Perovskite Solar Cells go Outdoors: Field Testing and Temperature Effects on Energy Yield

Perovskite solar cells (PSC) have shown that under laboratory conditions they can compete with established photovoltaic technologies. However, controlled laboratory measurements usually performed do not fully resemble operational conditions and field testing outdoors, with day‐night cycles, changing irradiance and temperature. In this contribution, the performance of PSCs in the rooftop field test, exposed to real weather conditions is evaluated. The 1 cm² single‐junction devices, with an initial average power conversion efficiency of 18.5% are tracked outdoors in maximum power point over several weeks. In parallel, irradiance and air temperature are recorded, allowing us to correlate outside factors with generated power. To get more insight into outdoor device performance, a comprehensive set of laboratory measurements under different light intensities (10% to 120% of AM1.5) and temperatures is performed. From these results, a low power temperature coefficient of ?0.17% K^?1 is extracted in the temperature range between 25 and 85 °C. By incorporating these temperature‐ and light‐dependent PV parameters into the energy yield model, it is possible to correctly predict the generated energy of the devices, thus validating the energy yield model. In addition, degradation of the tested devices can be tracked precisely from the difference between measured and modelled power.     

Indoor Thin‐Film Photovoltaics: Progress and Challenges

Energy generation and consumption have always been an important component of social development. Interests in this field are beginning to shift to indoor photovoltaics (IPV) which can serve as power sources under low light conditions to meet the energy needs of rapidly growing fields, such as intelligence gathering and information processing which usually operate via the Internet‐of‐things (IoT). Since the power requirements for this purpose continue to decrease, IPV systems under low light may facilitate the realization of self‐powered high‐tech electronic devices connected through the IoT. This review discusses and compares the characteristics of different types of IPV devices such as those based on silicon, dye, III‐V semiconductors, organic compounds, and halide perovskites. Among them, specific attention is paid to perovskite photovoltaics which may potentially become a high performing IPV system due to the fascinating photophysics of the halide perovskite active layer. The limitations of such indoor application as they relate to the toxicity, stability, and electronic structure of halide perovskites are also discussed. Finally, strategies which could produce highly functional, nontoxic, and stable perovskite photovoltaics devices for indoor applications are proposed.     

Accelerating Atomic Catalyst Discovery by Theoretical Calculations‐Machine Learning Strategy

Atomic catalysts (AC) are emerging as a highly attractive research topic, especially in sustainable energy fields. Lack of a full picture of the hydrogen evolution reaction (HER) impedes the future development of potential electrocatalysts. In this work, the systematic investigation of the HER process in graphdyine (GDY) based AC is presented in terms of the adsorption energies, adsorption trend, electronic structures, reaction pathway, and active sites. This comprehensive work innovatively reveals GDY based AC for HER covering all the transition metals (TM) and lanthanide (Ln) metals, enabling the screening of potential catalysts. The density functional theory (DFT) calculations carefully explore the HER performance beyond the comparison of sole H adsorption. Therefore, the screened catalysts candidates not only match with experimental results but also provide significant references for novel catalysts. Moreover, the machine learning (ML) technique bag‐tree approach is innovatively utilized based on the fuzzy model for data separation and converse prediction of the HER performance, which indicates a similar result to the theoretical calculations. From two independent theoretical perspectives (DFT and ML), this work proposes pivotal guidelines for experimental catalyst design and synthesis. The proposed advanced research strategy shows great potential as a general approach in other energy‐related areas.     

New Lithium Salt Forms Interphases Suppressing Both Li Dendrite and Polysulfide Shuttling

Lithium–sulfur batteries (LSBs) are considered promising candidates for the next‐generation energy‐storage systems due to their high theoretical capacity and prevalent abundance of sulfur. Their reversible operation, however, encounters challenges from both the anode, where dendritic and dead Li‐metal form, and the cathode, where polysulfides dissolve and become parasitic shuttles. Both issues arise from the imperfection of interphases between electrolyte and electrode. Herein, a new lithium salt based on an imide anion with fluorination and unsaturation in its structure is reported, whose interphasial chemistries resolve these issues simultaneously. Lithium 1, 1, 2, 2, 3, 3‐hexafluoropropane‐1, 3‐disulfonimide (LiHFDF) forms highly fluorinated interphases at both anode and cathode surfaces, which effectively suppress formation of Li‐dendrites and dissolution/shuttling of polysulfides, and significantly improves the electrochemical reversibility of LSBs. In a broader context, this new Li salt offers a new perspective for diversified beyond Li‐ion chemistries that rely on a Li‐metal anode and active cathode materials.     

