贫PbI_(2)基体的胶体量子点固体用于高效红外太阳能电池

胶体量子点(CQD)具有优异的红外光吸收能力和光谱可调特性,是用于制备高效太阳能电池最有前途的红外光电材料之一。然而,以醋酸铵(AA)为添加剂的液相配体交换会导致CQD固体中产生宽带隙PbI_(2)基质,其将作为电荷传输势垒,在很大程度上影响了CQD太阳能电池(CQDSC)中载流子的提取,从而影响了光伏性能。本文报道利用二甲基碘化铵(DMAI)调节CQD配体交换过程,使载流子在CQD固体中的传输势垒大幅降低。通过对CQD固体进行全面的表征和理论计算,充分揭示了DMAI和CQD之间的相互作用。结果表明,通过DMAI调节CQD配体交换过程,使CQD固体均匀堆积,提高了载流子输运性能,并且陷阱辅助复合受到显著抑制。因此,CQDSC器件中的载流子提取得到了大幅提高,能量转换效率(PCE)比用AA制备的CQDSC器件提高了17.8%。此工作为调控CQD表面化学特性提供了新的研究思路,并为降低CQD固体中载流子输运的势垒提供了可行的方法。

Local density of optical states calculated by the mode spectrum in stratified media

The local density of optical states(LDOS)is an important physical concept,which can characterize the spontaneous emission of microcavities.In order to calculate the LDOS,the relationship between the mode spectrum and the LDOS is established.Then,based on the transfer matrix method and the effective resonator model,the leaky loss of the leaky mode and the mode spectrum in the one-dimensional photonic bandgap crystal waveguide are calculated,results of which indicate that the mode spectrum can characterize the leaky loss of the leaky mode.At last,the density of optical states(DOS),and the LDOS in each layer are calculated.The partial DOS and the partial LDOS in the quantum well,related to the fundamental leaky mode,can be used to find out the optimal location of the quantum well in the defect layer to couple more useful photons into the lasing mode for lasers.

Rapid and user-friendly open-source CRISPR/Cas9 system for single-or multi-site editing of tomato genome

CRISPR/Cas9-induced genome editing is a powerful tool for studying gene function in a variety of organisms,including plants.Using multi-sgRNAs to target one or more genes is helpful to improve the efficacy of gene editing and facilitate multi-gene editing.Here,we describe a CRISPR/Cas9 system which can be conveniently developed as a CRISPR kit.SgRNA expression cassettes can be rapidly generated by one-step PCR using our CRISPR kit.In our kit,there are two binary vectors pHNCas9 and pHNCas9HT.The binary vector pHNCas9 was constructed to allow to assemble up to eight sgRNA expression cassettes by one-step Golden Gate cloning.Another binary vector pHNCas9HT can be used to generate a large number of single target constructs by directly transforming ligation reactions products into A.tumefaciens without several procedures,such as PCR and plasmid extraction.The two binary vectors are designed according to the principles of standard BioBrick assembly to be used as an open-source tool.For example,we used BioBrick as a visual T-DNA tag.We also developed a primer design aid to complement the system.With this primer design aid,researchers can rapidly obtain primers and GC content,and sgRNA sequence of target site.Our CRISPR/Cas9 system can perform single-and multi-site editing and multiple gene editing to produce various types of mutations in tomato.This rapid and user-friendly CRISPR/Cas9 system for tomato can be potentially used for mutagenesis of important crop species for genetic improvement and is suitable for research into the function of genes.

Analysis of the gluon distribution with next-to-leading order splitting function at small-x^(*)

An approximated solution for the gluon distribution from DGLAP evolution equations with the NLO splitting function in the small-x limit is presented.We first obtain simplified forms of the LO and NLO splitting functions in the small-x limit.With these approximated splitting functions,we obtain the analytical gluon distribution using the Mellin transform.The free parameters in the boundary conditions are obtained by fitting the CJ15 gluon distribution data.We find that the asymptotic behavior of the gluon distribution is consistent with the CJ15 data;however,the NLO results considering the"ladder"structure of gluon emission are slightly better than the LO results.These results indicate that the corrections from NLO have a significant influence on the behavior of the gluon distribution in the small-x region.In addition,we investigate the DGLAP evolution of the proton structure function using the analytical solution of the gluon distribution.The differential structure function reveals that our results have a similar tendency to the CJ15 data at small-x.

