Publications

Prof. Wilson’s Google Scholar page.
Prof. Wilson’s ORCID page.

31. Philippe B. Green, Zhibo Wang, Christian J. Imperial, Oleksandr Voznyy, and Mark W.B. Wilson
Glycol ether additives control the size of PbS nanocrystals at reaction completion
Journal of Materials Chemistry C, 8:12068-12074 (2020)

In the colloidal synthesis of PbS quantum dots, added glycol ethers variably suppress the formation of metastable cluster intermediates. This achieves control of nanocrystal size in reactions run to completion.

Improving chemical control over the nucleation and growth of colloidal nanocrystals advances optoelectronic applications. Here, we followed from our previous work, and found that added glycol ethers promote the nucleation of PbS nanocrystals over the formation of metastable clusters, offering orthogonal control of nanocrystal size at reaction completion. This effect correlates with multidentate co-ordination to Pb(oleate)_2, corroborated by DFT calculations from our collaborators in Prof. Voznyy’s Clean Energy group at UofT Scarborough.

Want the story straight from Philippe? Check out his WilsonLab ResearchTalk , where he gives an overview of his discovery of the key role of pre-nucleation clusters in the colloidal synthesis of PbS quantum dots.

30. Minhal Hasham and Mark W.B. Wilson
Sub-Bandgap Optical Modulation of Quantum Dot Blinking Statistics
Journal of Physical Chemistry Letters, 11:6404-6412 (2020)

We develop an all-optical modulation scheme and demonstrate that sub-bandgap light tuned to the stimulated emission transition perturbs the blinking statistics of individual CdSe/ZnS core/shell QDs. Resonant optical modulation progressively suppresses long-duration ON events, quantified by a power-law slope that is more negative on average (Δα_ON = 0.46 ± 0.09), while OFF distributions and truncation times are unaffected. Colloidal quantum dots (QDs) suffer from ‘blinking’—a pervasive phenomenon where their fluorescence erratically switches on and off. Though blinking frustrates applications and correlates with irreversible photodegradation, the mechanism has remained unclear despite extensive study. Here, Minhal describes how we developed a technique to perturb individual CdSe|ZnS quantum dots using a sub-bandgap laser while monitoring their fluorescence, which included designing an algorithm to robustly distinguish the weak emission of a single quantum dot from the background laser scatter. This allowed us to examine the statistics of blinking and find something unexpected—not only does optical modulation resonant to the stimulated emission transition suppress long-duration ON events, it does so (statistically speaking) in a timescale-free manner. Our observations support mechanistic descriptions of blinking that go beyond first-order kinetics, and show that optical modulation of individual quantum dots can be a new experimental avenue to disentangle the complex photophysics of blinking.

Would you like to hear more? You’re in luck! In one of the first WilsonLab ResearchTalks , Minhal gives a nine-minute overview of his work!

29. Philippe B. Green, Pournima Narayanan, Ziqi Li, Philip Sohn, Christian J. Imperiale, and Mark W.B. Wilson
Controlling Cluster Intermediates Enables the Synthesis of Small PbS Nanocrystals with Narrow Ensemble Line Widths
Chemistry of Materials, 32(9):4083–4094 (2020)

Graphs showing that amine additives accelerate PbS nanocrystal nucleation by suppressing a cluster intermediate, leading to narrower ensemble linewidths for small (diameter less than 4nm) nanocrystalsPhilippe discovered that small, lead-rich pre-nucleation clusters are formed pervasively in conventional synthesis of PbS nanocrystals. These clusters complicate the kinetics of nucleation and growth, and have frustrated efforts to obtain narrow size-dispersities. Philippe then found that the clusters can be controllably suppressed with amine additives to yield unprecedentedly narrow ensemble line-widths for ultra-small (<4nm) particles. Better energetic dispersity will improve energy transport in quantum dot devices 

28. Christian J. Imperiale, Philippe B. Green, Ethan G. Miller, Niels H. Damrauer, and Mark W.B. Wilson
Triplet-Fusion Upconversion Using a Rigid Tetracene Homodimer
Journal of Physical Chemistry Letters, 10(23):7463–7469 (2019)

