PL Studies Research Articles

In-situ fabricated poly (vinylidene fluoride)-Incorporated perovskite nanocrystals with better Schottky performance and enhanced stability

The inherent defect states in perovskite nanocrystals (PNCs) have been known to cause degradation in device performance. Hydrophobic polymers with long chained repeating units are frequently employed as protecting layers to passivate the perovskite surface and improve their performance and stability. Here, we report the preparation and Schottky analysis of Formamidinium lead halide PNCs incorporating polyvinylidene fluoride (PVDF) as an additive. The structural characterization of the polymerized compounds confirms the formation of PNCs with better crystallinity and larger grains. The PVDF- incorporated samples (PVDF/PNCs) showed enhanced absorption in the entire visible region along with a decrease in non-radiative recombination events confirmed from dynamic PL studies. In consequence, the PVDF/PNCs Schottky device reveals better electrical performance with higher values of rectification and ideality factor close to unity. Also, from the C–V analysis of the devices, an almost 5-fold increase in carrier concentration is observed. Additionally, the thermal stability of the polymerized PNCs samples improved owing to the interaction between the organic cation and the polymer functional group. This study provides a new design strategy for interface engineering by PVDF incorporation into PNCs that can improve device performance and stability.

Novel Zn2SiO4: Nb phosphor for light emitting applications

The researchers have focussed on finding new novel phosphors with enhanced emissions under UV/near UV excitation in a suitable host due to the limitation of commercial phosphors. In this study, niobium (Nb) doped zinc silicate (Zn2SiO4) by varying different wt. % of Nb was synthesized through the sol-gel method at 1200 °C under normal atmospheric conditions. The incorporation of Nb in the Zn2SiO4 host lattice significantly modifies their crystallinity, morphology, optical, and photoluminescent behaviours. In the PL study, Zn2SiO4: Nb phosphor shows a broad blue emission peak at 460 nm under 315 nm excitation. The highest PL emission intensity at 460 nm is obtained in 4 wt % of Nb-doped Zn2SiO4 materials among the prepared materials. The highest quantum yield and average lifetime were achieved for 4 wt % Nb-doped Zn2SiO4 materials which enunciates that the 4 wt % Nb-doped Zn2SiO4 is a potential candidate for light-emitting applications.

Bandgap engineering approach for designing CuO/Mn3O4/CeO2 heterojunction as a novel photocatalyst for AOP-assisted degradation of Malachite green dye

A ternary nanohybrid CuO/Mn3O4/CeO2 was developed in the present work using a co-precipitation-assisted hydrothermal method. The designed photocatalyst's structural, morphology, elemental composition, electronic states of elements, and optical properties were studied using corresponding analytical techniques. Results from PXRD, TEM/HRTEM, XPS, EDAX, and PL showed that the desired nanostructure had formed. Using Tauc's energy band gap plot, it was determined that the nanostructures band gap was ~ 2.44 eV, which showed the band margins of the various moieties, CeO2, Mn3O4, and CuO, had modified. Thus, improved redox conditions led to a substantial decrease in the recombination rate of electron–hole pairs, which was further explained by a PL study in that charge separation plays a key role. Under exposure to visible light irradiation for 60 min, it was revealed that the photocatalyst achieved 98.98% of photodegradation efficiency for malachite green (MG) dye. The process of photodegradation proceeded according to a pseudo-first-order reaction kinetic model with an excellent rate of reaction of 0.07295 min−1 with R2 = 0.99144. The impacts of different reaction variables, inorganic salts, and water matrices were investigated. This research seeks to create a ternary nanohybrid photocatalyst with high photostability, visible spectrum activity, and reusability up to four cycles.

