Study on Diamond NV Centers Excited by Green Light Emission from OLEDs

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

The authors presented a method of exciting NV centers using ITO-anode OLED devices, followed by the fabrication of GO/PEDOT: PSS hybrid anodes via spin-coating. However, this study does not show the method of preparing NV center. Therefore, I do not recommend the publication of this manuscript in Photonics.

Author Response

Comments： The authors presented a method of exciting NV centers using ITO-anode OLED devices, followed by the fabrication of GO/PEDOT: PSS hybrid anodes via spin-coating. However, this study does not show the method of preparing NV center. Therefore, I do not recommend the publication of this manuscript in Photonics.

 

Reply: We sincerely appreciate the reviewer's expert comments regarding the preparation methods of nitrogen-vacancy (NV) centers. In response to the specific concerns about sample preparation, we would like to emphasize that the key innovation of this study lies in the development of an OLED-based excitation system. The experiments utilized commercially available Ib-type diamond substrates (3 mm × 3 mm × 1 mm, (110) crystal plane, nitrogen concentration ~100 ppm, supplied by Yuxin Company) prepared by standard CVD methods. These substrates were subsequently processed with electron beam irradiation (dose: 1×10¹⁸ e⁻/cm²) followed by thermal annealing at 800°C for 1 hour to generate NV centers. We fully acknowledge the importance of sample preparation details and have accordingly supplemented this information in the revised manuscript. All additional content has been clearly marked in red font for the reviewer's convenience. The reviewer's rigorous and professional comments have been invaluable in enhancing the quality of our manuscript, for which we are deeply grateful. Should any further clarification be required, we remain fully available to provide additional information.

 

In the 2. Materials and Methods (P.2, L.98).

The experiment utilized type Ib diamond substrates (3 mm × 3 mm × 1 mm, (110) plane, nitrogen concentration ~100 ppm) prepared by standard CVD method provided by Yuxin Company. The samples were first subjected to electron beam irradiation with a dose of 1×10¹⁸ e⁻/cm² using an electron irradiation system supplied by Shanghai Gaoying Technology Co., Ltd. During irradiation, the samples were cooled by a water-cooling system and placed in a chemically stable copper vessel with excellent thermal conductivity. Subsequently, annealing was performed in a tube furnace (SKGL-1200, Shanghai Jujing Precision Instrument Manufacturing Co., Ltd.) with the sample positioned at the central zone of the furnace tube. The annealing process was conducted at 800°C for 1 hour under high-purity nitrogen protective atmosphere, ultimately yielding diamond samples with high-density NV centers.

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

In the main manuscript (#photonics-3781420), a green OLED is used as the excitation source for the diamond NV center, integrated with a diamond substrate and a microwave strip line to propose a compact quantum sensor. This device has successfully demonstrated NV luminescence and ODMR measurements, showcasing its potential to expand the application range of new quantum sensors, making it a significant achievement.

However, there are some points in the explanation of the device structure that are somewhat insufficient, making it difficult to understand for those who are not experts in both organic electronics and quantum sensors. 

For example, from the perspective of a quantum sensor expert who is not specialized in organic electronics, the following points may be difficult to understand:

-What does the "O" in OLED stand for? Is it "Organic"?

-What is the device structure of OLED? What is PEDOT? It is presumed to be the anode as you read on, but the structure should be presented first.

-GO/PEDOT:PSS synthesizes GO (Graphene Oxide) by changing the ratio, but is GO originally a solution? Graphene is a well-known solid 2D material.

Conversely, for those not specialized in quantum sensors, the following points may be difficult to understand:

-The microwave antenna is embedded in the package and can be understood as a line-shaped copper wire (micro-strip line?) from Fig. 4.

-The ODMR contrast corresponds to the dip structure in Fig. 5(a)-(c), and the higher the value, the better the sensitivity as a sensor.

Furthermore, additional detailed explanations are requested to deepen the reader's understanding on the following points:

-(P.7, L221) "This improvement originates from the hybrid anode's … ODMR signal quality." stated by the authors, but the increase in NV center fluorescence intensity and improvement in ODMR contrast are not related (although it contributes to SNR improvement). For example, if the OLED's emission spectrum changes, the ODMR contrast might improves, but it seems not to apply based on Fig. 3. Some additional comments are requested.

-In the 4. Conclusion (P.7, L.233), the authors state "Through interfacial engineering of the OLED anode," but where interfaces are involved? What can be given rise from setting the ratio to 40%?