Colloidal quantum dot for infrared-absorbing solar cells:State-oftheart and prospects

Colloidal quantum dot(CQD)shows great potential for application in infrared solar cells due to the simple synthesis techniques,tunable infrared absorption spectrum,and high stability and solution-processability.Thanks to significant efforts made on the surface chemistry of CQDs,device structure optimization,and device physics of CQD solar cells(CQDSCs),remarkable breakthroughs are achieved to boost the infrared photovoltaic performance and stability of CQDSCs.In particular,the CQDSC with a high power conversion efficiency of~14%and good stability is reported,which is very promising for infrared-absorbing solar cells.In this review,we highlight the unique optoelectronic properties of CQDs for the development of infrared-absorbing solar cells.Meanwhile,the latest advances in finely controlling surface properties of CQDs are comprehensively summarized and discussed.Moreover,the device operation of CQDSCs is discussed in-depth to highlight the impact of the device structure optimization of CQDSCs on their photovoltaic performance,and the emerging novel types of CQDSCs,such as semitransparent,flexible,and lightweight CQDSCs,are also demonstrated.The device stability of CQDSCs is also highlighted from the viewpoint of practical applications.Finally,the conclusions and possible challenges and opportunities are presented to promote the development steps of the CQDSCs with higher infrared photovoltaic performance and robust stability.

浙江海域海龟记录及其种群现状

东海浙江海域分布着5种海龟,分别为棱皮龟(Dermochelys coriacea)、绿海龟(Chelonia mydas)、红海龟(Caretta caretta)、玳瑁(Eretmochelys imbricata)和太平洋丽龟(Lepidochelys olivacea),均被列为国家一级重点保护野生动物。目前,针对浙江海域的海龟种群现状调查较为缺乏。为此,本研究通过搜集互联网平台上1981年4月1日至2022年12月31日的浙江海域海龟发现记录,尤其是整合了短视频平台渔民上传的影像记录这一新颖来源的数据,对浙江海域海龟种群现状进行评估。共搜集到互联网上浙江海域海龟报道109笔,共计234只,其中红海龟个体数占79.1%,绿海龟占9.4%,棱皮龟占6.0%,太平洋丽龟占4.3%,玳瑁占1.3%。5种海龟所有个体均为成体。同时,通过短视频平台获取的记录案例数最多,占总记录案例的66.1%,占近10年所有记录案例的93.6%。本研究结果表明浙江海域红海龟数量最多,绿海龟、棱皮龟和太平洋丽龟相对较少,玳瑁最少。同时,短视频数据从2020年开始急剧增多,这提示短视频数据可能是未来海洋爬行动物种群数量调查的重要数据源。

Improvement on the topological localized interface enabled by chiral symmetry

Zero-energy topological states,which are protected by chiral symmetry against certain perturbations topologically,localize at interfaces between trivial and non-trivial phases in the Su–Schrieffer–Heeger(SSH)chain model.Here,we propose and demonstrate a method to manipulate chiral symmetry itself to improve the localized interfaces and enlarge the mode volume of topological states in the SSH model,thus optimizing the lasing performance of localized interfaces.As multiple defects corresponding to off-diagonal perturbations in an eigenmatrix are introduced,the topological state expands and extends to extra defects at the topological interface without breaking chiral symmetry.We apply the proposed method in electrical pumping semiconductor laser arrays to verify our theoretical prediction and optimize the output characteristics of the devices.The measured results of the proposed multi-defect SSH laser array show that the output power has been increased by 27%,and the series resistance and far-field divergence have been reduced by half compared to the traditional SSH laser array,establishing a high-performance light source for integrated silicon photonics,infrared light detection and ranging,and so on.Our work demonstrates that the proposed method is capable of improving topological localized interfaces and redistributing zero-energy topological states.Furthermore,our method can be applied to other platforms and inspire optimizations of more devices in broader areas.

