离子液体界面修饰的高效稳定FAPbI_(3)钙钛矿太阳能电池

碘铅甲眯(FAPbI_(3))钙钛矿太阳能电池因其优异的光伏性能而受到广泛关注,但器件的长期稳定性仍然是FAPbI_(3)太阳能电池的关键问题。FAPbI_(3)黑色钙钛矿相在室温下会相变为黄色非钙钛矿相,且水分会加速这一相变。界面工程是提高钙钛矿太阳能电池稳定性的常用方法之一。作为绿色溶剂,离子液体被认为是有毒界面修饰剂的潜在替代品,这也提高了它们的商业可行性,并加速了它们在可再生能源市场的应用。本研究利用具有低挥发性、低毒性、高导电性和高热稳定性的离子液体1-乙基-3-甲基咪唑四氟硼酸盐(EMIM[BF_(4)])来修饰钙钛矿太阳能电池的电子传输层和钙钛矿层之间的界面。离子液体的引入不仅减少了界面缺陷,而且提高了钙钛矿薄膜的质量。密度泛函理论计算表明,离子液体与钙钛矿表面之间存在较强的界面相互作用,有利于降低钙钛矿表面缺陷态密度,稳定钙钛矿晶格。除钙钛矿薄膜缺陷外,溶液处理的SnO_(2)也存在表面缺陷。在SnO_(2)表面的缺陷产生缺陷态,也会导致能带对准问题和稳定性问题。密度泛函理论计算表明,有离子液体的表面间隙态比没有离子液体的表面间隙态小,这种减弱的表面间隙态表明表面区域载流子复合减少,有利于提高器件性能。因此,我们实现了功率转换效率大于22%的离子液体修饰的FAPbI_(3)钙钛矿太阳能电池(对照21%)。在相对湿度~20%的干箱中存放1800h以上后,冠军器件保留了初始状态的~90%,而控制器件降解为非钙钛矿黄色六方相(δ-FAPbI_(3))。

轻质可压缩壳聚糖/石墨烯复合气凝胶的制备与性能

以石墨烯气凝胶(GA)为骨架,向其浇注壳聚糖(CS)醋酸溶液制备出多重网络结构的壳聚糖/石墨烯复合气凝胶(CGA),并探究了气凝胶的微观结构与性能的关系。采用扫描电镜、红外光谱、比表面积分析、热常数分析以及压缩性能测试等方法详细表征了材料的结构和性能。研究发现,杂化气凝胶丰富发达的孔洞结构赋予了材料轻质低密度的特性;多重网络结构的构筑,使材料具有良好的回弹性;CS与GA在界面上交联,使杂化气凝胶的压缩强度由10.02 kPa提高到99.83 kPa,弹性模量由19.75 kPa增加至244.66 kPa。这种有机-无机多重网络结构的设计,提高了GA的可压缩性,解决了GA压缩易破碎的问题。

Crystallization and Orientation Modulation Enable Highly Efficient Doctor-Bladed Perovskite Solar Cells

With the rapid rise in perovskite solar cells(PSCs)performance,it is imperative to develop scalable fabrication techniques to accelerate potential commercialization.However,the power conversion efficiencies(PCEs)of PSCs fabricated via scalable two-step sequential deposition lag far behind the state-of-the-art spin-coated ones.Herein,the additive methylammonium chloride(MACl)is introduced to modulate the crystallization and orientation of a two-step sequential doctorbladed perovskite film in ambient conditions.MACl can significantly improve perovskite film quality and increase grain size and crystallinity,thus decreasing trap density and suppressing nonradiative recombination.Meanwhile,MACl also promotes the preferred face-up orientation of the(100)plane of perovskite film,which is more conducive to the transport and collection of carriers,thereby significantly improving the fill factor.As a result,a champion PCE of 23.14%and excellent longterm stability are achieved for PSCs based on the structure of ITO/SnO_(2)/FA_(1-x)MA_xPb(I_(1-y)Br_y)_3/Spiro-OMeTAD/Ag.The superior PCEs of 21.20%and 17.54%are achieved for 1.03 cm~2 PSC and 10.93 cm~2 mini-module,respectively.These results represent substantial progress in large-scale two-step sequential deposition of high-performance PSCs for practical applications.

Organic additives in all-inorganic perovskite solar cells and modules:from moisture endurance to enhanced efficiency and operational stability

Power conversion efficiency(PCE) of perovskite solar cells(PSC) has been skyrocketed to certified 25.5% owing to their improved and tunable optoelectronic properties. Although, various strategies have been adopted to date regarding PCE and stability enhancement within PSC technology, certain instability factors(moisture, heat, light) are hindering their commercial placement. Recently, all-inorganic PSCs got hype in the photovoltaic research community after they attained PCE > 20% and due to their significant endurance against heat and light mishmashes, but there only left moisture sensitivity as the only roadblock for their industrial integration. Here, we review the recent progress of additive inclusion into allinorganic(CsPbX_(3)) PSCs to stabilize their intrinsic structure and to withstand the performance limiting factors. We start with the detailed description of chemical instability of different perovskite compositions, phase segregation, and how organic molecules and dyes help to repair the structural defects to improve the overall PCE and stability of PSCs. Moisture endurance as a result of chemical passivation through organic additives, low-dimensional inorganic PSCs to enhance device stability and scalable fabrication of CsPbX_(3) PSCs are also reviewed. The challenges of module degradation and design implications with proposed strategies and outlook are interpreted in the ending phrases of this review.

