Se Atoms Research Articles

Development and Creation of a New Class of Silicon-Based Varizone Structures Involving Zn and Se Atoms

A possibility of the formation of structures such as compounds of elements between chalcogenides and the transition group of metals in the crystal lattice of silicon is studied. This is an urgent problem in electronics. It is shown that, under certain technological conditions, a sufficient concentration of unit cells is formed, which leads to a change in the band structure of silicon itself, i.e. a micro- and nanoscale inclusion in silicon with a direct-gap structure is obtained. The possibilities of creating a fundamentally new class of photocells with an extended spectral sensitivity region, as well as light-emitting devices, light-emitting diodes and lasers based on them are shown.

Interfacial Engineering of Copper-Nickel Selenide Nanodendrites for Enhanced Overall Water Splitting in Alkali Condition.

Fabricating heterogeneous interfaces is an effective approach to improve the intrinsic activity of noble-metal-free catalysts for water splitting. Herein, 3D copper-nickel selenide (CuNi@NiSe) nanodendrites with abundant heterointerfaces are constructed by a precise multi-step wet chemistry method. Notably, CuNi@NiSe only needs 293 and 41mV at 10mA cm-2 for oxygen evolution reaction (OER) and hydrogen evolution reaction (HER), respectively. Moreover, the assembled CuNi@NiSe system just requires 2.2V at 1000mA cm-2 in anion exchange membrane (AEM) electrolyzer, which is 2.0 times better than Pt/C//IrO2 . Mechanism studies reveal Cu defects on the Cu2-x Se surface boost the electron transfer between Cu atoms and Se atoms of Ni3 Se4 via Cu2-x Se/Ni3 Se4 interface, largely lowering the reaction barrier of rate-determining step for HER. Besides, the intrinsic activity of Ni atoms for in situ generated NiOOH is largely enhanced during OER because of the electron-modulating effect of Se atoms at Ni3 Se4 /NiOOH interface. The unique 3D structure also promotes the mass transfer during catalysis process. This work emphasizes the essential role of interfacial engineering for practical water splitting.

Tuning the exciton binding energy of covalent organic frameworks for efficient photocatalysis

Owing to the large exciton binding energy (>100 meV) of most organic materials, the process of exciton dissociation into free electrons and holes is seriously hindered, which plays a key role in the photocatalytic system. In this study, a series of chalcogen (S, Se)-substituted mesoporous covalent organic frameworks (COFs) have been synthesized for enhanced photocatalytic organic transformations. Photoelectrochemical measurements indicate that the introduction of semi-metallic Se atom and the enlargement of conjugation degree can not only reduce the exciton binding energy accelerating the charge separation, but also reduce the band gap of COFs. As a result, the COF-NUST-36 with the lowest exciton binding energy (39.5 meV) shows the highest photocatalytic performance for selective oxidation of amines (up to 98% Conv. and 97.5% Sel.). This work provides a feasible method for designing COFs with high photocatalytic activity by adjusting exciton binding energy.

Giant piezoresistivity in a van der Waals material induced by intralayer atomic motions

The presence of the van der Waals gap in layered materials creates a wealth of intriguing phenomena different to their counterparts in conventional materials. For example, pressurization can generate a large anisotropic lattice shrinkage along the stacking orientation and/or a significant interlayer sliding, and many of the exotic pressure-dependent properties derive from these mechanisms. Here we report a giant piezoresistivity in pressurized β′-In2Se3. Upon compression, a six-orders-of-magnitude drop of electrical resistivity is obtained below 1.2 GPa in β′-In2Se3 flakes, yielding a giant piezoresistive gauge πp of −5.33 GPa−1. Simultaneously, the sample undergoes a semiconductor-to-semimetal transition without a structural phase transition. Surprisingly, linear dichroism study and theoretical first principles modelling show that these phenomena arise not due to shrinkage or sliding at the van der Waals gap, but rather are dominated by the layer-dependent atomic motions inside the quintuple layer, mainly from the shifting of middle Se atoms to their high-symmetric location. The atomic motions link to both the band structure modulation and the in-plane ferroelectric dipoles. Our work not only provides a prominent piezoresistive material but also points out the importance of intralayer atomic motions beyond van der Waals gap.

