**2.3 Solubility of manganese and cobalt in ZnTe nanocrystals embedded in P2O5 - ZnO - Al2O3 - BaO - PbO glassy matrix**

The incorporation of magnetic ions into the crystal structure of ZnTe semiconductor nanocrystals, which grow in glassy systems, has become very interesting due to the various applications in spintronics are governed by sp–d spin interaction between carriers and magnetic ions [25]. Some possible applications require nanoparticles to be embedded in highly stable, robust, and transparent host materials, as glassy systems [26]. The present study reports on the investigation of the solubility/saturation of Mn2+ ions in Zn1-xMnxTe [13, 26, 27] and competition between Co2+ and Mn2+ ions into Zn0.99-xMn0.01CoxTe [14, 28] nanosized DMS embedded in a glassy system with a wider Mn/Co concentration range (x = 0.000– 0.800). According to the literature, the Mn2+/Co2+ ion can be thermodynamically incorporated into II-VI semiconductors up to its solubility limit [29, 30]. Above this limit, saturation occurs, and Mn2+/Co2+ ions tend to be expelled toward the semiconductor nanocrystal surface [30].

**Figure 2** presents OA (a) and PL (c) spectra and photographs (b) of the samples containing Zn1-*x*MnxTe NCs, with Mn-concentrations ranging from *x* = 0.000 to *x* = 0.800, and with PZABP (65P2O5 · 14ZnO · 1Al2O3 · 10BaO · 10PbO (mol %)) glassy matrix doped only 80Mn (% wt of Zn). The OA spectra show absorption bands centered attributed to Zn1-*x*MnxTe NCs (quantum dots (QDs) and bulk NCs) and the incorporation of Mn2+ ions. This substitutional incorporation is confirmed from the EPR spectra (**Figure 2(f )**) that showed six lines associated to S = 5/2 spin half-filled d-state, characteristic of Mn2+ ions (as detailed in the energy diagram) [26]. For x > 0, additional bands are observed.

The absorption band centered at 3.54 eV is attributed at MnO2, and the bands centered at 3.02, and 2.43 eV is attributed at MnO [31]. The TEM images in **Figure 2(e)** (for x = 0.100), revealed interplanar distances corresponding to Zn0.9Mn0.1Te NCs (d ~ 0.347 nm) [32], MnO (d ~ 0.224 nm) [33] and MnO2 (d ~ 0.582 nm) NCs [34]. This result can be confirmed by the PL spectra, on what the observed redshift shows that it was possible to tune Mn emission energy from orange to near-infrared as a function of concentration. These results confirm the successful inclusion of Mn2+ ions in the Zn1-*x*MnxTe up to the nominal solubility limit of x = 0.100. Above this solubility limit, one can observe Mn′s saturation, forming MnO and MnO2 NCs, as represented in **Figure 2(d)**. Thus, one of the main motivations for studying semiconductors doped with transition metals, especially Mn2+ ions, is for applications in luminescent devices.

**Figure 3** presents OA (a), PL (b) and EPR (c) spectra and photographs (between OA and PL spectra) of the samples containing Zn0.99-xMn0.01CoxTe NCs, with Co-concentrations ranging from *x* = 0.000 to *x* = 0.800. **Figure 3(d)** presents the energy diagram of all transitions related to OA and PL data, and **Figure 3(e)** shows the transitions satisfying the selection rules ΔMS = ±1 and ΔMI = 0. The AO spectra, besides the bands attributed to Zn1-*x*MnxTe QDs and bulk NCs, as previously presented in **Figure 3**, four characteristic bands in the visible spectrum for all doped samples with cobalt. These four are due to the spin-allowed transitions: 4 A2(F) → <sup>2</sup> T1(P) (2.13 eV); and spin-forbidden transitions: 4 A2(F) → <sup>2</sup> A1(G) (2.33 eV), 4 A2(F) → <sup>4</sup> T1(G) (1.95 eV) and 4 A2(F) → <sup>2</sup> E(G) (1.91 eV) [14]. These bands show the substitutional incorporation of Co2+ ions in tetrahedral Zn2+ ions sites. The PL spectra show emissions from two NC groups: QDs (Eexc ~ 2.53 eV) and bulk NCs (Eb ~ 2.21 eV); defects related to zinc vacancies (EVZn ~ 2.53 eV) and oxygen centers (Eo ~ 1.91 eV) [14, 27].

