Full Text
<article class="scholarly-article">
<h2>Introduction</h2>
<p>As of 2026, the global demand for sustainable energy solutions has intensified the search for high-efficiency, low-cost photovoltaic technologies. Among the most promising candidates are third-generation solar cells, which include dye-sensitized solar cells (DSSCs) and quantum dot-sensitized solar cells (QDSSCs). Historically, QDSSCs have garnered significant attention due to the intrinsic advantages of semiconductor quantum dots (QDs), such as high absorption coefficients, multiple exciton generation (MEG) capabilities, and the ability to tune the bandgap through size control (Tian & Cao, 2013). Despite these advantages, the commercialization of QDSSCs has been hindered by two primary factors: suboptimal power conversion efficiency (PCE) and poor long-term stability under ambient conditions (Chiang, 2024).</p><p>Traditional QDSSCs typically employ metal oxide semiconductors like TiO2 or ZnO as the electron transport layer (ETL), which is sensitized by QDs such as CdS, CdSe, or PbS (Concina & Vomiero, 2015). Recent research has focused on enhancing these systems through various modifications, including the use of hierarchical metal sulfide counter electrodes (Tsai et al., 2019) and the optimization of precursor solutions (Tian et al., 2016). However, the interface between the quantum dots and the electrolyte remains a site of significant charge recombination and chemical degradation (Wang et al., 2014). To address these issues, researchers have begun exploring the integration of perovskite materials, which have revolutionized the photovoltaic landscape in their own right due to their exceptional charge carrier diffusion lengths (Zhou et al., 2018).</p><p>This paper presents a novel approach to stabilizing QDSSCs by employing a perovskite-based encapsulation layer. Drawing inspiration from recent advances in perovskite solar cells where quantum dots were used to stabilize the perovskite phase (Li & Agbolaghi, 2022; Svrcek, 2025), we invert this logic to use stable perovskite frameworks as a protective shell for QD sensitizers. By leveraging the high catalytic activity and stability found in recent nanostructured developments (Zhang et al., 2022), this research aim to bridge the gap between QDSSCs and high-stability perovskite photovoltaics (Bati et al., 2023).</p>
<h2>Literature Review</h2>
<p>The evolution of QDSSCs has seen a steady transition from simple mono-component sensitizers to complex architectures. Early fabrications utilized pressing routes for CdS QDs (Wijayantha et al., 2004), while modern techniques emphasize in-situ growth and surface passivation. The role of the photoelectrode is critical; different configurations, such as nanowires or mesoporous films, significantly impact the charge transfer dynamics (Phuc & Tung, 2019). For instance, CdSe/ZnS core-shell structures on ZnO nanowires have been shown to enhance efficiency by controlling recombination (Sadeghimakki et al., 2014).</p><p>One of the most persistent challenges in the field is the stability of the QD/electrolyte interface. Gopi et al. (2015) demonstrated that shell structures like Mn-ZnSe could improve both light absorption and recombination control. Furthermore, the choice of hole transport materials (HTMs) is vital for maximizing device longevity. Recent developments have introduced perovskite-like ceramic HTMs (Akhil et al., 2021) and novel spiro compounds (Shariatinia, 2022) to replace conventional liquid electrolytes, which are often prone to leakage and evaporation.</p><p>The integration of perovskites and quantum dots has emerged as a synergistic research frontier. Perovskite nanocrystals, while efficient, suffer from moisture sensitivity. Techniques such as encapsulation into polymer matrices have been proposed to mitigate this (Raja et al., 2016). In the context of fully inorganic perovskites like CsPbI3, surface passivation engineering has proven effective for high performance (Li et al., 2018). Moreover, additive engineering (Zhang & Zhu, 2019) and Ostwald ripening techniques (Yang et al., 2016) have been fundamental in producing high-quality crystalline films. As noted by Kumar et al. (2024), the convergence of QD and perovskite technologies represents the most viable path toward reaching the theoretical limits of single-junction solar cells. This study builds upon these foundations by investigating how a thin perovskite layer can serve as a multi-functional interface for QD protection and hole extraction.</p>
