TY - JOUR
T1 - Photochemical upconversion of near-infrared light from below the silicon bandgap
AU - Gholizadeh, Elham M.
AU - Prasad, Shyamal K.K.
AU - Teh, Zhi Li
AU - Ishwara, Thilini
AU - Norman, Sarah
AU - Petty, Anthony J.
AU - Cole, Jared H.
AU - Cheong, Soshan
AU - Tilley, Richard D.
AU - Anthony, John E.
AU - Huang, Shujuan
AU - Schmidt, Timothy W.
N1 - Publisher Copyright:
© 2020, The Author(s), under exclusive licence to Springer Nature Limited.
PY - 2020/9/1
Y1 - 2020/9/1
N2 - Photochemical upconversion is a strategy for converting infrared light into more energetic, visible light, with potential applications ranging from biological imaging and drug delivery to photovoltaics and photocatalysis. Although systems have been developed for upconverting light from photon energies in the near-infrared, upconversion from below the silicon bandgap has been out of reach. Here, we demonstrate an upconversion composition using PbS semiconductor nanocrystal sensitizers that absorb photons below the bandgap of silicon and populate violanthrone triplet states below the singlet oxygen energy. The triplet-state violanthrone chromophores luminesce in the visible spectrum following energy delivery from two singlet oxygen molecules. By incorporating organic chromophores as ligands onto the PbS nanocrystals to improve energy transfer, we demonstrate that violanthrone upconverts in the absence of oxygen by the triplet–triplet annihilation mechanism. The change in mechanism is shown by exploiting the magnetic field effect on triplet–triplet interactions.
AB - Photochemical upconversion is a strategy for converting infrared light into more energetic, visible light, with potential applications ranging from biological imaging and drug delivery to photovoltaics and photocatalysis. Although systems have been developed for upconverting light from photon energies in the near-infrared, upconversion from below the silicon bandgap has been out of reach. Here, we demonstrate an upconversion composition using PbS semiconductor nanocrystal sensitizers that absorb photons below the bandgap of silicon and populate violanthrone triplet states below the singlet oxygen energy. The triplet-state violanthrone chromophores luminesce in the visible spectrum following energy delivery from two singlet oxygen molecules. By incorporating organic chromophores as ligands onto the PbS nanocrystals to improve energy transfer, we demonstrate that violanthrone upconverts in the absence of oxygen by the triplet–triplet annihilation mechanism. The change in mechanism is shown by exploiting the magnetic field effect on triplet–triplet interactions.
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U2 - 10.1038/s41566-020-0664-3
DO - 10.1038/s41566-020-0664-3
M3 - Article
AN - SCOPUS:85088243319
SN - 1749-4885
VL - 14
SP - 585
EP - 590
JO - Nature Photonics
JF - Nature Photonics
IS - 9
ER -