The emission centered at approximately 2.03 eV and 1.89 eV corresponds to tetrahedrally (Td) and octahedrally (Oh) coordinated Mn2+ ions. Already, when the

#### **Figure 2.**

*OA (a) and PL (c) spectra and photographs (b) of samples containing Zn1-xMnxTe NCs, with Mn-concentrations ranging from x = 0.000 to x = 0.800. In (d) Mn2+ ions located in tetrahedral sites (td) of ZnTe NCs (concentration x < 0.100) and Mn2+ and Mn4+ located in octahedral sites (oh) of MnO and MnO2 NCs (concentration x* ⦥ *0.100); (e) TEM images for concentration x = 0.100; (f) EPR spectra of Zn1-xMnxTe NCs with Mn concentrations varying from x = 0.00 to x = 0.100 and selection rules ΔMS = ±1 and ΔMI = 0 (next to).*

spin-allowed transitions centred around 1.69 eV (4 T1( 4 P) → <sup>4</sup> A2( 4 F), named E1Co2+) and 1.52 eV (4 T1( 4 P) → <sup>4</sup> T2( 4 F), named E2Co2+) [14]. The energy diagram in **Figure 3(d)**shows these OA and PL spectra transitions. The EPR spectra, besides proving the substitutional incorporation of Mn2+ in Zn1-*x*MnxTe, as justified by **Figure 3(f )**, also reveals that as the Co doping, an intense central line with g = 2.012 attributed to interacting Co2+ [14]. For both Mn2+ and Co2+ ions the transitions observed satisfy the selection rules ΔMS = ±1 and ΔMI = 0 (**Figure 3(e)**). Thus, the EPR spectra suggest a kind of competition between Mn2+ and Co2+ ions to substitute Zn2+ ions, controlled by the Co concentration.

### **2.4 Effects of symmetry and concentration of cobalt-doped Bi2S3 nanocrystals embedded in host glass matrix**

Bi2S3 semiconductor nanocrystals (NCs) present radioactive recombination of electron–hole carriers adjustable according to the temperature, time, and concentration of doping ions in the system [15, 35–37]. The occupation of vacancies in the Bi2S3 orthorhombic network by Co2+ ions (0.72 A) replacing Bi3+ ions (1.03 A) can reduce intrinsic point defects and consequently increase the efficiency of semiconductor nanocrystals, for applications in solar cells [38], photocatalytic devices of visible light [39], thermoelectric [40] and spintronic [41]. Therefore, the control of the magnetic saturation of the energy states located of the Co2+ ions in the Bi2S3 NCs

**131**

structure.

**Figure 3.**

*and ΔMI = 0 (e).*

coordination complex [CoS4]

tronic configuration (spin) 3d7

*Diluted Magnetic Semiconductors Nanocrystals: Saturation and Modulation*

bandgap allows assigning new magnetic and optoelectronic properties. In this context, we investigated the effect of the molar fraction and the coordination symmetry of Co2+ ions in cobalt-doped Bi2S3 NCs embedded in a host glass matrix

*OA (a), PL (b) and EPR (c) spectra and photographs (between OA and PL spectra) of the samples containing Zn0.99-xMn0.01CoxTe NCs, with Co-concentrations ranging from x = 0.000 to x = 0.800. Energy diagram of all transitions related to OA and PL data (d). Transitions satisfying the Mn2+ and Co2+ selection rules ΔMS = ±1* 