That's all.

Author Response

Comments 1：What does the "O" in OLED stand for? Is it "Organic"?

Reply: We sincerely appreciate the reviewer's attention to terminological accuracy. We confirm that OLED stands for "Organic Light-Emitting Diode," where the letter "O" specifically denotes "Organic." The manuscript's introduction section already includes a standardized description of OLED technology. We are grateful for the reviewer's emphasis on terminological precision, which significantly contributes to enhancing the academic rigor of this paper.

In the 1. Introduction (P.2, L.45).

However, LED excitation systems still require focusing lenses, whereas OLEDs (Organic Light-Emitting Diodes), as planar light sources [16-18], can significantly simplify system architecture and better facilitate miniaturization of NV center excitation.

 

Comments 2：What is the device structure of OLED? What is PEDOT? It is presumed to be the anode as you read on, but the structure should be presented first.

Reply: Organic light-emitting diodes (OLEDs) are luminescent devices composed of multiple layers of organic thin films. The fundamental structure typically consists of an anode, a cathode, and various functional layers sandwiched between them. A standard configuration, from bottom to top, includes: a substrate (e.g., glass or flexible polymer), an anode (commonly indium tin oxide, ITO), a hole injection layer (HIL), a hole transport layer (HTL), an emissive layer (EML), an electron transport layer (ETL), an electron injection layer (EIL), and a cathode (e.g., aluminum or silver). Each functional layer is designed with optimized energy-level alignment to facilitate charge carrier injection, transport, and radiative recombination, ultimately enabling highly efficient electroluminescence. In the fabrication of OLED devices, molybdenum trioxide (MoO₃) was used as the hole injection layer (HIL), N,N'-diphenyl-N,N'-(1-naphthyl)-1,1'-biphenyl-4,4'-diamine (NPB) as the hole transport layer (HTL), tris(8-hydroxyquinolinato) aluminum (Alq₃) as the emissive layer (EML), LiF as the electron injection layer (EIL), and aluminum (Al) as the cathode. All materials were used without further purification. When the vacuum level was below 5×10^⁻4 Pa, MoO₃ (1 nm), NPB (40 nm), Alq₃ (70 nm), BPhen (10 nm), LiF (0.5 nm), and Al (100 nm) were sequentially evaporated. The energy levels and device structure were shown in Figure 1(c).

 

In the 1. Introduction (P.2, L.51).

OLED is a light-emitting device composed of multiple organic thin films, with its basic structure typically consisting of an anode, cathode, and various functional layers sandwiched in between. The standard configuration from bottom to top includes: substrate, anode, hole injection layer (HIL), hole transport layer (HTL), emissive layer (EML), electron transport layer (ETL), electron injection layer (EIL), and cathode. Currently, indium tin oxide (ITO) serves as the primary transparent electrode material for OLEDs due to its excellent optical transparency and electrical conductivity. Nevertheless, its practical applications are limited by several drawbacks, including high cost and substantial interfacial total internal reflection caused by its high refractive index. Alternative materials such as conductive polymers [20–22], metal nanowires [23–25], graphene [26–28], and carbon nanotubes (CNTs) [29-30], have been explored. Among them, poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT: PSS), as an anode material, has attracted considerable attention due to its compatibility with flexible substrates and low production costs.

 

Comments 3：GO/PEDOT:PSS synthesizes GO (Graphene Oxide) by changing the ratio, but is GO originally a solution? Graphene is a well-known solid 2D material.

Reply: We sincerely appreciate the reviewer's valuable suggestions regarding material terminology. We fully acknowledge that graphene is intrinsically a solid two-dimensional material, while graphene oxide (GO) typically exists as a solid powder. It should be specifically noted that all references to "graphene oxide" in this study exclusively denote its aqueous dispersion form. To ensure terminological precision, we will uniformly use the term "aqueous graphene oxide dispersion" throughout the revised manuscript. In this work, composite electrodes were fabricated by mixing aqueous graphene oxide dispersion with PEDOT: PSS aqueous dispersion at optimized ratios, followed by spin-coating deposition and interfacial treatment processes.

 

Comments 4：Conversely, for those not specialized in quantum sensors, the following points may be difficult to understand:

-The microwave antenna is embedded in the package and can be understood as a line-shaped copper wire (micro-strip line?) from Fig. 4.

