Lattice marginal reconstruction enabled high ambient-tolerance Perovskite Quantum Dots phototransistors

Perovskite quantum dots (PeQDs) have been developed rapidly as photoactive materials in hybrid phototransistors because of their strong light absorption, broad bandgap customizability, and defect-tolerance in charge-transport properties. The solvent treatment has been well recognized as a practical approach for improving the charge transport of PeQDs and the photoresponsivity of PeQD phototransistors. However, there is a lack of fundamental understanding of the origin of its impacts on the material’s ambient stability as well as phototransistor’s operational lifetime. Especially, the relationship between surface ligands dissociation and their microstructural reconstruction has not been fully elucidated so far. Herein, we report that a simultaneous enhancement of photoresponsivity and ambient tolerance for PeQD-based hybrid phototransistors can be realized via medium-polarity-solvent treatment on solid-state PeQDs. Our comprehensive optoelectronic characterization and electron microscopic study reveals that the crystal morphology, instead of surface ligands, is the dominating factor that results in the PeQD’s stability enhancement associated with the preservation of optical property and quantum confinement. Besides, we unveil a marginal reconstruction process occurred during solvent treatment, which opens up a new route for facets-oriented attachment of PeQDs along the zone axis to suppress the damage from water molecules penetration. Our study yields a new understanding of the solvent impact on PeQD microstructures reconstruction and suggests new routes for perovskite materials and corresponding device operational stability enhancement

Lattice Marginal Reconstruction Enabled High Ambient-Tolerance Perovskite Quantum Dots Phototransistors

Perovskite quantum dots (PeQDs) have been developed rapidly as photoactive materials in hybrid phototransistors because of their strong light absorption, broad bandgap customizability, and defect-tolerance in charge-transport properties. The solvent...</p

FATIGUE DESIGN FACTORS AND SAFETY LEVEL IMPLIED IN FATIGUE DESIGN OF OFFSHORE STRUCTURES

ABSTRACT With the publication of the ABS Guide for Fatigue Assessment of Offshore Structures (2003) and the Commentary to the Guide for the Fatigue Assessment of Offshore Structures (2004), application of the Fatigue Design Factor (FDF) is highlighted in fatigue assessments of offshore structures. Following review of FDF&apos;s in available Rules/Guides from other authorities, FDF&apos;s applied in the ABS Guide is presented and quantified with a corresponding safety level thus helping the user to relate FDF&apos;s to estimated failure probability levels

Flexible UV detectors based on in-situ hydrogen doped amorphous Ga2O3 with high photo-to-dark current ratio

Amorphous Ga _2 O _3 (a-Ga _2 O _3 ) has been attracting more and more attention due to its unique merits such as wide bandgap (∼4.9 eV), low growth temperature, large-scale uniformity, low cost and energy efficient, making it a powerful competitor in flexible deep ultraviolet (UV) photodetection. Although the responsivity of the ever-reported a-Ga _2 O _3 UV photodetectors (PDs) is usually in the level of hundreds of A/W, it is often accompanied by a large dark current due to the presence of abundant oxygen vacancy ( V _O ) defects, which severely limits the possibility to detect weak signals and achieve versatile applications. In this work, the V _O defects in a-Ga _2 O _3 thin films are successfully passivated by in-situ hydrogen doping during the magnetron sputtering process. As a result, the dark current of a-Ga _2 O _3 UV PD is remarkably suppressed to 5.17 × 10 ^−11 A at a bias of 5 V. Importantly, the photocurrent of the corresponding device is still as high as 1.37 × 10 ^−3 A, leading to a high photo-to-dark current ratio of 2.65 × 10 ^7 and the capability to detect the UV light with the intensity below 10 nW cm ^−2 . Moreover, the H-doped a-Ga _2 O _3 thin films have also been deposited on polyethylene naphtholate substrates to construct flexible UV PDs, which exhibit no great degradation in bending states and fatigue tests. These results demonstrate that hydrogen doping can effectively improve the performance of a-Ga _2 O _3 UV PDs, further promoting its practical application in various areas