Engineering of dendritic dopant-free hole transport molecules:enabling ultrahigh fill factor in perovskite solar cells with optimized dendron construction

Developing dopant-free hole-transporting materials(HTMs)for high-performance perovskite solar cells(PVSCs)has been a very active research topic in recent years since HTMs play a critical role in optimizing interfacial charge carrier kinetics and in turn determining device performance.Here,a novel dendritic engineering strategy is first utilized to design HTMs with a D-A type molecular framework,and diphenylamine and/or carbazole is selected as the building block for constructing dendrons.All HTMs show good thermal stability and excellent film morphology,and the key optoelectronic properties could be fine-tuned by varying the dendron structure.Among them,MPA-Cz-BTI and MCz-Cz-BTI exhibit an improved interfacial contact with the perovskite active layer,and non-radiative recombination loss and charge transport loss can be effectively suppressed.Consequently,high power conversion efficiencies(PCEs)of 20.8%and 21.35%are achieved for MPA-Cz-BTI and MCz-Cz-BTI based devices,respectively,accompanied by excellent long-term storage stability.More encouragingly,ultrahigh fill factors of 85.2%and 83.5%are recorded for both devices,which are among the highest values reported to date.This work demonstrates the great potential of dendritic materials as a new type of dopant-free HTMs for high-performance PVSCs with excellent FF.

Vitamin C Attenuates Hemorrhagic Shock-induced Dendritic Cell-specific Intercellular Adhesion Molecule 3-grabbing Nonintegrin Expression in Tubular Epithelial Cells and Renal Injury in Rats

Background： The expression of dendritic cell-specific intercellular adhesion molecule 3-grabbing nonintegrin （DC-SIGN） in renal tubular epithelial cells has been thought to be highly correlated with the occurrence of several kidney diseases, but whether it takes place in renal tissues during hemorrhagic shock （HS） is unknown. The present study airned to investigate this phenomenon and the inhibitory effect of Vitamin C （VitC）. Methods： A Sprague Dawley rat HS model was established in vivo in this study. The expression level and location of DC-SIGN were observed in kidneys. Also, the degree of histological damage, the concentrations of tumor necrosis factor-or and interleukin-6 in the renal tissues, and the serum concentration of blood urea nitrogen and creatinine at different times （2-24 h） alter HS （six rats in each group）, with or without VitC treatment belbre resuscitation, were evaluated. Results： HS induced DC-SIGN expression in rat tubular epithelial cells. The proinflarnmatory cytokine concentration, histological damage scores, and functional injury of kidneys had increased. All these phenornena induced by HS were relieved when the rats were treated with VitC before resuscitation. Conclusions： The results of the present study illustrated that HS could induce tubular epithelial cells expressing DC-SIGN, and the levels of proinflarnmatory cytokines in the kidney tissues improved correspondingly. The results also indicated that VitC could suppress the DC-SIGN expression in the tubular epithelial cells induced by HS and alleviate the inflammation and functional injury in the kidney.

Chemically Amplified Resist Based on Dendritic Molecular Glass for Electron Beam Lithography

A novel dendritic molecular glass(MG)containing adamantane core(AD-15)was synthesized and characterized.It exhibits good solubility in common organic solvents and a stable amorphous state at room temperature,which contributes to forming films with different thicknesses by spin-coating.The thermal analysis of AD-15 indicates that no apparent glass transition temperature(Tg)is observed before the thermal decomposition temperature(Td=160℃).The good thermal resistance suggests that it can satisfy the lithographic process and is a candidate for photoresist materials.The patterning properties of AD-15 resist were evaluated by electron beam lithography(EBL).By optimizing the lithographic process parameters,AD-15 resist can achieve 40 nm half-pitch patterns with a line-edge roughness of 4.0 nm.The contrast and sensitivity of AD-15 resist were 1.9 and 67µC/cm^(2),respectively.Compared with the commercial PMMA(950k)electron beam resist,the sensitivity of AD-15 resist increases by 6 times.This study provides a new example of molecular glass resist with high resolution and sensitivity for EBL.