**Figure 4(a)** shows the UV–VIS–NIR optical absorption spectrum (OA) of the Bi2-xCoxS3 NCs embedded in a SNAB glass matrix, at temperature (300 K), as a function of the increasing concentration of doping xCo ions (x = 0.000; 0.005; 0.010; 0.050; 0.100). The OA spectrum of the SNAB matrix is transparent in the spectral region where the Bi2-xCoxS3 NCs can absorb and emit a photon. The OA spectrum of the samples shows energy bands of the exciton charge carrying states and the d-d transitions of the Co2+ ions in the Bi2-xCoxS3 NCs. The structure of the absorption bands is due to that of the ligand field of S2− ions in distorted tetrahedral sites around the Co2+ ions. Such bands of electronic level transitions have increased due to the increasing concentration of Co2+ ions in the Bi2S3 NCs

Furthermore, the p-d and spin-orbit interactions in an asymmetric tetrahedral

(S = 3/2) [15, 20, 36, 42].

15, 20, 42]. Therefore, the exotic properties of these new materials called diluted magnetic semiconductors (DMS) NCs are linked to the nature of the sp-d exchange interaction that occurs between the charge carriers of the Bi2S3 semiconductor bands around the electrons in the central metal ion orbital (Co2+) with 3d7

6− provide a higher intensity for 3d-3d transitions [14,

elec-

(SNAB - 45SiO2 · 30Na2CO3 · 5Al2O3 · 20B2O3) (mol%).

*DOI: http://dx.doi.org/10.5772/intechopen.96679*

*Diluted Magnetic Semiconductors Nanocrystals: Saturation and Modulation DOI: http://dx.doi.org/10.5772/intechopen.96679*

#### **Figure 3.**

*Materials at the Nanoscale*

spin-allowed transitions centred around 1.69 eV (4

Zn2+ ions, controlled by the Co concentration.

Bi2S3 orthorhombic network by Co2+ ions (0.72 A)

**embedded in host glass matrix**

 T2( 4 T1( 4 P) → <sup>4</sup>

F), named E2Co2+) [14]. The energy diagram in

**Figure 3(d)**shows these OA and PL spectra transitions. The EPR spectra, besides proving the substitutional incorporation of Mn2+ in Zn1-*x*MnxTe, as justified by **Figure 3(f )**, also reveals that as the Co doping, an intense central line with g = 2.012 attributed to interacting Co2+ [14]. For both Mn2+ and Co2+ ions the transitions observed satisfy the selection rules ΔMS = ±1 and ΔMI = 0 (**Figure 3(e)**). Thus, the EPR spectra suggest a kind of competition between Mn2+ and Co2+ ions to substitute

*Mn-concentrations ranging from x = 0.000 to x = 0.800. In (d) Mn2+ ions located in tetrahedral sites (td) of ZnTe NCs (concentration x < 0.100) and Mn2+ and Mn4+ located in octahedral sites (oh) of MnO and MnO2 NCs (concentration x* ⦥ *0.100); (e) TEM images for concentration x = 0.100; (f) EPR spectra of Zn1-xMnxTe NCs with Mn concentrations varying from x = 0.00 to x = 0.100 and selection rules ΔMS = ±1 and ΔMI = 0* 

*OA (a) and PL (c) spectra and photographs (b) of samples containing Zn1-xMnxTe NCs, with* 

**2.4 Effects of symmetry and concentration of cobalt-doped Bi2S3 nanocrystals** 

Bi2S3 semiconductor nanocrystals (NCs) present radioactive recombination of electron–hole carriers adjustable according to the temperature, time, and concentration of doping ions in the system [15, 35–37]. The occupation of vacancies in the

reduce intrinsic point defects and consequently increase the efficiency of semiconductor nanocrystals, for applications in solar cells [38], photocatalytic devices of visible light [39], thermoelectric [40] and spintronic [41]. Therefore, the control of the magnetic saturation of the energy states located of the Co2+ ions in the Bi2S3 NCs

