Quaternary Chalcogenide Research Articles

In4Pb5.5Sb5S19: A Stable Quaternary Chalcogenide with Low Thermal Conductivity.

Transition-metal-based chalcogenides are a series of intriguing semiconductors with applications spanning various fields because of their rich structure and numerous functionalities. This paper reports the crystal structure and basic physical properties of a new quaternary chalcogenide In4Pb5.5Sb5S19. The crystal structure of In4Pb5.5Sb5S19 was determined by both powder and single-crystal X-ray diffraction techniques. In4Pb5.5Sb5S19 crystallizes in the monoclinic system with I2/m space group, and the structure parameters are a = 26.483 Å, b = 3.899 Å, c = 32.696 Å, and β = 111.86°. The polyhedral double chains of Sb3+ and Sb/Pb2+ as the main cations are parallel to each other and form a Jamesonite-like mineral structure through the short chain links of the distorted In, Pb, and Sb polyhedron. In4Pb5.5Sb5S19 exhibits a moderate experimental band gap of 1.42 eV, indicating its potential for application in solar cells and photocatalysis. In addition, In4Pb5.5Sb5S19 exhibits good ambient stability, and differential scanning calorimetry tests demonstrate that it is stable up to 892 K in a nitrogen atmosphere. Moreover, In4Pb5.5Sb5S19 exhibits extremely low thermal conductivity (0.438-0.478 W m-1 K-1 ranging from 300 to 700 K) compared with binary counterparts such as PbS and In2S3. Future chemical manipulation via elemental doping or defect engineering may make the title compound a potential thermoelectric or thermal insulating material.

EuHgGeSe4 and EuHgSnS4: Two Quaternary Eu-Based Infrared Nonlinear Optical Materials with Strong Second-Harmonic-Generation Responses

Metal chalcogenides play a critical role in the infrared (IR) nonlinear optical (NLO) field. However, Eu-based chalcogenide-type IR NLO materials are still scarce up to now. In this paper, two new quaternary Eu-based chalcogenides, EuHgGeSe4 and EuHgSnS4, containing the "NLO active groups" [HgQ4]6- (Q = S, Se) and [GeSe4]4-/[SnS4]4- were synthesized through traditional high-temperature solid-state reactions. They possess noncentrosymmetric structures, crystallizing in the Ama2 space group, and exhibit strong phase-matchable second-harmonic-generation (SHG) responses (3.1× and 1.77× that of AgGaS2 for EuHgGeSe4 and EuHgSnS4, respectively). Meanwhile, the optical band gaps of EuHgGeSe4 (1.97 eV) and EuHgSnS4 (2.14 eV) were determined from UV-vis-NIR diffuse reflectance spectra. Differential scanning calorimetry (DSC) analyses reveal the congruent-melting behavior of EuHgGeSe4. Furthermore, structural analysis and theoretical calculations verify the critical driving effects of [HgQ4]6- tetrahedra on the strong SHG activity. The overall results demonstrate that EuHgGeSe4 and EuHgSnS4 are potential IR NLO materials.

Effect of sulfur amount during post-growth sulfurization process on the structural, morphological and thermoelectric properties of sol-gel grown quaternary chalcogenide Cu2ZnSnS4 thin films

In this work, the CZTS thin films (TFs) have been grown using sol-gel spin coating method on Si substrate. The effect of sulfur concentration on the structural, morphological and thermoelectric properties was investigated using various amounts of sulfur (100–400 mg) during post growth sulfurization process. XRD data evident that the best crystallinity of the CZTS thin film was obtained when the sample was sulfurized using 400 mg amount of sulfur. The vibrational modes of CZTS thin films were observed using Raman spectroscopy with major A1 mode at 331 cm−1 and secondary B(TO) and B(LO) modes at 292 cm−1 and 367 cm−1 respectively. SEM images showed that higher amount of sulfur contents resulted in the compact and smooth surface when compared with the samples sulfurized at lower concentration of sulfur. The thermoelectric properties such as Seebeck coefficient, electrical conductivity and power factor have improved from (249–334 μV/°C), (69–117 S/cm) and (4.28 × 104–1.305 × 103 Wm−1C−2) respectively with increasing the amount of sulfur during sulfurization process. This behavior of thermoelectric properties explained in detail using standard formulas and available literature.