Constructing trinary heterostructure of TiO2/CoCr2O4/SrTiO3 to enhance photocatalytic activity toward degradation of yellow 28 dye

Today, the design of efficient visible light-driven photocatalytic systems for the degradation of organic dyes is of great interest in human health and environmental protection. Constructing heterostructured nanocomposites using coupling metal oxide semiconductors with visible-light-responsive photocatalytic materials is an effective strategy to improve the photocatalytic potential. For this purpose, a trinary TiO2/CoCr2O4/SrTiO3 heterostructured photocatalyst with enhanced visible-light photocatalytic activity was fabricated using the intimate interfacial contact of TiO2/SrTiO3 nanotubes with CoCr2O4 nanoparticles. Compared with single or binary photocatalysts, trinary TiO2/CoCr2O4/SrTiO3 nanocomposite demonstrated enhanced photocatalytic activity and cycling stability in the degradation of basic yellow 28 (BY28) dye under visible-light irradiation. The optimal TiO2/CoCr2O4/SrTiO3 nanocomposite degraded almost 99% of BY28 under visible light in 2 h, compared to approximately 37%, 66%, and 71% for the SrTiO3 nanorods, CoCr2O4 nanoparticles, and TiO2 nanotubes, respectively. This superior photocatalytic performance can be ascribed to the synergistic effects of elevated photon absorption, charge transfer, and efficient charge separation. In addition, the probable mechanism for the degradation of BY28 dye over TiO2/CoCr2O4/SrTiO3 nanocomposite is also elucidated using PL and active species scavenger studies.

Hydrogen-Treated TiO2 Nanorods Decorated with Bimetallic Pd–Co Nanoparticles for Photocatalytic Degradation of Organic Pollutants and Bacterial Inactivation

Herein, first, we synthesize a multifunctional photocatalyst via metal oxides loaded (Co/Pd) on acid-treated TiO2 nanorods (ATO) and further introduce hydrogen annealing treatment. The hydrogen annealing treatment introduces metal oxides converted into a bimetallic form and delays the photogenerated charge recombination process. Also, oxygen vacancies are formed due to the partial reduction of Ti4+ to Ti3+ sites. In addition, oxygen vacancies help to improve photocatalytic degradation and antibacterial activity. The hydrogen-treated photocatalyst (Pd(1)Co(1)/ATO (red)) demonstrates high degradation efficiencies of 99.63 and 99.90% (180 min) for orange II dye and BPA degradation, respectively, and an antibacterial activity of 97.00% (120 min) under one sun irradiation. In the photocatalytic removal of abiotic pollutants and live bacteria, the trapping experiment suggests that radical species (•O2– and •OH), assisted by photoinduced holes, are responsible for the high activities. The photoelectrochemical performance and time-resolved PL (TRPL) study illustrate that Pd(1)Co(1)/ATO (red) reveals superior photoelectrochemical charge separation (electron–hole), lower resistance, and shorter lifetime (τ1 = 0.40 ns) as a photocatalyst. Finally, plausible charge transport mechanisms are proposed for the photocatalytic degradation of organic dye and bacterial disinfection over the Pd(1)Co(1)/ATO (red) photocatalyst.

Synthesis and photoluminescence characteristics of the near white emitting Dy3+ ions activated NaMBi2−x(PO4)3 [M: Ba/Ca/Ca0.5+Sr0.5/Sr/Sr0.5+Ba0.5] phosphors