A2( 4

replacing Bi3+ ions (1.03 A)

F), named E1Co2+)

can

**130**

and 1.52 eV (4

**Figure 2.**

*(next to).*

T1( 4 P) → <sup>4</sup>

*OA (a), PL (b) and EPR (c) spectra and photographs (between OA and PL spectra) of the samples containing Zn0.99-xMn0.01CoxTe NCs, with Co-concentrations ranging from x = 0.000 to x = 0.800. Energy diagram of all transitions related to OA and PL data (d). Transitions satisfying the Mn2+ and Co2+ selection rules ΔMS = ±1 and ΔMI = 0 (e).*

bandgap allows assigning new magnetic and optoelectronic properties. In this context, we investigated the effect of the molar fraction and the coordination symmetry of Co2+ ions in cobalt-doped Bi2S3 NCs embedded in a host glass matrix (SNAB - 45SiO2 · 30Na2CO3 · 5Al2O3 · 20B2O3) (mol%).

**Figure 4(a)** shows the UV–VIS–NIR optical absorption spectrum (OA) of the Bi2-xCoxS3 NCs embedded in a SNAB glass matrix, at temperature (300 K), as a function of the increasing concentration of doping xCo ions (x = 0.000; 0.005; 0.010; 0.050; 0.100). The OA spectrum of the SNAB matrix is transparent in the spectral region where the Bi2-xCoxS3 NCs can absorb and emit a photon. The OA spectrum of the samples shows energy bands of the exciton charge carrying states and the d-d transitions of the Co2+ ions in the Bi2-xCoxS3 NCs. The structure of the absorption bands is due to that of the ligand field of S2− ions in distorted tetrahedral sites around the Co2+ ions. Such bands of electronic level transitions have increased due to the increasing concentration of Co2+ ions in the Bi2S3 NCs structure.

Furthermore, the p-d and spin-orbit interactions in an asymmetric tetrahedral coordination complex [CoS4] 6− provide a higher intensity for 3d-3d transitions [14, 15, 20, 42]. Therefore, the exotic properties of these new materials called diluted magnetic semiconductors (DMS) NCs are linked to the nature of the sp-d exchange interaction that occurs between the charge carriers of the Bi2S3 semiconductor bands around the electrons in the central metal ion orbital (Co2+) with 3d7 electronic configuration (spin) 3d7 (S = 3/2) [15, 20, 36, 42].

#### **Figure 4.**

*(a) Optical absorption spectra at room temperature of Bi2-xCoxS3 NCs (x = 0.000; 0.005; 0.010; 0.050; 0.100) embedded in the SNAB glass matrix annealed for 2 h at 500°C. for comparison purposes, the absorption spectrum of the SNAB glass matrix is represented on the black bottom line. The inset shows the energy level diagram for Co2+ (3d7 ) in a tetrahedral site and the respective spin allowed and forbidden transitions. (b) Bi2S3 orthorhombic unit cell and Bi2-xCoxS3 quantum dots with the interstitial replacement of Bi3+ ions by Co2+ at distorted tetrahedral sites. (c) TEM image of Bi2-xCoxS3 NCs (x = 0.100). (d) EPR spectra (77 K) of Bi2-xCoxS3 NCs (x = 0.005; 0.010; 0.050; 0.100) embedded in the SNAB glass matrix.*

