Photo-generated Carriers Research Articles

Magnetic-supported catalyst derived from red mud-based Fe-Co PBA for efficient degradation of organic pollutants by activating peroxymonosulfate under visible light

To alleviate the environmental pressure caused by the continuous accumulation of solid waste red mud (RM) and organic pollutants, we developed a magnetic-supported catalyst derived from RM-based Fe-Co Prussian blue analogues (RM-Co PBA-D) using RM as the iron source and carrier. Then, the catalyst was used to activate peroxymonosulfate (PMS) under visible light for the degradation of tetracycline (TC) and rhodamine B (RhB). Due to the superior dispersion, strong visible light response, and high photo-generated carrier separation efficiency of the RM-Co PBA-D, the RM-Co PBA-D/PMS/Vis system could completely degrade both TC (10 mg/L) and RhB (20 mg/L) in 30 min, with mineralization efficiencies as high as 70.12 % and 60.59 %, respectively. Several reactive oxygen species (ROS) such as SO4⋅−, ⋅OH−, ⋅O2−, 1O2, and h+ were involved in the degradation process, with SO4⋅− and 1O2 playing a dominant role. More importantly, except for the production of ROS, the regeneration of active sites (Co2+/Fe2+) mediated by photo-generated carriers was also a critical factor in enhancing the removal of organic pollutants. In addition, the constructed system demonstrated significant potential for practical applications, which was attributed to the stable structure and catalytic performance of the catalyst as well as the strong ability of the system to resist interference by impurity anions and detoxify organic pollutants.

Developing Z-scheme Bi2MoO6@α-MnO2 beaded core-shell heterostructure in photoelectrocatalytic treatment of organic wastewater

Photoelectrocatalysis (PEC) oxidation technology with the combination of electrocatalysis and photocatalysis is an ideal candidate for treatment of dyeing wastewater containing multifarious intractable organic compounds with high chroma. Constructing high-quality heterojunction photoelectrodes can effectively suppress the recombination of photo-generated carriers, thereby achieving efficient removal of pollution. Herein, a beaded Bi2MoO6@α-MnO2 core-shell architecture with tunable hetero-interface was prepared by simple hydrothermal-solvothermal process. The as-synthesized Bi2MoO6@α-MnO2 had larger electrochemically active surface area, smaller charge transfer resistance and negative flat band potential, and higher separation efficiency of e−/h+ pairs than pure α-MnO2 or Bi2MoO6. It is noteworthy that the as-synthesized Bi2MoO6@α-MnO2 showed Z-scheme heterostructure as demonstrated by the free radical quenching experiments. The optimized Bi2MoO6@α-MnO2-2.5 exhibited the highest degradation rate of 88.64% in 120 min for reactive brilliant blue (KN-R) and accelerated stability with long-term(∼10000s) at the current density of 50 mA cm−2 in 1.0 mol L−1 H2SO4 solution. This study provides valuable insights into the straightforward preparation of heterogeneous electrodes, offering a promising approach for the treatment of wastewater in various industrial applications.

Oxygen vacancy mediated photocatalysis of Ti3C2 MXene quantum dots/W18O49 hybrid membrane for peroxymonosulfate-enhanced oxidation degradation

Photocatalytic membrane technology shows great prospects in water decontamination. Coupling photocatalysis with peroxymonosulfate (PMS) can boost oxidation capacity by combining their superiorities sufficiently. Herein, 0D Ti3C2 MXene quantum dots (TMQDs) embedded oxygen vacancy-rich 3D sea urchin-like W18O49 microspheres (OTW) were synthesized via facile interface engineering combined with green plasma etching strategy. The visible-light driving flow-through membrane reactor was capable of degrading cyclophosphamide, a typical anticancer drug, and other common pollutants (5-fluorouracil, carbamazepine, bisphenol A, rhodamine B), with the removal and mineralization efficiencies of 10 μM pollutants reaching over 99 % and 63 %−79 % in 60 min with 0.5 mM PMS. Moreover, the long-term reliability of OTW membrane was validated through continuous treatment of 20 L sewage. Significantly, the newly designed photocatalytic membrane exhibited good tolerance to wide pH ranges, common coexisting substances in water, and various actual water matrix. The results of experimental and DFT theoretical calculations revealed that Schottky junction formed on the TMQDs/W18O49 interfaces and tunable O-defects could optimize electronic configuration, improve solar energy utilization, prevent photogenerated carriers’ recombination, promote H2O and PMS dissociation, making it possible that more •OH and SO4•− radicals participated in the oxidation degradation reaction. This study offers a design idea for preparing efficient and robust photocatalytic membrane via interface engineering and defect engineering strategies, which might contribute to bridging the translational gap between emerging photocatalytic techniques and practical environmental applications in near future.

