The Laboratory of Nanotechnology and Solar Energy (LNES) proudly congratulates Professor Ana Flávia Nogueira on being named among the 100 best scientists in Brazil in Chemistry and the top 50 in Materials Science, according to the annual ranking published by Research.com.

This distinction highlights the significance and scientific impact of Professor Ana Flávia’s research, which focuses on innovative studies of hybrid materials and perovskites for solar energy applications.

The Research.com ranking is based on bibliometric metrics that consider both the number and impact of scientific publications, reflecting the influence of researchers within their respective fields.

This achievement further reinforces the prominent role of Professor Ana Flávia and the LNES team in both the national and international scientific community, contributing to the advancement of science and the development of new renewable energy technologies.

Congratulations, Professor Ana Flávia, on this well-deserved recognition!

The post Ana Flávia Nogueira stands out as one of the 100 leading scientists in Brazil first appeared on LNES.

We are excited to share our latest research article published in Journal of Materials Chemistry A, titled:

“The influence of the buried interface on the orientational crystallization and thermal stability of halide perovskite thin films”

This study sheds light on how the choice of buried interface materials—used as underlayers in both regular (n–i–p) and inverted (p–i–n) perovskite solar cell architectures—affects the crystal orientation and long-term stability of FA₀.₉Cs₀.₁PbI₃ perovskite films.

Key Highlights:

🔹 Oriented Crystal Growth: We demonstrate that the nature of the underlayer influences the preferential crystallographic orientation of the perovskite film, which plays a central role in both performance and stability.

🔹 Thermal Stress Response: By subjecting perovskite films and devices to 500 hours of continuous heating at 85 °C, we reveal how buried interfaces impact phase segregation and long-term thermal stability.

🔹 Interface-Driven Stability: Our results draw a direct correlation between the initial crystal orientation—induced by the underlayer—and the resistance of the film to degradation under thermal stress.

This work provides valuable insights for designing more stable and efficient perovskite solar cells by engineering the buried interface to control crystal orientation from the very first stages of film formation.

📄 You can access the full article here:
https://doi.org/10.1039/D4TA03063B

Stay tuned for more research updates from our group!

#PerovskiteSolarCells #ThinFilmStability #JMaterChemA #InterfaceEngineering #EnergyMaterials #Photovoltaics #CrystalOrientation

The post Published Paper: The influence of the buried interface on the orientational crystallization and thermal stability of halide perovskite thin films first appeared on LNES.

We are proud to share that Professor Ana Flávia Nogueira (Unicamp), researcher and director of CINE – Center for Innovation on New Energies, was one of only 24 researchers worldwide — and the only representative from Latin America — selected for this recognition.

Professor Nogueira was honored as the corresponding author of the letter “In Situ PL Tracking of Halide Exchange at 3D/QD Heterojunction Perovskite Solar Cells” published in June 2023. The study, co-authored by several CINE members, highlights the use of perovskite quantum dots to enhance performance and minimize degradation in solar cells — a significant contribution to advancing solar energy technologies.

We invite you to read the inspiring testimonies of Professor Ana Flávia Nogueira and other remarkable female scientists who are shaping the future of clean energy research.

👉 Access the full article here: [Link to the article]

The post Prof. Ana Flávia Nogueira Featured Among Women Leaders in Clean Energy Research first appeared on LNES.

We are excited to announce the publication of our latest research paper in ACS Applied Materials & Interfaces, titled:

“2D Phase Formation on 3D Perovskite: Insights from Molecular Stiffness”

This study investigates the relationship between molecular stiffness and the formation of two-dimensional (2D) phases on three-dimensional (3D) perovskite films, offering valuable insights into enhancing both efficiency and stability in perovskite solar cells.

Key Highlights:

• 2D Phase Formation on Grain Boundaries: Using cathodoluminescence in scanning electron microscopy, we identified that the 2D phase forms predominantly on the grain boundaries of the 3D perovskite. This phenomenon offers an explanation for the passivation mechanisms that improve 3D perovskite film performance.
• Molecular Stiffness and Steric Hindrance: Through in situ grazing-incidence wide-angle X-ray scattering, we explored the role of organic cations with varying stiffness. The formation and crystallization of the 2D phase were found to be influenced by both steric hindrance around the ammonium group and the molecular rigidity of the cations.
• Efficiency Boost: Solar cells incorporating flexible cations in the 2D/3D perovskite heterointerface achieved a power conversion efficiency of 21.5%, underscoring the practical importance of molecular design in optimizing device performance.

This research enhances our understanding of the critical factors that govern the interaction between low-dimensional and 3D perovskites and their impact on solar cell efficiency.

