Giant enhancement of photoluminescence emission in monolayer WS2 by femtosecond laser irradiation

Abstract

Monolayer transition metal dichalcogenides have emerged as promising materials for optoelectronic and nanophotonic devices. However, the low photoluminescence (PL) quantum yield (QY) hinders their various potential applications. Here we engineer and enhance the PL intensity of monolayer WS2 by femtosecond laser irradiation. More than two orders of magnitude enhancement of PL intensity as compared to the asprepared sample is determined. Furthermore, the engineering time is shortened by three orders of magnitude as compared to the improvement of PL intensity by continuouswave laser irradiation. Based on the evolution of PL spectra, we attribute the giant PL enhancement to the conversion from trion emission to exciton, as well as the improvement of the QY when exciton and trion are localized to the new-formed defects.We have created microstructures on the monolayer WS2 based on the enhancement of PL intensity, where the engineered structures can be stably stored for more than three years. This flexible approach with the feature of excellent long-term storage stability is promising for applications in information storage, display technology, and optoelectronic devices.

Vanadium-Doped Monolayer MoS2 with Tunable Optical Properties for Field-Effect Transistors

“…However, monolayer (ML) MoS 2 always shows a relatively lower PL intensity due to the existence of sulfur vacancies . In this regard, several approaches including electrostatic gating, chemical treatment, , laser irradiation, − and chemical doping have been adopted to improve the optoelectronic propertied of ML MoS 2 . Among these methods, chemical doping was believed to be an efficient and facile method to modify the carrier density of ML MoS 2 .…”

Criteria for Assessing the Interlayer Coupling of van der Waals Heterostructures Using Ultrafast Pump–Probe Photoluminescence Spectroscopy

“…After assuming the thermalization of the transferred electrons following exponential decay behavior, the electron transfer can be expressed as η transferring and the larger the ratio. Assuming η = 0.03 (considering that the quantum yield of monolayer TMDC is between 0.01% and 100%, 45,46 this assumption is reasonable), we determine the PL trajectory (i.e., PL intensity evolution of heterostructures as a function of time delays), as the solid line shown in Figure 1e. Intriguingly, a PL enhancement occurs at zero time delay, and then PL decays to a plateau level.…”

Effect of Different Ratios of Mentha spicata Aqueous Solution Based on a Biosolvent on the Synthesis of AgNPs for Inhibiting Bacteria

“…Synthesis of AgNPs formed using green synthesis: [25][26][27][28][29][30][31][32][33][34][35], and various chemical and green synthesis methods [36,37], biomolecules including DNA [38][39][40][41][42], protein [43][44][45], enzyme [26], protein [43][44][45], and plant extracts [26,[46][47][48][49] with their biological properties [50][51][52].…”