Precisely Regulating Asymmetric Charge Distribution by Single-Atom Central Doped Ag-Based Series Clusters for Enhanced Photoreduction of CO2 to Alcohol Fuels.

High efficiently photocatalytic CO2 reduction (CO2RR) into liquid fuels in pure water system remains challenged. Iron polyphthalocyanine (FePPc) with strong light harvesting, unique Fe-N4 structure, abundant pores, and good stability could serve as a promising catalyst for CO2 photoreduction. To further improve the catalytic efficiency, herein, symmetry-breaking Fe sites are constructed by coupling with atomically precise M1Ag24 (M=Ag, Au, Pt) series clusters. Especially, the introduction of Pt1Ag24 causes the most asymmetric charge distribution of Fe in FePPc (followed by Au1Ag24 and Ag25), leading to the favorable CO2 adsorption and activation. In addition, Pt1Ag24-FePPc exhibits the most effective photogenerated carriers transfer and separation. As a result, Pt1Ag24-FePPc shows the methanol/ethanol yield of 48.55/32.97 μmol·gcat-1·h-1 in H2O-CO2 system under visible light irradiation, ~ 1.65/1.25-fold, 1.83/1.37-fold, and 3.6/1.61-fold higher than that of Au1Ag24-FePPc, Ag25-FePPc, and FePPc, respectively. This work provides a concept for precisely construction and regulation symmetry-breaking sites of cluster-based catalysts for effective CO2 conversion.

Photocatalytic degradation of tetracycline by g-C3N4/stilbite under visible light: Mechanistic insights and degradation pathways

In this study, the g-C3N4/stilbite composite was fabricated by the in-situ synthesis method, and the photocatalytic performance was investigated by degrading tetracycline (TC) under visible light. The results indicated that the photocatalytic degradation efficiency of g-C3N4/stilbite-6 (86.8 %) was about 2.7 times higher than that of pure g-C3N4 (31.8 %). The introduction of the stilbite carrier effectively resolved the issues of g-C3N4 such as easy self-agglomeration and the difficulty in separating photo-generated carriers, thereby improving the photocatalytic activity of g-C3N4. From the quenching experiment, it was found that h+ and •O2− were main active species for TC degradation. By HPLC-MS analysis, TC degradation products were identified, and three degradation pathways were proposed. In addition, the impacts of solution pH, light intensity, and catalyst dosage on TC degradation performance were also evaluated. Overall, a simple and successful strategy has been proposed to synthesize high-performing visible-light-driven photocatalysts for efficiently eliminating organic contaminants from wastewater.

Nitrogen-Doped 3D-Graphene Advances Near-Infrared Photodetector for Logic Circuits and Image Sensors Overcoming 2D Limitations.

The limitations of two-dimensional (2D) graphene in broadband photodetector are overcome by integrating nitrogen (N) doping into three-dimensional (3D) structures within silicon (Si) via plasma-assisted chemical vapor deposition (PACVD) technology. This contributes to the construction of vertical Schottky heterojunction broad-spectrum photodetectors and applications in logic devices and image sensors. The natural nanoscale resonant cavity structure of 3D-graphene enhances photon capture efficiency, thereby increasing photocarrier generation. N-doping can fine-tune the electronic structure, advancing the Schottky barrier height and reducing dark current. The as-fabricated photodetector exhibits exceptional self-driven photoresponse, especially at 1550 nm, with an excellent photoresponsivity (79.6 A/W), specific detectivity (1013 Jones), and rapid response of 130 μs. Moreover, it enables logic circuits, high-resolution pattern image recognition, and broadband spectra recording across the visible to near-infrared range (400-1550 nm). This research will provide new views and technical support for the development and widespread application of high-performance semiconductor-based graphene broadband detectors.

