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Electrochemical modulation of nonlinear optical (NLO) absorption has recently garnered significant attention. In this work, we demonstrate the effective modulation of the third-order NLO absorption of layered molybdenum trioxide (MoO3) by cation intercalation. Upon application of different negative voltages to samples in different electrolytes, we observe varying degrees of enhancement in MoO3's nonlinear absorption corresponding to different cations and different electrochemical processes. Cation intercalation of H + , Li + , Na + , K + , and Mg 2 + is found to be more effective in enhancing the nonlinear absorption of MoO3 than electrochemisorption of Al 3 + cations. Notably, Li + intercalation leads to the most significant performance improvement, with an enhancement of 11.6 times and a nonlinear absorption coefficient of − 7 9. 8 8 ± 1 1. 2 1 cm GW − 1 . This improvement is ascribed to the increasing number of defect states in MoO3 during ion intercalation, which strengthens its saturation absorption behavior. Our work provides valuable insights into the electrically controlled NLO performance of MoO3 and can be applied to other similar materials. [ABSTRACT FROM AUTHOR]

The nonlinear optical properties of carbon dots have been in the spotlight in recent years. In light of the complexity and diversity of factors affecting the nonlinear optical properties of carbon dots, how to reveal the origin and physical mechanism of the nonlinear optical properties of carbon dots accurately has become a problem. In this work, a template-free method was designed to prepare carbon dots via solid-phase reaction with phloroglucinol as a single carbon source and sodium bisulfate as the catalyst. This method is simple, green, safe, and easy to be prepared on a large scale. Three carbon dots with different luminous colors were obtained by simply adjusting the reaction temperature. The rise of reaction temperature affects the surface functional groups, and then hinders the luminescence of surface states, leading to the change of luminescence properties. The nonlinear optical properties of carbon dots were analyzed by the Z-scan technique. Surprisingly, all carbon dots have nonlinear optical responses, but there are differences in performance. Results prove the increase in sp2 domains may contribute to the significant improvement of the nonlinear optical properties of carbon dots, indicating a direction to improve the nonlinear optical properties of carbon dots. [ABSTRACT FROM AUTHOR]

Using praseodymium nitrate, cobalt acetate and citric acid as main raw materials, the PrCoO3 photocatalyst was prepared by sol-gel method. The PrCoO3 samples were characterized by thermogravimetry and differential scanning calorimetry (TG-DSC), powder X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR). The photocatalytic activity of PrCoO3 was tested by simulating polluted water with 10 mg/L methyl orange solution under ultraviolet light irradiation. The results show that pure PrCoO3 can be prepared by calcination in the range of 600 to 900 °C. The average particle size of PrCoO3 is about 30 μm. The photocatalytic performance of PrCoO3 is the best under the conditions of 700 °C calcination and ultraviolet light irradiation for 120 min, and the degradation rate of methyl orange (10 mg/L) can reach 98%. The PrCoO3 samples are consistent with first-order kinetics for the degradation of methyl orange. And the apparent rate constants is k = 0.0346 min−1. PrCoO3 sample shows good ultraviolet light photocatalytic activity and has a broad application prospect in the field of photocatalysis. [ABSTRACT FROM AUTHOR]

Using thulium oxide, nitric acid, ammonium metavanadate and citric acid as main raw materials, TmVO4 was successfully prepared by hydrothermal method. TmVO4 samples were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), thermogravimetry differential scanning calorimetry (TG-DSC), and Fourier transform infrared spectroscopy (FT-IR). Taking methyl orange solution as simulated sewage, the effects of synthesis temperature and illumination time on the photocatalytic activity of TmVO4 were studied. The results show that pure tetragonal zircon TmVO4 samples can be obtained under hydrothermal conditions of 120 °C to 180 °C. The sample prepared at 140°Chas uniform grain size, and the average grain size is about 50 nm. Under ultraviolet light illumination for 30 min, the degradation rate of 10 mg/L methyl orange can reach more than 77% in the presence of TmVO4. The photocatalysis experiment indicated that TmVO4 has good photocatalytic degradation activity for methyl orange. [ABSTRACT FROM AUTHOR]

