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Violet phosphorus quantum dots have been produced for the first time, which are effective fluorescent probes to selectively detect Cu2+. The morphology, microstructure and fluorescence properties have been tuned using synthesis parameters.

A hetero-phase crystal growth method was proposed by introducing a heteroelement to yield large antimony single crystals with high quality.

Violet phosphorus quantum dots (VPQDs) are promising structures for bioimaging, solar cells, LEDs, diode lasers, and transistors due to the quantum confinement effects. Bandgap tuning is important for QDs to adjust their emissions for various applications. Nevertheless, no bandgap tuning of VPQDs has been investigated, since the violet phosphorus has just recently been successfully produced and confirmed. In this work, the bandgap of VPQDs has been demonstrated to be effectively tuned from 2.3 to 3.1 eV by a facile solvothermal path in different solvents to introduce different functional groups. The HOMO-LUMO gaps of VPQDs from different functionalizations have also been calculated by density functional theory to be 2.73, 2.77, 2.74, 2.80, 2.51, and 2.56 eV, respectively, which are well-consistent with the experimental results. Our results provide a simple pathway for bandgap tuning of VPQDs, which can be used for future optoelectronic applications.

Violet phosphorus quantum dots (VPQDs) have been recently produced to give intense green photoluminescence with excellent stability. Quantum dots are promising temperature sensors. However, the temperature-dependent photoluminescence of VPQDs is still unexplored. Herein, both the steady-state and time-resolved photoluminescence of VPQDs have been investigated at 263–353 K. With increasing temperature, the photoluminescence of VPQDs has been demonstrated to have decreasing intensity, blue shifts, and broaden bandwidth with excellent temperature reversibility. The non-radiative heat escape was found to cause the intensity to decrease. The blue shift was deduced to be due to the interplay between the electron–phonon renormalization and the thermal expansion. The enhanced exciton–phonon coupling was found to be the main cause of broaden bandwidth. The photoluminescence lifetime of VPQDs was measured to be stable at different temperatures. The non-radiation recombination processes have been demonstrated to play a crucial role in the photoluminescence by linking static and dynamic processes to calculate the radiative rate and non-radiative rate variation with temperature. The activation energy of VPQDs was deduced to be 90.25 meV, which is suitable for temperature sensing. The linear correlation of photoluminescence intensity and peak position to temperature gives more accurate dual mode sensing for a wide-range of ratiometric temperature sensors.