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A downshifting Eu3+ doped glass embedded with concave pyramid microstructure to improve the efficiency of silicon solar cell
摘要： The average photoelectric conversion efficiency (PCE) of a bare mono crystalline silicon solar cell is 14.71(±0.03)% under AM1.5. It decreases to 14.20(±0.005)% when covering an un-doped flat glass on the solar cell, and it goes down to 14.10(±0.005)% by using a 5 wt% Eu3+ doped glass. The absorptions of the Eu3+ doped CPM glass one-to-one match the excitation spectrum at 362, 381, 393, 400, 413 and 464 nm, which are related to the transitions of 7F0→(5D4, 5G2, 5L6, 5D3), 7F1→5D3, and 7F0→5D2, respectively. In addition, a concave pyramid microstructure (CPM) is embedded in the glass surface to increase light transmittance. The average PCE increases to 14.61(±0.07)% when a 5 wt% Eu3+ doped CPM glass covers on the silicon solar cell. Comparing to the un-doped flat glass, a net increase of the PCE is 0.41%, where the 0.16% increment of PCE is from the lighting trapping of the CPM structure, and the downshifting of near ultraviolet (NUV) light by Eu3+ ion donates the other 0.25% increment. It confirms that the as-prepared Eu3+ doped CPM glass has a good downshifting and antireflection function.
关键词： solar cell,photoelectric conversion efficiency,Eu3+ doped glass,rare earths,concave pyramid microstructure
更新于2025-09-12 10:27:22
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Green and red phosphor for LED backlight in wide color gamut LCD
摘要： Wide color gamut (WCG) backlight for liquid crystal display (LCD) utilizing white light-emitting diodes (LED) has attracted considerable attention for their high efficiency and color reduction. In this review, recent developments in crystal structure, luminescence and applications of phosphors for wide color gamut LED backlight are introduced. As novel red phosphors, Mn4+ activate fluoride and aluminate phosphors are advanced in quantum efficiency, thermal quenching and color saturation for their characteristic spectrum with broad excitation band and linear emission. The crystal structure and fluorescence properties of Mn4+ doped fluosilicate, fluorogermanate, fluotitanate, as well as Sr4Al14O25, CaAl12O19 and BaMgAl10O17 phosphors are discussed in detail. A serial of narrow-band red-emitting Eu2+, Eu3+ and Pr3+-doped nitride silicates and molybdate phosphors are also introduced. Rare-earth-doped oxynitride and silicate green-emitting phosphors have attracted more and more attention because of the wide excitation, narrow emission, high quenching temperature, high quantum efficiency, such as β-sialon:Eu2+, Ba3Si6O12N2:Eu2+, MSi2O2N2:Eu2+ (M=Ca, Sr, Ba), γ-AlON: Mn2+ and Ca3Sc2Si3O12:Ce3+. All above phosphors demonstrate their adaptability in wide color gamut LCD display. Especially for Mn4+ doped fluosilicate red phosphor and β-sialon: Eu2+ green phosphor. To achieve an ultra-high color gamut in white LED backlight and against the OLED, innovative narrow-band emission red and green phosphor materials with independent intellectual property rights are continuously pursed.
关键词： Rare earths,Liquid crystal display,Backlight,Wide color gamut,White LED,Phosphor
更新于2025-09-12 10:27:22
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Solid-state synthesis of LnOCl/Ln2O3 (Ln?= Eu, Nd) by using chitosan and PS-co-P4VP as polymeric supports
摘要： A series of lanthanide materials of type LnOCl or Ln2O3 (Ln ? Eu, Nd) were successfully prepared via a convenient and straightforward two-step procedure. Firstly, and by using chitosan and PS-co-P4VP as polymeric supports, macromolecular complexes of type chitosan$LnCl3 and PS-co-P4VP$LnCl3 were prepared. These macromolecular complexes were treated in solid state at 800 (cid:2)C under air, leading to the corresponding LnOCl or Ln2O3 materials (Ln ? Eu, Nd) with moderate to good yields. The nature of the as-prepared lanthanide materials (LnOCl and/or Ln2O3) is strongly in?uenced by the polymeric template (i.e., chitosan or PS-co-P4VP), the lanthanide salt precursor, and the polymer/lanthanide molar ratio. Thus, when chitosan$EuCl3 and PS-co-P4VP$EuCl3 are used as macromolecular precursors, a mixture of crystalline phases of both EuOCl and Eu2O3 are obtained. However, when chitosan$NdCl3 and PS-co-P4VP$NdCl3 are used, a sole pure crystalline phase of NdOCl is obtained. The nanostructured lanthanide materials were characterized by means of XRD (X-ray diffraction of powder), SEM, EDS, TEM, and HRTEM. The luminescent spectra of the as-prepared EuOCl/Eu2O3 mixture materials show an emission pattern whose intensity is strongly in?uenced by the nature of the polymeric precursor, as well as on the metal/polymer molar ratios.
