Quantum dots-doped microlenses made by photolithography

Microlenses doped with quantum dot emitters offer promising potential for photonics applications, but they require complex fabrication. In this work, we present a method to fabricate microlenses incorporating core/shell CdSe/CdxZn1-xS quantum dot red emitters using photolithography. The quantum dots were first synthesized and dispersed in propylene glycol monomethyl ether acetate solvent using suitable ligand exchange. This quantum dot-loaded solvent was then combined with a transparent commercial photoresist and patterned via ultraviolet lithography to create micro-disks with diameters ranging from 20 to 5 µm. The microstructures were then annealed, forming microlenses through the thermal reflow of the photoresist. Micro-photoluminescence and lifetime measurements confirm the homogeneous and efficient emission of the quantum dots within the microlenses. This work demonstrates the feasibility of fabricating microlenses doped with CdSe-based core/shell quantum dots through photolithography and thermal reflow, offering a straightforward approach for photonics applications.