Inducing Cu2+ species to SrTiO3 nanofibers based on blend electrospinning for boosting CO2 photoreduction to CH3OH

Photocatalytic CO2 reduction presents a promising strategy to alleviate environmental issues caused by massive CO2 emissions. SrTiO3, a potential photocatalyst for photocatalytic CO2 reactions, is limited by poor photoresponsivity and fast photogenerated carrier recombination. In this work, a series of Cu2+ species modified SrTiO3 nanofibers (xCuO/STO) was prepared combining sol-gel method and electrospinning with different copper content. The CH3OH yield of the 0.08CuO/STO photocatalyst reached up to 5.75 ± 0.27 μmol g−1 h−1, which was 2.2 times higher than that of pure SrTiO3. It was attributed that the blend electrospinning promoted Cu2+ species to be well dispersed on the surface of the SrTiO3 nanofibers. The strategy effectively enhanced the light absorption of the photocatalyst and inhibited the recombination of the photogenerated carriers. Part of appropriate characterizations were employed to elucidate the above point. In addition, to explore the inherent mechanism between the two species, the Density Functional Theory (DFT) calculations were further applied in the inherent mechanism between the species. This work provided a blend electrospinning approach for designing cocatalyst-modified SrTiO3 nanofibers for photocatalytic reduction of CO2.

Facile Construction of a Double-Heterojunction Perovskite Quantum Dot System for Efficient Photocatalytic Cr6+ Reduction.

Based on their excellent stability, high carrier mobility, and wide photoresponse range, composites formed by embedding perovskite quantum dots (PQDs) into metal-organic frameworks (PQDs@MOF) show great development potential in the field of photocatalysis, including the toxic hexavalent chromium (Cr6+) degradation, CO2 reduction, H2 production, etc. However, the rapid recombination of photogenerated carriers is still a major obstacle to the improvement of photocatalytic performance, and the internal mechanism of photocatalysis is still unclear. In this work, we construct a novel double heterojunction photocatalyst by encapsulating CsPbBr3 PQDs in Zr-based metal-organic frameworks (UiO-67) and loading additional hole-acceptor pentylenetetrazol (PTZ). Spontaneous photoinduced charge-transfer and separation between interfaces are confirmed by time-resolved photoluminescence and transient absorption spectroscopy. Furthermore, compared with pure UiO-67, the photoactivity of CsPbBr3 PQDs@UiO-67@PTZ increased 3-fold due to the long-lived charge-separated state. Our findings provide a new guideline for the design of PQDs@MOF-based photocatalysts with long-lived photogenerated carriers and outstanding photocatalytic activity.

Unequilibrated Charge Carrier Mobility in Organic Semiconductors Measured Using Injection Metal–Insulator–Semiconductor Charge Extraction by Linearly Increasing Voltage

The charge carrier mobility in tris(4‐carbazoyl‐9‐ylphenyl)amine (TCTA), a host and hole transport material typically used in organic light‐emitting diodes (OLEDs), is measured using charge carrier electrical injection metal–insulator–semiconductor charge extraction by linearly increasing voltage (i‐MIS‐CELIV). By employing the injection current i‐MIS‐CELIV method, charge transport at time scales shorter than the transit times typically observed in standard MIS‐CELIV is measured. The i‐MIS‐CELIV technique enables the experimental measurement of unequilibrated and pretrapped charge carriers. Through a comparison of injection and extraction current transients obtained from i‐MIS‐CELIV and MIS‐CELIV, it is concluded that hole trapping is negligible in evaporated neat films of TCTA within the time‐scales relevant to the operational conditions of optoelectronic devices, such as OLEDs. Furthermore, photocarrier generation in conjunction with i‐MIS‐CELIV (photo‐i‐MIS‐CELIV) to quantify the properties of charge injection from the electrode to the semiconductor of the MIS devices is utilized. Based on the photo‐i‐MIS‐CELIV measurements, it is observed that the contact resistance does not limit the injection current at the TCTA/molybdenum oxide/silver interface. Therefore, when TCTA is employed as the hole transport/electron‐blocking layer in OLEDs, it does not significantly reduce the injection current and remains compatible with the high injection current densities required for efficient OLED operation.

Sign reversal of visible to UV photocurrent in core–shell n-InGaN/p-GaN nanowire photodetectors

We demonstrate the change of the sign from negative to positive of the self-powered photovoltaic photocurrent in core–shell n-InGaN/p-GaN nanowire heterojunctions within the visible to UV wavelength range. Such dual-polarity photodetectors are of broad interest to provide extended functionalities for optoelectronic devices, starting with dual-wavelength photodetectors. The physics of the photocurrent sign reversal is understood by a well-balanced selective absorption and photocarrier generation, photocarrier transfer, and thermal excitation paths in the core–shell n-InGaN/p-GaN nanowire functional absorber with different bandgap energies and opposite inner- and surface energy band bendings. The basic dual-wavelength photodetector operation parameters are given.

