Thermoluminescence Behavior of Yttrium‐Doped ZnO Nanoparticles Synthesized by Sol–Gel Method

ABSTRACT

The development of efficient thermoluminescent materials is essential for precise radiation dosimetry. In this study, yttrium‐doped ZnO (Y:ZnO) nanoparticles were synthesized and systematically analyzed to explore their structural and thermoluminescence (TL) properties. X‐ray diffraction confirmed the preservation of the hexagonal ZnO phase, while transmission electron microscopy revealed well‐dispersed nanoparticles. TL measurements exhibited a strong dose‐dependent response, with glow curves showing multiple peaks associated with distinct trapping centers. Deconvolution analysis identified three primary trap levels with activation energies of 0.77, 1.12, and 1.29 eV, indicating the presence of deep and shallow traps. The TL intensity followed a linear trend with radiation dose, suggesting the suitability of Y:ZnO nanoparticles for dosimetric applications. Photoluminescence (PL) analysis was conducted to investigate the influence of yttrium doping on the optical properties of ZnO nanoparticles, and it was found that Y doping significantly enhanced defect‐related emissions. These findings highlight the potential of Y:ZnO as a promising candidate for advanced radiation sensing technologies.

The thermoluminescence response of the material exhibits a linear increase in peak area with increasing radiation dose, confirming its potential use as a reliable dosimetric material.

1. Introduction

Zinc oxide (ZnO) has garnered significant attention as a versatile semiconductor with wide‐ranging applications in microelectronics, optoelectronics, and sensing technologies [1, 2, 3]. Its remarkable combination of electrical, optical, and structural properties has enabled its integration into numerous advanced devices, including light‐emitting diodes (LEDs) [4], ultrasonic transducers [5], photocatalysts [6, 7], and solar cells [8, 9]. However, ZnO has historically received limited consideration as a dosimetric material. This oversight is likely due to its primary utilization in optoelectronics. However, the luminescent behavior of ZnO is intrinsically linked to its defect structure, which can be significantly altered by doping [10, 11]. In recent years, the exploration of ZnO as a potential radiation dosimeter has gained momentum, driven by the understanding that controlled doping can modify its charge trapping and luminescence properties [12, 13, 14, 15]. Investigating the dosimetric characteristics of ZnO through strategic dopant incorporation offers new opportunities for developing highly sensitive and stable TL materials.

Defects play a crucial role in determining the electronic and optical behavior of semiconductors, influencing both their efficiency and functional capabilities. In optoelectronic applications, such as LEDs and laser diodes, defect states act as nonradiative recombination centers, thereby impacting emission efficiency and device stability. Similarly, in electronic devices, defects contribute to carrier scattering, reducing mobility and affecting high‐frequency performance. The precise characterization of defect states is therefore essential, not only for optimizing semiconductor performance but also for understanding their behavior under irradiation conditions. Among the various techniques employed for defect analysis, thermoluminescence (TL) stands out as a powerful tool for probing charge trapping mechanisms. By examining the temperature‐dependent photon emission resulting from trapped charge carrier recombination, TL analysis provides key insights into defect structures and their role in luminescent materials.

In recent studies, various rare‐earth dopants such as Gd³⁺ and Yb³⁺ have been investigated for enhancing the TL properties of ZnO nanoparticles due to their ability to introduce stable trapping centers [16, 17, 18]. Yttrium (Y³⁺), although less frequently studied in the context of TL, presents promising structural and electronic characteristics such as a larger ionic radius and nonluminescent behavior, which may lead to the formation of deep traps with minimal spectral interference. Beyond its thermoluminescent properties, Y‐doped ZnO has also been recognized for its potential in photocatalytic applications, including electrochemical water splitting and hydrogen production [19]. Previous studies have demonstrated that Y doping in ZnO influences key material properties, such as UV sensing performance, by altering sensitivity, response time, and decay characteristics [20]. Such tunability suggests that Y incorporation could also impact the charge trapping and recombination processes relevant to TL, making it a valuable approach for optimizing dosimetric materials. Yttrium, with its unique electronic configuration and ability to introduce tailored defect states, has the potential to enhance charge trapping and luminescence characteristics in ZnO. Understanding how Y doping affects the TL and dosimetric behavior of ZnO is crucial for advancing its application in radiation sensing and measurement technologies. In this study, we investigate the structural and thermoluminescent properties of Y‐doped ZnO nanoparticles produced by sol–gel technique. The TL response of the material was evaluated under different radiation doses, and trap activation energies were determined through glow curve deconvolution. Our findings provide new insights into the defect states introduced by Y incorporation and their impact on the dosimetric performance of ZnO. The results suggest that Y‐doped ZnO nanoparticles exhibit promising characteristics for radiation dosimetry applications, paving the way for further advancements in TL‐based sensing materials.