Reply: We sincerely appreciate the reviewers' valuable comments and fully agree with the suggestion that the description of the microwave antenna should be more clear and accessible. Accordingly, in the revised manuscript, we have standardized the original "microwave antenna" terminology to the more precise technical term "microstrip antenna" to better reflect the device characteristics.

 

In the 3. Results and discussion (P.7, L.238).

Figure 4. (a) Microstrip antenna design for miniaturized OLED-excited NV-center sensor. (b) Integrated quantum sensing device based on miniaturized OLED-excited NV centers.

 

Comments 5：The ODMR contrast corresponds to the dip structure in Fig. 5(a)-(c), and the higher the value, the better the sensitivity as a sensor.

Furthermore, additional detailed explanations are requested to deepen the reader's understanding on the following points:

-(P.7, L221) "This improvement originates from the hybrid anode's … ODMR signal quality." stated by the authors, but the increase in NV center fluorescence intensity and improvement in ODMR contrast are not related (although it contributes to SNR improvement). For example, if the OLED's emission spectrum changes, the ODMR contrast might improves, but it seems not to apply based on Fig. 3. Some additional comments are requested.

Reply: The light emitted from the OLED device (centered at 540 nm) effectively excites the NV centers in diamond, as this wavelength falls within the phonon sideband absorption range of the NV centers. In ODMR measurements, when the excitation intensity is below the spin polarization saturation threshold of the NV centers, increasing the excitation power enhances the spin polarization rate, thereby improving the ODMR spectral modulation depth (contrast ratio, CR). However, once the excitation intensity exceeds the saturation threshold, the spin polarization approaches its maximum (~90%), and further increasing the excitation power only raises the background fluorescence without significantly altering the ODMR modulation depth [1-2].

 

[1] Yuan-Yao F, Zhong-Hao L, Yang Z, et al. Optimization of optical control of nitrogen vacancy centers in solid diamond[J]. Acta Physica Sinica, 2020, 69(14).

[2] Barry J F, Schloss J M, Bauch E, et al. Sensitivity optimization for NV-diamond magnetometry[J]. Reviews of Modern Physics, 2020, 92(1): 015004.

 

In the 3. Results and discussion (P.8, L.258).

 

The ODMR CR achieved with the ITO anode was measured to be 1.7% (Figure 5a), whereas the GO/PEDOT: PSS (40%) composite anode demonstrated a significant enhancement, reaching 3% (Figure 5b). This performance improvement primarily stems from the superior excitation brightness characteristics of the hybrid anode. Through optimized energy-level structure design, this anode not only effectively enhances the fluorescence emission intensity of NV centers but, more importantly, significantly improves ODMR signal quality. Notably, the current OLED excitation intensity remains below the spin polarization saturation threshold of NV centers. Within this operational regime, increasing the excitation power can further improve the spin polarization rate, thereby effectively enhancing the modulation depth (CR) of ODMR spectra [39-40].

 

Comments 6：In the 4. Conclusion (P.7, L.233), the authors state "Through interfacial engineering of the OLED anode," but where interfaces are involved? What can be given rise from setting the ratio to 40%?

Reply: We sincerely appreciate the reviewers’ valuable comments. In this study, the acid-modification interfacial engineering was specifically optimized for the GO/PEDOT: PSS composite anode system (see Section 2. Materials and Methods, P.2, L.81), where the 40% doping ratio demonstrated an optimal performance combination including a record high electrical conductivity of 4032 S/cm and a maximum work function of 5.256 eV, ultimately enabling the acid-treated GO/PEDOT:PSS (40%) composite anode to achieve a 3.7-fold enhancement in NV color-center fluorescence intensity (see Section 2. Results and Discussion, P.5, L.202; and Section 4. Conclusions, P.8, L.274).

 

In the 2. Materials and Methods (P.2, L.81).

The fabrication of hybrid anodes involved two critical steps: spin-coating film formation and acid-modified hybrid anode interface engineering. The PEDOT: PSS solution was first filtered through a 0.45 µm aqueous membrane and then blended with GO at 10%, 40%, and 100% ratios, followed by ultrasonication for 1 h to ensure homogeneous dispersion. Meanwhile, the quartz and ITO substrates were sequentially cleaned with acetone, ethanol, and deionized water (DI), dried at 120°C for 2 h, and treated with ozone plasma for 15 min. The films were spin-coated using a KV-SC-1550 spin coater at 3000 rpm for 30 s and subsequently annealed on a hotplate at 120°C for 20 min. For the acid-modified interface engineering, two approaches were employed: the HCl treatment involved immersing the films in 1 M HCl at 160°C for 30 min, followed by three DI water rinses; alternatively, the H₂SO₄ treatment consisted of film immersion in 1 M H₂SO₄, rinsing, and annealing at 160°C for 1 h. These treatments effectively removed moisture, improved surface morphology, and significantly enhanced charge carrier injection and transport properties. The complete experimental procedure is illustrated in Figure 1b.