Red laser light is converted to yellow emission by a solution including a norbornyl-bridged tetracene dimerChristian headed a collaborative effort that discovered that TIPS-bistetracene, a rigid molecular dimer recently synthesized in the Damrauer Group at University of Colorado Boulder, not just achieves triplet fusion upconversion, but does so with unusual efficiency. Moreover, our comprehensive effort—combining optical spectroscopy and kinetic modelling—showed that the upconversion photophysics of the dimer are fundamentally different than conventional monomeric annihilators, and hint that the beneficial involvement of the overall-spin-quintet biexcitonic state might break through the conventional spin-statistical performance limit! 

27. Philippe B. Green, Ziqi Li, and Mark W.B. Wilson
PbS Nanocrystals Made with Excess PbCl2 Have an Intrinsic Shell that Reduces Their Stokes Shift
Journal of Physical Chemistry Letters, 10(19):5897–5901 (2019)

Philippe and Ziqi show that PbS nanocrystals synthesized using excess PbCl2 (per Wiedman after Cademartiri) are physically larger than nanocrystals with the same optical gap made conventionally (per Hines). We then found that  excess-lead-chloride nanocrystals show lattice strain and reduced Stokes shifts at intermediate sizes, all consistent with the presence of an chloride-containing shell. Our work, alongside contemporary reports, reconciles previously-unexplained differences between these materials and gives guidance for their use in devices


26. Lea Nienhaus, Mengfei Wu, Nadav Geva, James J. Shepherd, Mark W.B. Wilson, Vladimir Bulovic, Troy Van Voorhis, Marc A. Baldo, and Moungi G. Bawendi
A Speed Limit for Triplet Exciton Transfer in Solid-State PbS Nanocrystal-Sensitized Photon Upconversion
ACS Nano, 11(8):7848–7857 (2017)

25. Riley E. Brandt, Jeremy R. Poindexter, Prashun Gorai, Rachel C. Kurchin, Robert L. Z. Hoye, Lea Nienhaus, Mark W. B. Wilson, J. Alexander Polizzotti, Raimundas Sereika, Raimundas Žaltauskas, Lana C. Lee, Judith L. MacManus-Driscoll, Moungi Bawendi, Vladan Stevanovic, and Tonio Buonassisi
Searching for “defect-tolerant” photovoltaic materials: Combined theoretical and experimental screening
Chemistry of Materials, 29(11):4667–4674 (2017)

24. Oliver T. Bruns†, Thomas S. Bischof†, Daniel K. Harris, Daniel Franke, Yanxiang Shi, Lars Riedemann, Alexander Bartelt, Frank B. Jaworski, Jessica A. Carr, Christopher J. Rowlands, Mark W.B. Wilson, Ou Chen, He Wei, Gyu Weon Hwang, Daniel Montana, Igor Coropceanu, Odin B. Achorn, Jonas Kloepper, Joerg Heeren, Peter T.C. So, Dai Fukumura, Klavs F. Jensen, Rakesh K. Jain, and Moungi G. Bawendi
Next-generation in vivo optical imaging with short-wave infrared quantum dots
Nature Biomedical Engineering, 0056 (2017)
†These authors contributed equally.
* Highlighted in a ‘News & Views’ in Nature Biomedical Engineering
* Highlighted in an MIT Press Release
* Highlighted in a ‘News & Events‘ by the National Institute of Biomedical Imaging and Bioengineering

23. Daniel Franke, Daniel K. Harris, Ou Chen, Oliver T. Bruns, Jessica A. Carr, Mark W.B. Wilson, and Moungi G. Bawendi
Continuous injection synthesis of indium arsenide quantum dots emissive in the short-wavelength infrared
Nature Communications 12749 (2016)

22. Justin R. Caram, Sophie N. Bertram, Hendrik Utzat, Whitney R. Hess, Jessica A. Carr, Thomas S. Bischof, Andrew P. Beyler, Mark W.B. Wilson, and Moungi G. Bawendi
PbS Nanocrystal Emission Is Governed by Multiple Emissive States
Nano Letters 16(10):6070–6077 (2016)

