We have systematically investigated the temperature dependent Raman spectroscopy behavior of a few layered MoS2 and WS2 nanosheets synthesized using simple hydrothermal method. Our result reveals A1g and E12g modes soften as temperature increases from 77 K to 623 K. This behavior can be explained in terms of a double resonance process which is active in single- and few layer thick nanosheets. The frequency shifts and peak broadening can provide unambiguous, nondestructive, and accurate information of a few layered MoS2 and WS2. This mechanism can also be applicable in characterizing the structural, optical, electronic, and vibrational properties of other emerging layered materials.

An ordered self-assembly of CsPbBr quantum dots (QDs) was generated on the surface of few-layer black phosphorus (FLBP). Strong quenching of the QD fluorescence was observed, and analyzed by time-resolved photoluminescence (TR-PL) studies, DFT calculations, and photoconductivity measurements. Charge transfer by type I band alignment is suggested to be the cause of the observed effects.

Atomically thin two-dimensional tungsten disulfide (WS2) sheets have attracted much attention due to their potential for future nanoelectronic device applications. We report first experimental investigation on temperature dependent Raman spectra of single-layer WS2 prepared using micromechanical exfoliation. Our temperature dependent Raman spectroscopy results shows that the E(1)2g and A1g modes of single-layer WS2 soften as temperature increases from 77 to 623 K. The calculated temperature coefficients of the frequencies of 2LA(M), E(1)2g, A1g, and A1g(M) + LA(M) modes of single-layer WS2 were observed to be -0.008, -0.006, -0.006, and -0.01 cm(-1) K(-1), respectively. The results were explained in terms of a double resonance process which is active in atomically thin nanosheet. This process can also be largely applicable in other emerging single-layer materials.

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An ordered self‐assembly of CsPbBr3 quantum dots (QDs) was generated on the surface of few‐layer black phosphorus (FLBP). Strong quenching of the QD fluorescence was observed, and analyzed by time‐resolved photoluminescence (TR‐PL) studies, DFT calculations, and photoconductivity measurements. Charge transfer by type I band alignment is suggested to be the cause of the observed effects.