Inorganic semiconductor nanocrystals interfaced with spin-triplet exciton-accepting organic molecules have emerged as promising materials for converting incoherent long-wavelength light into the visible range. However, these materials to date have made exclusive use of nanocrystals containing toxic elements, precluding their use in biological or environmentally sensitive applications. Here, we address this challenge by chemically functionalizing non-toxic silicon nanocrystals with triplet-accepting anthracene ligands. Photoexciting these structures drives spin-triplet exciton transfer from silicon to anthracene through a single 15 ns Dexter energy transfer step with a nearly 50% yield. When paired with 9,10-diphenylanthracene emitters, these particles readily upconvert 488–640 nm photons to 425 nm violet light with efficiencies as high as 7 ± 0.9% and can be readily incorporated into aqueous micelles for biological use. Our demonstration of spin-triplet exciton transfer from silicon to molecular triplet acceptors can critically enable new technologies for solar energy conversion, quantum information and near-infrared driven photocatalysis.
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Experimental data and fits to this data produced using the MATLAB software are available from the authors upon request.
The MATLAB code used in the fitting analysis of transient absorption spectra is available from the authors upon request.
Ravetz, B. D. et al. Photoredox catalysis using infrared light via triplet fusion upconversion. Nature 565, 343–346 (2019).
Tayebjee, M. J. Y., McCamey, D. R. & Schmidt, T. W. Beyond Shockley–Queisser: molecular approaches to high-efficiency photovoltaics. J. Phys. Chem. Lett. 6, 2367–2378 (2015).
Chen, S. et al. Near-infrared deep brain stimulation via upconversion nanoparticle–mediated optogenetics. Science 359, 679–684 (2018).
Lin, X. et al. Core–shell–shell upconversion nanoparticles with enhanced emission for wireless optogenetic inhibition. Nano Lett. 18, 948–956 (2018).
Wu, M. et al. Solid-state infrared-to-visible upconversion sensitized by colloidal nanocrystals. Nat. Photon. 10, 31–34 (2015).
Huang, Z. et al. Hybrid molecule–nanocrystal photon upconversion across the visible and near-infrared. Nano Lett. 15, 5552–5557 (2015).
Mongin, C., Garakyaraghi, S., Razgoniaeva, N., Zamkov, M. & Castellano, F. N. Direct observation of triplet energy transfer from semiconductor nanocrystals. Science 351, 369–372 (2016).
Li, X., Fast, A., Huang, Z., Fishman, D. A. & Tang, M. L. Complementary lock-and-key ligand binding of a triplet transmitter to a nanocrystal photosensitizer. Angew. Chem. Int. Ed. 56, 5598–5602 (2017).
Li, X., Huang, Z., Zavala, R. & Tang, M. L. Distance-dependent triplet energy transfer between CdSe nanocrystals and surface bound anthracene. J. Phys. Chem. Lett. 7, 1955–1959 (2016).
Garakyaraghi, S. & Castellano, F. N. Nanocrystals for triplet sensitization: molecular behavior from quantum-confined materials. Inorg. Chem. 57, 2351–2359 (2018).
Mangolini, L., Thimsen, E. & Kortshagen, U. High-yield plasma synthesis of luminescent silicon nanocrystals. Nano Lett. 5, 655–659 (2005).
Limpens, R., Pach, G. F. & Neale, N. R. Nonthermal plasma-synthesized phosphorus–boron co-doped Si nanocrystals: a new approach to nontoxic NIR-emitters. Chem. Mater. 31, 4426–4435 (2019).
Hessel, C. M. et al. Synthesis of ligand-stabilized silicon nanocrystals with size-dependent photoluminescence spanning visible to near-infrared wavelengths. Chem. Mater. 24, 393–401 (2012).
Wilson, M. W. B. et al. Ultrafast dynamics of exciton fission in polycrystalline pentacene. J. Am. Chem. Soc. 133, 11830–11833 (2011).
