Mitigating Surface Deficiencies of Perovskite Single Crystals Enables Efficient Solar Cells with Enhanced Moisture and Reverse-Bias Stability

Metal halide perovskite single crystals are promising for diverse optoelectronic applications due to their outstanding properties. In comparison to the bulk, the crystal surface suffers from high defect density and is moisture sensitive; however, surface modification strategies of perovskite single crystals are relatively deficient. Herein, solar cells based on methylammonium lead triiodide (MAPbI₃) thin single crystals are selected as a prototype to improve single-crystal perovskite devices by surface modification. The surface trap passivation and protection against moisture of MAPbI₃ thin single crystals are achieved by one bifunctional molecule 3-mercaptopropyl(dimethoxy)methylsilane (MDMS). The sulfur atom of MDMS can coordinate with bare Pb²⁺ of MAPbI₃ single crystals to reduce surface defect density and nonradiative recombination. As a result, the modified devices show a remarkable efficiency of 22.2%, which is the highest value for single-crystal MAPbI₃ solar cells. Moreover, MDMS modification mitigates surface ion migration, leading to enhanced reverse-bias stability. Finally, the cross-link of silane molecules forms a protective layer on the crystal surface, which results in enhanced moisture stability of both materials and devices. This work provides an effective way for surface modification of perovskite single crystals, which is important for improving the performance of single-crystal perovskite solar cells, photodetectors, X-ray detectors, etc.     

Single Crystal Perovskite Solar Cells: Development and Perspectives

The efficiency of perovskite solar cells has increased to a certified value of 25.2% in the past 10 years, benefiting from the superior properties of metal halide perovskite materials. Compared with the widely investigated polycrystalline thin films, single crystal perovskites without grain boundaries have better optoelectronic properties, showing great potential for photovoltaics with higher efficiency and stability. Additionally, single crystal perovskite solar cells are a fantastic model system for further investigating the working principles related to the surface and grain boundaries of perovskite materials. Unfortunately, only a handful of groups have participated in the development of single crystal perovskite solar cells; thus, the development of this area lags far behind that of its polycrystalline counterpart. Therefore, a review paper that discusses the recent developments and challenges of single crystal perovskite solar cells is urgently required to provide guidelines for this emerging field. In this progress report, the optical and electrical properties of single crystal and polycrystalline perovskite thin films are compared, followed by the recent developments in the growth of single crystal perovskite thin films and the photovoltaic applications of this material. Finally, the challenges and perspectives of single crystal perovskite solar cells are discussed in detail.     

Roles of stress response-related signaling and its contribution to the toxicity of zearalenone in mammals

Zearalenone (ZEA) is a mycotoxin frequently found in cereal crops and cereal-derived foodstuffs worldwide. It affects plant productivity, and is also a serious hazard to humans and animals if being exposed to food/feed contaminated by ZEA. Studies over the last decade have shown that the toxicity of ZEA in animals is mainly mediated by the various stress responses, such as endoplasmic reticulum (ER) stress, oxidative stress, and others. Accumulating evidence shows that oxidative stress and ER stress signaling are actively implicated in and contributes to the pathophysiology of various diseases. Biochemically, the deleterious effects of ZEA are associated with apoptosis, DNA damage, and lipid peroxidation by regulating the expression of genes implicated in these biological processes. Despite these findings, the underlying mechanisms responsible for these alterations remain unclear. This review summarized the characteristics, metabolism, toxicity and the deleterious effects of ZEA exposure in various tissues of animals. Stress response signaling implicated in the toxicity as well as potential therapeutic options with the ability to reduce the deleterious effects of ZEA in animals were highlighted and discussed.     

Low‐Noise and Large‐Linear‐Dynamic‐Range Photodetectors Based on Hybrid‐Perovskite Thin‐Single‐Crystals

Organic–inorganic halide perovskites are promising photodetector materials due to their strong absorption, large carrier mobility, and easily tunable bandgap. Up to now, perovskite photodetectors are mainly based on polycrystalline thin films, which have some undesired properties such as large defective grain boundaries hindering the further improvement of the detector performance. Here, perovskite thin‐single‐crystal (TSC) photodetectors are fabricated with a vertical p–i–n structure. Due to the absence of grain‐boundaries, the trap densities of TSCs are 10–100 folds lower than that of polycrystalline thin films. The photodetectors based on CH₃NH₃PbBr₃ and CH₃NH₃PbI₃ TSCs show low noise of 1–2 fA Hz^?1/2, yielding a high specific detectivity of 1.5 × 10¹³ cm Hz^1/2 W^?1. The absence of grain boundaries reduces charge recombination and enables a linear response under strong light, superior to polycrystalline photodetectors. The CH₃NH₃PbBr₃ photodetectors show a linear response to green light from 0.35 pW cm^?2 to 2.1 W cm^?2, corresponding to a linear dynamic range of 256 dB.     

