Interparticle Charge Transport in CuInS2 Quantum Dot Aerogels Enables Label-Free Electrochemiluminescence Immunosensing.

Quantum dots (QDs) are attractive electrochemiluminescence (ECL) luminophores because of their quantum confinement and tunable band structures; however, QD-based ECL is often limited by low efficiency and inadequate operational stability. Here, low-toxic CuInS2 QDs (CIS) are assembled into an aerogel through a facile in situ gelation strategy to enhance ECL emission. The aerogel architecture strengthens interparticle electronic coupling, lowers the interparticle charge-transfer barrier, and facilitates charge separation and transport. As a result, the CIS aerogel delivers a 76-fold enhancement in ECL intensity compared with individual CIS QDs. Notably, the in situ gelation strategy is scalable, producing 0.54 g of CIS aerogel per batch, which supports practical use in ECL sensing. As a proof-of-concept, the CIS aerogel is integrated into an ECL immunosensor for carcinoembryonic antigen (CEA), affording a satisfactory linear range of 1 pg mL-1 to 100 ng mL-1 and a detection limit of 0.34 pg mL-1 (S/N = 3). The immunosensor also exhibits excellent selectivity and reproducibility. This work highlights interparticle charge transport as an effective lever for boosting QD-based ECL and underscores the potential of QD aerogels for advanced ECL biosensing.