关键词： NdOCl,EuOCl/Eu2O3,Lanthanides,Luminescence,Rare earths,Solventless method
更新于2025-09-10 09:29:36
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Recovery of rare earths from waste cathode ray tube (crt) phosphor powder by selective sulfation roasting and water leaching
摘要： Until recently, most displays, such as television and computer screens, were based on cathode ray tubes (CRTs). With the introduction of new types of displays including liquid crystal displays, CRTs have been widely replaced, leading to a gradual build-up of hazardous CRT powder waste. In this paper, a new approach is introduced where the valuable rare-earth elements (REEs) (i.e. yttrium and europium) in the powder are selectively recovered, leaving behind a zinc-rich residue and glass for further recycling. The main rare-earth compound in the waste powder is Y2O2S:Eu3+ (YOS). The fine-grained CRT powder was mixed with zinc sulfate monohydrate (ZnSO4.H2O) and roasted at 600-900 °C for short periods of time. In this way, Y2O2S:Eu3+ was transformed into water-soluble rare-earth sulfates. Meanwhile, ZnS underwent a two-stage reaction with ZnSO4.H2O, where first a partially water-soluble intermediate (ZnO.2ZnSO4) and then the water-insoluble ZnO was formed. Addition of a sufficient amount of ZnSO4.H2O ensured the recovery of ≥ 95% of the rare earths in a subsequent water leaching step, but there was also co-dissolution of about 5% of the total amount of zinc present. Several purification methods were tested and compared to separate the REEs from the zinc impurity in the solutions. In addition to the conventional precipitation methods with sulfides and oxalic acid, Versatic Acid 10 was tested. Finally, a complete flow sheet is proposed for the (almost complete) valorization of REEs as well as the total zinc present.
关键词： CRT phosphor,zinc,water leaching,Versatic acid,rare earths,roasting
更新于2025-09-09 09:28:46
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<i>In My Element</i> : Yttrium
摘要： After a near 7-year pathway devoted solely to late transition metal systems, my hunt in the world of catalysis drove me progressively towards the very left side of the periodic table. Group 4, then group 3, and now group 2 elements. Rare-earths and alkali-earths are really unique elements. Even though going down those two columns and running through the lanthanide row, physicochemical properties most often vary monotonously, their reactivity remains sometimes quite mysterious: who has ever truly rationalized the “peak activity” of neodymium catalyst systems in diene and ethylene polymerization?! But my favorite element isn’t neodymium: its paramagnetism makes for too nasty an NMR spectra to satisfy a molecular chemist in the search for understanding what’s going on in the coordination sphere… No, my special one is yttrium. This one is diamagnetic, providing beautiful, informative NMR spectra. And, importantly for the single-site polymerization catalysis community, some complexes of this abundant element have proved really unique in the ring-opening polymerization of cyclic esters, featuring high activity and unequaled stereocontrol abilities—not unrelated to its small size, which makes for a crowded, discriminative coordination sphere.
关键词： rare-earths,polymerization,alkali-earths,yttrium,catalysis
更新于2025-09-04 15:30:14
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The Modification Mechanism of Lanthanum Doping in Ti/Sb- SnO2 Electrode and its Electrocatalytic Behavior of Degradation of p-nitrophenol
摘要： Element doping is one of the effective means to improve the electrochemical performance of electrode. In order to improve the electrocatalytic performance of Ti/Sb-SnO2 electrode, lanthanum was selected as a promoter to dop in the electrode coating. The micrograph and the structure of the electrode were characterized by SEM and XRD. Element composition of catalyst layer was determined by EDS. The electrochemical performance of Ti/Sb-SnO2-La electrode was detected by electrochemical workstation. Doped and undoped electrodes were used to treat simulated p-nitrophenol (p-NP) wastewater. The electrochemical degradation efficiency of the two electrodes for treating p-NP was compared. The results showed that 92.8% p-NP was removed when using Ti/Sb-SnO2-La as anode, which is much higher than that when using Ti/Sb-SnO2 as anode. The effect of electrolytic parameters (electrolytic voltage, applied voltage, electrode distance, electrolyte concentration and pH value) on p-NP degradation were also studied. On the basis of electric catalytic oxidation mechanism, the degradation mechanism of p-NP was deduced. According to the experimental results, the electrocatalytic performance of the La doped electrode was superior for the treatment of p-NP wastewater.
关键词： p-NP wastewater,electrocatalytic,rare earths,Ti/Sb-SnO2-La electrode
更新于2025-09-04 15:30:14