Review of roll-to-roll fabrication techniques for colloidal quantum dot solar cells

Colloidal quantum dots(CQDs)are of great interest to photovoltaic(PV)technologies as they possess the benefits of solution-processability,size-tunability,and roll-to-roll manufacturability,as well as unique capabilities to harvest near-infrared(NIR)radiation.During the last decade,lab-scale CQD solar cells have achieved rapid improvement in the power conversion efficiency(PCE)from~1%to 18%,which will potentially exceed 20%in the next few years and approach the performance of other PV technologies,such as perovskite solar cells and organic solar cells.In the meanwhile,CQD solar cells exhibit long lifetimes either under shelf storage or continuous operation,making them highly attractive to industry.However,in order to meet the industrial requirements,mass production techniques are necessary to scale up the fabrication of those lab devices into large-area PV modules,such as roll-to-toll coating.This paper reviews the recent developments of large-area CQD solar cells with a focus on various fabrication methods and their principles.It covers the progress of typical large-area coating techniques,including spray coating,blade coating,dip coating,and slot-die coating.It also discusses next steps and new strategies to accomplish the ultimate goal of the low-cost large-area fabrication of CQD solar cells and emphasizes how artificial intelligence or machine learning could facilitate the developments of CQD solar cell research.

Endophytic bacteria associated with endangered plant Ferula sinkiangensis K. M. Shen in an arid land： diversity and plant growth-promoting traits

Ferula spp. are traditional medicinal plants found in arid land. Large-scale excavation for extracting bioactive compounds from the plants in arid regions of Xinjiang over the last few years has, however, significandy decreased their distributions. Due to the urgent need for preservation of these plant resources, along with the need of searching for alternative source of the useful metabolites, it is important to screen the endophytic microbial resources associated with the plant Ferula sinkiangensis K. M. Shen. In the study, a total of 125 endophytic bacteria belonging to 3 phyla, 13 orders, 23 families, and 29 genera were isolated based on 16S rRNA gene sequencing data. Among the different isolates, three strains isolated from roots were potential novel species of the genera Porphyrobacter, Paracoccus and draycofatopsis. In this study, 79.4% and 57.1% of the total isolates were capable of producing indole-3-acetic acid （IAA） and siderophore, respectively. And, 40.6% of the strains inhibit the growth of fungal pathogen Afternaria alternata, 17.2% and 20.2% strains were positive for antagonism against Vertidllium dahlia 991 and V. dahlia 7, respectively. These results demonstrated that E sinkiangensis is a rich reservoir of endophytic bacterial resources with potential for production of biologically important functions such as plant growth-promoting factors.

Highly Conductive Zinc-Tin-Oxide Buffer Layer for Inverted Polymer Solar Cells

Thin-films of Zinc Tin Oxide(ZTO)with an extremely high charge carrier mobility and superior optical transmittance are synthesized using a simple solution method.These ZTO films have been systematically studied for the application in inverted polymer solar cells(PSCs).The Hall effects measurements show that the charge

Influence of Mn Doping on the Sensing Properties of SnO₂Nanobelt to Ethanol

Mn doped SnO2 nanobelts (Mn:SnO2 NBs) and pure SnO2 nanobelts (SnO2 NBs) were synthesized by thermal evaporation technique at 1355°C with Ar carrier gas (25 sccm, 150 Torr). The SEM, EDS, XRD, TEM, HRTEM, SAED, XPS, UV-Vis techniques were used to characterize the attained samples. The band gap of Mn doped SnO2 NBs by UV-Vis was measured to be 3.43 eV at room temperature, lower than that of the pure counterpart with ~3.66 eV. Mn:SnO2 NB and pure SnO2 NB sensors were developed. It is found that Mn:SnO2 NB device exhibits a higher sensitivity with 62.12% to 100 ppm of ethanol at 210°C, which is the highest sensitivity among the three tested VOC gases (ethanol, ethanediol, and acetone). The theoretical detection limit for ethanol of the sensor is 1.1 ppm. The higher response is related to the selective catalysis of the doped Mn ions.