Inter-relationship of the Structural Properties of Quaternary Chalcogenides CuZn2Ga(S/Se)4: A First-Principles Study

Quaternary chalcogenides based on stannite I-II $$_2$$ -III-VI $$_4$$ structure are the best potential candidates to overcome the current generation of solar harvesting materials. First-principles electronic structure simulations were performed on semiconducting CuZn $$_2$$ Ga(S/Se) $$_4$$ (CZGS/Se) to understand the inter-relationship of the structural properties. These structures contain a cubic close packing (ccp) array of S/Se-centered tetrahedrons, coordinated by one Cu, two Zn and one Ga atom occupying one half of the ccp tetrahedral voids. The remarkable variations in the crystal structures are explained by the influence of ionic radii of various atoms. The electronic and optical properties calculated using hybrid functional (Heyd, Scuseria and Ernzerhof, HSE06) show a suitable band gap of 1.59 eV for CZGSe with high optical absorption. The current density and maximum upper limit of theoretical energy conversion efficiency (P(%)) of CZGSe is enhanced when compared to that of CZGS. Our results suggest that the stannite CZGSe structure could be a promising candidate for efficient earth-abundant thin-film solar cell applications.

Marigold flower like structured Cu2NiSnS4 electrode for high energy asymmetric solid state supercapacitors

The growth in energy devices and the role of supercapacitors are increasingly important in today’s world. Designing an electrode material for supercapacitors using metals that have high performance, superior structure, are eco-friendly, inexpensive and highly abundant is essentially required for commercialization. In this point of view, quaternary chalcogenide Cu2NiSnS4 with fascinating marigold flower like microstructured electrodes are synthesized using different concentrations of citric acid (0, 0.05 M, 0.1 M and 0.2 M) by employing solvothermal method. The electrode materials physicochemical characteristics are deliberated in detail using the basic characterization techniques. The electrochemical studies revealed better electrochemical performances, in particular, Cu2NiSnS4@0.1 M-CA electrode revealed high 1029 F/g specific capacitance at 0.5 A/g current density. Further, it retained 78.65% capacity over 5000 cycles. To prove the practical applicability, a full-cell asymmetric solid-state device is fabricated, and it delivered 41.25 Wh/Kg and 750 Wh/Kg energy and power density at 0.5 A/g. The optimum citric acid added Cu2NiSnS4 electrode is shown to be a promising candidate for supercapacitor applications.

Thermal Properties of the Quaternary Chalcogenide BaCdSnSe4

The fields of nonlinear optics, photovoltaics, and thermoelectrics have been strongly impacted by materials research, and quaternary chalcogenides are one general class of materials that has recently generated strong interest. An understanding of the thermal properties is paramount in these and other applications of interest. The thermal properties of BaCdSnSe4, a quaternary chalcogenide that is of interest for applications in nonlinear optics, are reported. Specifically, the thermal conductivity over a large temperature range and heat capacity are evaluated in light of the structural features of this material. Low thermal conductivity results from the complex unit cell as well as local dynamic disorder from Cd in the CdSe4 tetrahedra in the crystal structure. The results and analyses reported herein are presented to enhance the fundamental understanding of the thermal properties of these materials, and can be related and applied to other quaternary chalcogenides that are of interest for energy‐related applications.

Physical properties evolution of sprayed Cu2MgSnS4 thin films with growth parameters and vacuum annealing

Quaternary chalcogenide Cu2MgSnS4 (CMTS) thin films were grown by spray pyrolysis technique on glass substrates using methanol as solvent. CMTS thin films growth methodology has been based on three steps in order to optimize structural and optical properties. X-ray diffraction, Raman spectroscopy, Spectrophotometer and SEM were used to investigate physical properties of CMTS thin films. The first step was searching for optium substrate temperature by performing synthesis of CMTS thin films at different temperatures (250, 200, 175 and 150 °C). Structural analysis has shown that the best grain size was found for thin films deposited at 175 °C but with presence of secondary phases. The second step was a simultaneous decrease in solvent volume, sulfur and copper concentrations in order to remove undesirable phases. The third step was a vacuum annealing of CMTS thin films at different temperatures 225, 300, 375 and 450 °C for 1 h in order to improve more physical properties. XRD analysis have shown that vacuum annealing at 450 °C temperature has eliminated completely secondary phases and increased grain size up to 51.82 nm. During these steps, band gap energy has been varied from 1.33 eV to a maximum value of 1.91 eV with an absorption coefficient α value near 105 cm−1. These experimental results have shown that CMTS thin film was successfully grown by spray pyrolysis technique and can be considered as promising absorber for photovoltaic applications.