Ternary compound heterojunction from isomerism h-CdS/c-CdSe exhibits boosting photoelectrochemical and hydrogen evolution reaction properties

A novel h-CdS/c-CdSe ternary compound heterojunction catalyst CdSS is constructed from isomerism hexagonal CdS and cubic CdSe. The isomerism hexagonal CdS and cubic CdSe is the key factor to obtain the CdSS heterojunction, as compared, ternary compound CdSSe can only be prepared from isomorphic hexagonal CdS and hexagonal CdSe. Under different S:Se ratio, the main XRD peaks of CdSS displayed continuous shift between related CdS and CdSe peaks that confirms the S and Se atoms embedding CdSe and CdS lattice respectively to form atomic level ternary compound heterojunction. The photoelectrochemical and electrocatalytic results show that the CdSS catalysts have boosting properties. Under an optimal S:Se ratio, the photocurrent density of the CdSS reach 8.23 μA/cm2, which was 4.5 times that of original CdS (1.83 μA/cm2), 4.9 times of CdSe (1.67 μA/cm2) and 5.1 times of CdSSe (1.60 μA/cm2). The hydrogen evolution reaction Tafel slope of CdSS also declined 60% compared with CdS and 64% compared with CdSe. The electrocatalytic impedance and fluorescence spectra fully show that CdSS has lower internal resistance and low electron-hole recombination efficiency due to the atomic level heterojunction. The work develops a new strategy to construct high efficiency atomic level ternary compound heterojunction between isomerism homologous element compounds.

Selenium‐Based Nonfused Electron Acceptors for Efficient Organic Photovoltaic Cells

Selenium heterocycles are widely used in constructing organic semiconductors due to their advantages in narrowing the bandgap and enhancing the intermolecular packing. Herein, the application of Se substitution in designing nonfused electron acceptors (nfEAs) is studied. From a thiophene analog (A4T‐16), three nfEAs with two (ASe‐1 and ASe‐2) or four (ASe‐3) selenophene units are synthesized. The results suggest that the incorporation of Se atoms will downshift the lowest unoccupied molecular orbit level, upshift the highest occupied molecular orbit level, and exhibit redshifted absorption spectra due to the enhanced quinoidal character. The crystallographic data indicate that Se‐containing molecules exhibit more planar conjugate skeleton and thus lead to the improvement of carrier mobility. When blended with a polymer donor PBDB‐TF, ASe‐1‐, ASe‐2‐, and ASe‐3‐based organic photovoltaic (OPV) cells obtain power conversion efficiencies of 12.7%, 11.0%, and 10.4%, respectively. This work provides a comprehensive study of the application of Se substitution in designing low bandgap nfEAs for efficient OPV cells.

Synergistic Fe-Se Atom Pairs as Bifunctional Oxygen Electrocatalysts Boost Low-Temperature Rechargeable Zn-Air Battery.

Herein, we successfully construct bifunctional electrocatalysts by synthesizing atomically dispersed Fe-Se atom pairs supported on N-doped carbon (Fe-Se/NC). The obtained Fe-Se/NC shows a noteworthy bifunctional oxygen catalytic performance with a low potential difference of 0.698 V, far superior to that of reported Fe-based single-atom catalysts. The theoretical calculations reveal that p-d orbital hybridization around the Fe-Se atom pairs leads to remarkably asymmetrical polarized charge distributions. Fe-Se/NC based solid-state rechargeable Zn-air batteries (ZABs-Fe-Se/NC) present stable charge/discharge of 200 h (1090 cycles) at 20 mA cm-2 at 25 °C, which is 6.9 times of ZABs-Pt/C+Ir/C. At extremely low temperature of -40 °C, ZABs-Fe-Se/NC displays an ultra-robust cycling performance of 741 h (4041 cycles) at 1 mA cm-2 , which is about 11.7 times of ZABs-Pt/C+Ir/C. More importantly, ZABs-Fe-Se/NC could be operated for 133 h (725 cycles) even at 5 mA cm-2 at -40 °C.