Influence of Anthracite-to-Ilmenite-Ratio on Element Distribution in Titanium Slag Smelting in Large DC Furnaces

The distribution of titanium,carbon and associated elements(calcium,magnesium,silicon and aluminum)in a smelting process is studied by means of a chemical equilibrium calculation method for multiphase and multicomponent systems,and verified through comparison with production results.In particular,using the coexistence theory for titanium slag structures,the influence of the AIR(anthracite to ilmenite ratio)on the distribution of such elements is analyzed.The results show that the AIR can be adjusted to achieve a selective reduction of oxides in the melt.

Blue-White Colony Selection of Virus-Infected Isogenic Recipients Based on a Chrysovirus Isolated from Penicillium italicum

Mycoviruses have been found to infect more than 12 species of Penicillium, but have not been isolated from Penicillium italicum(P. italicum). In this study, we isolated and characterized a new double-stranded RNA(ds RNA) virus, designated Penicillium italicum chrysovirus 1(Pi CV1), from the citrus pathogen P. italicum HSPi-YN1. Viral genome sequencing and molecular characterization indicated that Pi CV1 was highly homologous to the previously described Penicillium chrysogenum virus. We further constructed the mutant HSPi-YN1 Dpks P defective in the polyketide synthase gene(pks P), which is involved in pigment biosynthesis, and these mutants formed albino(white) colonies. Then we applied hyphal anastomosis method to horizontally transmit Pi CV1 from the white virus-donors(i.e., HSPi-YN1 mutants) to wild-type recipients(i.e., P.italicum strains HSPi-CQ54, HSPi-HB4, and HSPi-HN1), and the desirable Pi CV1-infected isogenic recipients, a certain part of blue wild-type strains, can be eventually selected and confirmed by viral genomic ds RNA profile analysis. This bluewhite colony screening would be an easier method to select virus-infected P. italicum recipients, according to distinguishable color phenotypes between blue virus-recipients and white virus-donors. In summary, the current work newly isolated and characterized Pi CV1, verified its horizontal transmission among dually cultured P. italicum isolates, and based on these, established an effective and simplified approach to screen Pi CV1-infected isogenic recipients.

Large enhancement of magnetocaloric effect induced by dual regulation effects of hydrostatic pressure in Mn_(0.94)Fe_(0.06)NiGe compound

MM'X(M,M'=transition metals,X=carbon or boron group elements)compounds could exhibit large magnetocaloric effect due to the magnetostructural transition,and the composition regulation has been widely studied to realize the magnetostructural transition.Moreover,the magnetostructural transition is also sensitive to the pressure.Herein,the effect of hydrostatic pressure on magnetostructural transformation and magnetocaloric effect has been investigated in Mn_(0.94)Fe_(0.06)NiGe compound.Dual regulation effect of lowering structural transition temperature and strengthening ferromagnetic(FM)state of martensite is realized by applying hydrostatic pressure,which would greatly improve the magnetocaloric effect of Mn_(0.94)Fe_(0.06)NiGe compound.Moreover,the first-principles calculations have also been performed to discuss the origin of the regulation effect under hydrostatic pressure,and it indicates that the hydrostatic pressure can stabilize the hexagonal structure and decrease the structural transition temperature.The maximum isothermal entropy change increases by 109%from 4.3 J/(kg K)under 0 GPa to 9.0 J/(kg K)under 0.402 GPa for a magnetic field change of 0-3 T.This work proves that the hydrostatic pressure is an effective method to regulate the magnetostructural transition and enhance magnetocaloric effect in MM'X compounds.

