Scalable Photocatalytic Microlens Arrays Imprinted in Carbon Dot-Based Photoresists

Regulated photocatalysis by integration of optics presents a powerful avenue to enable high-efficiency energy conversion under the fluctuating conditions of natural sunlight. Yet inefficiency arises when the concentrated photonic energy and the nanoscale catalytic sites mismatch in dimensions. To address this, a hybrid photocatalytic microlens array is designed and manufactured with scalable imprinting technology. Photocatalytic carbon dots (CDs) are uniformly integrated into the imprinted plano-convex microlens array. The convex microlens focuses the incident light onto the flat back surface, where the photocatalytic reactions take place at the nanoscale CD sites. As a proof-of-concept, we verify the structural and functional synergy of the photocatalytic microlens arrays via the degradation of Eosin Y under weak light, achieving a reduction of 64% on the illumination lower threshold to initiate photochemical reactions. Further integration of the photocatalytic microlens arrays with a continuous-flow photochemical reactor results in a 78 fold increase in pollutant removal efficiency compared to batch conditions. The scalability, flexibility, and superior photocatalytic performance of the CD-based microlens array not only present a viable solution for environmental applications like water treatment, but also pave a hybrid pathway for the design of high-efficiency photochemical reactors.