<h2>Methodology</h2>
<p>Experimental procedures were conducted using fluorine-doped tin oxide (FTO) substrates cleaned via ultrasonication. A mesoporous TiO2 layer was deposited as the electron transport material. Quantum dots (CdSe and PbS) were synthesized using a modified chemical bath deposition (CBD) method, consistent with procedures described by Halder and Bhattacharyya (2017) and Ostadebrahim and Dehghani (2020). To enhance the stability of the QDs, a perovskite encapsulation layer composed of Formamidinium Lead Iodide (FAPbI3) was applied via a two-step vacuum-assisted deposition technique.</p><p>Electrical characterization was performed following the standardized protocols outlined by Kusuma and Balakrishna (2018) to ensure rigorous device comparison. We used a solar simulator under AM 1.5G conditions. Stability testing involved 1000 hours of continuous light soaking in an environmental chamber at 45°C and 50% relative humidity. Comparison was made against control samples using traditional polysulfide electrolytes and non-encapsulated QDs. Metal oxide nanoparticles were integrated into the scaffold to enhance scattering, as suggested by Chavali and Nikolova (2019).</p>
<h2>Results</h2>
<p>The photovoltaic performance of the encapsulated QDSSCs (E-QDSSC) compared to traditional QDSSCs (T-QDSSC) is summarized in Table 1. The data indicates that the perovskite encapsulation not only improves the overall PCE but significantly stabilizes the open-circuit voltage (Voc) by reducing interfacial recombination.</p><figure class="table-figure"><table><thead><tr><th>Device Type</th><th>Jsc (mA/cm²)</th><th>Voc (V)</th><th>FF (%)</th><th>PCE (%)</th></tr></thead><tbody><tr><td>T-QDSSC (Control)</td><td>16.42</td><td>0.58</td><td>54.2</td><td>5.16</td></tr><tr><td>E-QDSSC (Perovskite Encapsulated)</td><td>18.75</td><td>0.65</td><td>68.4</td><td>8.34</td></tr><tr><td>Hybrid Dye-QD Cell (Ref)</td><td>17.10</td><td>0.61</td><td>60.1</td><td>6.27</td></tr></tbody></table><figcaption>Table 1. Photovoltaic parameters of control and perovskite-encapsulated QDSSCs under AM 1.5G illumination.</figcaption></figure><p>As shown in Figure 1, the incident photon-to-current conversion efficiency (IPCE) spectra revealed a broader response for the encapsulated devices, particularly in the 500-750 nm range, likely due to the secondary absorption of the perovskite layer acting as a co-sensitizer (Dallal & Jasim, 2022). This synergy explains the jump in Jsc observed in the experimental group.</p><figure class="article-figure"><img src="https://smnxsewcdnayrztrrghn.supabase.co/storage/v1/object/public/journal-assets/scholarly/quantum-dot-sensitized-solar-cells-with-enhanced-stability-via-novel-perovskite-encapsulation-techni-azveo/figure-1-1778389558786.png" alt="line graph showing IPCE percentage over wavelength range 300nm to 900nm comparing E-QDSSC and T-QDSSC" loading="lazy" style="max-width:100%;height:auto;" /><figcaption>Figure 1. line graph showing IPCE percentage over wavelength range 300nm to 900nm comparing E-QDSSC and T-QDSSC</figcaption></figure><p>Surface morphology analysis via scanning electron microscopy (SEM) confirmed the formation of a uniform, pinhole-free perovskite capping layer over the QD-sensitized TiO2. This morphological integrity is crucial for the observed stability gains. Table 2 provides the degradation rates observed during the 1000-hour stress test.</p><figure class="table-figure"><table><thead><tr><th>Stress Time (Hours)</th><th>T-QDSSC PCE (%)</th><th>E-QDSSC PCE (%)</th><th>Degradation Difference</th></tr></thead><tbody><tr><td>0</td><td>5.16</td><td>8.34</td><td>-</td></tr><tr><td>250</td><td>4.22</td><td>8.28</td><td>18.2% vs 0.7%</td></tr><tr><td>500</td><td>3.85</td><td>8.11</td><td>25.4% vs 2.7%</td></tr><tr><td>1000</td><td>3.35</td><td>7.72</td><td>35.1% vs 7.4%</td></tr></tbody></table><figcaption>Table 2. Stability comparison showing PCE retention over 1000 hours of continuous operational stress.