Temperature-Time profile effects on evolution of physical and electronic properties in visible light Cu2CoSnS4 photodetectors

Earth-abundant quaternary chalcogenide Cu2CoSnS4 (CCTS) films on soda-lime glass (SLG) substrates are prepared via non-vacuum, cost-effective direct solution spin coating technique. The phase formation mechanism of CCTS films is investigated via TGA, FTIR, XRD, and RAMAN characterization. Annealing temperature effects on the crystalline phase, chemical composition, and grain growth, strongly linked with electrical and photodetection parameters of CCTS films, are systematically investigated through XRD, Raman, FEG-SEM, and EDS analysis. Through the transfer length measurement (TLM) method, the electrical properties of CCTS films annealed at 575 °C exhibit noticeable 92% reduction of both contact resistance (Rc) and resistivity (ρ), compared to those of the film processed at 300 °C. The highest photoresponsivity (7.50 A/W) and specific detectivity (4.70 × 1010 Jones) of CCTS devices have been demonstrated with annealing conditions at 575 °C and a bias voltage of 10 V as well. The present study reveals the impact of both annealing temperature and bias voltage on photodetector performance.

Heteroleptic Tin-Antimony Sulfoiodide for Stable and Lead-free Solar Cells

Summary The quaternary chalcogenide halides of group IV and V elements have attracted much attention due to their interesting semiconducting properties as well as a suitable band gap for solar cells. Here, for the first time, we report on solar cells using tin-antimony sulfoiodide (Sn2SbS2I3). Sn2SbS2I3 solar cells were fabricated using a chemical single-step deposition process with a solution containing a SbCl3-thiourea complex and SnI2 with the configuration of TiO2 and poly[2,6-(4,4-bis(2-ethylhexyl)-4H-cyclopenta[2,1-b;3,4-b′]dithiophene)-alt-4,7-(2,1,3-enzothiadiazole)] as the electron- and hole-transporting layers, respectively. The best-performing cell exhibits a power conversion efficiency of 4.04% under the illumination of standard AM 1.5G conditions (100 mW cm−2). These unencapsulated cells exhibited good stabilities at 80% relative humidity, 85°C in air, and under illumination, respectively. These results provide guidelines for fabrication of lead-free heteroleptic perovskite solar cells by hosting divalent or combinations of monovalent and trivalent metal cations.

Layered and Cubic Semiconductors AGaM'Q4 (A+ = K+, Rb+, Cs+, Tl+; M'4+ = Ge4+, Sn4+; Q2- = S2-, Se2-) and High Third-Harmonic Generation.

Eighteen new quaternary chalcogenides AGaM'Q4 (A+ = K+, Rb+, Cs+, Tl+; M'4+ = Ge4+, Sn4+; Q2- = S2-, Se2-) have been prepared by solid-state syntheses and structurally characterized using single-crystal X-ray diffraction techniques. These new phases crystallize in a variety of layered structure types. The tin analogues also adopt an extended three-dimensional network structure as polymorphs. The polymorphism and phase-stability in these cases were studied by thermal analysis and high-temperature in situ X-ray powder diffraction. All compounds are semiconductors with the colored selenides absorbing light in the infrared-green region (1.8 eV < Eg < 2.3 eV) and the mostly white sulfides absorbing light in the blue-ultraviolet range (2.5 eV < Eg < 3.6 eV). Based on third-harmonic generation (THG) measurements, the third-order nonlinear optical (NLO) susceptibilities χ(3) of the new and previously reported AGaM'Q4 compounds were determined. These measurements revealed an apparent correlation between the THG response of the sample and its band gap, rather than the crystal structure type. While low-gap materials possess higher nonlinearity in general, we found that layered orthorhombic RbGaGeS4 exhibits an impressive χ(3) value (about four times larger than that of AgGaS2) even with a large band gap and shows stability under ambient conditions with no significant irradiation damage.

Structural, electronic and optical properties of Ag2MgSn(S/Se)4 quaternary chalcogenides as solar cell absorber layer: An Ab-initio study

In this work, generalized gradient approximation (GGA) and the Heyd-Scuseria-Ernzerhof (HSE) hybrid functional within the framework of density functional theory (DFT) are used to investigate the structural, electronic and optical properties of Ag2MgSn(S/Se)4 quaternary chalcogenides in kesterite and stannite phases. The kesterite and stannite phases of Ag2MgSn(S/Se)4 are optimized and the values of lattice constants are calculated. The predicted energy bandgaps are found to be direct in nature along the Γ direction, with highest bandgap energy of less than 1.64 eV for Ag2MgSnS4 in kesterite phase. The total and partial density of states are analysed in detail. The optical properties such as imaginary and real parts of dielectric function, refractive index, reflectivity and extinction coefficient are also discussed. Further, in order to understand the light trapping capacity, we examine the absorption coefficients of Ag2MgSnS4 and Ag2MgSnSe4 materials and explore their applicability as solar cell absorber layers. The predicted values of all parameters will help researchers to carry out further investigations on these materials for photovoltaic applications.