Synergistic Fe−Se Atom Pairs as Bifunctional Oxygen Electrocatalysts Boost Low‐Temperature Rechargeable Zn‐Air Battery

AbstractHerein, we successfully construct bifunctional electrocatalysts by synthesizing atomically dispersed Fe−Se atom pairs supported on N‐doped carbon (Fe−Se/NC). The obtained Fe−Se/NC shows a noteworthy bifunctional oxygen catalytic performance with a low potential difference of 0.698 V, far superior to that of reported Fe‐based single‐atom catalysts. The theoretical calculations reveal that p‐d orbital hybridization around the Fe−Se atom pairs leads to remarkably asymmetrical polarized charge distributions. Fe−Se/NC based solid‐state rechargeable Zn‐air batteries (ZABs−Fe−Se/NC) present stable charge/discharge of 200 h (1090 cycles) at 20 mA cm−2at 25 °C, which is 6.9 times of ZABs−Pt/C+Ir/C. At extremely low temperature of −40 °C, ZABs−Fe−Se/NC displays an ultra‐robust cycling performance of 741 h (4041 cycles) at 1 mA cm−2, which is about 11.7 times of ZABs−Pt/C+Ir/C. More importantly, ZABs−Fe−Se/NC could be operated for 133 h (725 cycles) even at 5 mA cm−2at −40 °C.

Grain Growth Mechanism of CZTSSe Films Controlled by the Evaporation Area of Se

Thermally evaporated Se, including the molecules of Se2, Se5, Se6, Se7, and Se8 in the vapor at 550–600 °C, is widely used for the selenization of CZTSSe films. However, active small‐molecule Se2 tends to form large clusters of Se atoms at saturation vapor pressure, resulting in the large Se deficiency and poor crystallization of CZTSSe films. To regulate the time for Se to reach saturation vapor pressure and promote the role of active small‐molecule Se, the evaporation area of Se is controlled. Then the corresponding grain growth mechanism of CZTSSe films and device efficiency are systematically investigated. The results demonstrate that the appropriate evaporation area of Se can not only optimize the time for Se vapor to reach saturation, promote the rapid reaction crystallization between the precursor films and active Se2, but also inhibit the nucleation at the CZTSSe/Mo interface, thus making the CZTSSe films show a perfect top‐down grain growth mode. By preliminary optimization, when the evaporation area of Se is 245 mm2, a large‐grain spanning monolayer CZTSSe thin film is obtained; meanwhile, a device with a high efficiency of 12.39% is achieved. This study provides a new selenization strategy for improving the crystallinity of CZTSSe thin films.

Octylamine‐Supporting Interlayer Expanded Molybdenum Diselenide as a High‐Power Cathode for Rechargeable Mg Batteries

Rechargeable Mg batteries (RMBs) are a promising large‐scale energy‐storage technology with low cost and high safety, but the performance is limited by the inferior kinetics of Mg‐intercalation cathodes. In the present study, an octylamine‐supporting interlayer expanded molybdenum diselenide (e‐MoSe2) is synthesized and used as cathode for RMBs, in comparison with ordinary crystalline MoSe2. The octylamine molecules introduced show a strong interaction with the MoSe2 layers and increase the layer spacing significantly from 6.46 to 11.5 Å. e‐MoSe2 shows a high Mg‐storage capacity of 238 mAh g−1 at 50 mA g−1 and a superior rate performance of 39 mAh g−1 at 10 A g−1, far advantageous over crystalline MoSe2. e‐MoSe2 also shows a considerably high structure stability during repeated magnesiation/demagnesiation, providing an outstanding cycling stability for 1000 cycles. Further electrochemical tests demonstrate the high Mg2+ diffusion coefficients in e‐MoSe2. Theoretical computation indicates the interlayer expansion changes the Mg2+ diffusion paths from “hollow site → hollow site” to “hollow site → Se atom site → hollow site”, largely decreasing the energy barrier and improving the Mg2+ diffusion kinetics. The present work highlights an efficient strategy for the improvement of Mg‐storage performance for RMB cathodes.

Synthesis, Reactions, and Antioxidant Properties of Bis(3-amino-1-hydroxybenzyl)diselenide.

