Luminescence Efficiency of Zn-Cu-In-S / ZnS Quantum Dot films

The aim of this work was to prepare three composite ZnCuInS/ZnS (core/shell) quantum dot (QD) flexible films and to examine their luminescent properties under X-ray excitation for potential use in medical imaging modalities. Three PMMA/ QD ZnCuInS composite films, with emission at 530 nm prepared, with concentrations 2.5, 10.0 and 15.0 %w/v. Composite films prepared by homogenously diluting dry powder QD samples in toluene and subsequently mixing with a PMMA/MMA polymer solution. The Absolute Luminescence Efficiency (AE) of the produced films was assessed using medical X-ray excitation. It found that the AE of the films is decreasing in an almost linear way, with increasing X-ray tube voltage. Also, it found that for QDs concentration up to 10.0 %w/v, the AE is increasing rapidly while after that point the relative increase of AE is rather limited. The spectral compatibility of the ZnCuInS/ZnS screen, with various existing optical detectors, was investigated after emission spectra measurements. Highest compatibility (over 90%) found for most CMOS and CCD detectors used in modern imaging modalities.