For Bi2-xCoxS3 NCs, the spin allowed transitions <sup>4</sup> A2 (4 F) → <sup>4</sup> T1 (4 F) and <sup>4</sup> A2 ( 4 F) → <sup>4</sup> T1 (4 P) are obtained with the energy value of the barycenter for a normal distribution of the bands observed in the spectrum absorption in the range of 0.62–1.24 eV and 1.70–2.60 eV. The bands observed in the OA spectrum of **Figure 4(a)** correspond to the spin allowed and forbidden transitions, <sup>4</sup> A2 ( 4 F) → <sup>4</sup> T1 (4 F) (0.84 eV), <sup>4</sup> A2( 4 F) → <sup>2</sup> E (<sup>2</sup> G) (1.93 eV), <sup>4</sup> A2( 4 F) → <sup>2</sup> T1( 2 G) (1.99 eV), <sup>4</sup> A2( 4 F) → <sup>4</sup> T1( 4 P) (2.08 e V), <sup>4</sup> A2( 4 F) → <sup>2</sup> A1( 2 G) (2.19 eV) and 4 A2( 4 F) → <sup>2</sup> T2( 2 G) (2.29 eV). Such identified 3d-3d transitions are attributed to the crystal field strength (∆ = 3882 cm−1) and the electronic repulsion parameter (Racah, B = 772 cm−1), based on the crystal field theory and the Tanabe-Sugano diagram d7 , tetrahedral for C/B = 4.5 [20, 43, 44]. The wide absorption band in the infrared is due to a spin-orbit coupling interaction that split the excited state 4 T1 (4 F) into three energy sub-states: Ã6 (0.97 eV), Ã7 (0.84 eV) e à Ã 7 8 + (0.72 eV) [12, 13]. Therefore, the excited states of the Co2+ ions are located in the energy gap (2.65 eV) of electrons and holes confined between the ground state and the conduction band of the Bi2-xCoxS3 NCs. The energy level diagram of Co2+ ions (3d7 ) in a ligand field of S2− ions at tetrahedral coordination sites [CoS4] 6− is shown in the inset in Figure x (a). The energy band associated with the spin allowed transition <sup>4</sup> A2 (4 F) → <sup>4</sup> T1 (4 F) (0.48 eV) does not appear in the OA spectrum (**Figure 4a**) due to the low intensity and energy [15, 43].

The redshift observed at the OA band edge for the Bi2-xCoxS3 NCs with increasing concentration xCo, from x = 0.000 (2.75 eV) to x = 0.100 (2.56 eV) (see **Figure 4a**), are consequences of sp-d exchange interactions between sp. electrons confined in states of quantum dots and localized states partially filled with 3d electrons of the Co2+ ions [10]. No significant changes occur in the quantum size of the Bi2-xCoxS3 NCs with the incorporation of Co. The TEM image (**Figure 4c**) shows an average size

**133**

*Diluted Magnetic Semiconductors Nanocrystals: Saturation and Modulation*

of 6 nm for Bi2-xCoxS3 NCs (x = 0.100) with quantum dot properties. The interplanar distance (d211 = 0.310 nm) shows the crystal plane (211) characteristic of the orthorhombic structure of the mineral Bismuthinite. **Figure 4(b)** illustrates the Bi2S3 orthorhombic structure unit cell doped with Co2+ ions at distorted tetrahedral sites and the respective Bi2-xCoxS3 quantum dots function of the xCo concentration.

**Figure 4(d)** shows the EPR spectra obtained in the best conditions at 77 K and 9.75 GHz for samples of Bi2-xCoxS3 NCs embedded in SNAB glass matrix, with xCo concentration ranging from x = 0.005 to 0.100. The intense central signal at (g ≈ 2.005; ΔH ≈ 8 mT) corresponds to free Co+2 ions, dispersed in the glass matrix and not incorporated in the Bi2S3 NCs [2, 10]. The inset in Figure x (d) presents a diagram with the allowed hyperfine lines Δ*M*S = ±1 with Δ*M*I = 0, related to the transition between the levels of fine interaction *MS* =+ ↔− ½ ½. The anisotropic characteristic of the eight lines (hf1; hf2; hf3; hf4; hf5; hf6; hf 7; hf8) of the hyperfine interaction between the electron spin (S = 3/2) and the nuclear spin (I = 7/2) and its similar shapes for all xCo concentrations confirms magnetic doping in distorted tetrahedral sites. The result is compatible with a region where there is a large, inhomogeneous crystal field due to the lack of interface between the host glass