The present work deals with the preparation and characterization of the NaBaBi2−x(PO4)3:xDy3+ phosphors and the impact of the host cation (M) replacement in the NaMBi1.91(PO4)3:9%Dy3+ (M: Ca/Ca0.5+Sr0.5/Sr/Sr0.5+Ba0.5/Ba) phosphors on the PXRD profile and the PL emission data. All the phosphors are prepared by simple solid state reaction method and their PXRD data confirms the single phase formation. For the NaBaBi2−x(PO4)3:9%Dy3+ phosphor, the morphology, elemental composition and the band gap estimation were carried out by FESEM-EDAX analysis and DRS studies respectively. The PL emission properties revealed that the Dy3+ occupied the low symmetry sites in the NaBaBi2(PO4)3 host lattice and the optimum emission observed for the concentration, xC = 9 mol%. The PL-lifetime of Dy3+ ions in the NaBaBi2(PO4)3 phosphors are in the range of millisecond. The temperature dependent PL studies showed that at 150 °C, the phosphor was able to retain 74.7% of its initial PL intensity value (at 27 °C) and the activation energy for thermal quenching was determined to be 0.192 eV. For λex = 349 nm, the calculated CIE color coordinates (0.339, 0.359), and the CCT value (5250 K) of the NaBaBi1.91(PO4)3:9%Dy3+ phosphor are found closer to the ideal white light. The Na(Sr0.5,Ba0.5)Bi1.91(PO4)3:9%Dy3+ phosphor has yielded the highest PL intensity, which is twice that of the NaCaBi1.91(PO4)3:9%Dy3+ phosphor. The estimated CIE color coordinates of this phosphor revealed its near white light emission property.

Rational design of ZnO–CuO–Au S-scheme heterojunctions for photocatalytic hydrogen production under visible light

An integration of S-scheme heterojunction catalyst with surface plasmon resonance effect is the prime focus of current research activites in the field of visible light driven photocatalytic hydrogen (H2) evolution. Herein, a sol-gel route is used to design a heterojunction of ZnO–CuO–Au. The effect of process parameters, including irradiation time, catalyst dose, and sacrificial reagents on the hydrogen evolution is studied. The S-scheme ZnO–CuO–Au heterojunction catalyst demonstrated high surface area, better optical absorption response in the visible part of light spectrum, and improved separation and transportion of charge carriers as verified by DRS, PL, and photoelectrochemical studies. The maximum H2 evolution rateof ZnO–CuO–Au reaches 4655 μmolh−1g−1, which is 5 and 3.2 times higher than ZnO–CuO and Au–ZnO catalysts, respectively. A possible reason of this increase in H2 evolution rate is inhibited recombination of charge carriers because of the S-scheme design to increase electrons with strong reduction potential and prolong lifetime, Au serves as an SPR source and conductive channel to swift the transfer of electrons and high density of active sites. This work offers innovative insight into designing plasmonic metals-modified S-scheme systems for solar fuel production.

Comparative Genomic Analysis of Bacterial Strain PL and Detection of Sustainable Bio-Electricity Producing Features

This study aimed to analyze the whole genome of the bacterial strain PL, isolated from pond sediment, to evaluate its genetic characteristics in the degradation of waste and toxic substrates and the generation of bioelectricity. This was compared to the type strain of the bacterial species Geobacter sulfurreducens (G. sulfurreducens) (PCA) and the strain KN400. Genomic taxonomy on the TYGS platform established the affiliation of strain PL with the bacterial species G. sulfurreducens. Subsequently, a genomic study of strains PL, PCA, and KN400 was performed using various bioinformatics tools. These included the study of genes associated with functional categories (COG) through genome annotation using the RAST server, followed by gene identification using the Prokka program to discover and identify genes related to electricity production. The results of the genomic analysis of the PL strain showed that it possesses many genes necessary for generating electric current. These included genes related to the formation of thick biofilms, adhesion to the anode of microbial fuel cells (MFCs), oxidation of various substrates and environmental pollutants, and extracellular electron transfer. Overall, the obtained results indicate that the PL strain is a promising candidate for sustainable bioenergy generation. KEYWORDS bioinformatics tools, genomic analysis, geobacter sulfurreducens, MFCs, sustainable bioenergy, whole genome

"Synergistic effect" based novel and ultrasensitive approach for the detection of serotonin using DEM-modulated bimetallic nanosheets.

