Pure-red PeLEDs are indispensable for high-definition displays and advanced imaging technologies due to their specific emission wavelength and color fidelity. However, these devices often suffer from significant efficiency roll-off when driven under high current densities—a phenomenon that dramatically reduces their luminous output and hampers practical applications. The research team addressed this challenge by meticulously probing the underlying mechanisms that trigger efficiency decline. Employing an innovative technique known as electrically excited transient absorption spectroscopy, they directly observed the dynamic processes of charge carriers within working devices, identifying hole leakage as a critical source of efficiency loss.

This insightful discovery prompted the team to engineer a heterostructure inside the perovskite grains themselves. Traditionally, 3D CsPbI₃₋ₓBrₓ perovskites have exhibited excellent carrier mobility but lacked sufficient confinement for injected carriers, resulting in inefficiencies under operational conditions. The newly developed intragrain heterostructure cleverly integrates narrow bandgap emitter domains surrounded by wide bandgap barrier regions. This architecture effectively confines both electrons and holes, preventing undesirable leakage and non-radiative recombination pathways, which are prevalent in conventional homogenous perovskite films.

Achieving this heterostructure required a sophisticated chemical strategy to manipulate the perovskite lattice. The researchers introduced strongly bonding molecules into the [PbX₆]⁴⁻ octahedral framework. These molecules expanded the lattice of the 3D CsPbI₃₋ₓBrₓ perovskite, thereby creating wide bandgap barriers. Such lattice engineering is a subtle yet powerful approach: by tailoring the local electronic structure without compromising the material’s intrinsic transport properties, the team successfully established spatial carrier confinement within single grains, a feat rarely accomplished in perovskite LED technology.

The impact of this design is profound. The resulting pure-red PeLEDs demonstrated a record-high brightness level of 24,600 cd m⁻² and a maximum external quantum efficiency (EQE) of 24.2%. More impressively, these devices exhibited remarkably low efficiency roll-off, maintaining an EQE of 10.5% even at an ultra-high luminance of 22,670 cd m⁻². Such performance metrics represent a significant leap forward compared to previous iterations of CsPbI₃₋ₓBrₓ based PeLEDs, which often suffered from rapid efficiency degradation beyond moderate luminance levels.

Beyond the sheer performance enhancements, the study highlights the vital role of intragrain nanostructuring in perovskite optoelectronics. By conceptualizing the emitter material as a heterostructured entity rather than a uniform lattice, researchers can finely tune the balance between charge injection, recombination, and leakage. This paradigm shift could inspire a wave of new material designs not only for LEDs but also for related applications such as laser diodes and photodetectors where carrier management is critical.

The refinement of carrier dynamics within crystalline grains further underscores the versatility of perovskite materials. Unlike traditional semiconductor heterostructures, often fabricated using complex epitaxial growth techniques, the molecular engineering approach demonstrated here offers a scalable and potentially low-cost route to heterostructured emitters. The chemical versatility inherent to perovskite frameworks allows for precise adjustments in lattice parameters and band alignments, unlocking functional architectures tailored to specific device requirements.

From a broader perspective, this work addresses one of the fundamental challenges in perovskite optoelectronics: how to reconcile the trade-off between device brightness and efficiency stability. High brightness often comes at the expense of efficiency due to the exacerbated influence of non-radiative pathways at elevated currents. By confining carriers and suppressing leakage-induced losses intrinsically within the grain structure, the newly engineered heterostructured perovskites break this trade-off, enabling devices that can operate at both high brightness and high efficiency.

The implications for display technology are especially exciting. Pure-red LEDs with such luminance and efficiency parameters can contribute to displays with wider color gamuts, improved energy efficiency, and better long-term stability. The progress demonstrated here brings perovskite-based displays tantalizingly close to commercialization, offering a competitive alternative to incumbent technologies such as organic LEDs and quantum dots.

Additionally, the methodological advances, particularly the use of electrically excited transient absorption spectroscopy, provide a powerful toolset for in situ characterization of operating devices. This technique enables researchers to visualize real-time carrier dynamics and uncover loss mechanisms that are otherwise challenging to diagnose. Such insights are essential for iterating material design and device architectures rapidly.

Future research building on this foundation is likely to explore the integration of similar heterostructures with other perovskite compositions and device configurations. Optimizing the molecular species used to modify the lattice, exploring different dimensionalities, and enhancing the stability under operational stress are promising avenues. The principle of intragrain heterostructuring could also be extended towards multicolor emission and white light generation by carefully engineering band alignments and charge distributions.

In conclusion, the work by Song, YH., Li, B., Wang, ZJ., and colleagues marks a significant milestone in the quest for high-performance red perovskite LEDs. Their elegant combination of transient spectroscopy insights and lattice engineering has unlocked a unique pathway to devices featuring ultra-high brightness combined with exceptional efficiency and stability. This breakthrough promises to accelerate the adoption of perovskite LEDs in commercial applications and inspires a new phase of materials innovation across the optoelectronics domain.

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Subject of Research: Metal-halide perovskite materials and their application in high-performance pure-red perovskite LEDs.