2. Experimental Details

Y‐doped ZnO powder, containing a 1 at.% Y fraction, were synthesized using the nitric acid method. The synthesis involved ZnO nanocrystals prepared via the sol–gel method and high‐purity yttrium oxide (Y₂O₃, 99.9%). Controlled amounts of ZnO and Y₂O₃ powders were precisely weighed to get the target composition Zn_1‐xY_xO (x = 0.01). The precursor materials were blended at 80°C in a 1‐M nitric acid (HNO₃) solution, ensuring uniform dissolution and mixing. The acid‐to‐powder ratio was maintained at 60 mL per 1 g of initial powders. Stirring continued until a dry precursor was obtained, which was subsequently ground in an agate mortar. The resulting precursor was then calcined at 450°C for 5 h to remove any residual organic compounds and release volatile gases such as NO and NO₂, ensuring the complete conversion of metal nitrates into oxides. The final annealing process was conducted at 700°C for 2 h, yielding Zn_1−x Y _x O (x = 0.01). After annealing, the powders were cooled to room temperature and finely triturated in an agate mortar for further characterization.

The structural characterization Y‐doped ZnO powders was carried out using X‐ray powder diffraction (XRD) measurements acquired over a 2θ range of 20°–80°, utilizing a Rigaku Miniflex X‐ray diffractometer (Cu‐Kα radiation, λ = 1.5405 Å). Transmission electron microscopy (TEM) was employed to analyze the morphology and particle size distribution of the synthesized nanoparticles. FTIR measurements were carried out using a PerkinElmer Spectrum 100 FT‐IR spectrometer in the range of 4000–520 cm⁻¹. For TL measurements, ZnO:Y powder samples were uniformly deposited onto stainless steel disks using a fine grain technique. TL glow curves were obtained using a Risø TL/OSL DA‐20 reader, equipped with Corning 7/59 and Schott BG/39 optical filters in a nitrogen atmosphere. A preheating process up to 140°C was applied before TL signal acquisition, followed by heating up to 450°C at a rate of 5°C/s. The TL response was systematically examined under radiation doses ranging from 1.43 to 60 Gy, utilizing a ⁹⁰Sr (40 mCi) beta source integrated into the reader setup. The photoluminescence (PL) properties of the nanoparticles were investigated using a PerkinElmer LS 55 Fluorescence Spectrometer with an excitation wavelength of 400 nm.

3. Results and Discussions

XRD pattern of the synthesized sample was recorded in the 2θ range of 20°–80°, revealing a total of 11 diffraction peaks (see Figure 1). Among these, three peaks were observed to be sharp and intense, while three were significantly weak. The identified peak positions were 31.76°, 34.41°, 36.26°, 47.51°, 56.56°, 62.86°, 66.41°, 67.91°, 69.06°, 72.61°, and 76.91°, corresponding to the (100), (002), (101), (102), (110), (103), (200), (112), (201), (004), and (202) crystallographic planes, respectively. To further analyze the crystallographic structure, the XRD data were fitted using the MAUD software, confirming a hexagonal phase. The refined lattice parameters were determined as a = 3.2513 Å and c = 5.2066 Å, indicating a well‐defined hexagonal crystal structure with a unit cell volume of 47.66 ų (see Table 1). The quality of the refinement was assessed using statistical indicators, yielding R _wp = 1.36%, R _b = 0.6%, R _exp = 4.02%, and a goodness of fit (GoF) value of 0.34, indicating a reliable fitting. The lattice parameters are in good agreement with previously reported values of a = 3.253 Å and c = 5.197 Å for 1% Y‐doped ZnO nanoparticles, further supporting the reliability of the structural analysis [19]. The consistency of these findings with prior studies suggests that the synthesized material maintains its expected crystallographic characteristics.

