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InP Quantum Dots: An Environmentally Friendly Material with Resonance Energy Transfer Requisites

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journal contribution
posted on 20.02.2014, 00:00 by Anoop Thomas, Pratheesh V. Nair, K. George Thomas
Growing demand for clean energy has intensified the interest in understanding the properties of environmentally friendly materials for future energy devices. Indium phosphide (InP) is relatively nontoxic as compared to cadmium chalcogenides, and herein we demonstrate the successful use of this material for resonance energy transfer applications. Three chromophoric dyes, namely, lissamine rhodamine B ethylene diamine (LiRh), Texas red cadavarine C5 (TxRed), and rhodamine 101 (Rh101), possessing free anchoring groups were used as acceptors in InP quantum dot (QD)-based donor–acceptor pairs. The energy transfer process was monitored by steady-state and time-resolved emission spectroscopic techniques. Large values of quenching constant (kq), in the range of 1013–1014 M–1 s–1, observed on addition of chromophoric dyes to InP overcoated with zinc sulphide (InP/ZnS), confirm that the interaction is predominantly static in nature. Selective excitation of the QD component at 405 nm showed a rapid decay of InP/ZnS emission and a concomitant growth of the acceptor emission (rise time of ∼200 ps), indicating that all these systems follow a nonradiative energy transfer mechanism. Time-resolved emission studies confirm that the photoexcited InP/ZnS QDs decays to the ground state by transferring the excitation energy to the chromophoric dyes leading to the formation of its excited state. The high efficiency of energy transfer observed in these systems further confirms that InP is an excellent energy harvester with potential use in biomedical and photovoltaic applications.