Enhanced efficiency of interfacial charge transfer in Ag3PO4/BiPO4@CNTs photocatalyst for amoxicillin degradation: Synergistic effect of p-n heterojunction and conjugated channels

Inspired by the remarkable efficiency in separating photogenerated carriers achieved through the fabrication of conjugated polymeric photocatalysts, we have developed a novel photocatalytic system. This system utilizes carbon nanotubes coated with an Ag3PO4/BiPO4 p-n heterostructure (ABCx) for the degradation of amoxicillin in aquatic environments under visible light. The ABCx conjugated photocatalysts demonstrate excellent efficiency in photogenerated charge separation, material stability, and effective amoxicillin removal. The first-order kinetic constants for ABCx (x[‰]=2, 5, 7) show enhancements of 1.40-fold, 2.53-fold, and 2.10-fold, respectively, compared to those of Ag3PO4/BiPO4 in the degradation of amoxicillin. FT-IR and photochemical conversion studies reveal the presence of delocalized π-bonds within the conjugated system (P = CC = C···C = O), which can lead to the formation of a rapidly generated and long-lived triplet state T1 rather than the lowest singlet excited state S1 generated from either direct excitation or reverse intersystem crossing. In situ XPS analysis confirms that photogenerated charges migrate from BiPO4 to Ag3PO4 through a conjugated redox pathway. Density Functional Theory (DFT) was employed to investigate the work function, determining the Fermi levels of Ag3PO4 and BiPO4 to be -4.27 eV and -5.09 eV, respectively, and further confirming the direction of charge migration. In summary, the incorporation of conjugated π bonds via an inorganic semiconductor heterojunction enhances the efficiency of photogenerated charge separation and transport.

Construction of an S-scheme electron transfer channel in Cu0/CuFe2O4 magnetic plate column reactor for the LEV degradation: New strategy of visible Photo-Fenton system application

The complicated loading process and easy falling off of powder catalysts still restrict the wide application of Photo-Fenton technology in practical water treatment. In this study, a magnetic fixed film plate column water treatment equipment is designed as a visible Photo-Fenton reactor to remove levofloxacin (LEV). The effect of magnetic force can ensure that the catalyst is firmly fixed, and the multi-level shallow column plate structure achieves full contact and efficient reaction between the catalyst and wastewater. Simultaneously, the Cu0/CuFe2O4 (STCCF) utilizes Cu0 to construct an S-scheme electron transfer channel, which improves the separation efficiency of photo-generated carriers and provides sufficient photo-generated electrons for the reduction of Fe (Ⅲ) and Cu (Ⅱ). The pseudo-first-order reaction kinetic constant k for the degradation of LEV in the visible Photo-Fenton system is 0.0349 min−1, which is 15.9 times that of the photocatalytic system and 4.8 times that of the Fenton system. After continuous operation for 72 h, the magnetic fixed film plate column reactor can still remove more than 90 % of LEV and 82 % of COD in the secondary effluent of simulated antibiotic pharmaceutical wastewater treatment process, and the effluent is stable and meets the standard. The magnetic fixed film plate column reactor can be used for advanced treatment of antibiotic pharmaceutical wastewater. This study provides a new insight into the application of the Photo-Fenton process.

Molten salt defect engineering regulation of Bi4TaO8Cl perovskite structure for boosting photo-Fenton degradation of antibiotics

Defect engineering offers a feasible avenue to ameliorate the photocatalytic activities of semiconductors, but the traditional preparation processes for introducing the defects would destroy the pristine morphology of the materials. Herein, a controllable defect engineering on CeO2 nanodots loaded Bi4TaO8Cl perovskite nanosheets was approached to synthesize well-defined CeO2/Bi4TaO8Cl (CE-BTC) heterojunction with stable oxygen vacancies (OVs) via a molten-salt-mediated strategy. Due to the coexistence of OVs and Ce4+/Ce3+ redox couple, the photo-Fenton degradation rate of ofloxacin by optimal CE-BTC heterojunction (0.09610 min−1) was 7.78 and 4.98 times higher than that by individual Bi4TaO8Cl and CeO2, respectively. Moreover, the CE-BTC also exhibited excellent degradation performance towards other antibiotics including norfloxacin, ciprofloxacin, tetracycline, and sulfamethoxazole, while maintaining good recyclability and stability. The high efficiency of CE-BTC was also attributed to its enhanced light-harvesting capability, low photogenerated carrier recombination, and minimal electron transfer resistance. Mechanism study indicated that ⋅OH and ⋅O2– were the dominant reactive species, whereas h+ also participated in the removal of ofloxacin with a lower contribution. This study demonstrated the enormous potential of CE-BTC heterojunction in the degradation and risk control of antibiotics, providing a promising strategy for designing highly dispersed heterojunction catalysts with surface defects.