Neurotransmitters have been of immense scientific interest due to their importance as human-health biomarkers. Several reports suggest necessary improvisations in the sensing capabilities of these neurotransmitters. Herein, the authors report a novel synthesis methodology for bimetallic aluminum-tungsten (Al-W) nanosheets, with the hybrid nanostructure showing high specificity toward serotonin neurotransmitters. The inspiration to design hybrid metallic nanosheets depends on the inherited optical properties of the parent precursors. The interstate conversion (ISC) between Al-W nanosheets promoted photoluminescent behavior with serotonin. The PL study shows that serotonin drastically enhanced λem at 335 nm. The importance of emission below the visible spectrum is to modulate any possible aggregation-induced emissions, which earlier troubled analytical chemists. The understanding of the selective detection of serotonin from a group of similar neurotransmitters is discussed with nanomolar quantification. The quantified detection limit using Al-W nanosheets is 0.05 nm with high linearity (R2 = 0.9906). Furthermore, real-world quantification studies have been performed on human urine and serum samples with R2 of 0.9938 and 0.9801, respectively.

Nitrogen doped graphene supported mixed metal sulfide photocatalyst for high production of hydrogen using natural solar light

We have developed a strategy to prevent the photo-corrosion of cadmium sulfide nanorods (CdSNRs) by coating them with cerium sulfide (Ce2S3) as co-catalyst and N-doped Graphene (NG) for a solar light-driven H2 production application. The uniform deposition and coating of Ce2S3 and NG over the CdSNRs were confirmed by both FESEM and HRTEM analyses. The incorporation of Ce2S3 and NG into CdSNRs not only increased its stability but also extended its absorption in visible and NIR regions. As a result, the prepared CdSNRs/Ce2S3 photocatalysts produced ∼16,181 µmol h−1 g–1 of H2 under solar light irradiation, which was ∼ 10 times higher than the pure CdSNRs. Interestingly, N atom doped graphene-supported CdSNRs/Ce2S3 photocatalysts has shown a paramount effect on the H2 production by 24 times higher compared to bare CdSNRs (35,946 µmol h−1g–1). In addition, the NG-CdSNRs/Ce2S3 photocatalysts exhibited high stability up to 5 continuous cycles. The high stability was achieved due to the covering of CdSNRs by Ce2S3 and NG, which may effectively prevent the leaching out of S2- ions from CdSNRs. On the other hand, the NG played a dual role by preventing the photo-corrosion and also improving the charge carrier separation as evidenced by the PL, TRPL, and Impedance studies. The present work may open a new direction in designing a highly photostable metal sulfide photocatalyst for energy conversion applications in aqueous medium.

Eco-friendly synthesis, characterization, catalytic, antibacterial, antidiabetic, and antioxidant activities of Embelia robusta seeds extract stabilized AgNPs

The current research study is to develop and easy and eco-friendly method for the synthesis of AgNPs using aqueous seed extract of Embelia robusta (Er-AgNPs) and evaluated the extract to know the effects of catalytic, anti-bacterial, anti-diabetic, and anti-oxidant activity. Er-AgNPs were characterized via several techniques including UV-vis absorption, PL, XRD, FTIR, and TEM UV-vis study confirmed the formation of Er-AgNPs. Face centered cubic (FCC) crystal structure of biosynthesized Er-AgNPs was governed by the XRD analysis. FTIR study confirmed the presence of OH and NH functional groups of secondary molecules of seed extract capped on the AgNPs surface. The produced Er-AgNPs were dark brown in color with almost spherical shape in the size ranging from 5 to 15 nm. The presence of Er-AgNPs (1 mL) exhibited considerably enhanced dyes degradation (CY, 95.12% and EY, 97.82% in 18 min), antibiotics degradation (TC, 96.45% and CIP, 98.01% in 21 min), and nitroaromatics reduction (4-NP, 88.12% and 4-NA, 92.45% in 15 min). The Er-AgNPs have showed significant antibacterial activity on multi drug resistance bacteria. The synthesized Er-AgNPs exhibited strong antioxidant activities for the DPPH assay. Remarkable anti-diabetic (α-glucosidase, α-amylase, and HbA1C) activities were noticed for biosynthesized Er-AgNPs. This is the first report on the biosynthesis of AgNPs using seeds extract of Embelia robusta. • Eco-friendly synthesis of AgNPs were carried out using Embelia robusta seeds extract. • The synthesized Er-AgNPs were found to be fcc structure and average diameter is 8±2 nm. • Biosynthesized Er-AgNPs exhibited excellent catalytic activity for the degradation of dyes, antibiotics, and nitrocompounds reduction at low NaBH 4 content. • Biogenic Er-AgNPs showed good antibacterial, antidiabetic and antioxidant activities. • Er-AgNPs were developed as a four-in-one platform for the environmental remediation of waste water treatment and biological applications.