Burdett, J. J., Müller, A. M., Gosztola, D. & Bardeen, C. J. Excited state dynamics in solid and monomeric tetracene: the roles of superradiance and exciton fission. J. Chem. Phys. 133, 144506 (2010).
Sanders, S. N. et al. Quantitative intramolecular singlet fission in bipentacenes. J. Am. Chem. Soc. 137, 8965–8972 (2015).
Zirzlmeier, J. et al. Singlet fission in pentacene dimers. Proc. Natl Acad. Sci. USA 112, 5325–5330 (2015).
Eaton, S. W. et al. Singlet exciton fission in polycrystalline thin films of a slip-stacked perylenediimide. J. Am. Chem. Soc. 135, 14701–14712 (2013).
Le, A. K. et al. Singlet fission involves an interplay between energetic driving force and electronic coupling in perylenediimide films. J. Am. Chem. Soc. 140, 814–826 (2018).
Johnson, J. C., Nozik, A. J. & Michl, J. High triplet yield from singlet fission in a thin film of 1,3-diphenylisobenzofuran. J. Am. Chem. Soc. 132, 16302–16303 (2010).
Wang, C. & Tauber, M. J. High-yield singlet fission in a zeaxanthin aggregate observed by picosecond resonance Raman spectroscopy. J. Am. Chem. Soc. 132, 13988–13991 (2010).
Lukman, S. et al. Efficient singlet fission and triplet-pair emission in a family of zethrene diradicaloids. J. Am. Chem. Soc. 139, 18376–18385 (2017).
Hanna, M. C. & Nozik, A. J. Solar conversion efficiency of photovoltaic and photoelectrolysis cells with carrier multiplication absorbers. J. Appl. Phys. 100, 074510 (2006).
Futscher, M. H., Rao, A. & Ehrler, B. The potential of singlet fission photon multipliers as an alternative to silicon-based tandem solar cells. ACS Energy Lett. 3, 2587–2592 (2018).
Weiss, L. R. et al. Strongly exchange-coupled triplet pairs in an organic semiconductor. Nat. Phys. 13, 176–181 (2017).
Einzinger, M. et al. Sensitization of silicon by singlet exciton fission in tetracene. Nature 571, 90–94 (2019).
Han, Y. et al. Visible-light-driven sensitization of naphthalene triplets using quantum-confined CsPbBr3 nanocrystals. J. Phys. Chem. Lett. 10, 1457–1463 (2019).
Huang, Z. et al. Enhanced near-infrared-to-visible upconversion by synthetic control of PbS nanocrystal triplet photosensitizers. J. Am. Chem. Soc. 141, 9769–9772 (2019).
Mahboub, M., Huang, Z. & Tang, M. L. Efficient infrared-to-visible upconversion with subsolar irradiance. Nano Lett. 16, 7169–7175 (2016).
Huang, Z. & Tang, M. L. Designing transmitter ligands that mediate energy transfer between semiconductor nanocrystals and molecules. J. Am. Chem. Soc. 139, 9412–9418 (2017).
Okumura, K., Mase, K., Yanai, N. & Kimizuka, N. Employing core-shell quantum dots as triplet sensitizers for photon upconversion. Chem. Eur. J. 22, 7721–7726 (2016).
Yanai, N. & Kimizuka, N. New triplet sensitization routes for photon upconversion: thermally activated delayed fluorescence molecules, inorganic nanocrystals, and singlet-to-triplet absorption. Acc. Chem. Res. 50, 2487–2495 (2017).
Wheeler, L. M. et al. Silyl radical abstraction in the functionalization of plasma-synthesized silicon nanocrystals. Chem. Mater. 27, 6869–6878 (2015).
Kroupa, D. M. et al. Control of energy flow dynamics between tetracene ligands and PbS quantum dots by size tuning and ligand coverage. Nano Lett. 18, 865–873 (2018).