Interfacial oxygen vacancy engineering of double Z-scheme heterojunction Bi2MoO6/MnWO4/g-C3N4 for efficient photocatalytic degradation of iodohydrin

The synthesis of a dual Z-scheme heterojunction, Bi2MoO6/MnWO4/g-C3N4 (BMCM-x), enriched with oxygen voids, has been synthesized by an in-situ generation method. The ideal composite specimen, BMCM-50, managed to break down over 85 % of Iohexol in a span of 40 min. The emergence of oxygen voids serves to inhibit the merging of photogenerated carriers and fosters the creation of reactive radicals. The dual Z-scheme heterojunction is capable of isolating photogenerated carriers and enhancing redox capacity, markedly boosting BMCM-50’s photocatalytic breakdown efficiency.

Interplanar spacing and nanosheet thickness regulation of carbon nitride and its “cold” catalytic hydrogen production performance under 10 W LED irradiation

Investigation of hydrogen production catalysis under low-temperature and low-power light irradiation, such as LEDs, is important for energy conservation in cold natural conditions. Interlayer charge transfer in g-C3N4 nanosheets is influenced by the crystal face spacing and nanosheet thickness, due to rapid photogenerated carrier recombination and slow charge transfer, thus enhancing hydrogen production capabilities. Few studies have controlled both crystal face spacing and nanosheet thickness simultaneously. In this research, copper-phosphorus co-doped g-C3N4 was synthesized through one-step thermal polymerization, achieving both control over nanosheet thickness and crystal surface spacing. The hydrogen production rate of 0.5 %Cu/1 %P doped g-C3N4 was increased by 5.25 times and reached 958.98 μmol/g/h under 10 °C and 10 W LED illumination. Copper and phosphorus doping that reduced (002) surface spacing of g-C3N4, resulting in thinner nanosheets. This structural modification facilitated interlayer charge transfer and suppressed photogenerated carrier recombination. This research provides a novel insight and strategy for designing hydrogen production photocatalyst at low temperatures and with low energy consumption.

Enhanced photocatalytic activity and antibacterial potential of a novel ternary ZnO-Ag2MoO4-AgI heterojunction photocatalyst

The construction of heterojunctions is a recognized strategy for enhancing photogenerated carrier separation. This research introduces a novel ZnO-Ag2MoO4-AgI photocatalyst with a double Z-type heterojunction, made using a straightforward precipitation technique. The precise position of energy levels endowed the ternary photocatalyst with the ability of directional electron flow, while the Z-type structure exhibits strong redox capabilities and facilitates the effective separation of photogenerated charge carriers. The structural characteristics, the photocatalytic activities, the antibacterial properties, and the cytotoxicity of the catalysts were evaluated. The results demonstrate that the catalytic ability of ternary composites work synergistically, surpassing the individual and binary photocatalysts. Notably, the ternary composites with 30 % AgI content exhibit the highest catalytic activity, achieving complete degradation of Rhodamine B in 30 minutes, and up to 71.2 % degradation of Norfloxacin in 60 minutes. Furthermore, more than 99.998 % of Staphylococcus aureus, and 100 % of Escherichia coli were eliminated within 40 minutes, while Human colorectal adenocarcinoma epithelial cells mortality reached 91.98 % at a dose of 250 μg/mL. Our study underscores the potential of this strategy for photocatalytic degradation of organic contaminants, and as an antibacterial agent, providing innovative insights into the design of ZnO-based heterostructure photocatalysts.

Constructing dual sulfite-mediated processes via inner-sphere complexation and photogenerated carrier modulation with Hematite/Fe2TiO5 heterojunction for ofloxacin degradation

Hitherto, various sulfite-based advanced oxidation processes have emerged with particular vantages of low cost and potential for efficient contaminant degradation, which still requires increasing strategies for addressing its drawback. To achieve system-neutral feasibility and overcome the limitations, a metal oxide composite catalyst Hematite/Fe2TiO5 integrated with S-scheme heterojunction was constructed for ofloxacin degradation under S(IV)-visible light conditions. Impressively, the as-built system manifested significant promotion on substrate removal (more than four times the original Fe2TiO5), which indicated the accelerated inner-sphere interactions between catalyst and S(IV) with beneficial Vis contributed primarily to the degradation, demonstrating the dual sulfite-mediated effective pathway through modulated photogenerated carriers and oxy-sulfur radical chain reactions. Additionally, the interfacial enhancement by the heterojunction structure was further investigated by First-principles computation, which confirmed the mechanism of facilitated electron-hole pair separation. Overall, this work reveals the critical mechanism of Vis-induced S(IV)-AOP and provides constructive perspectives to address the limitations of conventional processes.

