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Nitrogen fertilization can promote rice yield but decrease resistance to sheath blight (ShB). In this study, the nitrate transporter 1.1b ( nrt1.1b ) mutant that exhibited less susceptibility to ShB but without compromising yield under NH 4 + fertilization was screened. NRT1.1B's regulation of ShB resistance was independent of the total nitrogen concentration in rice under NH 4 + conditions. In nrt1.1b mutant plants, the NH 4 + application modulated auxin signaling, chlorophyll content, and phosphate signaling to promote ShB resistance. Furthermore, the findings indicated that NRT1.1B negatively regulated ShB resistance by positively modulating the expression of H + -ATPase gene OSA3 and phosphate transport gene PT8 . The mutation of OSA3 and PT8 promoted ShB resistance by increasing the apoplastic pH in rice. Our study identified the ShB resistance mutant nrt1.1b , which maintained normal nitrogen use efficiency without compromising yield.

Two-dimensional transition metal dichalcogenides (TMDs) possess large second-order optical nonlinearity, making them ideal candidates for miniaturized on-chip frequency conversion devices, all-optical interconnection, and optoelectronic integration components. However, limited by subnanometer thickness, the monolayer TMD exhibits low second harmonic generation (SHG) conversion efficiency (<0.1%) and poor directionality, which hinders their practical applications. Herein, we proposed a Fabry-Pérot (F-P) cavity formed by coupling an atomically thin WS 2 film with a silicon hole matrix to enhance the SH emission. A maximum enhancement (∼1580 times) is achieved by tuning the excitation wavelength to be resonant with the microcavity modes. The giant enhancement is attributed to the strong electric field enhancement in the F-P cavity and the oscillator strength enhancement of excitons from suspended WS 2 . Moreover, directional SH emission (divergence angle ∼5°) is obtained benefiting from the resonance of the F-P microcavity. Our research results can provide a practical sketch to develop both high-efficiency and directional nonlinear optical devices for silicon-based on-chip integration optics.

Perovskite micro/nanostructures have recently emerged as a highly attractive gain material for nanolasers. To explore their applications and further improve performance, it is essential to understand the optical gain and the anisotropic properties. Herein, we obtained high quality CsPbBr 3 microplatelets (MP) with anisotropic orthorhombic phase. Optical gain of CsPbBr 3 single crystal MP was investigated via microscale variable stripe-length measurement. A polarization-dependent optical gain was observed, and the gain along [002] was larger than that of [1-10]. The behavior was attributed to the lowest energy transition dipole moment of [002] induced by the smaller deviation of Br-Pb-Br bond from the perfect lattice. Along the [002] direction, we obtained the optical gain value up to 5077 cm -1 , which is the record value ever reported. Moreover, all optical switching of lasing is realized by periodical polarized excitation. Our results provide new perceptions in the design of novel functional anisotropic devices based on perovskite micro/nanostructures.

Here, we report on a new kind of compound, X δ Ir 4 X 12-δ (X = P, As), the first hole-doped skutterudites superconductor. We provide atomic-resolution images of the caging As atoms using scanning transmission electron microscopy (STEM). By inserting As atoms into the caged structure under a high pressure, superconductivity emerges with a maximum transition temperature ( T c ) of 4.4 K (4.8 K) in IrAs 3 (IrP 3 ). In contrast to all of the electron-doped skutterudites, the electronic states around the Fermi level in X δ Ir 4 X 12-δ are dominated by the caged X atom, which can be described by a simple body-centered tight-binding model, implying a distinct pairing mechanism. Our density functional theory (DFT) calculations reveal an intimate relationship between the pressure-dependent local-phonon mode and the enhancement of T c . The discovery of X δ Ir 4 X 12-δ provides an arena to investigate the uncharted territory of hole-doped skutterudites, and the method proposed here represents a new strategy of carrier doping in caged structures, without introducing extra elements.

Colloidal CdSe nanoplatelets (NPLs) have substantial potential in light-emitting applications because of their quantum-well-like characteristics. The self-trapped state (STS), originating from strong electron-phonon coupling (EPC), is promising in white light luminance because of its broadband emission. However, achieving STS in CdSe NPLs is extremely challenging because of their intrinsic weak EPC nature. Herein, we developed a strong STS emission in the spectral range of 450-600 nm by building superlattice (SL) structures with colloidal CdSe NPLs. We demonstrated that STS is generated via strong coupling of excitons and zone-folded longitudinal acoustic phonons with formation time of ∼450 fs and localization length of ∼0.56 nm. The Huang-Rhys factor, describing the EPC strength in SL structure, is estimated to be ∼19.9, which is much larger than that (∼0.1) of monodispersed CdSe NPLs. Our results provide an in-depth understanding of STS and a platform for generating and manipulating STS by designing SL structures.

Single-crystal perovskites with excellent photophysical properties are considered to be ideal materials for optoelectronic devices, such as lasers, light-emitting diodes and photodetectors. However, the growth of large-scale perovskite single-crystal films (SCFs) with high optical gain by vapor-phase epitaxy remains challenging. Herein, we demonstrated a facile method to fabricate large-scale thin CsPbBr 3 SCFs (∼300 nm) on the c -plane sapphire substrate. High temperature is found to be the key parameter to control low reactant concentration and sufficient surface diffusion length for the growth of continuous CsPbBr 3 SCFs. Through the comprehensive study of the carrier dynamics, we clarify that the trapped-related exciton recombination has the main effect under low carrier density, while the recombination of excitons and free carriers coexist until free carriers plays the dominate role with increasing carrier density. Furthermore, an extremely low-threshold (∼8 μJ cm -2 ) amplified spontaneous emission was achieved at room temperature due to the high optical gain up to 1255 cm -1 at a pump power of 20 times threshold (∼20 P th ). A microdisk array was prepared using a focused ion beam etching method, and a single-mode laser was achieved on a 3 μm diameter disk with the threshold of 1.6 μJ cm -2 . Our experimental results not only present a versatile method to fabricate large-scale SCFs of CsPbBr 3 but also supply an arena to boost the optoelectronic applications of CsPbBr 3 with high performance.

Perovskite and chalcogenide quantum dots (QDs) are important nano semiconductors. It has been a challenge to synthesize heterostructural QDs combining perovskite and chalcogenide with tailorable photoelectronic properties. In this report, heterostructural CsPbX 3 -PbS (X = Cl, Br, I) QDs were successfully synthesized via a room temperature in situ transformation route. The CsPbX 3 -PbS QDs show a tunable dual emission feature with the visible and near-infrared (NIR) photoluminescence (PL) corresponding to CsPbX 3 and PbS, respectively. Typically, the formation and evolution of the heterostructural CsPbBr 3 -PbS QDs with reaction time was investigated. Femtosecond transient absorption spectroscopy (TAS) was applied to illuminate the exciton dynamics in CsPbBr 3 -PbS QDs. The mild synthetic method and TAS proved perovskite to PbS energy transfer may pave the way toward highly efficient QD photovoltaic and optoelectronic devices.