最大泡压法测定吐温-80的表面参数及亲水基分子截面积

运用溶液表面吸附原理,以升级后的最大泡压装置测定了25℃下非离子表面活性剂吐温-80的表面吸附等温线,通过近似处理得到吐温-80的临界胶束浓度(CMC),进一步求得吐温-80的亲水基截面积,分析了图解法处理数据的不足和实验开展的优势。该实验对学生学习和解析复杂的表面吸附等温线具有重要的指导意义。

Studies on the Analgesic Activity and Acute Toxicities of Bidens alba(L.) DC

[Objectives]This study was conducted to investigate the analgesic effects and acute toxicities of Bidens alba (L.) DC.[Methods]The alcohol extract of B.alba (L.) DC was extracted and separated with petroleum ether and chloroform successively.The acute toxicities of the two extracts on mice were measured,and then the analgesic effects were measured with writhing pain model induced by acetic acid.[Results]No mice died when the crude dosages of B.alba (L.) DC from petroleum ether extract and chloroform extract were 5 016 and 5 100 mg/kg,respectively.When the petroleum ether extract was 60.0 mg/kg,the percentage of twisted mice induced by acetic acid was 40%,the analgesic rate was 77.5%,and the time of the first writhing was (294.0±165.8) s;when the chloroform extract was 20.0 mg/kg,the percentage of twisted animals was 55.6%,the analgesic rate was 51.5%,and the time of the first writhing was (273.8 ±153.4) s;and when the chloroform extract was 4.0 mg/kg,the percentage of twisted animals was 40%,and the analgesic rate was 62.1%,and the time of the first writhing was (370.6±231.3) s.[Conclusions]The petroleum ether extracts and chloroform extracts of B.alba (L.) DC have good analgesic effects and no acute toxicities.

Macromolecule’s Orientation in a Nanofiber by Bubble Electrospinning

In the search for sustainable alternatives to harmful synthetic fibers,an increasing amount of research focuses on biomimicry and natural fibers.Sea silk is an exceptional textile material.It is a kind of natural silk produced using the long silky filaments secreted by a specific bivalve mollusk(Pinna nobilis);now at edge of extinction.This paper suggests a simple but effective way to prepare artificial sea silk from Mytilus edulis.A sea silk solution is prepared using a Mytilus edulis protein,and a polyvinyl alcohol(PVA)solution is mixed with the sea silk solution in order to produce artificial sea silk through a bubble electrospinning technique.The effects of the sea silk concentration on the nanofiber’s morphology and mechanical properties are studied experimentally.

In-situ growth of low-dimensional perovskite-based insular nanocrystals for highly efficient light emitting diodes

Regulation of perovskite growth plays a critical role in the development of high-performance optoelectronic devices.However,judicious control of the grain growth for perovskite light emitting diodes is elusive due to its multiple requirements in terms of morphology,composition,and defect.Herein,we demonstrate a supramolecular dynamic coordination strategy to regulate perovskite crystallization.The combined use of crown ether and sodium trifluoroacetate can coordinate with A site and B site cations in ABX_(3) perovskite,respectively.The formation of supramolecular structure retard perovskite nucleation,while the transformation of supramolecular intermediate structure enables the release of components for slow perovskite growth.This judicious control enables a segmented growth,inducing the growth of insular nanocrystal consist of low-dimensional structure.Light emitting diode based on this perovskite film eventually brings a peak external quantum efficiency up to 23.9%,ranking among the highest efficiency achieved.The homogeneous nano-island structure also enables high-efficiency large area(1 cm^(2))device up to 21.6%,and a record high value of 13.6%for highly semi-transparent ones.

High-member low-dimensional Sn-based perovskite solar cells

Sn-based perovskites are promising thin-film photovoltaic materials for their ideal bandgap and the eco-friendliness of Sn,but the performance of Sn-based perovskite solar cells is hindered by the short carrier diffusion length and large defect density in nominally-synthesized Sn-based perovskite films.Herein we demonstrate that a long carrier diffusion length is achievable in quasi-2D Sn-based perovskite films consisting of high-member low-dimensional Ruddlesden-Popper(RP)phases with a preferred crystal orientation distribution.The key to the film synthesis is the use of a molecular additive formed by phenylethylammonium cations and optimally mixed halide-pseudohalide anions,which favorably tailors the quasi-2D Sn-based perovskite crystallization kinetics.The high-member RP film structure effectively enhances device short-circuit current density,giving rise to an increased power conversion efficiency(PCE)of 14.6%.The resulting device demonstrates a near-unity shelf stability upon1,000 h in nitrogen.A high reproductivity is also achieved with a count of 50 devices showing PCEs within a narrow range from minimum 13.0%to maximum 14.6%.

Stability improvement under high efficiency—next stage development of perovskite solar cells

With efficiency of perovskite solar cells(PSCs) overpassing 23%, to realize their commercialization, the biggest challenge now is to boost the stability to the same level as conventional solar cells. Thus, tremendous effort has been directed over the past few years toward improving the stability of these cells. Various methods were used to improve the stability of bulk perovskites,including compositional engineering, interface adjustment, dimensional manipulation, crystal engineering, and grain boundary decoration. Diverse device configurations, carrier transporting layers, and counter electrodes are investigated. To compare the stability of PSCs and clarify the degradation mechanism, diverse characterization methods were developed. Overall stability of PSCs has become one central topic for the development of PSCs. In this review, we summarize the state-of-the-art progress on the improvement of device stability and discuss the directions for future research, hoping it provides an overview of the current status of the research on the stability of PSCs and guidelines for future research.

Band alignment towards high-efficiency NiOx-based Sn-Pb mixed perovskite solar cells

Narrow-bandgap tin-lead(Sn-Pb)mixed perovskite solar cells(PSCs)play a key role in constructing perovskite tandem solar cells that are potential to overpass Shockley-Queisser limit.A robust,chemically stable and lowtemperature-processed hole transporting layer(HTL)is essential for building high-efficiency Sn-Pb solar cells and perovskite tandem solar cells.Here,we explore a roomtemperature-processed NiOx(L-NiOx)HTL based on nanocrystals(NCs)for Sn-Pb PSCs.In comparison with hightemperature-annealed NiOx(H-NiOx)film,the L-NiOx film shows deeper valence band and lower trap density,which increases the built-in potential and reduces carrier recombination,leading to a power conversion efficiency of 18.77%,the record for NiOx-based narrow-bandgap PSCs.Furthermore,the device maintains about 96%of its original efficiency after 50 days.This work provides a robust and room-temperatureprocessed HTL for highly efficient and stable narrow-bandgap PSCs.