 

In the 2. Results and discussion (P.5, L.202).

In our previous studies [38], the incorporation of GO into PEDOT: PSS leads to the interaction between negatively charged GO sheets and positively charged PEDOT⁺ chains, causing partial dissociation of PEDOT⁺ from PSS⁻ chains. Simultaneously, the hydroxyl and carboxyl groups on GO ionize to release H⁺ ions, which subsequently combine with PSS⁻ to form PSSH. Upon acidic interfacial treatment, the acid provides abundant H⁺ ions that further react with PSS⁻ in the film to generate neutral PSSH. This process promotes extensive dissociation of PEDOT⁺ from PSS⁻ chains, while the resulting PSSH can be removed from the film matrix through deionized water washing. After three cycles of deionized water rinsing, the PSS⁻ components in PEDOT: PSS dissolve into water, leaving the PEDOT⁺ chains retained on the substrate, thereby significantly enhancing the film's conductivity. The composite film exhibits maximum conductivity (4032 S/cm) at an optimal GO doping ratio of 40%. UPS measurements were conducted to determine the work function (Φ) and highest occupied molecular orbital (E_HOMO) energy levels of PEDOT: PSS and GO/PEDOT: PSS composite films with varying volume ratios (10%, 40%, 100%). The performance variations of OLED devices illustrated in Figure 3 elucidate the underlying mechanism responsible for the observed differences in NV center excitation intensity shown in Figure 2. UPS characterization revealed the influence of different anode materials on OLED performance characteristics, with detailed data presented in Table 1. Notably, the GO/PEDOT: PSS (40%) composite exhibited a maximum work function of 5.014 eV, significantly higher than that of pure PEDOT: PSS (4.787 eV). Comparative analysis of energy level differences between composite electrodes and the HIL demonstrated a maximum reduction of 0.556 eV in the energy barrier at the composite electrode/HIL interface when compared to conventional ITO electrodes. This reduced energy barrier facilitates improved energy level alignment and substantially enhances hole injection efficiency. Specifically, the E_HOMO level of the GO/PEDOT: PSS (40%) composite anode was measured at 5.256 eV, exceeding that of ITO (4.7 eV). This elevated E_HOMO energy effectively minimizes the energy barrier between the anode and the E_HOMO level of the HIL (MoO₃), thereby optimizing hole injection efficiency and reducing the device turn-on voltage. Consequently, OLED devices incorporating GO/PEDOT: PSS (40%) composite anodes demonstrated significantly enhanced luminance intensity compared to those with pure PEDOT: PSS anodes, ultimately leading to superior NV center excitation efficiency. Consequently, the GO/PEDOT: PSS (40%) composite anode demonstrates significantly enhanced hole injection efficiency due to the synergistic effect of its optimal electrical conductivity (4032 S/cm) and maximum work function (5.014 eV). OLED devices employing this composite anode exhibit superior luminescence intensity compared to those with pure PEDOT: PSS anodes, ultimately achieving more efficient NV center excitation.

 

In the 4. Conclusions (P.8, L.278).

This study demonstrates the feasibility of NV center excitation using OLED devices. Through acid-modified interfacial engineering of the OLED anode, a significant enhancement in NV center excitation efficiency was achieved. Experimental results show that the GO/PEDOT: PSS (40%) composite anode exhibits outstanding performance, with a conductivity of 4032 S/cm and a work function of 5.014 eV. Compared to conventional ITO-based devices, this novel anode architecture yields a 3.7-fold increase in NV center fluorescence peak intensity, conclusively demonstrating the performance-enhancing effect of the acid-modified interfacial engineering. By integrating NV centers with OLED technology, we have developed a novel approach for efficient green-light excitation. Furthermore, we have successfully implemented a miniaturized NV center sensor based on OLED excitation while demonstrating controllable spin-state manipulation. This OLED-based miniaturization technology enables potential applications in quantum sensing, facilitating the practical advancement of quantum technologies.

Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

The manuscript presents a novel method for exciting NV centers in diamond using organic light-emitting diodes (OLEDs) with hybrid anodes composed of graphene oxide (GO) and PEDOT:PSS, specifically optimized with a 40% GO ratio. The study claims to demonstrate enhanced excitation efficiency and reduced power consumption, offering potential for miniaturized quantum sensors. This topic is timely and relevant to the fields of quantum sensing, optoelectronics, and materials engineering. The manuscript is well-written, with clear experimental descriptions. However, I have some concerns that the authors need to address before I can make my recommendation.

- Although prior work on GO/PEDOT:PSS composites in OLEDs is cited, it is not critically compared to the authors’ approach. A clearer justification for why a 40% GO ratio provides optimal performance, beyond empirical results, is lacking.

- The manuscript should better differentiate itself from recent work using alternative excitation sources (e.g., micro-LEDs or fiber-coupled diode lasers). A comparative discussion in the Introduction or Discussion section would strengthen the claim of novelty.

- Figure 5d, which presents the SNR and CR comparison, would benefit from the inclusion of error bars or indicators of standard deviation.

- The manuscript does not address statistical robustness. How many devices were tested, and what is the variability among the results?

Author Response

The manuscript presents a novel method for exciting NV centers in diamond using organic light-emitting diodes (OLEDs) with hybrid anodes composed of graphene oxide (GO) and PEDOT:PSS, specifically optimized with a 40% GO ratio. The study claims to demonstrate enhanced excitation efficiency and reduced power consumption, offering potential for miniaturized quantum sensors. This topic is timely and relevant to the fields of quantum sensing, optoelectronics, and materials engineering. The manuscript is well-written, with clear experimental descriptions. However, I have some concerns that the authors need to address before I can make my recommendation.

Comments 1：Although prior work on GO/PEDOT:PSS composites in OLEDs is cited, it is not critically compared to the authors’ approach. A clearer justification for why a 40% GO ratio provides optimal performance, beyond empirical results, is lacking.

Reply:

We sincerely appreciate the reviewer's insightful comments regarding the mechanistic explanation for the optimal 40% GO doping ratio. As demonstrated in our previous study [38], the synergistic combination of 40% GO doping and acid-modified interfacial treatment maximizes conductivity (4032 S/cm) by facilitating the dissociation of PEDOT⁺ chains and removal of PSS⁻ components. UPS measurements further verified that this specific ratio yields an optimal work function (5.014 eV) and HOMO energy level (5.256 eV), effectively reducing the energy barrier at the electrode/HIL interface and significantly enhancing hole injection efficiency. The observed experimental superiority of the 40% GO doping ratio is thus mechanistically explained by this dual optimization of electrical conductivity and energy-level alignment.

 

In the 3. Results and discussion (P.5, L.202).

 

In our previous studies [38], the incorporation of GO into PEDOT: PSS leads to the interaction between negatively charged GO sheets and positively charged PEDOT⁺ chains, causing partial dissociation of PEDOT⁺ from PSS⁻ chains. Simultaneously, the hydroxyl and carboxyl groups on GO ionize to release H⁺ ions, which subsequently combine with PSS⁻ to form PSSH. Upon acidic interfacial treatment, the acid provides abundant H⁺ ions that further react with PSS⁻ in the film to generate neutral PSSH. This process promotes extensive dissociation of PEDOT⁺ from PSS⁻ chains, while the resulting PSSH can be removed from the film matrix through deionized water washing. After three cycles of deionized water rinsing, the PSS⁻ components in PEDOT: PSS dissolve into water, leaving the PEDOT⁺ chains retained on the substrate, thereby significantly enhancing the film's conductivity. The composite film exhibits maximum conductivity (4032 S/cm) at an optimal GO doping ratio of 40%.UPS measurements were conducted to determine the work function (Φ) and highest occupied molecular orbital (E_HOMO) energy levels of PEDOT: PSS and GO/PEDOT: PSS composite films with varying volume ratios (10%, 40%, 100%). The performance variations of OLED devices illustrated in Figure 3 elucidate the underlying mechanism responsible for the observed differences in NV center excitation intensity shown in Figure 2. UPS characterization revealed the influence of different anode materials on OLED performance characteristics, with detailed data presented in Table 1. Notably, the GO/PEDOT: PSS (40%) composite exhibited a maximum work function of 5.014 eV, significantly higher than that of pure PEDOT: PSS (4.787 eV). Comparative analysis of energy level differences between composite electrodes and the HIL demonstrated a maximum reduction of 0.556 eV in the energy barrier at the composite electrode/HIL interface when compared to conventional ITO electrodes. This reduced energy barrier facilitates improved energy level alignment and substantially enhances hole injection efficiency. Specifically, the E_HOMO level of the GO/PEDOT: PSS (40%) composite anode was measured at 5.256 eV, exceeding that of ITO (4.7 eV). This elevated E_HOMO energy effectively minimizes the energy barrier between the anode and the E_HOMO level of the HIL (MoO₃), thereby optimizing hole injection efficiency and reducing the device turn-on voltage. Consequently, the GO/PEDOT: PSS (40%) composite anode demonstrates significantly enhanced hole injection efficiency due to the synergistic effect of its optimal electrical conductivity (4032 S/cm) and maximum work function (5.014 eV). OLED devices employing this composite anode exhibit superior luminescence intensity compared to those with pure PEDOT: PSS anodes, ultimately achieving more efficient NV center excitation.

