Lewis base multisite ligand engineering in efficient and stable perovskite solar cells

Perovskite solar cells(PSCs) have stood out from many photovoltaic technologies due to their flexibility,cost-effectiveness and high-power conversion efficiency(PCE). Nevertheless, the further development of PSCs is greatly hindered by the trap-induced non-radiative recombination losses and poor long-term work stability. In the past decade, the huge advancements have been obtained on suppressing nonradiative recombination and enhancing device durability. Among them, the multisite ligands(MSLs) engineering plays a crucial role in precise control and directional modification of functional layers and interfaces,which contributes to markedly increased PCE and lifetimes of PSCs. In view of this, this review summarizes the advances of MSLs in PSCs. From the perspective of functional groups and chemical interaction,the modulation mechanisms of properties of different functional layers and interfaces and device performance via various MSLs are deeply investigated and revealed. Finally, the prospects for the application and development direction of MSLs in PSCs are legitimately proposed.

Reinforced copper matrix composites with highly dispersed nano size TiC in-situ generated from the Carbon Polymer Dots

In order to uniformly disperse the ceramic reinforcements synthesized in-situ in the copper matrix composites,this study used Carbon Polymer Dot(CPD)as the carbon source and Cu–1.0%Ti alloy powder as the matrix for supplying Ti source to prepare in-situ synthesized TiC/Cu composites.The results show that TiC nano-precipitates,having the similar particle sizes with the CPD,form at the grains interior and grain boundaries,and maintain a uniform distribution state.Compared with the matrix,0.3 wt%CPD/Cu composite displays the best strengthplastic compatibility,the ultimate tensile strength achieves 385 MPa accompanied with a corresponding elongation of 21%,owing to the dislocation hindrance caused by nano-carbide and excellent interface bonding between nano TiC and the Cu matrix.The density function theory calculation supports our experimental results by showing a tighter and stronger interface contact.This work presents a new approach for studying in-situ carbide precipitates.

Correlation analysis of breast fibroadenoma and the intestinal flora based on 16S rRNA sequencing

Objective To analyze the characteristics of the intestinal microflora in patients with breast fibroadenoma using 16S ribosomal RNA(rRNA)high-throughput sequencing.Methods Fecal samples from 20 patients with breast fibroadenoma and 36 healthy subjects were randomly collected and analyzed using high-throughput sequencing technology for 16S rRNA V4 region sequencing,and the alpha diversity(Chao index,Shannon index)was calculated using Mothur(v.1.39.5)software.Beta diversity was analyzed using QIIME(v1.80).SPSS software(version 23.0)and the t-test of two independent samples were used to analyze differences in the abundance of bacteria between the two groups.Results Compared with that in the healthy control group,theαdiversity of the intestinal microflora in breast fibroadenoma patients increased,but the difference was not statistically significant(P>0.05).At the phylum level,significant differences were observed between the two groups.The abundance of Firmicutes was higher in the breast fibroadenoma group(P<0.05),whereas the abundance of Synergistetes was higher in the healthy control group(P<0.005).A total of five bacterial genera showed significant differences between the two groups:the breast fibroadenoma group showed higher levels of Bautia(P<0.005),Coprococcus(P<0.005),Roseburia(P<0.05),and Ruminococcus(P<0.005),whereas Sutterella was more abundant in the healthy control group than in the breast fibroadenoma group(P<0.05).Conclusion The diversity and abundance of the intestinal flora in patients with breast fibroadenoma are significantly different from those in healthy subjects,suggesting that an imbalance in the intestinal flora is correlated with the occurrence of breast fibroadenoma.

Stabilization/solidification mechanisms of tin tailings and fuming slag-based geopolymers for different heavy metals