Giant photoelectric energy conversion via a 3C-SiC Nano-Thin film double heterojunction

Enhancing the energy conversion efficiency is utmost important in renewable energy and self-powered optoelectronic sensing applications. In this study, we propose the concept of a p-3C-SiC nano-thin film/p-Si/n-Si double junction (DJ) structure, which exhibits a massive photoelectric energy conversion efficiency and ultra-high sensitivity of optoelectronic sensors. The optoelectronic characteristics of this DJ heterostructure are compared to those of a p-3C-SiC/n-Si single-junction (SJ) heterostructure, which shares similarities in all technical and material parameters, except for the inclusion of the middle p-Si layer in the DJ structure. The experimental results reveal that the lateral photocurrent, sensitivity, theoretical power and maximum power of the DJ structure are more than 100 times (i.e. over 10,000%) greater than those of the SJ structure. We then demonstrated these excellent features of DJ heterostructure through developing of a self-powered position sensitive sensor, which showed an ultrahigh sensitivity. The enormous enhancement in the performance has been elucidated through the efficient photogeneration of charge carriers, electron-hole pair splitting, and the improved charge carrier transport mechanisms in the double heterojunction. This research represents a notable breakthrough in ultra-sensitive optoelectronic sensors and photoenergy conversion, since the proposed concept and theoretical model can be extended to multiple junctions of various semiconductor materials.

Built-in electric field mediated S-scheme charge migration and Co-N4(II) sites in cobalt phthalocyanine/MIL-68(In)-NH2 heterojunction for boosting photocatalytic nitric oxide oxidation

The efficiency of photocatalytic Nitric Oxide(NO) oxidation is limited by the lack of oxygen(O2) active sites and poor charge carrier separation. To address this challenge, we developed a molecular Cobalt Phthalocyanine modified MIL-68(In)–NH2 photocatalyst with a robust Built-in electric field(BIEF). In the 2 % CoPc-MIN sample, the BIEF strength is increased by 3.54 times and 5.83 times compared to pristine CoPc and MIL-68(In)–NH2, respectively. This BIEF facilitates the efficient S-scheme charge transfer, thereby enhancing photogenerated carrier separation. Additionally, the Co-N4(II) sites in CoPc can effectively trap the separated photoexcited electrons in the S-scheme system. In addition, the Co-N4(II) sites can also serve as active sites for O2 adsorption and activation, promoting the generation of superoxide radical (O2–), thereby driving the direct conversion of NO to nitrate(NO3–). Consequently, the 2 % CoPc-MIN sample exhibits a remarkable photocatalytic NO removal efficiency of 79.37 % while effectively suppressing the formation of harmful by-product nitrogen dioxide(NO2) to below 3.5 ppb. This study provides a feasible strategy for designing high-efficiency O2 activation photocatalysts for NO oxidation.

Optical and electrochemical studies on single-phase ZnSnO3 nanostructures—A photosensitive approach

A sol-gel-combustion reaction approach is used to synthesize nanocrystalline, single-phase ZnSnO3 phosphor. XRD with the Rietveld refinement investigation reveals a previously unreported orthorhombic structure of ZnSnO3. FTIR analysis confirms the formation of the ZnSnO3 phase. Microstructural SEM and TEM examinations affirm the petal-like morphology of the ZnSnO3 nanostructure. UV-DRS analysis signifies ZnSnO3 as a semiconducting material with a lowest energy band gap of 2.94 eV, which has never been recorded before. Photoluminescence (PL) studies reveal defect-related emission in ZnSnO3. Cyclic voltammetry measurements confirm the redox process and photo-generated carrier recombination via defect levels. ZnSnO3 is identified as a p-type semiconductor by Mott-Schottky analysis. When irradiated with 397 nm UV light, the semiconducting nanostructures emit near-white light. Finally, the investigation of ZnSnO3 nanopowder for latent fingerprint impressions reveals an unusual diffuse reflection and high-resolution images under a sodium vapour lamp and LASER-LED illumination.