电注入下的人工微结构模式调控激光研究进展

电注入半导体激光器相较于其他类型激光器具有电光转换效率高、体积小、寿命长等优势,近年来在显示、材料加工、医疗、通讯等领域的市场占有份额日益增长.激光器的模式特性直接影响激光器的输出性能,如功率、光束质量、光谱线宽等通过引入人工微结构,结合宇称时间对称、连续谱束缚态以及多模腔杂化调控手段,不仅可以拓展半导体激光器的物理研究范畴,同时有效优化激光器的性能,进一步增加了半导体激光器的多元应用场景.本文从模式调控的角度出发,对电注入下的人工微结构半导体激光器展开综述,包括国内外研究发展现状、物理原理以及相应的应用,最后进行了总结与展望.

Narrow vertical beam divergence angle for display applications of 645 nm lasers

We design a 645 nm laser diode(LD)with a narrow vertical beam divergence angle based on the mode expansion layer.The vertical beam divergence of 10.94°at full width at half-maximum is realized under 1.5 A continuous-wave operation,which is the smallest vertical beam divergence for such an LD based on the mode expansion layer,to the best of our knowledge.The threshold current and output power are 1.07 A and 0.94 W,limited by the thermal rollover for the 100μm wide and 1500μm long broad area laser,and the slope efficiency is 0.71 W/A.The low coherence device is fabricated with the speckle contrast of 3.6%and good directional emission.Such 645 nm LDs have promising applications in laser display.

Ligand exchange engineering of FAPbI_(3) perovskite quantum dots for solar cells

Formamidinium lead triiodide(FAPbI_(3))perovskite quantum dots(PQDs)show great advantages in photovoltaic applications due to their ideal bandgap energy,high stability and solution processability.The anti-solvent used for the post-treatment of FAPbI_(3) PQD solid flms signifcantly afects the surface chemistry of the PQDs,and thus the vacancies caused by surface ligand removal inhibit the optoelectronic properties and stability of PQDs.Here,we study the efects of diferent anti-solvents with diferent polarities on FAPbI_(3) PQDs and select a series of organic molecules for surface passivation of PQDs.The results show that methyl acetate could efectively remove surface ligands from the PQD surface without destroying its crystal structure during the post-treatment.The benzamidine hydrochloride(PhFACl)applied as short ligands of PQDs during the post-treatment could fll the A-site and X-site vacancies of PQDs and thus improve the electronic coupling of PQDs.Finally,the PhFACl-based PQD solar cell(PQDSC)achieves a power conversion efciency of 6.4%,compared to that of 4.63%for the conventional PQDSC.This work provides a reference for insights into the surface passivation of PQDs and the improvement in device performance of PQDSCs.

Recombination and repeat-induced point mutation landscapes reveal trade-offs between the sexual and asexual cycles of Magnaporthe oryzae

The fungal disease caused by Magnaporthe oryzae is one of the most devastating diseases that endanger many crops worldwide.Evidence shows that sexual reproduction can be advantageous for fungal diseases as hybridization facilitates host-jumping.However,the pervasive clonal lineages of M.oryzae observed in natural fields contradict this expectation.A better understanding of the roles of recombination and the fungi-specific repeat-induced point mutation(RIP)in shaping its evolutionary trajectory is essential to bridge this knowledge gap.Here we systematically investigate the RIP and recombination landscapes in M.oryzae using a whole genome sequencing data from 252 population samples and 92 cross progenies.Our data reveal that the RIP can robustly capture the population history of M.oryzae,and we provide accurate estimations of the recombination and RIP rates across different M.oryzae clades.Significantly,our results highlight a parent-of-origin bias in both recombination and RIP rates,tightly associating with their sexual potential and variations of effector proteins.This bias suggests a critical trade-off between generating novel allelic combinations in the sexual cycle to facilitate host-jumping and stimulating transposon-associated diversification of effectors in the asexual cycle to facilitate host coevolution.These findings provide unique insights into understanding the evolution of blast fungus.