Bender, J. A. et al. Surface states mediate triplet energy transfer in nanocrystal–acene composite systems. J. Am. Chem. Soc. 140, 7543–7553 (2018).
Davis, N. J. L. K. et al. Singlet fission and triplet transfer to PbS quantum dots in TIPS-tetracene carboxylic acid ligands. J. Phys. Chem. Lett. 9, 1454–1460 (2018).
Carroll, G. M., Limpens, R. & Neale, N. R. Tuning confinement in colloidal silicon nanocrystals with saturated surface ligands. Nano Lett. 18, 3118–3124 (2018).
Montalti, M., Credi, A., Prodi, L. & Gandolfi, M. T. Handbook of Photochemistry (CRC Press, Taylor and Francis, 2006).
Evans, D. F. Perturbation of singlet–triplet transitions of aromatic molecules by oxygen under pressure. J. Chem. Soc. 1351–1357 (1957).
Dexter, D. L. A theory of sensitized luminescence in solids. J. Chem. Phys. 21, 836–850 (1953).
Yu, Y. et al. Size-dependent photoluminescence efficiency of silicon nanocrystal quantum dots. J. Phys. Chem. C 121, 23240–23248 (2017).
Stolle, C. J., Lu, X., Yu, Y., Schaller, R. D. & Korgel, B. A. Efficient carrier multiplication in colloidal silicon nanorods. Nano Lett. 17, 5580–5586 (2017).
Garakyaraghi, S., Mongin, C., Granger, D. B., Anthony, J. E. & Castellano, F. N. Delayed molecular triplet generation from energized lead sulfide quantum dots. J. Phys. Chem. Lett. 8, 1458–1463 (2017).
Sanders, S. N., Gangishetty, M. K., Sfeir, M. Y. & Congreve, D. N. Photon upconversion in aqueous nanodroplets. J. Am. Chem. Soc. 141, 9180–9184 (2019).
Kouno, H., Sasaki, Y., Yanai, N. & Kimizuka, N. Supramolecular crowding can avoid oxygen quenching of photon upconversion in water. Chem. Eur. J. 25, 6124–6130 (2019).
Kim, J.-H. & Kim, J.-H. Encapsulated triplet–triplet annihilation-based upconversion in the aqueous phase for sub-band-gap semiconductor photocatalysis. J. Am. Chem. Soc. 134, 17478–17481 (2012).
Marsico, F. et al. Hyperbranched unsaturated polyphosphates as a protective matrix for long-term photon upconversion in air. J. Am. Chem. Soc. 136, 11057–11064 (2014).
Weissleder, R. A clearer vision for in vivo imaging. Nat. Biotechnol. 19, 316–317 (2001).
Dexter, D. L. Two ideas on energy transfer phenomena: ion-pair effects involving the OH stretching mode, and sensitization of photovoltaic cells. J. Lumin. 18, 779–784 (1979).
MacQueen, R. W. et al. Crystalline silicon solar cells with tetracene interlayers: the path to silicon-singlet fission heterojunction devices. Mater. Horiz. 5, 1065–1075 (2018).
S.T.R. and E.K.R. acknowledge support from the National Science Foundation (CHE-1610412), the Robert A. Welch Foundation (grant F-1885) and the Research Corporation for Science Advancement (grant no. 24489). E.K.R. also acknowledges partial support from a Leon O. Morgan fellowship. M.L.T. acknowledges an Air Force Office of Scientific Research (AFOSR) Award (FA9550-19-1-0092) for equipment, the DOE (DE-SC0018969) for salary support, and the Alfred P. Sloan Foundation. L.M. and D.C. acknowledge support from the National Science Foundation under CAREER award no. 1351386.
The authors declare no competing interests.
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Xia, P., Raulerson, E.K., Coleman, D. et al. Achieving spin-triplet exciton transfer between silicon and molecular acceptors for photon upconversion. Nat. Chem. 12, 137–144 (2020). https://doi.org/10.1038/s41557-019-0385-8
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