Enhanced Near-Infrared-to-Visible Upconversion by Synthetic Control of PbS Nanocrystal Triplet Photosensitizers [electronic resource]

• Ngôn ngữ: eng
• Ký hiệu phân loại: 621.36 Optical engineering
• Thông tin xuất bản: Washington, D.C. : Oak Ridge, Tenn. : United States. Dept. of Energy. Office of Science ; Distributed by the Office of Scientific and Technical Information, U.S. Dept. of Energy, 2019
• Mô tả vật lý: Size: p. 9769-9772 : , digital, PDF file.
• Bộ sưu tập: Metadata
• ID: 255631
• Chủ đề: 1. 30 direct energy conversion; 2. 32 energy conservation, consumption, and utilization; 3. 77 nanoscience and nanotechnology; 4. Energy transfer; 5. Excitons; 6. Light absorption; 7. Luminescence; 8. Precursors

Tóm tắt

Photon upconversion employing semicon- ductor nanocrystals (NCs) makes use of their large and tunable absorption to harvest light in the near-infrared (NIR) wavelengths as well as their small gap between singlet and triplet excited states to reduce energy losses. In this work, we report the highest QY (11.8%) thus far for the conversion of NIR to yellow photons by improving the quality of the PbS NC. This high QY was achieved by using highly purified lead and thiourea precursors. This QY is 2.6 times higher than from NCs prepared with commercially available lead and sulfide precursors. Transient absorption spectroscopy reveals two reasons for the enhanced QY: longer intrinsic exciton lifetimes of PbS NCs and the ability to support a longer triplet lifetime for the surface-bound transmitter molecule. Overall, this results in a higher efficiency of triplet exciton transfer from the PbS NC light absorber to the emitter and thus a higher photon upconversion QY.