Enhancing the Light Emission of Colloidal Quantum Dots with Dual-band Absorbers Based on Metasurfaces

Quantum dots (QDs) are essential light emitters with great tunability of spectrum and find important technological applications in various areas, including light-emitting devices, photovoltaics, and bioimaging. The recent advance of metamaterials has enabled the direct control of the light emission properties with patterned ultrathin metallic films, ranging from enhanced light emission and modified fluorescence spectrum to well-defined polarization and unidirectional radiation. However, the outcoupling efficiency of two-dimensional (2D) QD-based optoelectronic devices is still limited. Here we propose and demonstrate the enhancement of the light emission of QD-based 2D optoelectronic devices at around telecom wavelengths by employing dual-band perfect absorbers based on plasmonic metasurfaces. The two resonant peaks of the absorber simultaneously match the absorption and radiation wavelengths of non-blinking “giant” QDs at the telecom regime, thus enhancing the excitation pump meanwhile maintaining the efficient outcoupling of the light emission. These findings will not only benefit technological applications of QD-based optoelectronic devices but also offer better understanding of the fundamental physical mechanisms of light-matter interactions.