Understanding Grain Growth Mechanism in Vacuum Evaporated CdTe Thin Films by Different Halide Treatments: An Evolution of Ion Size Impact on Physical Properties for Solar Cell Applications

ABSTRACT In the present study, detailed investigation on postdeposition halides treatment using CdCl2, CdI2, MgF2, MgCl2 and MgI2 is undertaken over thermally evaporated CdTe films. As-deposited films are subjected to halide treatment and subsequent annealing at 385°C. Halide activation induced grain growth mechanism is presented along with anions and cations roles on change in films properties and formation of different complexes. XRD patterns of all CdTe thin films exhibited polycrystalline nature with preferential cubic phased (310) plane except for CdI2 treated films where preferred reflection is appeared corresponding to (220) plane. Grain growth is observed with treatment employing amicable estimation tools. All films have a conspicuous ohmic character owing to linear I–V plots. Optical study reveals that CdCl2 treated CdTe films have higher absorbance and optical energy band-gap is measured out in the range 1.42–1.53 eV with halide treatment. Surface topography and PL study revealed to variations in surface roughness and photoluminescence peaks intensity with halide treatments. Film growth and treatment are validated by EDS analysis and FESEM images demonstrated explicit grain growth. Findings warrant amazing role of halide activation on film properties and CdCl2 is found a suitable surface treatment agent to CdTe films in order to develop better devices.

Solvent Effects on the UV-Visible Absorption and Emission of Tris[4-Diethylamino)Phenyl]amine

Tris [4-(diethylamino) phenyl] amine (TDAPA) is an organic molecular semiconductor generally used to enhance the charge transport of the devices for some time now. TDAPA is dissolved in various Polar and Non-polar solvents like DMF, Acetone, Acetonitrile, Ethanol, Methanol, Toluene and Chloroform. Absorption spectrum of solution is recorded using UV-Vis spectroscopy and absorption peak for different solvents were observed in UV and Near-UV region. PL study and Pl Excitation study is also carried out for these solvents. Results for absorption and photoluminescence show some interesting phenomenon of Stokes’ shift. The colour coordinates for respective emission are represented by CIE 1931. The study is successfully carried out for better understanding of effect of these solvents on the optical properties of TDAPA.

Detection of ammonia gas at room temperature through Sb doped SnO2 thin films: Improvement in sensing performance of SnO2

This paper presents the effects of Sb doping on the gas-sensing properties of SnO2 thin films prepared through a nebulizer-assisted spray pyrolysis technique. An improvement in the inherent characteristics of the transparent conducting oxide after 0 to 5 wt% Sb doping is reported. The deposited films were used to sense the presence of 50 to 250 ppm of ammonia at room temperature. Various analytical techniques were used to analyze the properties of the Sb-doped SnO2 films. X-ray diffraction spectra revealed the tetragonal structure of crystallites, and the maximum crystallite size was observed in the 2-wt%-Sb-doped SnO2 film. The morphological images showed spherical grains in pristine SnO2 films and their transformation to a trigonal shape after Sb doping; particularly, a large grain size was observed at 2 wt% doping. PL studies of the materials revealed that a large number of oxygen vacancies exist in the 2-wt%-Sb-doped SnO2 thin film. The transmittance of the films remained at approximately 75%, and the band gap varied from 3.94 to 4.01 eV as the doping concentration varied from 1 to 5%. A high response of 138% was observed for 250 ppm of ammonia in the case of the 2-wt%-Sb-doped SnO2 film, with a 42 s response time and a 11 s recovery time. Thus, the 2-wt%-Sb-doped SnO2 thin film has suitable characteristics for application as an efficient gas sensor to detect ammonia.

