Tunable upconversion emission from oil-based carbon nanodots

Optical properties of carbon dots (CDs), prepared using 10-Undeceonic acid as an organic precursor, exhibited broad range excitation wavelength-dependent photoluminescence, with maximum emission intensity at 3.5 eV. Besides conventional down-conversion PL (DCPL), CDs show excitation wavelength-dependent upconversion PL (UCPL), produced by electromagnetic radiation in the green-NIR wavelength range. The difference between the excitation energy and the UCPL peak energy is found to be constant upon varying the excitation energy, whereas the energy difference with respect to DCPL peak energy decreases linearly. UCPL/DCPL have been explained with the help of surface states, shallow and deep trap states present in the proposed CDs.

Automated summary

Carbon dots prepared using 10-Undeceonic acid as an organic precursor exhibit broad range excitation wavelength-dependent photoluminescence, with excitation wavelength-dependent upconversion and downconversion photoluminescence. The UCPL/DCPL can be explained by the presence of surface states, shallow and deep trap states in the carbon dots.