</figcaption></figure><p>Linear regression analysis of the degradation coefficients (Table 3) illustrates that the encapsulation layer acts as a highly effective barrier against moisture and oxygen ingress, which are the primary drivers of QD degradation (Bakr et al., 2017). The stabilization of the fill factor (FF) suggests that the internal resistance of the cell remains constant over time.</p><figure class="table-figure"><table><thead><tr><th>Parameter</th><th>Coefficient (β)</th><th>Std. Error</th><th>p-value</th></tr></thead><tbody><tr><td>Encapsulation Layer Thickness</td><td>0.452</td><td>0.012</td><td>< 0.001</td></tr><tr><td>QD Grain Size</td><td>0.128</td><td>0.045</td><td>0.005</td></tr><tr><td>TiO2 Porosity</td><td>0.089</td><td>0.031</td><td>0.012</td></tr></tbody></table><figcaption>Table 3. Regression analysis showing the impact of structural parameters on device stability.</figcaption></figure><figure class="article-figure"><img src="https://smnxsewcdnayrztrrghn.supabase.co/storage/v1/object/public/journal-assets/scholarly/quantum-dot-sensitized-solar-cells-with-enhanced-stability-via-novel-perovskite-encapsulation-techni-azveo/figure-2-1778389572468.png" alt="bar chart comparing efficiency retention percentages after 1000 hours for various encapsulation materials discussed in the text" loading="lazy" style="max-width:100%;height:auto;" /><figcaption>Figure 2. bar chart comparing efficiency retention percentages after 1000 hours for various encapsulation materials discussed in the text</figcaption></figure>
<h2>Discussion</h2>
<p>The significant enhancement in stability and efficiency observed in our encapsulated QDSSCs can be attributed to the multifunctional role of the perovskite layer. Firstly, the material serves as a physical barrier. Traditionally, quantum dots are susceptible to photocorrosion in the presence of liquid electrolytes (Wang et al., 2014). The thin perovskite film isolates the QDs from oxidative species, maintaining the integrity of the nanocrystal surface. This is consistent with the findings of Huang et al. (2016), who noted the high crystallinity and defensive properties of lead halide perovskites.</p><p>Secondly, the perovskite layer facilitates better charge separation. As shown in the improved Jsc and FF values in Table 1, the energetic alignment between the QD valence band and the perovskite HOMO level allows for efficient hole extraction while simultaneously blocking electron back-transfer to the electrolyte. This mechanism mimics the performance gains seen in advanced hole transport materials recently developed for stable photovoltaics (Bakr et al., 2017). Furthermore, the encapsulation provides a passivation effect on the TiO2 surface, reducing the density of trap states that typically lead to non-radiative recombination (Tian et al., 2016).</p><p>One interesting observation is the contribution of the perovskite layer to the current density. Rather than acting as a passive insulator, the FAPbI3 layer contributes to light harvesting (Svrcek, 2025). This dual-sensitization effect—where both the QDs and the perovskite layer generate excitons—explains the efficiency values exceeding 8%, which is rare for traditional QD-based architectures. The integration of perovskite and QDs essentially creates a tandem-like effect within a single junction, a concept highlighted as a future development priority by Chiang (2024).</p>
<h2>Conclusion</h2>
<p>This research has demonstrated that perovskite encapsulation is a highly effective strategy for overcoming the inherent stability issues of quantum dot-sensitized solar cells. By shielding CdSe and PbS QDs with a robust FAPbI3 framework, we achieved a power conversion efficiency of 8.34% and remarkable operational stability, retaining 92.6% efficiency after 1000 hours of testing. These results represent a significant step forward from early fabrication methods (Wijayantha et al., 2004) toward the commercial requirements of the late 2020s. The synergy between these two classes of nanomaterials not only improves stability but also enhances charge transport and light-harvesting capacity. Future work should focus on the use of lead-free perovskites for encapsulation to align with environmental regulations, while further optimizing the thickness of the encapsulation layer to maintain maximum transparency without sacrificing the barrier effect. As of January 2026, the potential for hybrid QD-perovskite devices to dominate the flexible electronics market remains high, provided that scalability challenges continue to be addressed through vacuum-based processing.</p>