FIGURE 1.

XRD pattern of Y‐doped ZnO nanoparticles.

TABLE 1.

Crystal structure properties and figure of merit (FoM) values of refinement using MAUD software.

Crystal structure	Space group	Lattice parameter (Å)	Cell volume (Å3)	Crystalline size (nm)	Microstrain
	P63 mc	a = 3.2513 c = 5.2066	47.66	120.6	1.32 × 10−3
FoM values	Sig (χ 2)	R wp (%)	R b (%)	R exp (%)	GoF (R wp/R exp)
	0.34	1.36	0.6	4.02	0.34

The crystallite size and strain of nanoparticles were revealed using Williamson–Hall (W–H) method based on the XRD data. The equation proposed by Williamson and Hall is given as follows [21]:

$${\beta }_{\mathit{hkl}}={\beta }_d+{\beta }_{\epsilon }$$ (1)

where ${\beta }_{\mathit{hkl}}$, ${\beta }_d$, and ${\beta }_{\epsilon }$ correspond to the FWHM of the diffraction peak, broadening due to crystallite size, and broadening caused by strain‐induced effects, respectively. The parameters ${\beta }_d$ and ${\beta }_{\epsilon }$ are described by average crystallite size (D) and microstrain (ε) as

$${\beta }_d=0.94\lambda /\mathit{\text{Dcosθ}}$$ (2)

$${\beta }_{\epsilon }=4\mathit{\text{εtanθ}}$$ (3)

By substituting these into Equation (1), we obtain [22]

$${\beta }_{\mathit{hkl}}={\beta }_d+{\beta }_{\epsilon }=\frac{0.94\lambda }{\mathit{\text{Dcosθ}}}+4\mathit{\text{εtanθ}}$$ (4)

The linear fit of the βcosθ versus 4sinθ plot is presented in Figure 2. From the slope and intercept of the fitted line, the microstrain and crystallite size were determined to be $\epsilon$ = 1.32 × 10⁻³ and D = 120.6 nm, respectively. These results indicate that Y doping does not significantly deteriorate the crystalline quality of ZnO, as the obtained crystallite size remains relatively large, suggesting a well‐formed nanostructure. The positive strain value implies slight lattice distortions, likely due to the incorporation of Y ions into the ZnO lattice. This strain might influence the material's optical and electronic properties, which could be advantageous for specific applications such as luminescent or photocatalytic devices. The strain and crystallite size values obtained in this study are in good agreement with previously reported results for undoped ZnO nanoparticles synthesized by various sol–gel‐based methods. For instance, ZnO nanoparticles synthesized using the sol–gel autocombustion technique exhibited a strain of 1.30 × 10⁻³ and a crystallite size of 115 nm [23], while another study using the sol–gel method reported a strain of 0.951 × 10⁻³ [24]. The slightly higher strain value observed in Y‐doped ZnO may be related to the incorporation of Y ions, which can induce additional lattice distortions due to the ionic radius difference between Y and Zn [20].

FIGURE 2.

Williamson–Hall plot of βcosθ against 4sinθ. Solid line indicates the linear fit.

TEM image shown in Figure 3 reveals the morphology and size distribution of the synthesized Y‐doped ZnO nanoparticles. The image shows that the particles are approximately 40–50 nm in size and mostly exhibit spherical or slightly irregular morphology. A certain agglomeration is observed among the nanoparticles, which is an expected behavior due to their high surface energy. It is worth noting that the TEM analysis revealed particle sizes in the range of 40–50 nm, whereas the crystallite size obtained from the W–H method was 120.6 nm. This discrepancy suggests that the synthesized Y‐doped ZnO nanoparticles exhibit a polycrystalline nature, where individual particles are composed of multiple crystallites.

