Engineering Lattice Asymmetry via a Cs+‐Triggered Domino Effect for Ultra‐Broadband Visible Emission From a Single Sb3+ Luminophore

Why It Matters

The discovery provides a scalable, lead‑free route to efficient broadband light sources, accelerating the adoption of perovskite‑based LEDs and display technologies.

Key Takeaways

• Cs+ induces structural domino effect in layered perovskite.
• Lattice asymmetry creates two distinct InCl6 octahedra.
• Sb3+ doping yields ultra-broadband visible photoluminescence.
• Dual-site distortion modulates emission spectrum.
• Strategy offers lead‑free broadband luminescent materials.

Pulse Analysis

Lead‑free perovskite optoelectronics have long grappled with the challenge of delivering efficient, ultra‑broadband emission without resorting to toxic lead compounds. Traditional approaches rely on mixed‑phase systems or complex alloying, which often compromise stability and color purity. The recent introduction of a cesium‑triggered domino effect in a 2D perovskite framework represents a paradigm shift, leveraging B‑site chemistry to engineer lattice asymmetry directly within a single‑phase material. This strategy sidesteps the need for extrinsic co‑dopants, simplifying synthesis while maintaining the intrinsic advantages of perovskite crystals, such as high absorption coefficients and facile solution processing.

At the atomic level, the close‑packed CsCl9 8‑ prism forces adjacent chloride anions to engage with the biprotanated cystamine ligands, creating an uneven charge‑balancing environment. The resulting distortion splits the indium chloride octahedra into two inequivalent sites, each responding differently to Sb3+ incorporation. When antimony occupies these sites, its 5s2 lone‑pair electrons interact with the distorted lattice, generating a cooperative dual‑site emission pathway that spans the entire visible spectrum. This distortion‑modulated mechanism not only broadens the photoluminescence bandwidth but also enhances radiative efficiency under mild excitation, addressing a critical bottleneck for practical device integration.

The implications extend beyond academic curiosity. Ultra‑broadband emitters are essential for next‑generation solid‑state lighting, full‑color displays, and optical communication components that demand wide spectral coverage. By demonstrating that B‑site‑driven phase transitions can unlock such performance in a lead‑free matrix, the study opens avenues for scalable manufacturing of environmentally benign light‑emitting diodes. Future research will likely explore the tunability of the domino effect across different halide chemistries and organic spacers, aiming to tailor emission profiles for specific commercial applications while preserving the material’s structural robustness.