Wenhao Shao

While the photoluminescence of (Et ₂ NH ₂ ) ₃ SbCl ₆ is diminished by thermal quenching and FRET, Sb ³⁺ doping of the (Et ₂ NH ₂ ) ₃ InCl ₆ phase performed by three distinct approaches (solution, melting–cooling, and solid state) improved PLQYs up to 86%.

Quasi-2D tin iodide perovskites (TIPs) are promising lead-free alternatives for optoelectronic applications, but achieving stable lasing remains challenging due to their limited environmental stability. Here, we report air-stable, room-temperature lasing from quasi-2D TIP microcrystals as small as 4 μm. Incorporation of the organic spacer 5IPA3 significantly enhanced the stability of these materials compared with previously reported TIPs. Lasing was observed from both dielectric (n = 4) and plasmonic (n = 3 and n = 4) TIP microlasers. Under picosecond pumping, lasing was sustained for over 10⁸ pump pulses in ambient conditions. These results represent a significant step toward practical photonic applications of tin-based perovskites.

Room-temperature lasing is a key milestone in the development of miniaturized optoelectronic and photonic devices. We present a simple approach to synthesize phase-pure quasi-2D layered tin perovskite nanowires with varying quantum well thicknesses (n = 1 to 4). By incorporating a new organic spacer capable of forming a hydrogen-bonded organic framework, this method promoted anisotropic crystal growth and enhanced lattice rigidity. Furthermore, introducing molecular intercalants enabled controlled crystallization into well-defined nanowires that function as Fabry-Pérot cavities. Cavities made from n = 2 to 4 perovskites support efficient and robust near-infrared, room-temperature optically pumped lasing with the threshold as low as 75.8 μJ/cm², cavity quality factor over 3000, and negligible degradation over 10⁶ pulses. A cleaved coupled nanolaser was fabricated as a proof-of-concept device for photonic applications.

Metal organic chalcogenides (MOCs) are an emerging class of two-dimensional (2D) materials featuring tunable band gaps and strong light-matter interactions with great potential for optical and polaritonic applications. Lead organic chalcogenides (LOCs) stand out among MOCs for sustaining long-lived coherent optical phonons despite their distorted lattices. However, the strong electron-phonon coupling also leads to rapid charge carrier self-trapping, hindering carrier transport. Herein, we demonstrate that charge carrier self-trapping is suppressed in Se- and Te-based LOCs. Specifically, the expansive Se and Te orbitals give rise to more dispersive conduction bands and reduced electron effective masses, thereby mitigating carrier self-trapping. As a result of reduced carrier self-trapping, the Se- and Te-based LOCs exhibit enhanced band-to-band photoluminescence and improved charge transport performance. Our results provide a synthetic route to Se- and Te-based LOC single crystals and demonstrate the potential of orbital engineering to tune their electronic and phononic properties.

Metal halide perovskites show promise for next-generation light-emitting diodes, particularly in the near-infrared range, where they outperform organic and quantum-dot counterparts. However, they still fall short of costly III-V semiconductor devices, which achieve external quantum efficiencies above 30% with high brightness. Among several factors, controlling grain growth and nanoscale morphology is crucial for further enhancing device performance. This study presents a grain engineering methodology that combines solvent engineering and heterostructure construction to improve light outcoupling efficiency and defect passivation. Solvent engineering enables precise control over grain size and distribution, increasing light outcoupling to ~40%. Constructing 2D/3D heterostructures with a conjugated cation reduces defect densities and accelerates radiative recombination. The resulting near-infrared perovskite light-emitting diodes achieve a peak external quantum efficiency of 31.4% and demonstrate a maximum brightness of 929 W sr⁻¹ m⁻². These findings indicate that perovskite light-emitting diodes have potential as cost-effective, high-performance near-infrared light sources for practical applications.

Efficient light generation from triplet states of organic molecules has been a hot yet demanding topic in academia and the display industry. Herein, we propose a strategy for developing triplet emitter by creating heterostructures of organic chromophores and transition metal dichalcogenides (TMDs). These heterostructures emit microsecond phosphorescence at room temperature, while their organic chromophores intrinsically exhibit millisecond phosphorescence under vibration dissipation-free conditions. This enhancement in phosphorescence is indicative of significantly enhanced spin-orbit coupling efficiency through coupling with TMDs. Through detailed studies on these hybrids from various perspectives, we elucidate key features of each component essential for generating microsecond triplet emission, including 2H-TMDs with heavy transition metals and aromatic carbonyl with an ortho-hydroxy group. Our intriguing findings open avenues for exploring the universal applicability of fast and stable hybrid triplet emitters.