Size Selectivity in Heterolanthanide Molecular Complexes with a Ditopic Ligand.

The similar reactivity of lanthanides generally leads to statistically populated polynuclear complexes, making the rational design of ordered hetero-lanthanide compounds extremely challenging. Here we report on the site selectivity in hetero-lanthanide tetranuclear complexes afforded by the relatively simple ditopic pyterpyNO ligand (4'-(4-pyridil)-2,2':6',2"-terpyridine N-oxide). The sequential room temperature reaction of RE2 (tta)6 (pyterpyNO)2 (where RE=Y, (1); Eu, (2), Dy, (3) Htta=2-thenoyltrifluoroacetone) with La(tta)3 dme (dme=dimethoxyethane) yielded Y2 La2 (tta)12 (pyterpyNO)2 (4), Dy2 La2 (tta)12 (pyterpyNO)2 (5) and Eu2 La2 (tta)12 (pyterpyNO)2 (6). Single crystals X-ray diffraction studies showed that 4, 5 and 6 are isostructural, featuring a tetranuclear structure with two different metal coordination sites with coordination numbers 8 (CN8) and 9 (CN9). The two smaller cations are mainly bridged by the O-donor atoms of the NO groups of two pyterpyNO ligands (CN8), while the larger lanthanum centres are bound by a terpyridine unit (CN9). Size selectivity has been studied with structural and magnetic studies in the solid state and through 19 F NMR and photoluminescence studies in solution, showing a direct dependence on the difference of ionic radii of the ions and yielding a 91 % selectivity for 4. Furthermore, 19 F NMR, X-ray and PL studies pointed out that the nature of the product is independent from the synthetic route for compound Eu2 Y2 (tta)12 (pyterpyNO)2 (7), keeping the ion selectivity also for a self-assembly reaction. Unexpectedly, these studies have evidenced that selectivity is not exclusively governed by electrostatic interactions related to size dimensions.

Characterization of monolayer WSe2 sandwiched in a hetero-plasmonic dimer

Recent interests in layered transition-metal dichalcogenides (TMDCs), such as WSe2, MoS2, etc, arise due to their attractive electrical, optical, and mechanical properties with potential applications in energy storage, generation, and many more. Embedding these 2D materials in plasmonic cavities can further enhance light–matter interactions and alter their properties, resulting in diverse and efficient optoelectronic applications. The strain due to the geometry and charge transfer due to the plasmonic materials can further modify the TMDCs’ optical response for sensing applications and as single photon emitters in on-chip optoelectronic applications. This work discusses one such 2D-plasmonic hybrid configuration of a silver sphere on a gold disc with WSe2 sandwiched in between. We perform non-invasive Raman and PL studies of this system to estimate the field enhancement and discuss strain and doping induced in the TMDC.

Zinc-induced changes on structural pathways, optical parameters, optical constants extracted by Kramers-Kronig Formulas, Photoluminescence Spectra and photovoltaic characteristics of n-Cd50-xZnxS50/i-AgSe/p-Si solar cells

