Lorenzon Monica, Christodoulou Sotirios, Vaccaro Gianfranco, Pedrini Jacopo, Meinardi Francesco, Moreels Iwan, Brovelli Sergio
Dipartimento di Scienza dei Materiali, Università degli Studi di Milano-Bicocca, via Cozzi 55, I-20125 Milano, Italy.
1] Istituto Italiano di Tecnologia, via Morego 30, IT-16163 Genova, Italy [2] Department of Physics, University of Genoa, via Dodecaneso 33, 16146 Genova, Italy.
Nat Commun. 2015 Mar 16;6:6434. doi: 10.1038/ncomms7434.
Colloidal quantum wells combine the advantages of size-tunable electronic properties with vast reactive surfaces that could allow one to realize highly emissive luminescent-sensing varnishes capable of detecting chemical agents through their reversible emission response, with great potential impact on life sciences, environmental monitoring, defence and aerospace engineering. Here we combine spectroelectrochemical measurements and spectroscopic studies in a controlled atmosphere to demonstrate the 'reversed oxygen-sensing' capability of CdSe colloidal quantum wells, that is, the exposure to oxygen reversibly increases their luminescence efficiency. Spectroelectrochemical experiments allow us to directly relate the sensing response to the occupancy of surface states. Magneto-optical measurements demonstrate that, under vacuum, heterostructured CdSe/CdS colloidal quantum wells stabilize in their negative trion state. The high starting emission efficiency provides a possible means to enhance the oxygen sensitivity by partially de-passivating the particle surfaces, thereby enhancing the density of unsaturated sites with a minimal cost in term of luminescence losses.
胶体量子阱结合了尺寸可调电子特性的优点和巨大的反应表面，这使得人们能够实现高发射率的发光传感清漆，该清漆能够通过其可逆发射响应检测化学试剂，对生命科学、环境监测、国防和航空航天工程具有巨大的潜在影响。在这里，我们在可控气氛中结合光谱电化学测量和光谱研究，以证明CdSe胶体量子阱的“反向氧传感”能力，即暴露于氧气会可逆地提高其发光效率。光谱电化学实验使我们能够将传感响应与表面态的占据直接联系起来。磁光测量表明，在真空中，异质结构的CdSe/CdS胶体量子阱稳定在其负三重态。高起始发射效率提供了一种可能的方法，通过部分去钝化颗粒表面来提高氧敏感性，从而以最小的发光损失成本提高不饱和位点的密度。