Structural and magnetocaloric properties in hexagonal MnNiGa alloys with Co doping

Hexagonal MnNiGe-based alloys are a series of novel functional materials with potential magnetostructural transitions （MSTs）. Accordingly, it was investigated the magnetic features of bulk hexagonal MnNiGa alloy and attempted to partially substitute Mn by Co atoms to tailor its structural and magnetic properties. Nonetheless, the introduction of magnetic Co atom fails to bring about the first-order phase transition and gives rise to the emergence of second phase with cubic structure instead. For ternary MnNiGa parent alloy, the second-order nature of transition is confirmed by both the absence of thermal hysteresis and the standard Arrott plot. To the end, the values of isothermal entropy change are determined by Maxwell relation, and the maximal values follow the trend predicted by the mean-field theory. Its broad transition region （-53 K） leads to only a very small value of entropy change （- 2.4 J·kg^-1·K^- 1 at a field change of 3 T）. In turn, the wide transition ensures a relative large refrigerant capacity （-89.4 J·kg^-1）, which is comparable to that of MnNiGe-based systems. Although the substitution of Co for Mn site is unsuccessful, the chemically modified MnNiGa is still a promising candidate for the application of magnetocaloric effect （MCE） with merits of higher magnetization and better mechanical performance than MnNiGe-based systems.

Enhancing the magnetoelectric coupling of Co4Nb2O9[100] by substituting Mg for Co

We report experimental studies on enhancing the magnetoelectric （ME） coupling of Co4Nb2O9 by sub- stituting the non-magnetic metal Mg for Co. A series of single crystal Co4-xMgxNb2O9 （x = 0, 1, 2, 3） with a single-phase corundum-type structure are synthesized using the optical floating zone method, and the good quality and crystallographic orientations of the synthesized samples are confirmed by the Laue spots and sharp XRD peaks. Although the Neel temperatures （TN） of the Mg substituted crystals decrease slightly from 27 K for pure C04Nb2O9 to 19 K and 11 K for Co3MgNb2O9 and Co2Mg2Nb2O9, respectively, the ME coupling is doubly enhanced by Mg substitution when x = 1. The ME coefficient OlMg of Co3MgNb2O9 required for the magnetic field （electric field） control of electric polarization （magnetization） is measured to be 12.8 ps/m （13.7 ps/m）. These results indicate that the Mg substituted Co4-xMgxNb2O9 （x = 1） could serve as a potential candidate material for applications in future logic spintronics and logic devices.

Highly luminescent zero-dimensional lead-free manganese halides forβ-ray scintillation

Because of their moderate penetration power,β-rays(high-energy electrons)are a useful signal for evaluating the surface contamination of nuclear radiation.However,the development ofβ-ray scintillators,which convert the absorbed high-energy electrons into visible photons,is hindered by the limitations of materials selection.Herein,we report two highly luminescent zerodimensional(0D)organic-inorganic lead-free metal halide hybrids,(C_(13)H_(30)N)_(2)MnBr_(4)and(C_(19)H_(34)N)_(2)MnBr_(4),as scintillators exhibiting efficientβ-ray scintillation.These hybrid scintillators combine the superior properties of organic and inorganic components.For example,organic components that contain light elements C,H,and N enhance the capturing efficiency ofβparticles;isolated inorganic[MnBr_(4)]2−tetrahedrons serve as highly localized emitting centers to emit intense radioluminescence(RL)underβ-ray excitation.Both hybrids show a narrow-band green emission peaked at 518 nm with photoluminescence quantum efficiencies(PLQEs)of 81.3%for(C_(13)H_(30)N)_(2)MnBr_(4)and 86.4%for(C_(19)H_(34)N)_(2)MnBr_(4),respectively.To enable the solution processing of this promising metal halide hybrid,we successfully synthesized(C_(13)H_(30)N)_(2)MnBr_(4)colloidal nanocrystals for the first time.Being excited byβ-rays,(C_(13)H_(30)N)_(2)MnBr_(4)scintillators show a linear response toβ-ray dose rate over a broad range from 400 to 2,800 Gy·s^(−1),and also display robust radiation resistance that 80%of the initial RL intensity can be maintained after an ultrahigh accumulated radiation dose of 240 kGy.This work will open up a new route for the development ofβ-ray scintillators.