The synthesis and investigation of the DMS NC have allowed the production of new types of materials with possible technological applications in Engineering,

Medicine, Environment, Telecommunications, and others. We report the synthesis of the Zn1-xMnxO nanopowders and the Bi2-xCoxS3, Zn1-xMnxTe Zn0.99-xMn0.01CoxTe NCs in glass by fusion method. The formation of DMS NCs is observed by SEM and MET images. The EPR spectra confirm the incorporation of TR2+ ions (Mn2+ and Co2+) in the doped nanocrystals' crystalline structure. The optical properties of these materials were investigated by photoluminescence and Uv–Vis spectroscopy techniques, which show the influence of TR2+ ions (Mn2+ and Co2+) on the visible spectrum, altering the optical absorption and photoluminescence bands of undoped naocrystals. In this work, we hope to contribute significantly to the study of DMS NCs and their possible technological applications for

*DOI: http://dx.doi.org/10.5772/intechopen.96679*

matrix and the NCs [42].

**3. Conclusion**

society's benefit.

*Diluted Magnetic Semiconductors Nanocrystals: Saturation and Modulation DOI: http://dx.doi.org/10.5772/intechopen.96679*

of 6 nm for Bi2-xCoxS3 NCs (x = 0.100) with quantum dot properties. The interplanar distance (d211 = 0.310 nm) shows the crystal plane (211) characteristic of the orthorhombic structure of the mineral Bismuthinite. **Figure 4(b)** illustrates the Bi2S3 orthorhombic structure unit cell doped with Co2+ ions at distorted tetrahedral sites and the respective Bi2-xCoxS3 quantum dots function of the xCo concentration.

**Figure 4(d)** shows the EPR spectra obtained in the best conditions at 77 K and 9.75 GHz for samples of Bi2-xCoxS3 NCs embedded in SNAB glass matrix, with xCo concentration ranging from x = 0.005 to 0.100. The intense central signal at (g ≈ 2.005; ΔH ≈ 8 mT) corresponds to free Co+2 ions, dispersed in the glass matrix and not incorporated in the Bi2S3 NCs [2, 10]. The inset in Figure x (d) presents a diagram with the allowed hyperfine lines Δ*M*S = ±1 with Δ*M*I = 0, related to the transition between the levels of fine interaction *MS* =+ ↔− ½ ½. The anisotropic characteristic of the eight lines (hf1; hf2; hf3; hf4; hf5; hf6; hf 7; hf8) of the hyperfine interaction between the electron spin (S = 3/2) and the nuclear spin (I = 7/2) and its similar shapes for all xCo concentrations confirms magnetic doping in distorted tetrahedral sites. The result is compatible with a region where there is a large, inhomogeneous crystal field due to the lack of interface between the host glass matrix and the NCs [42].

### **3. Conclusion**

*Materials at the Nanoscale*

For Bi2-xCoxS3 NCs, the spin allowed transitions <sup>4</sup>

*NCs (x = 0.005; 0.010; 0.050; 0.100) embedded in the SNAB glass matrix.*

A2( 4 F) → <sup>2</sup>

P) (2.08 e V), <sup>4</sup>

G) (2.19 eV) and 4

A2 (4

A1( 2

F) (0.48 eV) does not appear in the OA

P) are obtained with the energy value of the barycenter for a normal

*) in a tetrahedral site and the respective spin allowed and forbidden transitions. (b) Bi2S3*

G) (1.93 eV), <sup>4</sup>

G) (2.29 eV). Such identified 3d-3d transitions are attributed to

, tetrahedral for C/B = 4.5 [20, 43, 44]. The wide absorption band in

F) into three energy sub-states: Ã6 (0.97 eV), Ã7 (0.84 eV) e à Ã 7 8 + (0.72 eV) [12, 13]. Therefore, the excited states of the Co2+ ions are located in the energy gap (2.65 eV) of electrons and holes confined between the ground state and the conduction band of the Bi2-xCoxS3 NCs. The energy level diagram of Co2+ ions

