Photophysical properties of CdSe quantum dot self-assemblies with zinc phthalocyanines and azaphthalocyanines

0392059 - ÚFCH JH 2014 RIV FR eng J - Journal Article
Suchánek, Jan - Lang, Kamil - Nováková, V. - Zimčík, P. - Zelinger, Zdeněk - Kubát, Pavel
Photophysical properties of CdSe quantum dot self-assemblies with zinc phthalocyanines and azaphthalocyanines.
Photochemical & Photobiological Sciences. Roč. 12, č. 5 (2013), s. 743-750. ISSN 1474-905X. E-ISSN 1474-9092
R&D Projects: GA ČR GAP208/10/1678
Institutional support: RVO:61388955 ; RVO:61388980
Keywords : photodynamic therapy * fluorescence spectra * singlet oxygen
Subject RIV: CF - Physical ; Theoretical Chemistry; CA - Inorganic Chemistry (UACH-T)
Impact factor: 2.939, year: 2013

The formation of self-assemblies between CdSe quantum dots (QDs) and Zn phthalocyanines (Pc) and azaphthalocyanines (AzaPc) bearing alkylsulfanyl substituents and the photophysical properties of these assemblies were studied using both steady-state and time-resolved luminescence/absorption spectroscopy. The formation of the self-assemblies was accompanied by a blue shift of the Q band of the dyes and by a quenching of the CdSe QDs luminescence. The largest spectral shift of the Q-band was approximately 7 nm and was observed for pentan-3-ylsulfanyl-functionalised phthalocyanine (3). Assuming a 1 : 1 stoichiometry, the calculated binding constant was 4 × 104 M−1. Pc substituted with the bulky tert-butylsulfanyl groups (1) exhibited a smaller shift of the Q band. The quenching of the CdSe QDs luminescence by 1 was more effective than that observed for 3. The results indicated that the luminescence quenching may be due to a photoinduced charge transfer between 1 or 3 and the CdSe QDs. In contrast, the AzaPc (2) with the same substituents as 1 had little effect on the QDs luminescence. For all cases, we found an inefficient resonance energy transfer between the attached dyes and the CdSe QD. The formation of the self-assemblies had negligible effects on the photogeneration of the singlet oxygen, O2(1Δg), that was fully controlled only by the absorption of the light by the macrocycles.
Permanent Link: http://hdl.handle.net/11104/0221046