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Development of an Aluminum Titanate-Based Nanocomposite for Interfacial Engineering of the TiO2 Electron Transport Layer/Perovskite Interface in Perovskite Solar Cells

Vahedi, Maziar | 2026

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 58861 (07)
  4. University: Sharif University of Technology
  5. Department: Materials Science and Engineering
  6. Advisor(s): Madaah Hosseini, Hamid Reza; Khachatourian, Adrine Malek
  7. Abstract:
  8. Perovskite solar cells (PSCs) are an attractive photovoltaic technology because they combine excellent optoelectronic properties with low-cost fabrication and compatibility with flexible substrates, but their performance and long-term stability are still strongly limited by interfacial losses at the TiO2 electron transport layer (ETL)/perovskite junction, where trap states, non-radiative recombination, and added resistive losses hinder simultaneous gains in efficiency and durability. In response, this study introduces a focused interfacial-engineering strategy that uses a novel semiconducting modifier as a discontinuous, island-like interlayer. To realize this concept, an aluminum titanate-based nanocomposite was synthesized and optimized by adjusting the calcination temperature: X-ray diffraction (XRD) showed that higher calcination temperatures increase crystallinity, accelerate the anatase-to-rutile transformation of TiO2, and ultimately result in rutile and corundum becoming dominant at elevated temperatures, while diffuse reflectance spectroscopy (DRS) revealed a non-linear evolution of the optical indirect bandgap together with reduced sub-bandgap disorder as temperature increased; meanwhile, field-emission scaaning electron microscopy (FESEM) captured the associated morphological evolution and improved interparticle connectivity, and X-ray photoelectron spectroscopy (XPS) confirmed the presence of Ti4+ and Al3+ along with their expected bonding environments. Guided by these material characteristics, the optimized nanocomposite was then implemented in a triple-cation, carbon-electrode-based PSC configuration, where FESEM and AFM verified that the modifier forms a discontinuous, island-like interlayer at the ETL/perovskite interface and is accompanied by improved perovskite film quality; consistent with this, FESEM and XRD of the perovskite layer indicated more uniform grain growth and enhanced crystallinity, and PL plus UV-Vis measurements supported suppressed recombination, while electrical diagnostics (dark J-V and resistance parameters extracted from J-V curves) pointed to reduced recombination-related losses and more efficient charge extraction. As a result, the best device, modified with the nanocomposite calcined at 700 °C, improved its power conversion efficiency from 13.47% (control) to 16.37%, with VOC increasing from 1.02 to 1.07 V and FF rising from 0.61 to 0.68, and maximum power point tracking further showed a drop in normalized power loss from about 14% to about 10% after roughly 700 s. Overall, by designing and optimizing an aluminum titanate-based nanocomposite and applying it as an interfacial modifier between the TiO2 ETL and the perovskite absorber, this work offers a practical route to reduce trap- and recombination-driven interfacial losses, strengthen charge extraction, and boost device performance
  9. Keywords:
  10. Aluminum Titanate ; Perovskite-Based Solar Cell ; Electron Transporting Layer ; Interfacial Engineering ; Field Emission Scanning Electron Microscopy (FESEM)

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