The redshift observed at the OA band edge for the Bi2-xCoxS3 NCs with increasing concentration xCo, from x = 0.000 (2.75 eV) to x = 0.100 (2.56 eV) (see **Figure 4a**), are consequences of sp-d exchange interactions between sp. electrons confined in states of quantum dots and localized states partially filled with 3d electrons of the Co2+ ions [10]. No significant changes occur in the quantum size of the Bi2-xCoxS3 NCs with the incorporation of Co. The TEM image (**Figure 4c**) shows an average size

distribution of the bands observed in the spectrum absorption in the range of 0.62–1.24 eV and 1.70–2.60 eV. The bands observed in the OA spectrum of **Figure 4(a)** correspond to the spin allowed and forbidden transitions, <sup>4</sup>

*(a) Optical absorption spectra at room temperature of Bi2-xCoxS3 NCs (x = 0.000; 0.005; 0.010; 0.050; 0.100) embedded in the SNAB glass matrix annealed for 2 h at 500°C. for comparison purposes, the absorption spectrum of the SNAB glass matrix is represented on the black bottom line. The inset shows the energy level* 

*orthorhombic unit cell and Bi2-xCoxS3 quantum dots with the interstitial replacement of Bi3+ ions by Co2+ at distorted tetrahedral sites. (c) TEM image of Bi2-xCoxS3 NCs (x = 0.100). (d) EPR spectra (77 K) of Bi2-xCoxS3*

E (<sup>2</sup>

the crystal field strength (∆ = 3882 cm−1) and the electronic repulsion parameter (Racah, B = 772 cm−1), based on the crystal field theory and the Tanabe-Sugano

the infrared is due to a spin-orbit coupling interaction that split the excited state

) in a ligand field of S2− ions at tetrahedral coordination sites [CoS4]

shown in the inset in Figure x (a). The energy band associated with the spin

A2( 4 F) → <sup>2</sup> F) → <sup>4</sup>

A2( 4 F) → <sup>2</sup>

T1 (4

F) and <sup>4</sup>

A2

6− is

T1( 2 G) A2

**132**

( 4 F) → <sup>4</sup>

**Figure 4.**

( 4 F) → <sup>4</sup>

4 T1 (4

(3d7

A2( 4 F) → <sup>2</sup>

T1 (4

*diagram for Co2+ (3d7*

T1 (4

allowed transition <sup>4</sup>

A2( 4 F) → <sup>4</sup>

T2( 2

(1.99 eV), <sup>4</sup>

diagram d7

F) (0.84 eV), <sup>4</sup>

T1( 4

A2 (4

F) → <sup>4</sup>

T1 (4

spectrum (**Figure 4a**) due to the low intensity and energy [15, 43].

The synthesis and investigation of the DMS NC have allowed the production of new types of materials with possible technological applications in Engineering, Medicine, Environment, Telecommunications, and others. We report the synthesis of the Zn1-xMnxO nanopowders and the Bi2-xCoxS3, Zn1-xMnxTe Zn0.99-xMn0.01CoxTe NCs in glass by fusion method. The formation of DMS NCs is observed by SEM and MET images. The EPR spectra confirm the incorporation of TR2+ ions (Mn2+ and Co2+) in the doped nanocrystals' crystalline structure. The optical properties of these materials were investigated by photoluminescence and Uv–Vis spectroscopy techniques, which show the influence of TR2+ ions (Mn2+ and Co2+) on the visible spectrum, altering the optical absorption and photoluminescence bands of undoped naocrystals. In this work, we hope to contribute significantly to the study of DMS NCs and their possible technological applications for society's benefit.

*Materials at the Nanoscale*
