Functional Materials Research

Freestanding ferroelectric films—ultrathin material layers liberated from rigid substrates—represent a paradigm shift in functional materials. By decoupling from lattice-mismatched substrates, these films exhibit enhanced polarization, strain tolerance, and unprecedented design flexibility. Their importance lies in enabling transparent, lightweight, and mechanically robust devices, overcoming traditional limitations of bulk ceramics or substrate-clamped thin films. This breakthrough is particularly crucial for applications demanding conformability, such as wearable tech and curved displays, where conventional materials fail.

Beyond flexibility, freestanding films unlock innovations in energy storage (higher breakdown fields), electrocaloric cooling (efficient ΔT), and sensors (ultra-high sensitivity). Our work focuses on polymer-assisted transfer techniques to create large-area films with 70% optical transparency, as well as HfO₂- and PZT-based heterostructures for integrated nanoelectronics. These advances pave the way for self-powered wearable devices, adaptive optics, and bio-compatible medical sensors—all while minimizing lead content and environmental impact.

This work is currently being carried out under the DST Ramahuna Fellowship.

Hafnium oxide (HfO₂) thin films have revolutionized ferroelectrics by enabling scalable, silicon-compatible memory and cooling devices. Unlike traditional perovskites, HfO₂ integrates seamlessly with CMOS processes, making it ideal for next-generation nanoelectronics. However, achieving stable ferroelectricity in HfO₂ requires overcoming the "wake-up effect"—a major hurdle for device reliability.

Our work addresses this through oxygen-engineering strategies that induce wake-up-free ferroelectricity in Y-doped HfO₂ (Y:HfO₂) films. Key breakthroughs include:

• Direct growth of polar phases via multi-step annealing (eliminating initialization cycles).

• Record electrocaloric cooling (ΔT = 24.8 K) for on-chip thermal management.

• Transparent capacitors on FTO/glass (>70% visible-light transmission) for flexible displays.

These advances, published in Advanced Materials and Energy & Environmental Science, demonstrate HfO₂’s potential for low-power memory, solid-state refrigeration, and transparent electronics.

Journal of Materials Chemistry A (IF 10.8) DOI  | Advanced Materials Interfaces (IF 4.3) DOI   | Journal of Alloys and Compounds (IF 5.8)  DOI 

Lead zirconate titanate (PZT) and its doped variants (PLZT, PZTH) remain the gold standard for high-performance ferroelectrics, but optimizing their properties demands precise compositional control. Through successive multiple doping—sequentially introducing La, Nb, and Fe into the PZT lattice—we engineered materials with:

• Enhanced polarization (up to 45 μC/cm²).

• Giant electrocaloric effect (ΔT > 12 K).

• Tunable bandgaps (2.8–3.2 eV) for optoelectronic compatibility.

Our patented Double Atmospheric Layer Sintering Method (IN 364983) minimized lead loss while achieving 95% density, critical for industrial adoption. These advances, published, enable:

• High-efficiency energy storage (150 J/cm³).

• Solid-state cooling for microelectronics.

• UV-tolerant sensors for harsh environments.

Journal of Materials Science (IF 3.5) | DOI  | Vacuum (IF 3.8) | DOI  | Vacuum (IF 3.8) | DOI  | Discover Applied Sciences (IF 2.8, 2025) | DOI