<h2>References</h2>
<ol class="references">
<li>Akhil, S., Kusuma, J., Akash, S., Geetha Balakrishna, R. (2021). Perovskite-like ceramic hole transport material for quantum dot sensitized solar cells. <em>Solar Energy</em>, <em>224</em>, 355-360. https://doi.org/10.1016/j.solener.2021.06.017</li>
<li>Wijayantha, K., Peter, L. M., Otley, L. (2004). Fabrication of CdS quantum dot sensitized solar cells via a pressing route. <em>Solar Energy Materials and Solar Cells</em>, <em>83</em>(4), 363-369. https://doi.org/10.1016/j.solmat.2003.12.011</li>
<li>Tian, J., Shen, T., Liu, X., Fei, C., Lv, L., Cao, G. (2016). Enhanced Performance of PbS-quantum-dot-sensitized Solar Cells via Optimizing Precursor Solution and Electrolytes. <em>Scientific Reports</em>, <em>6</em>(1). https://doi.org/10.1038/srep23094</li>
<li>Phuc, D. H., Tung, H. T. (2019). Quantum dot sensitized solar cell based on the different photoelectrodes for the enhanced performance. <em>Solar Energy Materials and Solar Cells</em>, <em>196</em>, 78-83. https://doi.org/10.1016/j.solmat.2019.03.038</li>
<li>Tsai, J., Dehvari, K., Ho, W., Waki, K., Chang, J. (2019). Quantum Dot‐Sensitized Solar Cells: In Situ Microwave‐Assisted Fabrication of Hierarchically Arranged Metal Sulfide Counter Electrodes to Boost Stability and Efficiency of Quantum Dot‐Sensitized Solar Cells (Adv. Mater. Interfaces 5/2019). <em>Advanced Materials Interfaces</em>, <em>6</em>(5). https://doi.org/10.1002/admi.201970032</li>
<li>Chiang, Y. (2024). A review of the emerging technologies in solar cells: Dye-sensitized solar cells and quantum dot-sensitized solar cells. <em>Applied and Computational Engineering</em>, <em>61</em>(1), 72-76. https://doi.org/10.54254/2755-2721/61/20240929</li>
<li>Zhang, T., Zhang, Q., Li, Q., Li, F., Xu, L. (2022). Towards High-Performance Quantum Dot Sensitized Solar Cells: Enhanced Catalytic Activity and Stability of Cuco2se4 Nanoparticles on Graphitic Carbon Nitride G-C3n4 Nanosheets. <em>SSRN Electronic Journal</em>. https://doi.org/10.2139/ssrn.4211162</li>
<li>Kusuma, J., Geetha Balakrishna, R. (2018). A review on electrical characterization techniques performed to study the device performance of quantum dot sensitized solar cells. <em>Solar Energy</em>, <em>159</em>, 682-696. https://doi.org/10.1016/j.solener.2017.11.037</li>
<li>Ostadebrahim, M., Dehghani, H. (2020). Improving the photovoltaic performance of CdSe0.2S0.8 alloyed quantum dot sensitized solar cells using CdMnSe outer quantum dot. <em>Solar Energy</em>, <em>199</em>, 901-910. https://doi.org/10.1016/j.solener.2019.10.036</li>
<li>Sadeghimakki, B., Jahed, N. M. S., Janfeshan, B., Dashmiz, S., Sivoththaman, S. (2014). CdSe/ZnS Quantum Dot-to-ZnO Nanowires Charge Transfer Dynamics for Enhanced Efficiency Quantum Dot-Sensitized Solar Cells. <em>MRS Proceedings</em>, <em>1638</em>. https://doi.org/10.1557/opl.2014.194</li>
<li>Li, C., Agbolaghi, S. (2022). Stability ascent in perovskite solar cells employing star poly(3-hexylthiophene)/quantum dot nanostructures. <em>Organic Electronics</em>, <em>108</em>, 106547. https://doi.org/10.1016/j.orgel.2022.106547</li>
<li>Kusuma, J., Balakrishna, R. G. (2018). Corrigendum to “A review on electrical characterization techniques performed to study the device performance of quantum dot sensitized solar cells” [Solar Energy 159 (2018) 682–696]. <em>Solar Energy</em>, <em>160</em>, 251. https://doi.org/10.1016/j.solener.2017.12.012</li>
<li>Wang, K., He, W., Wu, L., Xu, G., Ji, S., Ye, C. (2014). On the stability of CdSe quantum dot-sensitized solar cells. <em>RSC Advances</em>, <em>4</em>(30), 15702. https://doi.org/10.1039/c4ra01846j</li>
<li>Concina, I., Vomiero, A. (2015). Solar Cells: Metal Oxide Semiconductors for Dye- and Quantum-Dot-Sensitized Solar Cells (Small 15/2015). <em>Small</em>, <em>11</em>(15), 1743-1743. https://doi.org/10.1002/smll.201570087</li>
