Is There Real Upconversion Photoluminescence from Graphene Quantum Dots?

Authors


E-mail: hkxlwu@nju.edu.cn

Abstract

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Upconversion photoluminescence (PL) from graphene quantum dots (GQDs) excited by a xenon lamp is artificial. It is essentially excited by the second-order diffraction light of wavelength λ/2 co-existing in the red light. Real upconversion PL from GQDs is observed under excitation with a femtosecond pulsed laser, implying that coherent photons with high enough power density can be upconverted into blue light via GQDs.

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