FIGURE 3.

TEM image of the Y:ZnO nanoparticles.

The FTIR spectra of pure ZnO and Y‐doped ZnO (Y:ZnO) nanoparticles are shown in Figure 4. A broad absorption band observed at ~3373 cm⁻¹ in both samples is attributed to the stretching vibrations of surface hydroxyl (–OH) groups. The peaks at 1574 and 1414 cm⁻¹ in the ZnO spectrum are assigned to the asymmetric and symmetric stretching modes of carboxylate (COO⁻) groups, respectively. These vibrations likely originate from residual organic species (such as acetate or other carboxyl‐containing compounds) used during synthesis. The wavenumber difference between these two peaks (~160 cm⁻¹) supports this assignment, as it is consistent with previously reported values for carboxylate groups in Zn‐based nanomaterials [25]. Alternatively, the 1574 cm⁻¹ band may also correspond to the bending vibration of molecular water (H–O–H), depending on the level of adsorbed moisture. Compared with the undoped ZnO, these bands are significantly reduced or even suppressed in the Y:ZnO spectrum, suggesting that Y incorporation modifies surface chemistry, possibly reducing the adsorption of water and carboxylate species. A distinct absorption band near 535 cm⁻¹ in both samples is attributed to the Zn–O stretching vibration, confirming the presence of the ZnO lattice. In Y:ZnO, the broadening and slight shift of this band may reflect structural distortion due to Y³⁺ substitution into the ZnO lattice.

FIGURE 4.

FTIR spectra of undoped and Y‐doped ZnO nanoparticles.

TL is a powerful technique for investigating the trapping and recombination processes of charge carriers in materials exposed to ionizing radiation. TL measurements provide valuable insights into the defect structure, energy levels, and dosimetric properties of a material, making it particularly relevant for applications in radiation dosimetry and optoelectronic devices. In this study, TL measurements were performed on Y‐doped ZnO nanoparticles to examine their luminescent response under different radiation doses in between 1.43 and 60 Gy. Although this study primarily focuses on 1% Y‐doped ZnO nanoparticles, initial experiments were also conducted using 10% Y‐doped samples under the same irradiation conditions. However, the TL glow curves obtained from the 10% doped samples showed a high level of signal noise, which significantly affected the reliability of the deconvolution and dose–response analysis. After thorough internal evaluation, we decided to exclude this data to maintain the scientific integrity of the study and avoid misleading interpretations. The TL glow curves, shown in Figure 5, reveal two distinct peaks centered around 490 and 608 K, indicating the presence of at least two different types of trapping centers within the material. The intensity of these peaks increases with radiation dose, suggesting that the number of trapped charge carriers grows proportionally with the exposure level. It is important to note that the TL measurements in this study involved heating the samples up to 720 K. According to previous reports, ZnO nanoparticles are thermally stable at such temperatures, without undergoing significant morphological or structural changes [26, 27]. Furthermore, several TL studies conducted on ZnO nanoparticles have successfully recorded glow curves at temperatures exceeding 720 K without observing particle deformation or sintering [28, 29]. Therefore, it is unlikely that the heating cycles applied during the TL measurements caused any noticeable deformation in the Y‐doped ZnO nanoparticles used in this study.

FIGURE 5.

Dose‐dependent TL glow curves of Y:ZnO nanoparticles.