Thermal properties of BaCu2SnQ4 (Q = S, Se) quaternary chalcogenides

Quaternary chalcogenides form in different structure types and compositions and are of scientific interest, while their diversity of physical properties exemplifies why they continue to be investigated for potential technological applications. We investigate the thermal properties of BaCu2SnQ4 with trigonal (Q = S) and orthorhombic (Q = Se) crystal structures. BaCu2SnS2Se2 was also synthesized and characterized in order to investigate the effect of alloying on the thermal properties of these quaternary chalcogenides. The low thermal conductivity these materials possess originates from complex phonon spectra and local dynamics of distorted CuQ4 tetrahedra. Our results and analyses are presented in light of the ongoing fundamental interest in these materials as well as their continued interest for energy-related and opto-electronic applications.

Photoactive Cu2FeSnS4 thin films: Influence of stabilizers

Quaternary photo-active metal chalcogenide Cu2FeSnS4 (CFTS) were deposited by the sol–gel method. The negative differential resistance (NDR) phenomenon and resistive switching (RS) characteristics at room temperature was observed on ITO/CFTS/Al device. The formation of CFTS was studied in the presence of different stabilizers like lactic acid and monoethanolamine. The use of dissimilar stabilizers has led to the change in the absorption and reflectance properties of the CFTS. The impact of stabilizer on the optical band-gap energy was enumerated from UV–Vis studies. The electrical bistability of these samples was studied amongst which the thin film fabricated with the aid of lactic acid exhibited better performance and can be extensively used for memory applications like random access memory (RAM) applications. Finally, the as-fabricated CFTS thin films were sulfurized and the photo-electrical properties were examined. From these studies, it is inferred that the electrical bistability vanishes after sulfurization. However, the photo-response of the sulfurized sample was improved when compared to its counterpart. These works provide a breakthrough for exploring the memory application of multifunctional material with further multiple physical attributes.

Low cost hot injection synthesis of wurtzite Cu2ZnSnS4 nanocrystals

Herein, It is reported the synthesis of colloidal quaternary chalcogenide Cu2ZnSnS4 (CZTS) nanocrystals (usually 2–10 nm in size) via moderate low cost hot injection method. trioctylphosphine oxide (TOPO) is used as nanocrystal stabilizer. The influence of annealing temperature on the structural and optical properties is studied. Morphology of as prepared nanomaterial is defined by using HRTEM. It is publicised by XRD and TEM measurements that all the prepared samples of nanomaterials enclosed with both kesterite and novel wurtzite phase. The energy bandgap for obtained nanomaterial after annealing at 250 °C is found to be 1.49 eV, which validate its prospective use for solar devices.

Influence of phase transformation on structure–property relationship in quaternary In10Sb10Ag10Se70 chalcogenide films

This work reports the effect of thermal annealing (353–413 K) on structure and physical properties of thermally evaporated In10Ag10Sb10Se70 chalcogenide films. The samples were characterized by X-ray diffraction, transmission electron microscopy, TEM, Raman spectroscopy, optical absorption and photoconductivity measurements. Thermal annealing favours amorphous to polycrystalline structure transition with the growth of Se, AgInSe2 and AgSbSe2 phases. A significant change in position/shape of Raman bands upon annealing has been observed. The indirect optical gap decreases from 1.44 to 0.68 eV while tailing parameter increases with annealing. Photosensitivity decreases from 29.3 to 14.2 with annealing temperature. The decay of photocurrents is well fitted to stretched exponential function; the value of decay time constant increases while local minimum value of dispersion parameter at 353 K has been observed. These results are explained on the basis of amorphous crystalline phase transformation in chalcogenides and are important for developing new materials for emerging technologies.