Bis(3-amino-1-hydroxybenzyl)diselenide containing two ortho groups was synthesized from 7-nitro-3H-2,1-benzoxaselenole and in situ generated sodium benzene tellurolate (PhTeNa). One-pot synthesis of 1,3-benzoselenazoles was achieved from bis(3-amino-1-hydroxybenzyl)diselenide and aryl aldehydes using acetic acid as a catalyst. The X-ray crystal structure of chloro-substituted benzoselenazole revealed a planar structure with T-shaped geometry around the Se atom. Both natural bond orbital and atoms in molecules calculations confirmed the presence of secondary Se···H interactions in bis(3-amino-1-hydroxybenzyl)diselenide and Se···O interactions in benzoselenazoles, respectively. The glutathione peroxidase (GPx)-like antioxidant activities of all compounds were evaluated using a thiophenol assay. Bis(3-amino-1-hydroxybenzyl)diselenide and benzoselenazoles showed better GPx-like activity compared to that of the diphenyl diselenide and ebselen, used as references, respectively. Based on 77Se{1H} NMR spectroscopy, a catalytic cycle for bis(3-amino-1-hydroxybenzyl)diselenide using thiophenol and hydrogen peroxide was proposed involving selenol, selenosulfide, and selenenic acid as intermediates. The potency of all GPx mimics was confirmed by their in vitro antibacterial properties against the biofilm formation of Bacillus subtilis and Pseudomonas aeruginosa. Additionally, molecular docking studies were used to evaluate the in silico interactions between the active sites of the TsaA and LasR-based proteins found in Bacillus subtilis and Pseudomonas aeruginosa.

Selenium vacancies induced surface oxygen adsorption and sensitization mechanism of PbSe film: Experimental and computational

Lead selenide (PbSe) is widely considered to be an ideal material for room temperature mid-wave infrared (MWIR) detection. The MWIR response of PbSe leaps obviously after sensitization in a particular oxidizing process. However, the mechanism of such characteristics has not been specifically understood. Here, the oxygen (O) sensitization reaction process is affirmed by experiment and computation. In the process of film preparation, Se atoms fractionate from the (200) plane of PbSe lattice and leave Se vacancies (VSe). Then, O2 molecules adsorbed at VSe and subsequently disintegrate into O atoms occupying VSe. The O indrawing forms new energy levels and reduces the band gap (Eg), realizes the conductivity transformation from n- to p-type, decreases carrier concentration, and enhances carrier mobility. The variation of conductivity inhibits the dark current of PbSe detectors and increases the mobility of photon-generated carriers at the same time, resulting in the improvement of the IR detection performance.

Free-standing [0 0 1]-oriented one-dimensional crystal-structured antimony selenide films for self-powered flexible near-infrared photodetectors

Flexible optoelectronic is one of the key components for acquiring biological signals in wearable devices and implantable systems. Recently, antimony selenide (Sb2Se3) has shown an exciting potential for flexible optoelectronic applications due to its unique one-dimensional (1D) ribbon-typed crystal structure, low-cost constituents, and superior optoelectronic properties. However, the growth of [001]-oriented Sb2Se3 film, which can efficiently enhance the carrier transport, is still challenging, particularly for its application in flexible electronics. Herein, we propose to grow the free-standing [001]-oriented Sb2Se3 film for self-powered flexible photodiode through selenizing the highly (0001)-textured Sb film on mica substrate. The theoretical calculation reveals that Sb(0001) plane provides a high adsorption energy for Se atoms, which promotes the [001]-oriented growth of Sb2Se3 film. The weak vdW interaction between Sb2Se3 film and mica substrate enables the film separation, and results in a free-standing Sb2Se3 film. Benefiting from the enhanced carrier transport in [001]-oriented Sb2Se3 film, the flexible photodiode exhibits a high responsivity up to 0.74 A W−1, a specific detectivity of 5.1 × 1013 Jones, a linear dynamic range of 102 dB, rise/fall time of 0.16/0.15 ms for near-infrared light detection without any external bias, and excellent folding endurance after 1000 bending cycles. It has been also successfully employed as a wearable photodetector to detect a person’s heart rate. This work demonstrates a strategy for the orientation control of low-dimensional crystal-structured materials and a great potential of free-standing films in flexible electronics applications.

