Preparation, Characterization, and Photoelectric Properties of Langmuir–Blodgett Films of Some Europium-Substituted Polyoxometalates and 2-Aminofluorene with Tunable Emission Color



A new series of organic/inorganic composite Langmuir–Blodgett (LB) films consisting of 2-aminofluorene (Fl–NH2) as the π-conjugated organic molecule, an europium-substituted polyoxometalate (POM, POM = Na9EuW10O36, K13[Eu(SiW11O39)2] and K5[Eu(SiW11O39)(H2O)2], which are denoted by EuW10, EuW22 and EuW11, respectively) as the inorganic component, were prepared. Structural and photophysical characterization of these LB films were achieved by π–A isotherms, UV–Vis absorption and photoluminescence spectra, atomic force microscopy imaging, scanning tunneling microscopy, and surface photovoltage spectroscopy. Our experimental results indicate that stable Langmuir and LB films are formed in pure water and POM sub-phases. Luminescence spectra of the prepared hybrid LB films show that tunable emission color can be obtained due to the dual-emissive nature of the mixed Fl–NH2/POM blends. These 2-aminofluorene-based LB films displayed interesting electrical conductivity behavior. Among them, Fl–NH2/EuW11 3-layer films showed a good electrical response with the a tunneling current up to ± 100 nA when the voltage was monitored at −0.8 to 1.5 V. These LB composites show good photovoltage responses and a photovoltage of 2.7 μV can be obtained for the Fl–NH2/EuW22 system when it is excited by light.


2-Aminofluorene Luminescence Europium-substituted polyoxometalate Langmuir–Blodgett film Photovoltaic effect 



L. Liu acknowledges the financial support from National Natural Science Foundation of China (20671033, 21071049) and Natural Science Foundation of Hubei Province of China (2010CDB04702). W.-Y.W. thanks the Hong Kong Research Grants Council (HKBU202508 and HKUST2/CRF/10), Areas of Excellence Scheme from the University Grants Committee (AoE/P-03/08) and Hong Kong Baptist University (FRG2/11-12/156) for financial support.


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© Springer Science+Business Media New York 2013

Authors and Affiliations

  1. 1.Ministry of Education Key Laboratory for the Synthesis and Application of Organic Functional Molecules, School of Chemistry and Chemical Engineering, Hubei UniversityWuhanPeople’s Republic of China
  2. 2.Key Laboratory of Special Functional MaterialsHenan UniversityKaifengPeople’s Republic of China
  3. 3.Institute of Molecular Functional Materials (Areas of Excellence Scheme, University Grants Committee, Hong Kong) and Department of Chemistry and Institute of Advanced MaterialsHong Kong Baptist UniversityHong KongPeople’s Republic of China

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