Valleytronics in transition metal dichalcogenides materials

Valley degree of freedom in the first Brillouin zone of Bloch electrons offers an innovative approach to information storage and quantum computation.Broken inversion symmetry together with the presence of time-reversal symmetry endows Bloch electrons non-zero Berry curvature and orbital magnetic moment,which contribute to the valley Hall effect and optical selection rules in valleytronics.Furthermore,the emerging transition metal dichalcogenides(TMDs)materials naturally become the ideal candidates for valleytronics research attributable to their novel structural,photonic and electronic properties,especially the direct bandgap and broken inversion symmetry in the monolayer.However,the mechanism of inter-valley relaxation remains ambiguous and the complicated manipulation of valley predominantly incumbers the realization of valleytronic devices.In this review,we systematically demonstrate the fundamental properties and tuning strategies(optical,electrical,magnetic and mechanical tuning)of valley degree of freedom,summarize the recent progress of TMD-based valleytronic devices.We also highlight the conclusion of present challenges as well as the perspective on the further investigations in valleytronics.

Tip-assisted ambient electric arc ionization mass spectrometry for rapid detection of trace organophosphorus pesticides in strawberry

In this study,an ambient mass spectrometry(AMS)based method was developed for rapid detection of organophosphorus pesticides in strawberry.This method combines an electric arc and a microsyringe tip to realize tip-assisted ambient electric arc ionization(TAAEAI).A high-voltage electric arc can be applied to the microsyringe tip to generate an electric field,which results in corona discharge at the microsyringe tip.The juiced strawberry sample loaded on the tip could be directly ionized with TAAEAI and then analyzed by a mass spectrometer.TAAEAI-MS was successfully applied to analyze 6 organophosphorus pesticides in three strawberry samples.Malathion and profenofos were detected from the investigated strawberry samples.This method could quantitatively determine the contents of organophosphorus pesticides in strawberry with high reproducibility,high precision,and high sensitivity.Sample matrices did not interfere with the pesticide analysis.The recoveries of organophosphorus pesticides spiked in strawberry samples varied between 82.6%and 116%with relative standard deviations(RSDs)less than 9.2%.The limits of detection(LODs)varied between 0.0124µg/g and 0.0245µg/g,while the limits of quantification(LOQs)varied between 0.0413µg/g and 0.0817µg/g.The coefficients of determination(R2)of the method were determined to be>0.995.The method established here may have potential application in the detection of organophosphorus pesticides in vegetables and fruits.

Applications of ambient electric arc ionization mass spectrometry in saline samples

Salinity tolerance of ambient electric arc ionization(AEAI)was evaluated by comparing electrospray ionization for various samples at NaCl concentrations from 0 to 1000 mmol/L.AEAI-mass spectrometry(AEAI-MS)exhibited an excellent signal intensity even at NaCl concentrations of 1000 mmol/L,while the ESI-MS had no signal because high salinity has a strong inhibitory effect on analytes.The sodium adduct was verified using LiCl instead of NaCl.AEAI-MS successfully quantified saline samples with an excellent quantitative ability(R^(2)≥0.998).We also achieved some analytical samples in the buffer solution at a very high concentration and even in a saturated salt solution.Overall,AEAI-MS has protonated ions for most target analytes.In addition,the relationship between auxiliary temperature and the distance from the sample to the arc was investigated,and the results indicated that thermal desorption plays an important role in AEAI source.

Smart nanocarriers as therapeutic platforms for bladder cancer

Although patients benefit from surgical transurethral resection of bladder cancers,some niduses are missed or incompletely resected,and small malignant lesions may recur.Intravesical chemotherapy and immunotherapy are universally accepted as adjuvant treatments after surgery to avoid recurrence and progression.However,these treatments still have limitations,including an insufficient retention period,inefficient permeability of chemotherapeutic agents,and dilution of the agents by urine.Nanostructure-based smart therapeutic platforms can be tailored to be responsive to internal or external stimuli to ameliorate this situation.This unparalleled capability empowers the precise aggregation of stimulus–responsive nanocarriers in the target regions,namely,the tumors,and subsequent release of the anticancer materials.This review summarizes the current nanostructure-based therapeutic platforms,especially stimulus–responsive nanocarriers,and highlights their benefits and limitations in bladder cancer therapy.Novel innovations in nanotechnology have undoubtedly arrived at a new height and have become useful for practical applications.Nanotechnology will positively promote the development of anticancer agents not only for bladder cancer but also for other solid tumors.