You can read the full paper here.

Stay tuned for more updates from our group!

The post Published Paper: 2D Phase Formation on 3D Perovskite: Insights from Molecular Stiffness first appeared on LNES.

What Are Perovskite Solar Cells?

PSCs are a type of solar cell that uses perovskite-structured materials as the light-harvesting active layer. These materials are known for their excellent light absorption and charge-carrier mobilities, making them highly efficient at converting sunlight into electricity. However, PSCs are notoriously unstable when exposed to environmental factors like moisture and heat.

The Role of Quantum Dots

Quantum dots are tiny semiconductor particles that have unique electronic properties due to their small size. When integrated with bulk (3D) perovskites, QDs can passivate, or stabilize, the interfaces of the perovskite material, reducing defects and improving overall stability.

The Study: Tracking Halide Exchange

The research team focused on the halide exchange reaction at the heterojunction—the interface where the QDs and 3D perovskites meet. Using in situ photoluminescence (PL), they tracked the bromide-to-iodide exchange process. This exchange is crucial because it helps passivate surface defects and grain boundaries in the perovskite material.

Key Findings

1. Activation Energy and Passivation: The study determined the activation energy required for the bromide-to-iodide exchange. This process effectively passivates the surface defects and grain boundaries in the perovskite material.
2. Energy Level Realignment: When applied in solar cells, the QDs help realign energy levels, enhancing hole extraction and blocking unwanted electron transfer. This leads to reduced charge carrier recombination and higher efficiency.
3. Stability Under Stress: The researchers found that the halide composition at the interface remains stable even under thermal stress. Additionally, the hydrophobic nature of the QDs’ ligands prevents moisture from penetrating the perovskite films.

Implications for Solar Technology

The strategic incorporation of QDs into PSCs not only improves their efficiency but also significantly enhances their durability against environmental factors. This advancement could pave the way for more reliable and long-lasting perovskite solar cells, bringing us closer to widespread adoption of this cutting-edge photovoltaic technology.

This study highlights a crucial step forward in the quest to develop stable, efficient, and durable perovskite solar cells, showcasing the potential of nanomaterials to revolutionize solar energy.

Access the published paper

The post Published Paper: In Situ PL Tracking of Halide Exchange at 3D/QD Heterojunction Perovskite Solar Cells first appeared on LNES.

What Are Chiral 2D Perovskites?

Chiral 2D perovskites are layered materials with unique optical and electronic properties, making them ideal for devices that manipulate light and electron spin. These materials incorporate chiral organic cations, which give them their distinctive properties.

The Challenge: Film Formation and Crystallization

A major challenge in using chiral 2D perovskites is understanding and controlling how they form films and crystallize. When chiral ammonium-based organic cations, such as methylbenzylammonium (MBA), are used, they can interact with the halide species in the perovskite network, causing steric hindrance. This often leads to the formation of one-dimensional (1D) phase impurities within the 2D matrix, which adversely affect the material’s optical properties.

Key Findings: Tackling the 1D Phase Impurities

1. Manifestation in Photoluminescence: The study found that these 1D phase impurities manifest as an additional, weakly emissive, thermally activated state in the PL spectra of the 2D perovskite film. This state has a self-trapped excitonic character, resulting in an asymmetric PL response.
2. Role of Molecular Design By strategically introducing a methoxy (OMe) group at the para position of the MBA cations, the researchers were able to mitigate the formation of the 1D phase impurities. This modification led to a narrower and more symmetric emission band, and significantly higher PL quantum yield at room temperature.
3. Implications for Optical Properties: The findings highlight the importance of molecular design in controlling the phase purity and optical properties of chiral 2D perovskites. By fine-tuning the structure of the organic cations, it is possible to achieve the desired photoluminescence characteristics, making these materials more suitable for practical applications.

Impact on Future Technologies

This research provides a deeper understanding of the factors influencing the PL properties of chiral 2D perovskites. The ability to control these properties through molecular design opens up new possibilities for developing high-performance spintronic and chiroptical devices. The study demonstrates that careful molecular engineering can overcome challenges related to film formation and crystallization, paving the way for more efficient and stable perovskite-based technologies.

By elucidating the origins of asymmetry and broadband emission in MBA-based chiral 2D perovskites, this study marks a significant step forward in the field, underscoring the vital role of tailored organic cations in achieving optimal material performance.

Access the published paper

The post Published Paper: Understanding and Controlling the Photoluminescence Line Shapes of 2D Perovskites with Chiral Methylbenzylammonium-Based Cations first appeared on LNES.