In highlighted our study's scenarios, the importance of using a buffer layer of AgSe between an absorbent silicon substrate and a Cd50-xZnxS50 window layer with different Zn content with (x = 0, 10, 20, 30, 40, and 50 wt%) was discussed. The significant influence of the window layer on the properties of fabricated designs: (front electrode) Nickel (Ni)/n-Cd50-xZnxS50/i-AgSe/p-Si/(pt), platinum (back electrode) was also studied. This work devoted a large portion of its parts to investigate the structural, optical, photoluminesce, and thermopower properties of the CdZnS window layer to highlight the rationale for its application in the solar cells fabricated in this study. Pure phases of CdS and ZnS were confirmed through XRD and SEM analysis for the CdZnS window layers. Based on Tauc and Urbach's relationships, the optical parameters (bandgap energy Eg, tail energy Ee) were extracted. The optical constants (refractive index n, absorption index k) were calculated via the Kramers-Kronig formulas. In the visible region at 300–800 nm, the CdZnS thin layers showed a sharp peak in photoluminescence PL study results. The current density-voltage (J-V) characteristics in dark and illumination conditions were discussed. The highest power conversion efficiency (PCE) was for the last window layer. Thus, this layer was appropriate for the fabricated solar cells to obtain good photovoltaic properties.

Cadmium sulphide nanoparticles from Cadmium (II) complex of (Cyclododecylidineamino)thiourea

Novel ligand (Cyclododecylidineamino)thiourea (CDDATU) and its Cadmium (II) complex were synthesized and characterized by IR, CHNS and Thermo gravimetric analysis.The complex was found to give highly crystalline, good quality, mono-dispersed Cadmium sulphide nanoparticles through polyol synthesis method using Glycerol as high boiling solvent. Characterization of Cadmium sulphide nanoparticles were done using SEM, EDX, TEM, UV, PL and PXRD studies.

Synthesis of Bi/Sr doped zinc sulphide by spray pyrolysis technique : Effects of doping concentration on optoelectronic properties

Spray coated of Bi/Sr doped ZnS were prepared on glass substrate from a precursor solution of 0.045M zinc acetate dihydrate, 0.1M thioacetamide, 0.02M Bismuth nitrate and 0.07M Strontium hydroxide at deposition temperature of 200°C. The thin films were characterized using UV-Visible Spectrophotometry, scanning electron microscope (SEM), X-ray diffraction (XRD), flouromax-4 spectrofluorometer(PL) and Fourier transform infrared (FTIR) spectroscopy. The PL study revealed that 5ml Bi/Sr doped ZnS has the highest peak when compared with the pristine and it is closer to the visible region of the solar spectra. UV-visible analysis revealed a decrease in the bandgap energy from 3.25eV- 3.1eV at 5ml Bi/Sr doped ZnS. The structural analysis showed an increase in the intensity of the diffraction peak at 5ml Bi/Sr) doped ZnS thin film. It was concluded that 5ml Bi/Sr concentration is the best quantity of the dopant that can improve the properties of ZnS for optoelectronics application.

Insight into a strategy to improve charge carrier migration in lead-free bismuth-based halide perovskite for efficient selective oxidation of thioanisole under visible light

Lead-free halide perovskites have attracted a lot of attention as a new type of photoelectric conversion material in various solar energy-related applications involving photocatalysis. However, the perovskite photocatalysts still face the problem of insufficient performance arising mainly from the weak charge carrier migration currently. Exploring the strategies to promote the carrier separation efficiency maintains an urgent need. Different from the previous surface modification and construction of heterojunction, herein, we report a new lead-free perovskite solid solution of Cs3(BixSb1−x)2Br9 with tunable band gap prepared via a facile and efficient co-precipitation method. The introduction of Sb atoms in Cs3Bi2Br9 has obviously broadened the absorption of visible light, and making it to be a prominent visible-light photocatalyst for the selective oxidation of thioanisole to methyl phenyl sulfoxide in n-hexane. The single-particle PL study proves that the obtained CBSB (Cs3(BixSb1−x)2Br9) solid solution has a longer carrier lifetime than Cs3Bi2Br9 (CBB). In-situ ESR spectra demonstrate that O2− plays an important role during the oxidization process. The CBSB also has a superb stability, showing no apparent decrease in the catalytic activity in a five-cycle experiment. We believe our work can provide new understanding in promoting carrier lifetime of the lead-free perovskite materials, present a new approach for selective photo-oxidation, and may shed light on other solar energy conversion areas related to halide perovskites.