Solid Additive-Assisted Layer-by-Layer Processing for 19%Efficiency Binary Organic Solar Cells

Morphology is of great significance to the performance of organic solar cells(OSCs),since appropriate morphology could not only promote the exciton dissociation,but also reduce the charge recombination.In this work,we have developed a solid additive-assisted layer-by-layer(SAA-LBL)processing to fabricate high-efficiency OSCs.By adding the solid additive of fatty acid(FA)into polymer donor PM6 solution,controllable pre-phase separation forms between PM6 and FA.This intermixed morphology facilitates the diffusion of acceptor Y6 into the donor PM6 during the LBL processing,due to the good miscibility and fast-solvation of the FA with chloroform solution dripping.Interestingly,this results in the desired morphology with refined phase-separated domain and vertical phase-separation structure to better balance the charge transport/collection and exciton dissociation.Consequently,the binary single junction OSCs based on PM6:Y6 blend reach champion power conversion efficiency(PCE)of 18.16%with SAA-LBL processing,which can be generally applicable to diverse systems,e.g.,the PM6:L8-BO-based devices and thick-film devices.The efficacy of SAA-LBL is confirmed in binary OSCs based on PM6:L8-BO,where record PCEs of 19.02%and 16.44%are realized for devices with 100 and 250 nm active layers,respectively.The work provides a simple but effective way to control the morphology for high-efficiency OSCs and demonstrates the SAA-LBL processing a promising methodology for boosting the industrial manufacturing of OSCs.

Positively charged graphene/Fe3O4/polyethylenimine with enhanced drug loading and cellular uptake for magnetic resonance imaging and magnet-responsive cancer therapy

Enhanced cellular uptake efficiency of nanoparticles is important for their biomedical applications, including photothermal therapy （PTT） for cancer. In this study, a one-pot method was used to construct a positively charged and magnet-responsive nanocomposite comprising reduced graphene oxide anchoring iron oxide （RGI） with a polyethylenimine （PEI） modification, to improve the efficiency of cell internalization. The surface charge can be finely tuned using PEIs of different molecular weights. The obtained RGIlsk composite （RGI modified by 1.8 kDa PEI） could load indocyanine green （ICG） at a high mass ratio of 10：3 and ablate cancer cells using low-density laser irradiation because of its positively charged surface. In addition, the hybrids of RGI1.8k and ICG could kill most cancer cells at a laser density of 0.7 W/cm2 in vitro and 0.3 W/cm2 in vivo. At the same time, cell viability could be controlled by converting the external magnetic-field direction because of the enrichment of the magnet-responsive composite in vitro and in vivo. Furthermore, RGIr8k-ICGs could be used as T2-weighted magnetic resonance and infrared thermal imaging agents. Coupled with the magnetic target effect, the imaging signal could be improved significantly. Therefore, RGII^sk-ICGs represent a new highly efficient PTT and imaging agent with great potential for cancer treatment.

Highly emissive coordination polymer derived from tetraphenylethylene-tetrazole chromophore:Synthesis,characterization and piezochromic luminescent behavior

Solid-state materials that exhibit pressure stimulus-response characteristics in a manner of emission signal,known as piezochromic luminescence(PCL),demonstrate great potential in photoelectric devices.The weakened luminescence and insignificant color change in the aggregation state,however,hampers their practical applications.Herein,a highly emissive coordination polymer,[Zn2(H4TTPE)(H2O)4]·H2O(CUST-805),is successfully constructed by employing an AIE-active chromophore as the building block.The structural characterization and photophysical properties are systematically studied.Owing to intrinsic twisted conformation and AIE feature of tetraphenylethylene-tetrazole ligand,CUST-805 achieves the visible and reversible PCL from blue to green switched by different external stimuli.The transformation between crystalline and amorphous states is proved to be the origin of present PCL behavior.Moreover,on basis of electron and energy transfer quenching mechanism,the highly selective and sensitive sensor based on CUST-805 is realized,showing the low detection limit of 0.29 ppm towards 2,4,6-trinitrophenol.