Emission Control from Transition Metal Dichalcogenide Monolayers by Aggregation-Induced Molecular Rotors

Abstract

Organic–inorganic (O–I) heterostructures, consisting of atomically thin inorganic semiconductors and organic molecules, present synergistic and enhanced optoelectronic properties with a high tunability. Here, we develop a class of air-stable vertical O–I heterostructures comprising a monolayer of transition-metal dichalcogenides (TMDs), including WS2, WSe2, and MoSe2, on top of tetraphenylethylene (TPE) core-based aggregation-induced emission (AIE) molecular rotors. The created O–I heterostructures yields a photoluminescence (PL) enhancement of up to ∼950%, ∼500%, and ∼330% in the top monolayer WS2, MoSe2, and WSe2 as compared to PL in their pristine monolayers, respectively. The strong PL enhancement is mainly attributed to the efficient photogenerated carrier process in the AIE luminogens (courtesy of their restricted intermolecular motions in the solid state) and the charge-transfer process in the created type I O–I heterostructures. Moreover, we observe an improvement in photovoltaic properties of the TMDs in the heterostructures including the quasi-Fermi level splitting, minority carrier lifetime, and light absorption. This work presents an inspiring example of combining stable, highly luminescent AIE-based molecules, with rich photochemistry and versatile applications, with atomically thin inorganic semiconductors for multifunctional and efficient optoelectronic devices.

Mechanisms and Applications of Steady-State Photoluminescence Spectroscopy in Two-Dimensional Transition-Metal Dichalcogenides

“…For example, type I is utilized in optical devices such as LEDs and lasers due to its ability to pump up populations of electrons and holes in one material to boost radiative recombination rates. 198,238,243 Type II is particularly important in photovoltaic devices such as solar cells and photodetectors since the photogenerated carriers are split at the interface, with electrons moving to one material and holes to the other. 21,237,240 Type III is utilized in tunneling FETs for improving the tunneling current density and in inter sub-band superlattice lasers.…”

Retracted: Emerging 2D MXene/Organic Heterostructures for Future Nanodevices

“…For example, chemical doping, bio functionalization, applying strain, hybridization, etc., to 2D materials or the formation of 2D heterostructures are most widely used techniques at the present time. [118][119][120][121][122][123] However, among these various techniques, the formation of 2D heterostructures can be considered as one of the most effective methods. 2D heterostructures are particularly found to be effective for tailoring or increasing the physical properties of target materials.…”

2D Materials and Heterostructures at Extreme Pressure

“…[58] In the past decade, a majority of 2D ultrathin materials involving transition metal dichalcogenides (TMDs, e.g., MoS 2 , MoSe 2 , WSe 2 , WS 2 , TiS 2 , TaS 2 , etc. ), [49,[59][60][61] BN, [21][22][23][24][25][26]35,[62][63][64][65][66][67][68][69][70][71] BP, [72][73][74][75][76][77][78][79][80][81][82][83][84] 2D organic crystals (e.g., 2D small molecular and polymers), [85][86][87][88][89][90][91][92][93][94][95] 2D perovskites, [96][97][98][99]…”