Synthesis and chemistry of Ru-bimetallic homocubane clusters

Various ruthenium-incorporated tris- and bishomocubane analogues have been documented. The reaction between [Cp*RuCl2]2 (Cp* = η5-C5Me5) and [BH2Se3]Li at room temperature yielded bimetallic trishomocubane, [(Cp*Ru)2(μ3-Se)4(μ-Se)3(BH)2], 1; and bishomocubane, [(Cp*Ru)2(μ3-Se)5(μ-Se)2(BH)], 2. To the best of our knowledge, compound 1 is the first Se analogue of trishomocubane that has been isolated as a 1,2,3-isomer. With an objective of replacing the B–H vertex of compound 2 with an isolobal {Fe(CO)3} fragment, the reaction of compound 2 with [Fe2(CO)9] was carried out under photolytic conditions. Although the aim of obtaining a homocubane core compound was not achieved, the reaction yielded interesting heterometallic chalcogenide compounds, [{μ-Se(Cp*Ru(CO)2)}2{Fe(CO)3}4(μ4-Se)], 3, and [{Cp*Ru(CO)2}(μ4-Se){(μ-H)(Fe(CO)3)3}], 4. Compound 3 is a unique example of vertex-fused cluster, in which two butterfly {Fe2Se2} moieties are fused together through a common Se vertex and a {Cp*Ru(CO)2} unit is attached to each of the terminal Se atoms. In compound 4, the Se atom of a {Fe3Se} tetrahedron is connected to a {Cp*Ru(CO)2} fragment. Multinuclear NMR, infrared and UV–Vis spectroscopy, mass spectrometry as well as single crystal X-ray diffraction studies were performed for the characterization of compounds 1–4. Density functional theory methods were also employed for elucidating the bonding in these compounds.

Revealing 3D Ripple Structure and Its Dynamics in Freestanding Monolayer MoSe2 by Single-Frame 2D Atomic Image Reconstruction.

An atomic-scale ripple structure has been revealed by electron tomography based on sequential projected atomic-resolution images, but it requires harsh imaging conditions with negligible structure evolution of the imaged samples. Here, we demonstrate that the ripple structure in monolayer MoSe2 can be facilely reconstructed from a single-frame scanning transmission electron microscopy (STEM) image collected at designated collection angles. The intensity and shape of each Se2 atomic column in the single-frame projected STEM image are synergistically combined to precisely map the slight misalignments of two Se atoms induced by rippling, which is then converted to three-dimensional (3D) ripple distortions. The dynamics of 3D ripple deformation can thus be directly visualized at the atomic scale by sequential STEM imaging. In addition, the reconstructed images provide the first opportunity for directly testing the validity of the classical theory of thermal fluctuations. Our method paves the way for a 3D reconstruction of a dynamical process in two-dimensional materials with a reasonable temporal resolution.

Ni3S2/NiSe2 hollow spheres with low bonding energy Ni-Se bonds for excellent lithium-ion charge-discharge stability

The capacity and cycle stability of anode materials determine their application prospects in lithium-ion batteries (LIBs). Ni3S2 has attached much attention due to its high theoretical capacity as anode materials for LIBs. However, the inherent low conductivity and inevitable volume expansion during the charge-discharge process of Ni3S2 seriously limit its practical application. Compared with Ni3S2, NiSe2 owns higher Li+ conductivity for the lower binding energy of Ni-Se caused by the larger radius of Se. Herein, Ni3S2/NiSe2 hollow spheres have been prepared through an in situ gas phase selenization method, in which the sulfur atoms in Ni3S2 are partially replaced by Se atoms. When served as anode materials for LIBs, Ni3S2/NiSe2 exhibits an initial capacity of 1054.8 mA h g−1 at 100 mA g−1 and reversible capacity of 709 mA h g−1 at the current density of 100 mA g−1 after 200 cycles. Compared with Ni3S2 and NiSe2, the superior electrochemical performance of Ni3S2/NiSe2 can be attributed to the synergistic effect of two crystalline phases Ni3S2 and NiSe2 in Ni3S2/NiSe2, as well as the weaker electronegativity of Ni-Se benefiting to improve the reaction kinetics in the process of Li+ charge-discharge. Moreover, the pseudocapacitance behavior of Ni3S2/NiSe2 in the lithium storage process is also verified by electrode dynamic analysis. Our work provides a new strategy for the design of efficient lithium storage materials by constructing weak metal-chalcogen bonds to improve material conductivity and reduce energy consumption during conversion reactions.

