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In this work, structure designs and the corresponding energy loss analysis are conducted to achieve the high-efficiency n-type rear-junction solar cells with polysilicon passivated contact. We focus on the front-side structure design of solar cells, considering that the primary efficiency loss of the conventional n-type polysilicon passivated contact cells with boron-diffusion emitter is from the front side. A well-designed rear-junction solar cell with front localized n-type and rear full-area p-type polysilicon passivated contacts is expected to overcome these problems. However, the efficiency of rear-junction solar cells is sensitive to the front-side electrode contact resistivity. To accurately assess the practically achievable efficiency that the current technology can reach, we develop a simple modified TLM with wet-chemical etching to measure the contact resistivity of the n-type polysilicon contact. This method does not require relatively expensive photolithography and reactive ion etching tools and is easy to be used. When the contact resistivity of the front-side localized n-type polysilicon contact reaches 0.002 Ω·cm2 with a saturation current density of ~10 fA/cm2 in the front-side un-diffused area, the efficiency of the rear-junction n-type solar cell is expected to be ~26%, showing its potential for application in mass-production of high-efficiency crystalline silicon solar cells.

Hydrogenated amorphous silicon (a-Si:H) deposited using plasma-enhanced chemical vapor deposition (PECVD) is used as the passivation layer for p-type multi-crystalline black silicon (p-mc-b-Si) wafers. The effects of deposition conditions on passivation quality are investigated. The optimized a-Si:H passivation layer enables the best surface passivation with an implied open-circuit voltage (iVoc) of 710 mV, which is better than other conventional passivation materials. The excellent passivation quality possibly resulted from that the activated hydrogen from a-Si:H at ~200 °C was able to passivate both surface defect states and bulk trap states of p-mc-b-Si effectively. Moreover, an additional SiNx capping layer helps to reduce reflectance significantly and to keep passivation quality. This work suggests that b-Si passivated by a-Si:H/SiNx stack film shows potential for various optoelectronic devices that requires both excellent optical anti-reflectance and surface passivation.

Digital inclusion can bridge the digital divide and reduce the social exclusion of older adults, yet it is understudied in China. This research examined factors influencing the digital inclusion of older adults in China and the relationship between digital inclusion and quality of life. Data collected from 312 older people (M = 69.6 years old) in Nanjing were included in a multinomial logit model to tackle these questions. Their attitudes toward technology were the most significant factor predicting their digital inclusion. Other factors included party affiliation, living situation, personal average monthly income, occupation, and capacity for instrumental activities of daily living (IADLs). This study shows digital inclusion has a direct impact on quality of life. It also serves as an intermediate variable that affects older people's attitudes toward technology and their IADL capacities. Most importantly, digital inclusion promotes social integration of older adults and improves the quality of their lives. Hence, it should not be ignored. Older people's attitudes toward technology are one of the keys to promoting their digital inclusion.

With the rise of unmanned driving technology and advanced driver assistance systems (ADAS), millimeter-wave radar plays a key role in the field of autonomous driving due to its unique advantages. It can provide forward target information (distance, velocity and angle) for vehicle decision-making and execution systems. Linear frequency modulated continuous wave (LFMCW) automotive radar usually divides the velocity ambiguity resolution and angle estimation into two frames for processing, which will reduce the radar data rate. This paper proposes an improved automotive LFMCW radar multi-target recognition method, which uses the TMD method to transmit sawtooth signals with different time widths and the same bandwidth, and completes range velocity calculation, angle estimation and divides the velocity ambiguity resolution within one frame. This algorithm can simplify the steps of resolving velocity ambiguity and improve the angle measurement accuracy. And it has certain reference significance for the research and application of the LFMCW automotive radar.

Glyceollins are a class of antimicrobial prenylated pterocarpans produced in soybean seedlings upon fungus elicitation. Priming with reactive oxygen species (ROS) prior to elicitation with Rhizopus oligosporus/oryzae (R) was investigated for its potential to enhance glyceollin production. ROS-priming prior to R-elicitation (ROS + R) increased glyceollin production (8.6 ± 0.9 µmol/g dry weight (DW)) more than 4-fold compared to elicitation without priming (1.9 ± 0.4 µmol/g DW). Furthermore, ROS-priming was superior to two physical primers which were used as benchmark primers, namely slicing (5.0 ± 0.6 µmol glyceollins/g DW) and sonication (4.8 ± 1.0 µmol glyceollins/g DW). Subsequently, the robustness of ROS + R was assessed by applying it to another soybean cultivar, where it also resulted in a significantly higher glyceollin content than R-elicitation without priming. ROS-priming prior to elicitation provides opportunities for improving the yield in large-scale production of natural antimicrobials due to the ease of application and the robustness of the effect across cultivars.

