moreover, the technology developed herein opens the way to quantum experiments in free space involving long-distance interference of independent single photons.
Full text
Available for:
CMK, CTK, FMFMET, IJS, NUK, PNG, UL, UM
Two-dimensional materials stacked atomically at small twist angles enable the modification of electronic states, motivating twistronics. Here, we demonstrate that heterostrain can rotate the graphene ...flake on monolayer h-BN within a few degrees (- 4° to 4°), and the twist angle stabilizes at specific values with applied constant strains, while the temperature effect is negligible in 100-900 K. The band gaps of bilayers can be modulated from ~ 0 to 37 meV at proper heterostrain and twist angles. Further analysis shows that the heterostrain modulates the interlayer energy landscape by regulating Moiré pattern evolution. The energy variation is correlated with the dynamic instability of different stacking modes of bilayers, and arises from the fluctuation of interlayer repulsive interaction associated with p-orbit electrons. Our results provide a mechanical strategy to manipulate twist angles of graphene/h-BN bilayers, and may facilitate the design of rotatable electronic nanodevices.
Full text
Available for:
IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
To improve the safety and efficiency of the intelligent transportation system, particularly in complex urban scenarios, in this paper a game theoretic decision-making framework is designed for ...connected automated vehicles (CAVs) at unsignalized roundabouts considering their personalized driving behaviours. Within the decision-making framework, a motion prediction module is designed and optimized using model predictive control (MPC) to enhance the effectiveness and accuracy of the decision-making algorithm. Besides, the payoff function of decision making is defined with the consideration of vehicle safety, ride comfort and travel efficiency. Additionally, the constraints of the decision-making problem are constructed. Based on the established decision-making model, Stackelberg game and grand coalition game approaches are adopted to address the decision making of CAVs at an unsignalized roundabout. Three testing cases considering personalized driving behaviours are carried out to verify the performance of the developed decision-making algorithms. The testing results show that the proposed game theoretic decision-making framework is able to make safe and reasonable decisions for CAVs in the complex urban scenarios, validating its feasibility and effectiveness. Stackelberg game approach shows its advantage in guaranteeing personalized driving objectives of individuals, while the grand coalition game approach is advantageous regarding the efficiency improvement of the transportation system.
Owing to the Fermi pinning effect arose in the metal electrodes deposition process, metal–semiconductor contact is always independent on the work function, which challenges the next‐generation ...optoelectronic devices. In this work, a metal‐assisted transfer approach is developed to transfer Bi2O2Se nanosheets onto the pre‐deposited metal electrodes, benefiting to the tunable metal–semiconductor contact. The success in Bi2O2Se nanosheets transfer is contributed to the stronger van der Waals adhesion of metal electrodes than that of growth substrates. With the pre‐deposited asymmetric electrodes, the self‐powered near‐infrared photodetectors are realized, demonstrating low dark current of 0.04 pA, high Ilight/Idark ratio of 380, fast rise and decay times of 4 and 6 ms, respectively, under the illumination of 1310 nm laser. By pre‐depositing the metal electrodes on polyimide and glass, high‐performance flexible and omnidirectional self‐powered near‐infrared photodetectors are achieved successfully. This study opens up new opportunities for low‐dimensional semiconductors in next‐generation high‐performance optoelectronic devices.
By adopting the metal‐assisted transfer approach, tunable metal–semiconductor contacts of Ohmic contact, Schottky contact, and asymmetric contact are achieved in Bi2O2Se nanosheet MSM photodetectors. With the asymmetric contact, the MSM photodetector displays the typical self‐powered NIR photodetection behaviors with a low dark current of 0.04 pA, and high Ilight/Idark ratio of 380.
Full text
Available for:
BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
PDF