There are multiple techniques available to determine the activation energies of trapping centers. In this study, a widely recognized approach, the curve fitting method, was employed for quantitative analysis. This method, based on theoretical principles, involves modeling TL curves using temperature‐dependent functions and specialized software tools. TL intensity (I _TL) corresponding to a given TL peak as a function of temperature can be described using the following expression [30].

$$I_{\mathrm{TL}}=\mathit{\text{Cexp}}\left\{-\frac{E_{\mathrm{t}}}{\mathit{kT}}-\underset{T_0}{\overset{T}{\int }}\frac{v}{\beta }\exp \left(-\frac{E_{\mathrm{t}}}{\mathit{kT}}\right)\mathit{dT}\right\}\left(\text{first}-\text{order kinetics}\right)$$ (5)

$$I_{\mathrm{TL}}=\mathit{\text{Cexp}}\left(-\frac{E_{\mathrm{t}}}{\mathit{kT}}\right){\left[1+\left(b-1\right)\frac{n_{0}v}{\mathit{\beta N}}\underset{T_0}{\overset{T}{\int }}\exp \left(-E_{\mathrm{t}}/\mathit{kT}\right)\mathit{dT}\right]}^{-\frac{b}{b-1}}\left(\text{non}–\text{first}-\text{order kinetics}\right)$$ (6)

In this context, C represents a constant, n ₀ denotes the initial concentration of trapped charge carriers, and N corresponds to the total number of available trap centers. The parameter ν refers to the attempt‐to‐escape frequency, while b is the kinetic order parameter, which falls within the range 1 < b ≤ 2 for non–first‐order kinetics. Differentiating between first‐order and non–first‐order kinetics is essentially linked to the behavior of charge carrier retrapping. When retrapping is slow, charge carriers excited to the conduction band from trapping centers have a higher likelihood of recombining rather than being recaptured by another trap. In such scenarios, charge transport is mainly governed by carrier release from traps followed by recombination with oppositely charged carriers. On the other hand, under conditions of fast retrapping, charge carriers are more likely to be recaptured by trap states before recombination occurs. Trapping parameters were extracted by fitting the TL glow curve obtained at the highest irradiation dose, where the signal quality allowed for more accurate analysis. As the glow curve shapes and peak positions remained consistent across different doses, it was considered unnecessary to perform detailed trapping parameter calculations for each dose separately. Initially, the TL glow curve suggested the presence of two peaks, leading us to attempt a two‐peak deconvolution. However, the fitting process with only two peaks was unsuccessful, prompting a more detailed analysis of the curve's shape. Theoretically, TL glow peaks tend to exhibit a rapid decrease in intensity after reaching their maximum due to the nature of charge carrier recombination and trap emptying processes. Contrary to this expectation, the peak in our dataset displayed an unusually broad tailing effect on the higher temperature side. This anomaly raised suspicions about the possible presence of an additional overlapping peak. Furthermore, a review of the existing literature revealed that rare‐earth–doped ZnO materials frequently exhibit TL peaks in between 600 and 650 K, further supporting the hypothesis that a third peak might be contributing to the overall glow curve [29, 31, 32, 33]. Considering both the anomalous peak broadening and literature findings, we performed a three‐peak deconvolution, which resulted in a significantly improved fit, as depicted in Figure 6. The successful application of this model suggests that the TL response in Y‐doped ZnO is influenced by at least three distinct trapping centers, each contributing to the overall luminescence characteristics. Activation energies of three trapping centers were found to be 0.77, 1.12, and 1.29 eV. Table 2 presents the fitting parameters corresponding to each trap center. A comparison with the literature indicates that the 0.77 and 1.12 eV levels correspond to intrinsic trap centers commonly observed in undoped ZnO, which are typically associated with oxygen vacancies or Zn interstitials [28, 31].

FIGURE 6.

Deconvolution of TL glow curve of ZnO nanoparticles.

TABLE 2.

Kinetic parameters of undoped and Y‐doped ZnO nanoparticles.

Compound	Peak	T m (K)	E t (eV)	b	ν (s−1)
Y:ZnO	A	490.3	0.77	1.66	1.7 × 107
	B	607.8	1.12	1.42	3.7 × 108
	C	660.1	1.29	1.01	1.3 × 109

