Tuning the band gap of PbSe quantum dots in glasses by TiO doping
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Titanium monoxide (TiO) was added to host glass, which was heat-treated at 520 °C for 10 h to incorporate Ti2+ into PbSe quantum dots (QDs) to control their band gaps. Incorporation of Ti2+ ions into PbSe QDs was confirmed using electron energy loss spectroscopy analysis. Addition of TiO caused blue-shift of the absorption and photoluminescence (PL) bands of the QDs. Absorption bands moved from 1621 nm at TiO concentration [TiO] = 0.0% to 1418 nm at [TiO] = 0.4 mol%. Average diameters of QDs remained mostly unaffected (i.e., 6.25 ± 0.14 nm at [TiO] = 0.0% to 6.03 ± 0.1 nm at [TiO] = 0.4 mol%). The changes in absorption and PL bands originated from the incorporation of Ti2+ ions into PbSe QDs. Band gaps of PbSe QDs increased from 0.76 eV at [TiO] = 0% to 0.88 eV at [TiO] = 0.4 mol%. This simple method to tune the band gap of PbSe QDs has possible applications in optical communication fiber amplifiers, infrared laser sources and saturable absorbers.
KeywordsPbSe Saturable Absorber Electron Energy Loss Spectroscopy Host Glass Lead Chalcogenide
This research is supported by Basic Science Research Program (NRF-2014R1A1A2002789) and the Priority Research Center (NRF-2009-0094036) through the National Research Foundation of Korea (NRF) funded by the Ministry of Science, ICT and Future Planning.
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