Correlated fluorescence blinking in two-dimensional semiconductor heterostructures

Abstract

'Blinking', or 'fluorescence intermittency', refers to a random switching between 'ON' (bright) and 'OFF' (dark) states of an emitter; it has been studied widely in zero-dimensional quantum dots and molecules, and scarcely in one-dimensional systems. A generally accepted mechanism for blinking in quantum dots involves random switching between neutral and charged states (or is accompanied by fluctuations in charge-carrier traps), which substantially alters the dynamics of radiative and non-radiative decay. Here, we uncover a new type of blinking effect in vertically stacked, two-dimensional semiconductor heterostructures, which consist of two distinct monolayers of transition metal dichalcogenides (TMDs) that are weakly coupled by van der Waals forces. Unlike zero-dimensional or one-dimensional systems, two-dimensional TMD heterostructures show a correlated blinking effect, comprising randomly switching bright, neutral and dark states. Fluorescence cross-correlation spectroscopy analyses show that a bright state occurring in one monolayer will simultaneously lead to a dark state in the other monolayer, owing to an intermittent interlayer carrier-transfer process. Our findings suggest that bilayer van der Waals heterostructures provide unique platforms for the study of charge-transfer dynamics and non-equilibrium-state physics, and could see application as correlated light emitters in quantum technology.

Enhanced Two‐Photon‐Pumped Emission from In Situ Synthesized Nonblinking CsPbBr3/SiO2 Nanocrystals with Excellent Stability

“…[7,[9][10][11] Although all-inorganic lead halide perovskite nanomaterials can exhibit outstanding optoelectronic performance, such materials still suffer from poor stability due to a high sensitivity to moisture in the ambient environment and fluctuation of the fluorescence (blinking property), which can hinder further commercial applications. In addition, blinking, which was first discovered in CdSe quantum dots (QDs) in 1996, [18] is another critical factor limiting the further practical application of 0 D QDs. In addition, blinking, which was first discovered in CdSe quantum dots (QDs) in 1996, [18] is another critical factor limiting the further practical application of 0 D QDs.…”

“…[5][6][7][8][9][10][11][12][13] Since the first preparation of all-inorganic CsPbX 3 (X = Cl, Br, I) nanocrystals (NCs) with tunable bandgaps, [9] CsPbX 3 NCs have been intensively investigated for potential applications in light displays and nanolasers. In addition, blinking, which was first discovered in CdSe quantum dots (QDs) in 1996, [18] is another critical factor limiting the further practical application of 0 D QDs. [14][15][16][17] Therefore, improving stability in an air environment is one of the most critical factor that needs to be addressed for the realization of commercially available perovskite-based optoelectronic devices.…”

Optimal light harvesting in 2D semiconductor heterostructures

“…properties of each material in a device, which maintains a 2D character and can be ideally used in electronics and optoelectronics [1][2][3][4][5][6][7][8][9][10][11]. In comparison to a 'bulk' semiconductor-heterostructure with layer thickness of the order of the light wavelength or bigger, the multiple interfaces and the sub-wavelength thickness of each layer decisively influence the interaction of light with heterostructures, and the device performance.…”

Production Methods of Van der Waals Heterostructures Based on Transition Metal Dichalcogenides

“…As the family of 2D materials is increasing gradually in recent years, this kind of heterostructures allows a greater freedom and a far greater number of combinations than any traditional growth method. Furthermore, van der Waals heterostructures have already led to the observation of numerous exciting physical phenomena and novel applications such as correlated light emitters [28][29][30][31], ultra-high speed photodetectors [32,33], new generation field effect transistors [34][35][36][37], and memory devices [38][39][40][41] compared to their individuals. Therefore, the investigation of van der Waals heterostructures shows great importance.…”