Recent Progress of Electrode Materials for Flexible Perovskite Solar Cells

Flexible perovskite solar cells(FPSCs) have attracted enormous interest in wearable and portable electronics due to their high power-per-weight and low cost. Flexible and efficient perovskite solar cells require the development of flexible electrodes compatible with the optoelectronic properties of perovskite. In this review, the recent progress of flexible electrodes used in FPSCs is comprehensively reviewed. The major features of flexible transparent electrodes, including transparent conductive oxides, conductive polymer, carbon nanomaterials and nanostructured metallic materials are systematically compared. And the corresponding modification strategies and device performance are summarized. Moreover, flexible opaque electrodes including metal films, opaque carbon materials and metal foils are critically assessed. Finally, the development directions and difficulties of flexible electrodes are given.

Soil microbial communities as potential regulators of N2O sources in highly acidic soils

●Soil pH was a key driver of N2O emission and sources in acidic soils.●N2O emission was significantly positively associated with the ratio of ITS to 16S.●N2O was significantly correlated with bacterial and fungal community composition.●Fungi contributed to N2O in highly acidic tea plantations and vegetable fields.Acidic soil is a main source of global nitrous oxide(N2O)emissions.However,the mechanism behind the high N2O emissions from acidic soils remains a knowledge gap.The objective of this microcosm incubation study was to pin-point the microbial mechanisms involved in N2O production processes in acidic soils.For that purpose,the isotopic signatures and microbial community structure and composition of four soil samples were examined.The results showed that highly acid soils(pH=3.51)emitted 89 times more N2O than alkaline soils(pH=7.95)under the same nitrogen(N)inputs.Fungal denitrification caused high N2O emissions in acidic soils.ITS to 16S abundance ratio was positively correlated with cumulative N2O emissions from the tested soils.The highly acid soils(pH<4.5)showed greater fungal nirK gene abundance and lower abundance of AOA-amoA,AOB-amoA,nirK,nosZ I and nosZ II genes.The unclassified Aspergillaceae fungi(63.65%)dominated the highly acidic soils and was the most strongly correlated genus with N2O emissions.These findings highlight that soil microbial community structures,denitrifying fungi in particular,shaped by low pH(pH<4.5)lead to high N2O emissions from acidic soils.

Enhanced electromagnetic-interference shielding effectiveness and mechanical strength of Co-Ni coated aramid-carbon blended fabric

An efficient method was proposed to prepare high-performance conductive AramidCarbon Blend Fabrics(ACBF)with cobalt-nickel(Co-Ni)alloy coatings,which is conducive to industrial production.The grid-like substrate composed of aramid and carbon fibers was innovatively used in flexible Electromagnetic Interference(EMI)shielding materials.The natural network structure is advantageous to the uniform deposition of metal particles to the establishment of conductive pathways subsequently in order to improve conductivity.The induction of a synergistic effect from Electromagnetic(EM)wave-reflection and EM wave-absorption through the whole carbonCo-Ni-ternary system notably enhanced the EMI Shielding Effectiveness(SE)value to an average of 42.57 d B in the range of 30-6000 MHz.On the other hand,together with the inherent toughness of the alloy coatings,the tensile strength of the aramid fibers used for bulletproof made a significant contribution to the desired mechanical properties.The light weight of the resultant composite made it applicable to aerospace vehicles simultaneously.X-ray Photoelectron Spectroscopy(XPS)was conducted to investigate the variations of elements and groups on the sample surface in pretreating process.The elemental components and surface morphologies of fabric samples during different stages of the process were investigated by Scanning Electron Microscope(SEM)and Energy Dispersive spectrometer(EDX)measurements.X-Ray Diffraction(XRD)results indicated that the obtained Co-Ni alloy coating had a combined Hexagonal Closed-Packed(HCP)and FacedCentered Cubic(FCC)crystalline phase.The relatively high corrosion resistance demonstrated in different acid and alkaline conditions was instrumental in more complex environments as well.

Primary malignant tumours and malignant transformation of cysts in the retrorectal space:MRI diagnosis and treatment outcomes

Background:There are no clear guidelines for the diagnosis and treatment of malignant retrorectal tumours.The purpose of this study was to increase preoperative diagnostic knowledge and to describe the outcomes of treatment for these patients.Methods:This retrospective study was conducted on patients who underwent complete retrorectal tumour resection between May 2006 and July 2018,and had confirmed post-operative pathology reports.Demographic and clinical data(including imaging,perioperative,pathological,and prognostic data)were collected and analysed.Results:Malignant lesions were identified in 15(9[60%],female)patients.The median age of the patients was 59 years(range,34–72 years).Primary malignant tumours were identified in seven patients with solid tumours,in which gastrointestinal stromal tumours accounted for 71.4%(five of seven)and the remainder were chordoma or mucinous adenocarcinoma.Malignant transformation of cysts occurred in another eight patients with heterogeneous tumours,while histopathological features were present in 75%(six of eight)of patients with mucinous adenocarcinoma,and the remainder were squamouscell carcinoma or neuroendocrine tumour(Grade 2).The malignant characteristics of the solid portions observed using magnetic resonance imaging(MRI)were as follows:the cyst wall of the tumour was irregularly thickened;the surface was convex or lobed;the solid tumour had no capsule,or the capsule was destroyed;and the surface had a gyrus-like morphology.At a median follow-up time of 52 months(range,13–100 months),the overall recurrence-free survival rate was 40.0%and the survival rate was 46.7%.Conclusion:Some MRI features can be used to distinguish malignant retrorectal tumours from benign retrorectal tumours.The survival rate of patients with malignant retrorectal tumours is poor.