Simultaneous nitrogen and carbon removal in a packed A/O reactor: effect of C/N ratio on microbial community structure

In this research, a novel packed anoxic/oxic moving bed biofilm reactor (MBBR) was established to achieve high-organic matter removal rates, despite the carbon/nitrogen (C/N) ratio of 2.7–5.1 in the influent. Simultaneous nitrification–denitrification (SND) was investigated under a long sludge retention time of 104 days. The system exhibited excellent performance in pollutant removal, with chemical oxygen demand and total nitrogen (TN) enhanced to 93.6–97.4% and 34.4–60%, respectively. Under low C/N conditions, the nitrogen removal process of A/O MBBR system was mainly achieved by anaerobic denitrification. The increase of C/N ratio enhanced SND rate of the aerobic section, where dissolved oxygen was maintained at the range of 4–6 mg/L, and resulted in higher TN removal efficiency. The microbial composition and structures were analyzed utilizing the MiSeq Illumina sequencing technique. High-throughput pyrosequencing results indicated that the dominant microorganisms were Proteobacteria and Bacteroidetes at the phylum level, which contributes to the removal of organics matters. In the aerobic section, abundances of Nitrospirae (1.12–29.33%), Burkholderiales (2.15–21.38%), and Sphingobacteriales (2.92–11.67%) rose with increasing C/N ratio in the influent, this proved that SND did occur in the aerobic zone. As the C/N ratio of influent increased, the SND phenomenon in the aerobic zone of the system is the main mechanism for greatly improving the removal rate of TN in the aerobic section. The C/N ratio in the aerobic zone is not required to be high to exhibit good TN removal performance. When C/NH₄⁺ and C/TN in the aerobic zone were higher than 2.29 and 1.77, respectively, TN removal efficiency was higher than 60%, which means that carbon sources added to the reactor could be saved. This study would be vital for a better understanding of microbial structures within a packed A/O MBBR and the development of cost-efficient strategies for the treatment of low C/N wastewater.

     

Comparison of bacterial community structure and function under different petroleum hydrocarbon degradation conditions

Bioprocess and Biosystems Engineering - Bioremediation methods have been successfully applied to the removal of organic pollutants for decades, but the responses of the microbial community to...     

Upscale production of (R)-mandelic acid with a stereospecific nitrilase in an aqueous system

(R)-Mandelic acid (R-MA) is a key precursor for the synthesis of semi-synthetic penicillin, cephalosporin, anti-obesity drugs, antitumor agents, and chiral resolving agents for the resolution of racemic alcohols and amines. In this study, an enzymatic method for the large-scale production of R-MA by a stereospecific nitrilase in an aqueous system was developed. The nitrilase activity of the Escherichia coli BL21(DE3)/pET-Nit whole cells reached 138.6 U/g in a 20,000-L fermentor. Using recombinant E. coli cells as catalyst, 500 mM R,S-mandelonitrile (R,S-MN) was resolved into 426 mM (64.85 g/L) R-MA within 8 h, and the enantiomeric excess (ee) value of R-MA reached 99%. During the purification process, pure R-MA with a recovery rate of 78.8% was obtained after concentration and crystallization. This study paved the foundation for the upscale production of R-MA using E. coli whole cells as biocatalyst.

     

Economical production of isomaltulose from agricultural residues in a system with sucrose isomerase displayed on Bacillus subtilis spores

Bioprocess and Biosystems Engineering - A safe, efficient, environmentally friendly process for producing isomaltulose is needed. Here, the biocatalyst, sucrose isomerase (SIase) from Erwinia...     

新型冠状病毒肺炎疫情中医护人员个人防护装备的选择与使用

个人防护设备(personal protective equipment,PPE)是控制院内感染的必要装备,可有效降低医护人员职业暴露的风险。 目前,新型冠状病毒肺炎(coronavirus disease 2019,COVID-19)疫情引起国际高度关注,国内已确诊7万多例患者,死亡人数超过 2 700 人。此外,医护人员的感染超过 3 000 多例,这给医护人员(尤其是为COVID-19患者提供近距离诊疗和护理的医务人员),带来了新的风险和挑战。 本文从PPE的应用标准,正确穿、脱方法及预防防护后暴露的注意事项进行汇总和讨论。     

小儿肺热咳喘口服液联合三联吸入雾化治疗法对哮喘急性发作的影响

目的:探讨小儿肺热咳喘口服液联合三联吸入雾化治疗方案对哮喘患儿的治疗效果以及对肺功能的影响作用。方法:将我院自2017年1月至2018年11月间收治的哮喘患儿210例作为研究对象,按照随机数字表法分为两组各105例,研究组患儿在布地奈德、沙丁胺醇、异丙托溴铵三联吸入雾化治疗的基础上给予小儿肺热咳喘口服液进行治疗,对照组患儿仅给予三联雾化吸入治疗,对比观察两组患儿的疗效和预后。结果:研究组临床治疗后总有效率为95.24%,明显高于对照组77.14%(P0.05);治疗后研究组咳嗽消失时间、呼吸困难消失时间和急性发作随诊时间均明显短于对照组(P0.05),两组肺部喘鸣音消失时间比较差异无统计学意义(P0.05);治疗前患儿第一秒用力呼气量(forced expiratory volume in one second,FEV1)、最大肺活量(forced vital capacity,FVC)及FEV1/FVC值、呼气峰流速值(peak expiratory flowrate,PEF)对比无统计学意义(P0.05),治疗后1 d、3 d、7 d以上指标水平均明显升高,且在治疗后7 d,研究组明显高于对照组(P0.05)。治疗期间研究组有1例出现轻度腹泻,3例食欲减退,并发症的发生率为3.81%(4/105),对照组治疗期间2例出现轻度腹泻,4例食欲减退,并发症的发生率为5.71%(6/105),两组比较无统计学意义(P0.05)。结论:使用小儿肺热咳喘口服液联合三联吸入雾化法治疗儿童哮喘急性发作,可改善患儿临床症状和肺功能,疗效显著,可推广使用。