番茄GSNOR互作蛋白的筛选与鉴定

前期研究表明番茄S-亚硝基谷胱甘肽还原酶(GSNOR)基因参与硝酸盐胁迫应答,但其作用机理尚不清楚.本研究构建诱饵载体pGBKT7-GSNOR,将其转化至酵母感受态细胞Y2HGold中,结果显示重组质粒无自激活活性.利用酵母双杂交技术从拟南芥cDNA文库中筛选GSNOR的互作蛋白,对300个样品测序后通过NCBI BLAST进行分析,其中有260个获得基因号,占总数的92.9％.通过TAIR网站查找基因号对应的蛋白序列,得到了105个蛋白.利用Blast2 GO进行GeneOntology注释显示互作蛋白参与4个生物进程,11个细胞组分,4个分子功能过程.对得到的可能互作蛋白随机挑选了5个进行互作蛋白的分离和回复验证,结果发现,随机挑选的这些蛋白的菌落在营养缺陷型的平板上能够正常生长,从而验证了这些蛋白均为GSNOR的互作蛋白.此次酵母双杂交文库的成功筛选为进一步研究番茄GSNOR的分子作用机制奠定了基础.     

炭黑/白炭黑并用对胎侧胶性能的影响

研究炭黑/白炭黑并用对胎侧胶性能的影响。结果表明：混炼温度影响炭黑/白炭黑并用填充胶料的挤出性能和外观;炭黑/白炭黑并用填充胶料的门尼焦烧时间和t90与炭黑填充胶料相比均明显缩短,并随着白炭黑用量的增大呈延长趋势;随着炭黑/白炭黑并用体系中白炭黑用量的增大,硫化胶的100%和300%定伸应力减小,拉伸强度和拉断伸长率增大,耐臭氧老化性能明显改善,压缩疲劳温升和滞后损失减小,Payne效应呈现先减弱后增强的非线性变化趋势。     

Study of Water-Controlled and Environmentally Friendly Coal Mining Models in an Ecologically Fragile Area of Northwest China

Striking a balance between high-intensity coal mining and environmental protection has been a challenge in the Yushen mining area, which is an important coal production base in China located in an arid and semi-arid ecologically fragile environment. The 122,109 working face of the Caojiatan coal mine was used as a model to coordinate coal production with ecological protection. Theoretical analysis and field monitoring revealed that the maximum surface subsidence was 5.6 m, and the development height of the diversion fracture zone was 21 times the coal seam thickness. The influence of mining process parameters and mining methods on surface ecological damage and water loss was further analyzed using the fluid–solid coupling method. The results showed that exclusive pursuit of high-intensity mining would induce irreversible disasters including aquifer water loss and cultivated land damage; the degree of influence was directly proportional to the working face length, mining height, and mining method. Proper adjustments of these parameters could help realize water-controlled coal mining. The results provide an empirical basis for allowing both exploitation of coal resources and protection of the environment in ecologically fragile areas.

     

双组分钛基催化剂合成反式-1,4-聚异戊二烯/3,4-聚异戊二烯复合胶

以钛酸正戊酯[Ti(C5H11O)4]-TiCl4/MgCl2(简称Ti)-Al(Et)3(简称Al)组成的双组分钛基催化剂引发异戊二烯(Ip)聚合,原位合成反式-1,4-聚异戊二烯(TPI)/3,4-聚异戊二烯(PIp)复合胶,考察了聚合活性和复合胶在汽油中可溶性的影响因素,表征了复合胶的微观结构,并研究了复合胶的特性黏数。结果表明,在Ti/Ip(摩尔比)为6×10-5、Ti(C5H11O)4/Ip(摩尔比)为1.2×10-3、Al/Ti(C5H11O)4(摩尔比)为10的条件下,聚合活性最优;复合胶的汽油可溶物部分含量变化的趋势遵循以下规律:随着Ti(C5H11O)4用量的增加而增大;随着Al/Ti(C5H11O)4的增大先升高后降低最后趋于平稳;随着Ti/Ip的增大而逐渐降低。TPI的相对分子质量大于3,4-PIp。     

钴系催化剂催化异戊二烯的本体聚合

以环烷酸钴(简称Co)-三异丁基铝(简称Al)-CS2为催化剂引发异戊二烯(Ip)本体聚合合成了聚异戊二烯(PI),考察了单体转化率、催化剂效率(CE)和聚合物特性黏数([η])的影响因素,并对PI的微观结构和玻璃化转变温度(Tg)进行了表征。结果表明,在Co/Ip(摩尔比)为4.0×10-4、Al/Co(摩尔比)为60、CS2/Co(摩尔比)为15、反应温度为50℃下聚合48 h所得PI中1,4-结构、3,4-结构、1,2-结构质量分数分别为18.6%,41.2%,40.2%,Tg为-6.5℃;反应温度对PI的[η]影响最大,随着反应温度的升高,[η]呈下降趋势,且均小于1 dL/g;其他聚合条件的变化对PI的[η]影响不大。