A comparison study of ultrathin atomic layer deposited AlOx, wet-chemically oxidized SiOx, and their combination as the tunnel layer in TOPCon structure with both B-doped and P-doped poly-Si contact layers on n-type c-Si wafers was carried out. The passivation quality with the three types of tunnel layers was examined as a function of thickness and annealing temperature. Ideally, the high density of negative fixed charge in the AlOx is expected to provide a positive benefit on the passivation quality with p-type poly-Si as the contact layer, however, it is surprisingly observed that the AlOx and AlOx/SiOx do not yield a better passivation than the SiOx. Searching for the mechanisms behind, an interesting phenomenon is observed that the AlOx, especially the AlOx/SiOx bi-layer, significantly enhances B diffusion and suppresses P diffusion. It is also found a remarkable accumulation of B in the AlOx and AlOx/SiOx region, forming a reservoir for B diffusion. Furthermore, the free carrier assistant extrinsic diffusion is an additional factor for the enhanced B and retarded P diffusions by the AlOx/SiOx. The enhanced B diffusion causes extra Auger recombination as well as recombination through B–O pair defects and degrades the p-TOPCon passivation quality; additionally, a quantity of Al diffuse into the c-Si wafer could be another potential factor degrading passivation quality, because Al forms deep-level defects and induces a significant SRH recombination.

A rapid thermal anneal (RTA) is used to crystallize the plasma-enhanced chemical vapor deposition (PECVD) deposited hydrogenated amorphous silicon (a-Si:H) thin film to form the phosphorus-doped polysilicon passivated contact in tunnel oxide passivated contact (TOPCon) solar cells. The effects of annealing temperature, annealing time, cooling time, and the polysilicon thickness on the surface passivation are investigated. The primary advantage of the RTA is reducing the whole crystallization period to ~15 min, shorter than the conventional tube-furnace annealing period of >60 min. We find that the RTA is a robust method to prepare high-quality polysilicon passivated contact without introducing blistering when the thickness of the a-Si:H is less than 40 nm. The optimized RTA process leads to an implied open-circuit voltage (iVoc) of 712 mV and a single-sided dark saturation current density (J0,s) of 12.5 fA/cm2 in the as-annealed state, which is inferior to the surface passivation of the controlled one prepared by a tube furnace annealing. Fortunately, a subsequent Al2O3 capping hydrogenation improves the iVoc and J0,s to 727 mV and 4.7 fA/cm2, respectively. The champion conversion efficiency of 23.04% (Voc = 679.0 mV, Jsc = 41.97 mA/cm2 and FF = 80.86%) is achieved, which demonstrates the effectiveness of RTA for preparing a high-efficiency polysilicon passivated-contact solar cell.

To develop a solvent desorption gas chromatographic method for determination of n-pentanol in the workplace air.n-Pentanol in the workplace air was collected with activated carbon tubes, desorbed with 2% 2-propanol in carbon disulfide, separated with a nitroterephthalic acid-modified FFAP capillary column, and detected with flame ionization detector.The limit of detection was 0.2 mg/L; the lower limit of quantification was 0.6 mg/L; the linear range was 0.6-4072.0 mg/L. The minimum detectable mass concentration was 0.2 mg/m3 for 1.5 L of air sample. This method was highly repeatable. The relative standard deviations were 2.3%-5.4%. The average desorption efficiencies were 86.9%-94.2%. The absorption efficiencies were 100%. The breakthrough volume was above 8.0 mg in 100-mg activated carbon. The samples in activated carbon tubes could be stored for at least 14 days at room temperature.The method is feasible for determination of n-pentanol in the workplace air.

Since the cost of RFID tags reducing constantly, the scale of its applications enlarges in industries and extends to various fields in our daily work and life. However, due to the openness of RFID, it owns a high attack risk when applied. This paper presents a model based on AES and ECC, which can protect users' privacy and implement access controls. This model takes advantage of both the virtues of a symmetric encryption algorithm and asymmetric encryption algorithm, encrypting AES key with ECC and empowering the client to encrypt system's ECC public key by using an ECC private key.

Présentation (30 diapos); National audience

International audience

Autres productions; Does the Chinese National Petroleum Corporation (CNPC) intend to, and is it in a position to, engage in a race to the bottom regarding environmental standards and norms in Chad's oil sector? Based on recent empirical research, we will focus on the entangled relationships which are emerging following the arrival of CNPC in the Chadian oil sector (initially dominated by Exxon, a US oil major). Chinese environmental regulations in the oil sector and their increasing enforcement have resulted in a comprehensive and composite environmental management system, influenced by Chinese, international and local practices. When entering the Chadian oil sector in 2007, the CNPC thus appears to be well prepared to face comparison with the 'Exxon-Doba' project, a World Bank supported project (1998-2007). Large parts of the expected oil production in the CNPC fields will have to be exported. Among the several transport options available, the most viable appears to be using the pipeline built and administered by the Exxon consortium. The merger of the two oil streams appears as plausible but will put a burden on CNPC´s capacity to engage in meaningful dialogues with stakeholders and thus compete in the setting of new environmental best practices.

National audience