0D Nanocrystals as Light‐Driven, Localized Charge‐Injection Sources for the Contactless Manipulation of Atomically Thin 2D Materials

Abstract

A contactless charge‐injection scheme that allows the local and quasi‐permanent manipulation of atomically thin 2D materials, such as monolayer (1L‐)MoS2, over spatial extents of several tens of micrometers, is reported. The possibility to precisely position and localize the charge‐injection source to the micrometer scale post‐fabrication allows the investigation of local unperturbed electronic structure of the 2D material. Thanks to this novel approach, the important impact of sample inhomogeneity on the charge‐carrier percolation that occurs over the entire extent of the 2D flake and proliferates up to 40 μm away from the localized charge injection is elucidated. The apparent driving force for carrier relocation is the initial inhomogeneous electronic landscape of the 2D material. These studies demonstrate that local and contactless charge injection with submicrometer precision delivers an alternative route for charge injection and indicates that local 2D material electronic structure can serve as a key element for novel nanoscale device design.

Generation of Free Carriers in MoSe2 Monolayers Via Energy Transfer from CsPbBr3 Nanocrystals

“…[41][42][43][44] Therefore the trion contribution can be an indicator for the free carrier density in the ML-MoSe 2 even at room temperature. [41,[45][46][47][48][49] The carrier density can be quantified by considering the thermal equilibrium between exciton (n X ), trion (n T ), and the free carrier density (n e ), which follows a Boltzmann distribution at low excitation densities. [50,51] This model, based on the law of mass action, is given in Equation S4, Supporting Information.…”

Photodoping of metal oxide nanocrystals for multi-charge accumulation and light-driven energy storage

“…The possibility to modulate the carrier density of doped semiconductors via photodoping could be exploited to design transistors in which the gate input is replaced with light, or even developing all-opticalinput. 88,89 In fact, in a recent work MO NCs were employed as all-optical light-driven charge injection tools to inject multiple electrons into 2D TMDs, in analogy to 2D material gating. 89 This together displays that MO NCs photodoping opens horizons for novel application spaces as active elements in self-powered nano-electronics.…”

“…88,89 In fact, in a recent work MO NCs were employed as all-optical light-driven charge injection tools to inject multiple electrons into 2D TMDs, in analogy to 2D material gating. 89 This together displays that MO NCs photodoping opens horizons for novel application spaces as active elements in self-powered nano-electronics. Moreover, light-driven MO NCs in proper device architectures display a promising and viable strategy for novel solar-powered energy storage units.…”

Multi-charge transfer from photodoped ITO nanocrystals

“…[4][5][6][7] Doped MO NCs, in fact, combine both the ability to efficiently harvest NIR sunlight radiation through the excitation of doping-and size-dependent localized surface plasmon resonances (LSPR) and the potential to store multiple delocalized photo-excited carriers. [8][9][10] Photodoping, a light-driven charge accumulation of electrons induced by multiple absorption events of high-energy photons (beyond the bandgap of MO semiconductor), emerged as a contactless and promising tool to promote the photoconversion process. 7,[11][12][13][14][15][16] Photodoping of ITO NCs in presence of a sacrificial hole scavenger, such as ethanol, under anaerobic conditions, results in the reversible accumulation of tens to hundreds of electrons per single NC.…”