Tin mine tailings(TMT)and fuming slag(FS)contain many heavy metals(As,Cr,Cu,Zn and Mn)that cause severe pollution to the environment.Herein,geopolymers were prepared using TMT,FS and flue gas desulfurization gypsum(FGDG)to immobilize heavy metals,and their compressive strength and heavy metal leaching toxicity were investigated.It was first determined that T4F5(TMT:FS=4:5)sample exhibited the highest compressive strength(7.83 MPa).T4F5 achieved 95%immobilization efficiency for As and Cr,and nearly 100%for Cu,Zn and Mn,showing good immobilization performance.A series of characterization analyses showed that heavy metal cations can balance the charge in the geopolymer and replace Al in the geopolymer structure to form covalent bonds.In addition,about 2%–20%of heavy metal Fe was immobilized in hydration products,heavy metal hydroxides and non-bridging Si–O and Al–O coordination with silica-aluminate matrices.AsO_(3)^(3−) was oxidized into AsO_(4)^(3−),which may form Ca–As or Fe–As precipitates.Cr_(2)O_(7)^(2−)was converted to CrO_(4)^(2−)under alkaline environment and then combined with OH−to form Cr(OH)3 precipitates.Mn^(2+)may react directly with dissolved silicate to form Mn_(2)SiO_(4) and also form Mn(OH)_(2) precipitates.The unstable Mn(OH)_(2) can be further oxidized to MnO_(2).The heavy metal cations were immobilized in the silicoaluminate lattice,while the anions tended to form insoluble precipitates.These results may benefit the industry and government for better handling of TMT,FS and solid wastes containing the abovementioned five heavy metals.

Modification of LiMn_(0.6)Fe_(0.4)PO_(4)lithium-ion battery cathode materials with a fluorine-doped carbon coating

In this study,glucose and NH4F were utilized as sources of carbon and fluorine,respectively,for the synthesis of LiMn_(0.6)Fe_(0.4)PO_(4)(LMFP)nanoscales.These nanoscales were subsequently modified with varying levels of fluorine-doped carbon through co-precipitation and mechanical ball milling processes.The LMFP,incorporating carbon and varying levels of fluoride ions,exhibit higher specific discharge capacities at 0.2 Cand electrochemical characteristics compared to the original LMFP coated solely with carbon.The inclusion of fluorine-doped carbon in the composite material creates numerous pathways for expeditious electron transfer.Moreover,the partial formation of metal fluoride at the interface between the surface of LMFP and the layer of carbon coating doped with fluorine enhances the reduction in the charge-transfer resistance.The modified ferromanganese phosphate cathode material reveals an outstanding discharge capacity displaying a reversible discharge specific capacity value of 131.73 mA h g^(−1)at 10C and 154.6 mA h g^(−1)at 0.2C,due to its unique structure.

Highly efficient recovery of waste LiNi_(x)Co_(y)Mn_(z)O_(2) cathode materials using a process involving pyrometallurgy and hydrometallurgy

Substantial environmental and economic benefits can be achieved by recycling used lithium-ion batteries. Hydrometallurgy is often employed to recover waste LiNi_(x)Co_(y)Mn_(z)O_(2) cathode materials. As Ni, Co and Mn are transition metals, they exhibit similar properties;therefore, separating them is difficult. Thus, most researchers have focused on leaching processes, while minimal attention has been devoted to the separation of valuable metals from waste LiNi_(x)Co_(y)Mn_(z)O_(2) cathode materials. Herein, we propose an environment-friendly, gentle process involving the usage of pyrometallurgy and hydrometallurgy to gradually leach valuable metals and effectively separate them. Interestingly, Li is recovered through a reduction roasting and water leaching process using natural graphite powder, Ni and Co are recovered through ammonia leaching and extraction processes and Mn is recovered through acid leaching and evaporation–crystallization processes. Results show that ~87% Li, 97.01% Co, 97.08% Ni and 99% Mn can be leached using water, ammonia and acid leaching processes. The result obtained using the response surface methodology shows that the concentration of (NH4)2SO3 is a notable factor affecting the leaching of transition metals. Under optimal conditions, ~97.01% Co, 97.08% Ni and 0.64% Mn can be leached out. The decomposition of LiNi_(x)Co_(y)Mn_(z)O_(2) is a two-step process. This study provides valuable insights to develop an environment-friendly, gentle leaching process for efficiently recycling valuable metals, which is vital for the lithium-ion battery recycling industry.

Chelerythrine chloride from Macleaya cordata induces growth inhibition and apoptosis in human gastric cancer BGC-823 cells

This study aimed to investigate the ability of chelerythrine chloride(CHE),the main active ingredient of Macleaya cordata,to induce apoptosis in human gastric cancer BGC-823 cells.The results demonstrate that CHE inhibits cell proliferation in a time-and dose-dependent manner with accompanying S phase arrest.It also induces apoptosis by a mechanism involving a reduction in the mitochondrial mem brane potential,the release of cytochrome c,activation of caspase 3 and cleavage of poly-ADP-ribose polymerase.In addition,CHE-induced apoptosis is accompanied by down-regulation of Bcl-x1 and Bcl-2 proteins with no change in the levels of Bax proteins.Taken together,the results support the development of CHE as a potentially useful anticancer drug for the treatment of gastric cancer.