In our recent paper, two trapping centers were revealed for undoped ZnO nanoparticles at 0.84 and 1.05 eV [32]. The 1.29 eV trap level observed in Y‐doped ZnO is not typically present in undoped ZnO and is therefore attributed to defect states induced by Y incorporation. A recent first‐principles DFT study on Y‐doped ZnO monolayers reported the formation of impurity levels near the Fermi level, primarily due to the interaction between Y 4d and Zn 4 s orbitals [34]. Moreover, it was shown that when Y doping is combined with native defects such as oxygen vacancies (V_O), additional mid‐gap states emerge, and the bandgap is reduced significantly—from 4.03 eV to 2.24 eV—suggesting the introduction of deep‐level traps. These findings support the idea that the 1.29 eV level in our TL data may be attributed to a defect complex involving Y and V_O, such as a Y–V_O pair or a local distortion induced by their interaction. Such a configuration could introduce a deep electron trap level within the bandgap, which aligns well with the activation energy we extracted. Further DFT modeling and spectroscopic studies would be useful to confirm this mechanism. Similar additional trap centers have been reported in Gd‐, Yb‐, and Eu‐doped ZnO compounds, further supporting the idea that rare‐earth doping introduces new defect states within the ZnO matrix [32, 33, 35]. Moreover, previous density functional theory (DFT) studies on RE‐doped ZnO systems (e.g., La, Er, and Nd) have reported notable changes in the electronic structure upon doping. These include upward shifts in the Fermi level and a reduction in defect formation energies, particularly under oxygen‐rich conditions, which point to increased dopant stability and the possible formation of new trap levels within the bandgap [36]. Although yttrium was not explicitly examined in that study, its similar electronic configuration and ionic radius suggest that comparable effects could occur in Y‐doped ZnO systems. This theoretical background supports the experimental investigation of Y‐induced trap characteristics through TL measurements.

It would also be worthwhile to compare the TL sensitivity of various rare‐earth element–doped ZnO samples to better understand the role of specific dopants in enhancing luminescence properties. In a previous study [32], we investigated the TL behavior of undoped and Gd‐doped ZnO nanoparticles under similar experimental conditions. Based on that comparison, Y‐doped ZnO exhibits a TL intensity approximately 1.5–2 times higher than that of undoped ZnO. However, the TL intensity of Gd‐doped ZnO was found to be even higher than that of the Y‐doped samples. It is important to note that a meaningful benchmarking of TL sensitivity among rare‐earth element–doped ZnO systems requires strictly identical experimental parameters such as synthesis conditions, particle size distribution, dose rate, and heating profile. Variations in these parameters can significantly affect TL output. For this reason, we have limited the comparison to our own previously published data, which allows for a consistent and controlled evaluation of the dopant effect.

The kinetic parameters can be utilized to find the frequency factor (ν) of the trap levels. The frequency factor and other kinetic parameters (β, T _m, E _t) are related as follows:

$$\frac{\beta E_t}{k{T}_m^2}=\nu \exp \left(-E_t/k{T}_m\right)\left[1+\left(b-1\right){\mathrm{\Delta }}_m\right]$$ (7)

where ${\mathrm{\Delta }}_m=2k{T}_m/E_t$. The frequency factors are reported in Table 2.

Figure 7 illustrates the relationship between the integrated peak area of the TL glow curve and the radiation dose. The experimental data points, represented by star symbols, show a clear increasing trend with dose, indicating a direct correlation between the TL intensity and the amount of absorbed radiation. A linear fit was applied to the data, yielding the equation y = 2284.0 + 1340.3x, where y represents the peak area (in counts) and x denotes the radiation dose (in Gy). The strong linearity observed suggests that Y‐doped ZnO nanoparticles exhibit a well‐defined dose response, which is a crucial characteristic for their potential application in radiation dosimetry. The small y‐intercept value indicates minimal background signal, further confirming the material's sensitivity to radiation. Overall, the results demonstrate that the TL response of Y‐doped ZnO is highly dose dependent, making it a promising candidate for dosimetric applications. Similarly, previous studies on Gd‐ and Yb‐doped ZnO nanostructures have also reported a strong dose‐dependent TL response, further supporting the potential of rare‐earth–doped ZnO materials for dosimetric applications [32, 35].

FIGURE 7.

Dose‐dependence of TL peak area of Y‐doped ZnO nanoparticles. Solid line represents the linear fit.