Fabrication of High‐Responsivity Sb2Se3‐Based Photodetectors through Selenization Process

AbstractSb2Se3 has great potential for applications in near‐infrared sensors because of its narrow bandgap, environmental friendliness, and high absorption coefficient. However, the low conductivity of Sb2Se3 is an obstacle to the further development of high‐performance optoelectronic devices. In this study, to address this challenge, the selenization process is adopted. The incorporation of Se atoms into Sb2Se3 facilitates the crystallization of the films and the formation of [hk0]‐textured grains at a lower temperature than unselenized Sb2Se3. The selenized films possess larger grains than the unselenized ones at the same temperature. X‐ray photoelectron spectroscopy (XPS) results show that annealing causes the generation of donor‐like point defects (e.g., Vse and SbSe) and SeO2. The 250 °C‐annealed selenized Sb2Se3‐based photodetectors (PDs) have a high responsivity of 1130 mW A−1 and a specific detectivity of 4.62 × 1011 Jones. The PDs exhibit a fast response time (i.e., rise/fall time of 4.54 ms/8.50 ms), sensitivity of 94.2 at 20 mW cm−2, and external quantum efficiency of 155% at 200 µW cm−2. Further, the selenized PDs have good stability to moisture and air. Based on the XPS, X‐ray diffraction, and transmission electron microscope results, the improved performance of the selenized Sb2Se3‐based PDs is described and discussed.

Electronic Structures and NLO Properties of a Series of TMDs Lateral‐Core–Shell Heterostructures Quantum Dots

AbstractThe electronic structures and nonlinear optical (NLO) responses of eight triangle group‐VI transition metal dichalcogenides (TMDs) lateral‐core–shell heterostructures quantum dots (QDs) [MaX2MbX2 and MXa2MXb2; M (Ma, Mb) = Mo and W; X (Xa, Xb) = S and Se] have been explored by using quantum chemistry method. Frontier molecular orbital (FMOs) analyses indicate that the triangular frameworks with more active W and/or Se atoms at shell have smaller energy gaps than those with Mo and/or S atoms, and the active sites of the ultra‐small TMD heterostructures mainly locate at the edge and/or the corner of the frameworks. Generally speaking, active atoms at the shell are beneficial to the enhancement of the frequency‐dependent first hyperpolarizabilities compared with the active atoms in the cores. First hyperpolarizability density analyses show that the local contributions of the first hyperpolarizability in x direction is mainly located at the left and right corners, while that in y direction is mainly located at the bottom edge and top corner, confirming the important role that the shell of the TMDs lateral‐core–shell heterostructure QDs play in its NLO response. Further, the electronic transitions contributed to the SHG responses also occur at the shell of these triangular frameworks.

Selenium˗decorated nitrogen-rich honeycomb-like g-C3N4 as anode materials for lithium ion batteries

Heteroatom doping is an efficient method for modifying the electronic properties of carbon, especially its lithium storage capacity. On the other hand, selenium (Se) doping in various forms of heteroatoms has received insignificant attention despite its excellent physiochemical features. We report a straight-forward approach for the synthesis of selenium decorated honeycomb-like g-C3N4 (Se–H-g-C3N4) through pyrolysis and selenization for the serviceability of the anode of a Li-ion battery. Structural analysis using X-ray photoelectron spectroscopy (XPS) indicated that Se can serve as a stronger electron acceptor unit than carbon and nitrogen. Selenium doping also had a big effect on the electrical structure of the carbon skeleton. This is because Se atoms significantly widened the gap between carbon sheets, which made more active sites for storing Li-ions and sped up the rate of diffusion. Because of these effects, Se–H-g-C3N4 outperformed bulk g-C3N4 and honeycomb-like g-C3N4 (H-g-C3N4) as anode material in terms of rate capability and specific capacity. This method of powerful synergistic effects is a new way to find lithium ion battery anode materials with high electrochemical performance, as shown by their long cycle life and high capacity.

Organochalcogen (Se/Te) substituted Schiff bases: Syntheses and applications

Schiff base was originally proposed, synthesized by Hugo Schiff and widely used since 1864. They are synthesized by the reaction of aromatic aldehydes or ketones and the primary amines. It consists of CN functional group or azomethine. It is one of the most widely studied molecule just because of its ease to synthesize and append many functional moieties like selenium and tellurium as a part of its molecular structure. Schiff bases are mostly utilized by chemists, material scientists and the biologists. Chemists use them as catalysts and intermediates for the synthesis of fine chemicals, pigments, dyes and polymer stabilisers. Material scientists study their physical properties. However, biologists are highly fascinated by studying their biological activities such as antifungal, antibacterial, anti-malarial, anti-proliferative, anti-inflammatory, antiviral, etc. Schiff bases bearing larger Se and Te atoms are also used as sensors, light emitting diodes and solar cells. Therefore, this review article is mainly focused on the synthesis and applications of organochalcogen (Se/Te) substituted Schiff bases.