 

Comments 2：The manuscript should better differentiate itself from recent work using alternative excitation sources (e.g., micro-LEDs or fiber-coupled diode lasers). A comparative discussion in the Introduction or Discussion section would strengthen the claim of novelty.

Reply:

We sincerely appreciate the reviewers' constructive comments. In response, we have added a comprehensive comparison between OLED-excited NV centers and conventional LED-excited NV centers in the Results and Discussion section (Section 3).

 

In the 3. Results and discussion (P.8, L.246).

 

A miniaturized nitrogen-vacancy (NV) center quantum sensor based on organic light-emitting diode (OLED) excitation was developed, featuring a compact 22 mm × 14 mm × 7 mm prototype (Figure 4). The integrated design combines an OLED excitation source, NV-doped diamond samples, and a microstrip antenna in a single system. Unlike conventional light-emitting diode (LED) excitation systems [15], the sur-face-emitting nature of OLEDs eliminates complex optical focusing components, enabling substantial volume reduction while maintaining excitation efficiency.

 

In the 3. Results and discussion (P.8, L.271).

 

Experimental results demonstrate that the proposed design maintains sensing performance while achieving significant volume reduction compared to conventional LED-based systems. Notably, the inherent flexibility of OLED technology offers promising potential for NV center sensor applications in wearable devices and other emerging fields. This study provides an innovative solution for advancing the practical development of quantum sensors.

 

Comments 3： Figure 5d, which presents the SNR and CR comparison, would benefit from the inclusion of error bars or indicators of standard deviation.

Reply： We sincerely appreciate the reviewer’s valuable suggestion. We fully agree that adding error bars or standard deviation indicators to the comparison plot would enhance the reliability and interpretability of the data. In the revised manuscript, we have incorporated error bars (based on the standard deviation of five replicate experiments) into Figure 5d and supplemented the corresponding explanation in the figure caption. These additions provide a more comprehensive representation of data variability, ensuring clearer and more robust result comparisons.

 

In the 3. Results and discussion (P.7, L.243).

 

Figure 5. (d) the corresponding SNR and CR comparison of ODMR signals for different anodes.

Comments 4：The manuscript does not address statistical robustness. How many devices were tested, and what is the variability among the results?

Reply：We sincerely appreciate the reviewer's valuable comments regarding statistical robustness. In the revised manuscript, we have strengthened the statistical validation through systematic testing: twenty independent devices were fabricated and tested for each anode configuration (total N=100), with all devices subjected to identical testing conditions. As shown in Figure 2d, the box-plot analysis of the characteristic NV center emission peak intensity demonstrates consistently high median values across all groups, indicating excellent reproducibility of the data.

 

In the 3. Results and discussion (P.5, L.179).

 

Figure 2. (d) Box plot of characteristic peak intensities of NV centers excited by OLED devices with ITO anode, PEDOT: PSS anode, and hybrid anode at maximum emission intensity (N = 100).

 

In the 3. Results and discussion (P.4, L.167).

 

For the statistical validation of experimental results, this study fabricated and tested 20 independent devices for each anode configuration (total sample size N=100), with all devices evaluated under identical conditions. As shown in Figure 2d, the box-plot analysis of the characteristic NV center emission peak intensity demonstrates consistently high median values across all groups, confirming the excellent reproducibility and statistical robustness of the experimental data.

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

The article is generally well written and structured. It assesses a new Study on Diamond NV Centers Excited by Green Light Emission from OLEDs. Therefore, this article is suitable for publication in the targeted journal and can be accepted directly.