Exchange-correlation functional challenges in modeling quaternary chalcogenides

The development of next-generation quaternary chalcogenides, such as $\mathrm{C}{\mathrm{u}}_{2}\mathrm{ZnSn}{\mathrm{S}}_{4}$ (CZTS) and $\mathrm{C}{\mathrm{u}}_{2}\mathrm{ZnGe}{\mathrm{S}}_{4}$ (CZGS), for solar energy and thermoelectric applications hinges upon both careful experimentation and accurate quantum mechanical modeling. To address the latter, many have turned to density functional theory (DFT), which offers several choices for the approximate treatment of electron exchange and correlation (XC). Popular XC functionals include the Perdew-Burke-Ernzerhof (PBE) generalized gradient approximation (GGA) and the recently developed strongly constrained and appropriately normed (SCAN) meta-GGA. Extensions of DFT functionals, such as adding a Hubbard $U$ correction and introducing a fraction of the Fock exchange (hybrid functionals), have been used widely to model systems containing $3d$ metal ions. However, no studies yet have compared comprehensively PBE($+U$) and SCAN($+U$) in the quality of their predictions of the bulk and defect thermodynamics of quaternary chalcogenides, which play a critical role in device fabrication and performance. Hence, here we calculate the (i) 0 K formation energies of bulk Ge compounds and (ii) neutral defect formation energies including charge-balanced (e.g., $\mathrm{C}{\mathrm{u}}_{\mathrm{Zn}}+\mathrm{Z}{\mathrm{n}}_{\mathrm{Cu}}$) and charge-imbalanced (e.g., $\mathrm{C}{\mathrm{u}}_{\mathrm{Sn}}$) combinations of antisites and vacancies in CZTS and CZGS using the PBE, $\mathrm{PBE}+U$, SCAN, $\mathrm{SCAN}+U$, and the hybrid Heyd-Scuseria-Ernzerhof XC frameworks. We find that the formation energies of charge-imbalanced defects are more sensitive to the choice of the XC functional than those of charge-balanced defects, which can be explained by the differences in the extent of penalization of defect-generated delocalized electrons/holes by PBE, $\mathrm{PBE}+U$, SCAN, and $\mathrm{SCAN}+U$. Additionally, our results show that SCAN systematically underbinds Ge-containing compounds, thus highlighting the need for even further improvement of XC functionals. Based on our findings, we recommend the use of SCAN for modeling quaternary chalcogenides because its errors are systematic, and it has the firmest theoretical underpinning. Our work provides guidance for future modeling of quaternary chalcogenides.

Synthesis and characterization of Ge doped Cu2ZnSn(S,Se)4 bulk in the presence of reactive liquid phase sintering aid

The quaternary chalcogenide Cu2Zn(Sn1-xGex)(S,Se)4 bulks, where x is Ge/[Ge+Sn] molar ratios of 0, 0.15, 0.30, and 0.45 were synthesized via reactive liquid phase sintering at 600 °C for 30 min in the tube furnace and characterized systematically. Together with Sb2S3 as a reactive liquid phase sintering aid, the effects of Ge incorporation on densification, grain boundary, crystal phase purity, crystalline size, and electrical properties were studied. The morphology of the resulted Cu2Zn(Sn1-xGex)(S,Se)4 bulk was found to be more densified and compacted at Ge/[Ge+Sn] molar ratio of 0.15 compared to the rests. The X-ray diffraction peaks were shifted towards a higher angle as Ge fraction was increased. The hole concentrations for the entirely p-type bulks were determined to be 3.67 × 1018, 1.40 × 1018, 1.28 × 1018, and 8.90 × 1017 cm−3 at Ge/[Ge+Sn] molar ratios of 0, 0.15, 0.30, and 0.45, respectively. The effects on conductivity and mobility were consistent with their interrelations. Hence, the synthesis and study of Ge incorporated Cu2ZnSn(S,Se)4 bulk using powder technique allows identifying the composition which is expectedly more important for the fabrication of thin film solar cells.

Cu/(Co+Sn) ratio effects on physical and photodetective properties for visible light absorbing Cu2CoSnS4 nanoparticles via a one-pot hydrothermal process

