다중혈관 관상동맥 환자에서 y-문합을 이용하여 양쪽 내흉동맥만을 사용한 우회술의 조기 성적

[신간의 별자리x] 우리/미술, 그리고 ‘슬픔의 박물관’

The three-dimensional (3D) patterning of semiconductors is potentially important for exploring new functionalities and applications in optoelectronics1,2. Here, we show that it is possible to write on demand 3D patterns of perovskite quantum dots (QDs) inside a transparent glass material using a femtosecond laser. By utilizing the inherent ionic nature and low formation energy of perovskite, highly luminescent CsPbBr3 QDs can be reversibly fabricated in situ and decomposed through femtosecond laser irradiation and thermal annealing. This pattern of writing and erasing can be repeated for many cycles, and the luminescent QDs are well protected by the inorganic glass matrix, resulting in stable perovskite QDs with potential applications such as high-capacity optical data storage, information encryption and 3D artwork. Luminescent CsPbBr3 quantum dots can be written into glass using femtosecond laser pulses and thermal annealing, and erased by further femtosecond laser irradiation. The resulting quantum dot patterns could prove useful for data storage, decoration or security purposes.

Reversible 3D laser printing of perovskite quantum dots inside a transparent medium

Metal halide perovskites (MHPs) have been a hot research topic due to their facile synthesis, excellent optical and optoelectronic properties, and record-breaking efficiency of corresponding optoelectronic devices. Nowadays, the development of miniaturized high-performance photodetectors (PDs) has been fueling the demand for novel photoactive materials, among which low-dimensional MHPs have attracted burgeoning research interest. In this report, the synthesis, properties, photodetection performance, and stability of low-dimensional MHPs, including 0D, 1D, 2D layered and nonlayered nanostructures, as well as their heterostructures are reviewed. Recent advances in the synthesis approaches of low-dimensional MHPs are summarized and the key concepts for understanding the optical and optoelectronic properties related to the PD applications of low-dimensional MHPs are introduced. More importantly, recent progress in novel PDs based on low-dimensional MHPs is presented, and strategies for improving the performance and stability of perovskite PDs are highlighted. By discussing recent advances, strategies, and existing challenges, this progress report provides perspectives on low-dimensional MHP-based PDs in the future.

Low-Dimensional Metal Halide Perovskite Photodetectors.

Highly efficient blue-emitting three-dimensional (3D) lead-free halide perovskites with excellent stability have attracted worldwide attention. Herein, a doping route was adopted to incorporate Sb3+ ions into the Cs2NaInCl6 for decorating the electronic band structure. Due to the moderate electron-phonon coupling, the Sb3+-doped Cs2NaInCl6 double perovskites showed a narrow and relatively unusual blue emission of self-trapped excitons (STEs). Density functional theory (DFT) calculation indicated that the doped Sb3+ ions could break the parity-forbidden transition rule and modulate the density of state (DOS) population effectively to boost the PLQY of STEs drastically. The optimized Sb3+:Cs2NaInCl6 exhibited a PLQY of up to 75.89% and excellent stability under the consecutive illumination of 365 nm UV light for 1000 h. This kind of highly efficient lead-free Sb3+-doped Cs2NaInCl6 double perovskites may overcome the bottlenecks of severe toxicity and insufficient stability and therefore have an extensive application in the scarce blue photonic and optoelectronic fields.

Highly Efficient Blue Emission from Self-Trapped Excitons in Stable Sb3+-Doped Cs2NaInCl6 Double Perovskites.

In Situ Inkjet Printing Strategy for Fabricating Perovskite Quantum Dot Patterns

Room-temperature-operated
continuous-wave lasers have been intensively
pursed in the field of on-chip photonics. The realization of a continuous-wave
laser strongly relies on the development of gain materials. To date,
there is still a huge gap between the current gain materials and commercial
requirements. In this work, we demonstrate continuous-wave lasers
at room temperature using rationally designed in situ fabricated perovskite
quantum dots in polyacrylonitrile films on a distributed feedback
cavity. The achieved threshold values are 15, 24, and 58 W/cm2 for green, red, and blue lasers, respectively, which are
one order lower than the reported values for the conventional CdSe
quantum dot-based continuous-wave laser. Except for the high photoluminescence
quantum yields, smooth surface, and high thermal conductivity of the
resulting films, the key success of an ultralow laser threshold can
be explained by the interaction of polyacrylonitrile and perovskite
induced “charge spatial separation” effects. This progress
opens up a door to achieve on-chip continuous-wave lasers for photonic
applications.

Ultralow-Threshold and Color-Tunable Continuous-Wave Lasing at Room-Temperature from In Situ Fabricated Perovskite Quantum Dots.

Perovskite Quantum Dots Embedded Composite Films Enhancing UV Response of Silicon Photodetectors for Broadband and Solar-Blind Light Detection

We report an in-situ fabrication of halide perovskite (CH3NH3PbX3, CH3NH3 = methylammonium, MA, X= Cl, Br, I) nanocrystals in polyvinylalcohol (PVA) nanofibers (MAPbX3@PVA nanofibers) through electrospinning a perovskite precursor solution. With the content of the precursors increased, the resulting MAPbBr3 nanocrystals in PVA matrix changed the shape from ellipsoidal to pearl-like, and finely into rods-like. Optimized MAPbBr3@PVA nanofibers show strong polarized emission with the photoluminescence quantum yield of up to 72%. We reveal correlations between the shape of in-situ fabricated perovskite nanocrystals and the polarization degree of their emission by comparing experimental data from the single nanofiber measurements with theoretical calculations. Polarized emission of MAPbBr3@PVA nanofibers can be attributed to the dielectric confinement and quantum confinement effects. Moreover, nanofibers can be efficiently aligned by using parallel positioned conductor strips with an air gap as collector. A polarization ratio of 0.42 was achieved for the films of well-aligned MAPbBr3@PVA nanofibers with a macroscale size of 0.5 cm × 2 cm, which allows potential applications in displays, lasers, waveguides, etc.

In-situ fabricated anisotropic halide perovskite nanocrystals in polyvinylalcohol nanofibers: Shape tuning and polarized emission

Perovskite quantum dots have been attractive building blocks for novel photonic devices development, where patterning is usually one of the most critical steps. We report on the combination of in s...

Linghai Meng

Papers

In Situ Inkjet Printing Strategy for Fabricating Perovskite Quantum Dot Patterns

Ultralow-Threshold and Color-Tunable Continuous-Wave Lasing at Room-Temperature from In Situ Fabricated Perovskite Quantum Dots.

Perovskite Quantum Dots Embedded Composite Films Enhancing UV Response of Silicon Photodetectors for Broadband and Solar-Blind Light Detection

In-situ fabricated anisotropic halide perovskite nanocrystals in polyvinylalcohol nanofibers: Shape tuning and polarized emission

In Situ Patterning Perovskite Quantum Dots by Direct Laser Writing Fabrication