Using Pr(NO3)3·6H2O, NH4VO3 and C6H8O7·H2O as main raw materials, PrVO4 was successfully prepared by sol-gel method. The structure and morphology of samples were characterized by thermogravimetry and differential scanning calorimetry (TG-DSC), powder X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR) and UV-visible diffuse reflectance spectroscopy (DRS). The effects of different synthesis temperature and light time on the photocatalytic activity of PrVO4 samples were investigated using methyl orange solution as simulated sewage. The results show that PrVO4 of pure tetragonal zircon structure can be prepared at calcination temperature of 600 °C ∼900 °C. PrVO4 particles were relatively uniform with average grain size of 1 ∼ 3 μm. The photocatalytic activity of sample prepared at 800 °C was the best. After UV irradiation for 150 min, the degradation rate of 10 mg/L methyl orange is nearly 100% in presence of PrVO4 sample prepared at 800 °C. The PrVO4 showed excellent photocatalytic activity for degradation of methyl orange. [ABSTRACT FROM AUTHOR]

Using europium trioxide (Eu2O3), ammonium metavanadate (NH4VO3), nitric acid and citric acid as main raw materials, the EuVO4 was prepared by a facile sol-gel method. The prepared samples were characterized by thermogravimetry and differential scanning calorimetry (TG-DSC), X-ray diffraction (XRD), scanning electron microscopy (SEM) and Fourier transform infrared (FT-IR) spectroscopy. Under ultraviolet light, the photocatalytic activities of EuVO4 were investigated by methyl orange which was used as simulated sewage. The results showed that the pure rare earth perovskite structure EuVO4 was obtained in the range of calcination temperature of 300 °C∼900. The photocatalytic experiment demonstrated that EuVO4 is highly photocatalytic active for the degradation of methyl orange under ultraviolet light irradiation. The EuVO4 particles that calcined at 700 °C were uniform and spherical with an average grain size of about 1 ∼ 2 μm. The photocatalytic performance of sample that calcinated at 700 °C was the best. When the MO of 10 mg/L was degraded for 2 h in presence of EuVO4, the degradation rate of MO can reach 95%. [ABSTRACT FROM AUTHOR]

In this work, the electrical tuning of the fifth‐order nonlinear absorption of antimony‐doped tin oxide (ATO) by ionic liquid gating is demonstrated. The pristine ATO film exhibits two‐photon‐induced excited‐state absorption (2PA‐ESA) with laser excitation at 1030 nm. The fifth‐order nonlinear absorption coefficient (γeff) of the ATO film can be monotonically modified in the range of 0.51 to 3.46 cm3 GW−2 by varying the sample bias, with a maximum enhancement factor of 6.8. The fundamental processes occurring during electrical tuning are revealed. The electrostatic and electrochemical capacitance is responsible for the modification in the number of free carriers in the conduction band of ATO. The electrical modulation of the nonlinear absorption of the ATO is ascribed to the voltage‐dependent diameter of the undepleted core of ATO. A smaller voltage results in the charging of ATO and a larger undepleted core, and consequently the size of the active component for 2PA‐ESA is larger. The electrochemical capacitance results from the chemisorption of H+ and OH− on the surface of the ATO, the larger water content in the ionic liquid affording a larger modulation range for the number of free carriers and the γeff. [ABSTRACT FROM AUTHOR]

We synthesize a vertical heterostructure (HS) between tin sulfide (SnS) and molybdenum sulfide (MoS 2 ) by chemical vapor deposition based on the preferential adsorption of sulfur on MoS 2 . Most of the SnS grains nucleate on MoS 2 nanosheets, formatting partially stacked HS with large overlapping regions. Photoluminescence quenching of MoS 2 is observed and illustrates effective charge separation in HS. The HS shows increased reverse saturable absorption relative to MoS 2 and SnS. The preferential adsorption of sulfur powders on MoS 2 and HS growth reported herein will provide a promising approach to the synthesis of other two-dimensional HS.