Keleştemur, Y.Olutas M.Delikanlı, S.Güzeltürk, B.Akgül, M. Z.Demir, Hilmi Volkan2016-02-082016-02-0820151932-7447http://hdl.handle.net/11693/23136Solution-processed quantum wells, also known as colloidal nanoplatelets (NPLs), are emerging as promising materials for colloidal optoelectronics. In this work, we report the synthesis and characterization of CdSe/CdTe core/crown NPLs exhibiting a Type-II electronic structure and Type-II speci fic optical properties. Here, based on a core-seeded approach, the CdSe/CdTe core/crown NPLs were synthesized with well-controlled CdTe crown coatings. Uniform and epitaxial growth of CdTe crown region was verified by using structural characterization techniques including transmission electron microscopy (TEM) with quantitative EDX analysis and X-ray diffraction (XRD). Also the optical properties were systematically studied in these Type-II NPLs that reveal strongly red-shifted photoluminescence (up to ∼150 nm) along with 2 orders of magnitude longer fluorescence lifetimes (up to 190 ns) compared to the Type-I NPLs owing to spatially indirect excitons at the Type-II interface between the CdSe core and the CdTe crown regions. Photoluminescence excitation spectroscopy confirms that this strongly red-shifted emission actually arises from the CdSe/CdTe NPLs. In addition, temperature-dependent time-resolved fluorescence spectroscopy was performed to reveal the temperature-dependent fluorescence decay kinetics of the Type-II NPLs exhibiting interesting behavior. Also, water-soluble Type-II NPLs were achieved via ligand exchange of the CdSe/CdTe core/crown NPLs by using 3-mercaptopropionic acid (MPA), which allows for enhanced charge extraction efficiency owing to their shorter chain length and enables high quality film formation by layer-by-layer (LBL) assembly. With all of these appealing properties, the CdSe/CdTe core/crown heterostructures having Type-II electronic structure presented here are highly promising for light-harvesting applications. (Graph Presented). © 2015 American Chemical Society.EnglishCadmium tellurideElectronic structureFluorescenceFluorescence spectroscopyOptical propertiesPhotoluminescenceTransmission electron microscopyX ray diffraction3 - mercaptopropionic acidColloidal quantum wellsLayer - by - layer assembliesPhotoluminescence excitation spectroscopyStructural characterizationSynthesis and characterizationsTemperature dependent fluorescenceTime - resolved fluorescence spectroscopySemiconductor quantum wellsArticle10.1021/jp510466k