Halide Double Perovskites for Optoelectronic Applications

Halide double perovskites, typified by the A₂B′B″X₆ structure (where A is a monovalent cation such as Cs⁺ or MA⁺; B′ and B″ are heterovalent metals; and X is a halide), have emerged as promising lead-free alternatives for light-harvesting and light-emitting devices. Their ordered rock-salt arrangement of B′ and B″ sites affords greater structural stability than lead halide analogues, while compositional flexibility enables bandgap tuning from the visible to near-infrared. Key challenges include inherently indirect bandgaps, moderate charge-carrier mobilities and sub-optimal photoluminescence efficiencies. Recent advances in lattice engineering—through hydrogenation, heterovalent substitution and cation disorder—have progressively narrowed bandgaps, enhanced carrier lifetimes and improved optoelectronic performance. These materials now show real promise for photovoltaic cells, light-emitting diodes, photodetectors and photocatalysis, combining environmental benignity with scalable synthesis and operational stability under ambient conditions.

Research from Nature Portfolio

Recent studies have demonstrated that post-synthetic hydrogenation of Cs₂AgBiBr₆ films can modulate the bandgap from 2.18 eV down to 1.64 eV by interstitial incorporation of atomic hydrogen. This approach not only lowers the optical onset but also optimises conduction-band alignment, resulting in a record photoelectric conversion efficiency of 6.37 % for hydrogenated films. Concurrent improvements in carrier mobility and microsecond-scale lifetimes yield enhanced charge extraction and environmental robustness, marking a significant step towards high-performance, lead-free perovskite solar cells.

Halide Double Perovskites for Optoelectronic Applications publication trend

The graph below shows the total number of articles in halide double perovskites for optoelectronic applications across all publications each year (not limited to Nature Index journals).

Technical terms

Halide double perovskite: A lead-free perovskite variant with ordered B′ (monovalent) and B″ (trivalent) metal sites in an A₂B′B″X₆ lattice, offering structural stability and compositional flexibility.

Bandgap: The energy difference between the valence-band maximum and conduction-band minimum that determines light absorption and emission wavelengths.

Photoluminescence quantum yield (PLQY): The ratio of emitted photons to absorbed photons, a measure of emissive efficiency in luminescent materials.

Charge-carrier lifetime: The average time that an excited electron or hole remains mobile before recombination, critical for device performance.

References

1. Data driven high quantum yield halide perovskite phosphors design and fabrication. Materials Today (2024).
2. Conduction Band Tuning by Controlled Alloying of Fe into Cs2AgBiBr6 Double Perovskite Powders. Advanced Functional Materials (2023).
3. Can Pb-Free Halide Double Perovskites Support High-Efficiency Solar Cells?. ACS Energy Letters (2016).
4. Lead-Free Halide Double Perovskite Materials: A New Superstar Toward Green and Stable Optoelectronic Applications. Nano-Micro Letters (2019).
5. Hydrogenated Cs2AgBiBr6 for significantly improved efficiency of lead-free inorganic double perovskite solar cell. Nature Communications (2022).