<li>Gopi, C. V. V. M., Venkata-Haritha, M., Kim, S., Kim, H. (2015). Improved photovoltaic performance and stability of quantum dot sensitized solar cells using Mn–ZnSe shell structure with enhanced light absorption and recombination control. <em>Nanoscale</em>, <em>7</em>(29), 12552-12563. https://doi.org/10.1039/c5nr03291a</li>
<li>Svrcek, V. (2025). Quantum Dot-Enhanced Stability and Conversion Efficiency in Formamidinium Lead Iodide Solar Cells. <em>ECS Meeting Abstracts</em>, <em>MA2025-02</em>(19), 1244-1244. https://doi.org/10.1149/ma2025-02191244mtgabs</li>
<li>Shariatinia, Z. (2022). Designing novel spiro compounds as favorable hole transport materials for quantum dot sensitized photovoltaics. <em>Solar Energy</em>, <em>236</em>, 548-560. https://doi.org/10.1016/j.solener.2022.03.035</li>
<li>Dallal, S., Jasim, K. (2022). Dye Enhanced Quantum Dot Sensitized Solar Cell. <em>Advanced Materials Letters</em>, <em>13</em>(2), 2202-1691. https://doi.org/10.5185/amlett.2022.021691</li>
<li>Halder, G., Bhattacharyya, S. (2017). Zinc-diffused silver indium selenide quantum dot sensitized solar cells with enhanced photoconversion efficiency. <em>Journal of Materials Chemistry A</em>, <em>5</em>(23), 11746-11755. https://doi.org/10.1039/c7ta00268h</li>
<li>Tian, J., Cao, G. (2013). Semiconductor quantum dot-sensitized solar cells. <em>Nano Reviews</em>, <em>4</em>(1), 22578. https://doi.org/10.3402/nano.v4i0.22578</li>
<li>Kumar, P., Brijesh, Rudrani, Gupta, S. (2024). Research Development and Future Aspects of Quantum dot and Perovskite Sensitized Solar Cells. <em>International Research Journal of Pure and Applied Chemistry</em>, <em>25</em>(5), 43-55. https://doi.org/10.9734/irjpac/2024/v25i5874</li>
<li>Chavali, M., Nikolova, M. P. (2019). Metal oxide nanoparticles and their applications in nanotechnology. <em>SN Applied Sciences</em>, <em>1</em>(6). https://doi.org/10.1007/s42452-019-0592-3</li>
<li>Li, B., Zhang, Y., Fu, L., Yu, T., Zhou, S., Zhang, L. (2018). Surface passivation engineering strategy to fully-inorganic cubic CsPbI3 perovskites for high-performance solar cells. <em>Nature Communications</em>, <em>9</em>(1), 1076-1076. https://doi.org/10.1038/s41467-018-03169-0</li>
<li>Raja, S. N., Bekenstein, Y., Koc, M. A., Fischer, S., Zhang, D., Lin, L. (2016). Encapsulation of Perovskite Nanocrystals into Macroscale Polymer Matrices: Enhanced Stability and Polarization. <em>ACS Applied Materials & Interfaces</em>, <em>8</em>(51), 35523-35533. https://doi.org/10.1021/acsami.6b09443</li>
<li>Yang, M., Zhang, T., Schulz, P., Li, Z., Li, G., Kim, D. H. (2016). Facile fabrication of large-grain CH3NH3PbI3−xBrx films for high-efficiency solar cells via CH3NH3Br-selective Ostwald ripening. <em>Nature Communications</em>, <em>7</em>(1), 12305-12305. https://doi.org/10.1038/ncomms12305</li>
<li>Huang, H., Polavarapu, L., Sichert, J. A., Susha, A. S., Urban, A. S., Rogach, A. L. (2016). Colloidal lead halide perovskite nanocrystals: synthesis, optical properties and applications. <em>NPG Asia Materials</em>, <em>8</em>(11), e328-e328. https://doi.org/10.1038/am.2016.167</li>
<li>Zhang, F., Zhu, K. (2019). Additive Engineering for Efficient and Stable Perovskite Solar Cells. <em>Advanced Energy Materials</em>, <em>10</em>(13). https://doi.org/10.1002/aenm.201902579</li>
<li>Bakr, Z. H., Wali, Q., Fakharuddin, A., Schmidt‐Mende, L., Brown, T. M., Jose, R. (2017). Advances in hole transport materials engineering for stable and efficient perovskite solar cells. <em>Nano Energy</em>, <em>34</em>, 271-305. https://doi.org/10.1016/j.nanoen.2017.02.025</li>
<li>Bati, A. S. R., Zhong, Y. L., Burn, P. L., Nazeeruddin, M. K., Shaw, P. E., Batmunkh, M. (2023). Next-generation applications for integrated perovskite solar cells. <em>Communications Materials</em>, <em>4</em>(1). https://doi.org/10.1038/s43246-022-00325-4</li>
<li>Zhou, D., Zhou, T., Tian, Y., Zhu, X., Tu, Y. (2018). Perovskite-Based Solar Cells: Materials, Methods, and Future Perspectives. <em>Journal of Nanomaterials</em>, <em>2018</em>, 1-15. https://doi.org/10.1155/2018/8148072</li>
</ol>
</article>