Article Title: Intragrain 3D perovskite heterostructure for high-performance pure-red perovskite LEDs.

Article References:
Song, YH., Li, B., Wang, ZJ. et al. Intragrain 3D perovskite heterostructure for high-performance pure-red perovskite LEDs. Nature 641, 352–357 (2025). https://doi.org/10.1038/s41586-025-08867-6

Image Credits: AI Generated

DOI: https://doi.org/10.1038/s41586-025-08867-6

The exploration of organic and inorganic interactions in hybrid perovskites has historically centered on the well-trodden territory of hydrogen bonding. Guanjun Xiao, the lead researcher of the study, pointed out that past investigations mainly focused on how these hydrogen interactions influence the material’s photophysical properties. However, the absence of dedicated exploration into non-hydrogen-bonded hybrid perovskites has constituted a significant hurdle in the precise design of materials tailored for specific optical characteristics. This new study stands as a pivotal point in expanding the understanding of interaction mechanisms that play a critical role in the performance of these materials.

To probe this uncharted territory, Xiao and his team deployed high-pressure engineering as a means to investigate the specific sites in non-hydrogen-bonded hybrid perovskite, specifically the compound known as (DBU)PbBr3. Through the application of high pressure, the researchers were able to elucidate that the spatial arrangement of bromine (Br) and nitrogen (N) atomic pairs significantly shapes the organic-inorganic interactions present within the material. This important finding is expected to guide the design and development of next-generation materials by enabling the optimization of their optical properties.

This study was recently published on September 16 in the journal “Research,” which is the inaugural Science Partner Journal launched by the American Association for the Advancement of Science (AAAS) in collaboration with the China Association for Science and Technology (CAST). The publication underscores the shift towards collaborative research endeavors that harness diverse expertise to tackle the pressing scientific challenges of our time. Guanjun Xiao, serving as a professor in the State Key Laboratory of Superhard Materials at Jilin University, spearheaded this significant research effort.

In the course of their research, the Jilin team successfully synthesized microrods of (DBU)PbBr3 utilizing the hot injection method. This state-of-the-art synthetic approach laid the groundwork for systematic investigations into the material’s high-pressure optical and structural properties. Intriguingly, as pressure was applied, the researchers detected a remarkable enhancement in the material’s emission alongside a blue shift, culminating in an impressive photoluminescence quantum yield of 86.6% at 5.0 GPa. This discovery suggests that the photophysical characteristics of the material can be remarkably improved through the strategic manipulation of pressure.

Further elucidating the material’s behavior, the team conducted photoluminescence lifetime measurements that indicated a suppression of non-radiative recombination processes under high pressure conditions. This suppression is critical as it enhances the efficiency of light emission, thereby showcasing the potential of pressure engineering as a means to elevate the performance of photonic materials. The researchers also observed an anomalously enhanced Raman mode corresponding with the pressure range in which emission enhancement occurred, suggesting a compelling link between these two phenomena.

Through meticulous analysis, the researchers delved deep into the origin of the Raman mode and identified it as being associated with the interactions between the organic and inorganic components, particularly related to N-Br interactions. This understanding of the relationship between these interactions paves the way for further investigations and optimizations of hybrid perovskite materials.

Additionally, the study explored the structural evolution of (DBU)PbBr3 under varying pressures, complemented by first principles calculations. These calculations revealed that the primary determinants affecting interaction strength were the spatial configurations of nitrogen and bromine atoms—including their distances and dihedral angles. Importantly, the research identified an isostructural phase transition occurring at 5.5 GPa, a pivotal moment that altered the evolutionary path of the material.

Xiao articulated that the transition indicated a significant turning point where the interaction strength between organic and inorganic components initially escalated with increased pressure, only to eventually decline. This phenomenon aligned with the observed evolution of the material’s optical properties, underscoring the intricate balance between structural attributes and optical performance within non-hydrogen-bonded hybrid perovskites.

By bridging these vital gaps in knowledge regarding organic-inorganic interactions in hybrid halides, this research offers invaluable guidance for the future design of materials that are specifically tailored for their intended optical functionalities. In a landscape increasingly dominated by the quest for advanced materials with precise properties, this study sets the stage for subsequent innovations in the field of hybrid perovskites.

Thus, the findings presented by Xiao and his team not only enhance our scientific understanding but also promise to influence the trajectory of materials science moving forward. The interplay between high pressure and material behavior highlights a powerful tool at researchers’ disposal—a tool that could facilitate unprecedented advances in optical material design.

Subject of Research: Non-hydrogen-bonded hybrid metal perovskites
Article Title: Identifying Organic–Inorganic Interaction Sites Toward Emission Enhancement in Non-Hydrogen-Bonded Hybrid Perovskite via Pressure Engineering
News Publication Date: 16-Sep-2024
Web References: Research DOI
References: Not applicable
Image Credits: Not applicable

Keywords

organic-inorganic interactions, hybrid perovskites, pressure engineering, photoluminescence, material design, Jilin University, Guanjun Xiao, structural properties, optical properties, Raman mode, (DBU)PbBr3