Figure 8 shows the PL spectra of undoped ZnO and Y‐doped ZnO nanoparticles recorded at room temperature. Two prominent emission bands are observed for both samples. The first peak appears around 454 nm, corresponding to a blue defect‐related emission, which is commonly attributed to intrinsic defects such as oxygen vacancies (V_O) or zinc interstitials (Zn_i) within the ZnO lattice [37, 38, 39]. This emission arises from recombination processes involving defect states located within the bandgap, rather than from direct band‐to‐band transitions. The second and broader emission band is centered around 578 nm, which is typically associated with deep‐level emissions related to complex intrinsic or extrinsic defects, including deeper oxygen vacancy states or structural disorder [40, 41, 42]. The exact position of the reported emissions can vary depending on several factors such as synthesis methods, particle size, crystallinity, internal strain, and dopant distribution, all of which can slightly modify the bandgap energy and the nature of defect states. Notably, the intensity of both the emissions is significantly enhanced in the Y‐doped ZnO sample compared with the undoped ZnO. This observation suggests that yttrium incorporation modifies the defect structure of ZnO nanoparticles in two main ways: (i) Increased defect density: The stronger defect‐related emissions indicate a higher concentration of luminescence‐active defect centers introduced by Y doping. (ii) Modified recombination pathways: Y doping appears to facilitate radiative recombination through newly formed or altered defect levels. The strong defect‐related PL emissions are in excellent agreement with the TL findings, where Y‐doped ZnO exhibited approximately 1.5–2 times higher TL intensity than undoped ZnO [32]. These results together suggest that yttrium doping plays a crucial role in enhancing defect‐assisted luminescence processes, making Y:ZnO nanoparticles promising candidates for optoelectronic and dosimetric applications.

FIGURE 8.

PL spectra of undoped and Y‐doped ZnO nanoparticles.

4. Conclusion

In this study, the TL properties of Y‐doped ZnO nanoparticles were investigated to evaluate their potential for radiation dosimetry applications. XRD analysis confirmed a hexagonal crystal structure with refined lattice parameters a = 3.2513 Å and c = 5.2066 Å, while the crystallite size was determined to be 120.6 nm using the W–H method. FTIR results confirmed the presence of Zn–O bonds and surface hydroxyl groups in both ZnO and Y:ZnO samples. The reduced intensity of carboxylate‐related peaks in Y:ZnO suggests that yttrium doping alters surface chemistry and reduces organic residue adsorption. TL measurements revealed three distinct glow peaks at approximately 490.3, 607.8, and 660.1 K, indicating multiple trapping centers responsible for charge storage and recombination. The activation energies of trap centers were calculated as 0.77, 1.12, and 1.29 eV. The TL intensity showed a strong dependence on radiation dose, with a clear linear relationship between the integrated peak area and the applied dose. The linear relation confirms that the TL response is proportional to the dose in the studied range, demonstrating the suitability of Y‐doped ZnO nanoparticles for radiation dosimetry. The low background signal and the well‐defined peak structure further indicate the reliability and sensitivity of this material for detecting and quantifying ionizing radiation exposure. PL analysis revealed that Y‐doped ZnO exhibited emissions around 454 and 578 nm. This significant enhancement in both recombination pathways indicates that yttrium incorporation effectively modifies the electronic and defect structures of ZnO. The combined PL and TL results highlight the potential of Y‐doped ZnO nanoparticles for luminescence‐based applications, particularly in optical sensing and radiation dosimetry.

Author Contributions

Mehmet Isik: writing – original draft, investigation, formal analysis. Tacettin Yildirim: writing – original draft, investigation, resources. Nizami Mamed Gasanly: supervision, writing – review and editing.

Conflicts of Interest

The authors declare no conflicts of interest.

Declaration of Generative AI in Scientific Writing

During the preparation of this work, the authors used ChatGPT in order to check and improve the language of the study. After using this tool, the authors reviewed and edited the content as needed and take(s) full responsibility for the content of the publication.

Data Availability Statement

The data that support the findings of this study are available from the corresponding author upon reasonable request.