Positively charged nanofiltration membrane fabricated by poly(acid–base) complexing effect induced phase inversion method for heavy metal removal

Poly(arylene ether ketone)s with carboxylic groups(PAEK-COOH)is a good membrane fabrication material,a kind of polyacids,while polyethylenimine(PEI)is a weak organic base,a kind of polybases.Those polyacids and polybases would form ionic complexation at the interface of two liquid phases.In this paper,PAEK-COOH/N-methyl pyrrolidone(NMP)/1,4-dioxane(DO)mixture,employed as polymer casting solution and aqueous solution of PEI,used as coagulation bath,respectively.Then ion complexation induced phase inversion process is applied to prepare positively charged nanofiltration membrane with thinner but denser separation skin layer.The complexing reaction at the interface of two liquid phases has great influence on the kinetic aspects of phase inversion process,which in accordance would affect the morphology and performance of the membrane.The obtained membrane,fabricated via the ion complexation induced phase inversion method,is positively charged,has high water permeability,and possesses high rejection towards divalent cations,such as Mg^(2+),Ca^(2+),Pb^(2+)etc.,which could be used for removal of heavy metals from polluted water.At the optimal condition,the pure water flux of the PAEK-COOH-PEI nanofiltration membrane is 24.3 L·m^(-2)·h^(-1),with MgCl_2rejection of 92.2%.

Hyperbranched phthalocyanine enabling black-phase formamidinium perovskite solar cells processing and operating in humidity open air

The extreme instability of pureα-phase FAPbI_(3) under high humidity conditions restricts the highthroughput fabrication in unmodified air environments,resulting in poor performance ofα-phase FAPbI_(3) perovskite devices obtained by scalable fabrication methods.Here we synthesized hyperbranched copper phthalocyanine(HCuPc)as a supramolecular additive with twisted phthalocyanine units to realize the molecular-level encapsulation at the grain boundaries through supramolecular interaction,which greatly broadened the processing window of FAPbI_(3) under high humidity.At the same time,unlike traditional encapsulation layer that carrier can only be collected by tunneling effect,the twisted phthalocyanine ring of HCu Pc in perovskite films is more conducive to hole extraction.Finally,a record efficiency was achieved in pure FAPbI_(3) based inverted structured solar cell by blade-coating to the best of our knowledge,even under unmodified humid air conditions(relative humidity of 65%–85%).The best operational stability of 3D pure FAPbI_(3) devices can also be achieved at the same time and unencapsulated HCuPc-FAPbI_(3) device can even operate with negligible degradation for 100 h in the open air(RH 30%–40%).

Atomistic Surface Passivation of CH_(3)NH_(3)PbI_(3) Perovskite Single Crystals for Highly Sensitive Coplanar-Structure X-Ray Detectors

Organic-inorganic halide perovskites(OIHPs)are recognized as the promising next-generation X-ray detection materials.However,the device performance is largely limited by the ion migration issue of OIHPs.Here,we reported a simple atomistic surface passivation strategy with methylammonium iodide(MAI)to remarkably increase the ion migration activation energy of CH_(3)NH_(3)PbI_(3)single crystals.The amount of MAI deposited on the crystal surface is finely regulated by a self-assemble process to effectively suppress the metallic lead defects,while not introducing extra mobile ions,which results in significantly improved dark current stability of the coplanar-structure devices under a large electric field of 100Vmm^(-1).The X-ray detectors hence exhibit a record-high sensitivity above 700,000μC Gy^(-1)_(air) cm^(-2)under continuum X-ray irradiation with energy up to 50 keV,which enables an ultralow X-ray detection limit down to 1.5 nGy_(air)s^(-1).Our findings will allow for the dramatically reduced X-ray exposure of human bodies in medical imaging applications.

Detector-grade perovskite single-crystal wafers via stress-free gel-confined solution growth targeting high-resolution ionizing radiation

Solution-processed organic‒inorganic halide perovskite(OIHP)single crystals(SCs)have demonstrated great potential in ionizing radiation detection due to their outstanding charge transport properties and low-cost preparation.However,the energy resolution(ER)and stability of OIHP detectors still lag far behind those of melt-grown inorganic perovskite and commercial CdZnTe counterparts due to the absence of detector-grade high-quality OIHP SCs.Here,we reveal that the crystallinity and uniformity of OIHP SCs are drastically improved by relieving interfacial stress with a facial gel-confined solution growth strategy,thus enabling the direct preparation of large-area detector-grade SC wafers up to 4 cm with drastically suppressed electronic and ionic defects.The resultant radiation detectors show both a small dark current below 1 nA and excellent baseline stability of 4.0×10^(-8) nA cm^(-1) s^(-1) V^(-1),which are rarely realized in OIHP detectors.Consequently,a record high ER of 4.9% at 59.5 keV is achieved under a standard 241Am gamma-ray source with an ultralow operating bias of 5 V,representing the best gamma-ray spectroscopy performance among all solution-processed semiconductor radiation detectors ever reported.

Development of robust perovskite single crystal radiation detectors with high spectral resolution through synergetic trap deactivation and self-healing

Organic-inorganic halide perovskite single crystals(SCs)are promising materials for detecting ionizing radiation owing to their outstanding photoelectric conversion capability and inexpensive solution processability.However,the accuracy and stability of the detectors have been limited due to the charge traps and defects in SCs,especially when operated under high-precision photon-counting mode for energy spectrum acquisition.Here,we proposed a trap freezing deactivation route,which obviously suppressed dark current and noise by up to 97%and 92%,respectively.Furthermore,the bulk ion migration effect was essential for the ability to instantly self-heal defects induced by radiation damage at temperatures down to30C.Consequently,the detector exhibits a record high energy resolution of 7.5%at 59.5 keV for 241Amγ-ray source,which is the best solution-processed semiconductor radiation detectors at the same energy range.In addition,the detector maintains over 90%of its initial performance after 9 months of storage when tested in the air.Our results will represent a revision of the paradigm that high-spectral-resolution and robust radiation detectors can only be realized with high temperature grown inorganic semiconductor single crystals.