Intense, stable and excitation wavelength-independent photoluminescence emission in the blue-violet region from phosphorene quantum dots.
Nanoscale phosphorene quantum dots (PQDs) with few-layer structures were fabricated by pulsed laser ablation of a bulk black phosphorus target in diethyl ether. An intense and stable photoluminescence (PL) emission of the PQDs in the blue-violet wavelength region is clearly observed for the first time, which is attributed to electronic transitions from the lowest unoccupied molecular orbital (LUMO) to the highest occupied molecular orbital (HOMO) and occupied molecular orbitals below the HOMO (H-1, H-2), respectively. Surprisingly, the PL emission peak positions of the PQDs are not red-shifted with progressively longer excitation wavelengths, which is in contrast to the cases of graphene and molybdenum disulphide quantum dots. This excitation wavelength-independence is derived from the saturated passivation on the periphery and surfaces of the PQDs by large numbers of electron-donating functional groups which cause the electron density on the PQDs to be dramatically increased and the band gap to be insensitive to the quantum size effect in the PQDs. This work suggests that PQDs with intense, stable and excitation wavelength-independent PL emission in the blue-violet region have a potential application as semiconductor-based blue-violet light irradiation sources.
The Beijing Key Laboratory for Nano-Photonics and Nano-Structures, Department of Physics, Capital Normal University, Beijing 100048, China.
Shuaipeng
S
Ge
The Beijing Key Laboratory for Nano-Photonics and Nano-Structures, Department of Physics, Capital Normal University, Beijing 100048, China.
Lisheng
L
Zhang
The Beijing Key Laboratory for Nano-Photonics and Nano-Structures, Department of Physics, Capital Normal University, Beijing 100048, China.
Peijie
P
Wang
The Beijing Key Laboratory for Nano-Photonics and Nano-Structures, Department of Physics, Capital Normal University, Beijing 100048, China.
Yan
Y
Fang