The composition ratio plays a vital role in modulating the thermal, magnetic, and optoelectronic properties of earth-abundant quaternary chalcogenides. Here we report on an impact of Cu/(Co + Sn) ratio on secondary phase formation, size, and shape of Cu2CoSnS4 (CCTS) nanoparticles synthesized via monoethanolamine (MEA) promoted the hydrothermal process. The CCTS phase formation mechanism is experimentally elucidated by a time-dependent synthesis study during a one-pot facile hydrothermal reaction, and it is confirmed by using X-ray diffraction (XRD) and energy-dispersive X-ray spectroscopy (EDS) analysis. The morphology, particle size distribution, and shape of synthesized nanoparticles are examined by field emission scanning electron microscopy (FE-SEM) and high-resolution transmission electron microscopy (HR-TEM) analysis. The N-Methyl-2-pyrrolidone (NMP) solvent-based CCTS paste was drop-casted on a thermally oxidized silicon wafer (∼100 nm SiO2) to form films. The increase in optical bandgap from 1.48 eV to 2.00 eV is observed for an increase in Cu/(Co + Sn)) ratio of prepared CCTS films. The electrical, photodetection properties of the prepared films with respect to the (Cu/(Co + Sn)) ratio under dark and light illumination are studied. The lowest sheet resistance (Rsh= (13.56 ± 0.9) × 103 Ω/cm) and contact resistance (Rc= (108.31 ± 3.43) × 103 Ω) is obtained for devices made with a higher value of Cu/(Co + Sn) ratio = 1.17. On the other hand, the highest photosensitivity (Sph = 32%), photoresponsivity (Rph = 75.58 mA/W), and detectivity (Dph = 1.44 × 108 Jones) are demonstrated for device assembled with the lowest ratio (∼0.86) of Cu/(Co + Sn). The present study reveals that Cu/(Co + Sn) ratio affects a significant impact on such as a phase, morphology, chemical compositional ratio of nanoparticles, optical, electrical, and photoresponsive properties of prepared films.

Evaluation of nonlinear optical properties of quaternary chalcogenide halides Ba4Si3Se9Br2 and Ba4Ge3Se9Br2

The quaternary chalcogenide halides Ba4Si3Se9Br2 and Ba4Ge3Se9Br2 were obtained in the form of crystals from reactions of binary selenides and bromides at 1173 K and in the form of phase-pure polycrystalline samples from reactions at 1023 K. They adopt noncentrosymmetric crystal structures, as determined from single-crystal X-ray diffraction data (hexagonal, space group P63, Z = 2; a = 10.1672 (5) Å, c = 12.4362 (6) Å for Ba4Si3Se9Br2; a = 10.2345 (4) Å, c = 12.5306 (5) Å for Ba4Ge3Se9Br2). The structures contain discrete Tt3Se96− rings (Tt = Si, Ge) which are built up from corner-sharing TtSe4 tetrahedra and which are separated by Ba2+ and Br− ions. Relative to the benchmark infrared nonlinear optical (NLO) material AgGaS2, the second harmonic generation (SHG) response is more intense for Ba4Si3Se9Br2 (3.2 × ) and Ba4Ge3Se9Br2 (3.5 × ) over particle sizes of 20–40 μm. The measured optical band gaps are 2.96 eV for Ba4Si3Se9Br2 and 2.60 eV for Ba4Ge3Se9Br2. Both compounds melt congruently (778 °C for Ba4Si3Se9Br2 and 731 °C for Ba4Ge3Se9Br2). The calculated birefringence is small, which accounts for the non-phase-matching behaviour observed experimentally.

Conspicuous interatomic bonding in chalcogenide crystals and implications on electronic, optical, and elastic properties

Chalcogenide crystals are a unique class of materials very different from semiconductors or metallic alloys. They also have many practical applications, especially in relation to their optical properties. However, the fundamental understanding of their electronic structure and physical properties is rather scattered and incomplete. We present a detailed study using first-principles calculations on the electronic structure, interatomic bonding, and optical and mechanical properties for 32 chalcogenide crystals. They consist of 22 binary (AnBm) and 10 ternary (AnA′Bm) crystals with A = Ag, As, Cu, Ge, Sb, Sn, Cd, Zn; A′ = In, Ge, Sn; and B = S, Se, Te with n = 1, 2, 4 and m = 1, 2, 3, 4, 9. We use the novel concept of total bond order density as a single quantum mechanical metric to characterize the internal cohesion of these crystals and correlate them with the calculated properties, especially the mechanical properties. Based on this large database, we are able to identify some new and conspicuous observations to reach some useful conclusions related to the chemical composition of the chalcogenide compounds and their complex interatomic interactions. Specific examples from crystals and their unique properties in relation to the elements A and A′ and chalcogenide element B (S, Se, and Te) are discussed and highlighted. Finally, generalization of the observed trends and empirical rules can be extended to much larger classes of ternary and quaternary chalcogenide crystals and glasses so far unexplored.