21. Mengfei Wu†, Daniel N. Congreve†, Mark W.B. Wilson†, Joel Jean, Nadav Geva, Matthew Welborn, Troy Van Voorhis, Vladimir Bulovic, Moungi G. Bawendi, and Marc A. Baldo
Solid-state infrared-to-visible upconversion sensitized by colloidal nanocrystals
Nature Photonics 10:31–34 (2016)
†These authors contributed equally
*Cited more than 100 times

20. Robert L.Z. Hoye, Riley E. Brandt, Anna Osherov, Vladan Stevanovic, Samuel D. Stranks, Mark W.B. Wilson, Hyunho Kim, Austin J. Akey, John D. Perkins, Rachel C. Kurchin, Jeremy R. Poindexter, Evelyn N. Wang, Moungi G. Bawendi, Vladimir Bulovic, and Tonio Buonassisi
Methylammonium bismuth iodide as a lead-free, stable hybrid organic-inorganic solar absorber
Chemistry – A European Journal 22(8):2605–2610 (2016)
*Cited more than 100 times

19. Artem A. Bakulin, Sarah E. Morgan, Tom B. Kehoe, Mark W.B. Wilson, Alex W. Chin,
Donatas Zigmantas, Dassia Egorova, and Akshay Rao
Real-Time Observation of Multiexcitonic States in Ultrafast Singlet Fission Using Coherent 2D Electronic Spectroscopy
Nature Chemistry 8:16–23 (2016)
*Cited more than 100 times

18. Riley E. Brandt, Rachel C. Jurchin, Robert L.Z. Hoye, Jeremy R. Poindexter, Mark W.B. Wilson, Soumitra Sulekar, Frances Lenahan, Patricia X.T. Yen, Vladan Stevanocic, Juan C. Nino, Moungi G. Bawendi, and Tonio Buonassisi
Investigation of bismuth triiodide for photovoltaic applications
Journal of Physical Chemistry Letters 6:4297–4302 (2015)

17. Gyu Weon Hwang, Donghun Kim, Jose M. Cordero, Mark W.B. Wilson, Chia-Hao M. Chuang, Jeffrey C. Grossman, and Moungi G. Bawendi
Identifying and Eliminating Emissive Sub-bandgap States in Thin Films of PbS Nanocrystals
Advanced Materials 27(30):4481–4486 (2015)

16. Nicholas J. Thompson†, Mark W.B. Wilson†, Daniel N. Congreve†, Patrick R. Brown, Jennifer M. Scherer, Thomas S. Bischof, Mengfei Wu, Nadav Geva, Matthew Welborn, Troy Van Voorhis, Vladimir Bulovic, Moungi G. Bawendi, and Marc A. Baldo
Energy harvesting of non-emissive triplet excitons in tetracene by emissive PbS nanocrystals
Nature Materials 13:1039–1043 (2014)
†These authors contributed equally.
*Highlighted in a ‘News & Views’ in Nature Materials
*Cited more than 100 times

15. Shane R. Yost†, Jiye Lee†, Mark W.B. Wilson, Tony Wu, David P. McMahon, Rebecca R. Parkhurst, Nicholas J. Thompson, Daniel N. Congreve, Akshay Rao, Kerr Johnson, Matthew Y. Sfeir, Moungi G. Bawendi, Timothy M. Swager, Richard H. Friend, Marc A. Baldo, and Troy Van Voorhis
A transferable model for singlet-fission kinetics
Nature Chemistry 6:492–497 (2014)
*Cited more than 200 times

14. Mark W.B. Wilson, Akshay Rao, Kerr Johnson, Simon Gélinas, Riccardo di Pietro, Jenny Clark, and Richard H. Friend
Temperature-Independent Singlet Exciton Fission in Tetracene
Journal of the American Chemical Society 135(44):16680–16688 (2013)
*Selected for a ‘JACS Spotlight
*Cited more than 100 times

13. Jian Cui, Andrew P. Beyler, Thomas S. Bischof, Mark W.B. Wilson, and Moungi G. Bawendi
Deconstructing the photon stream from single nanocrystals: from binning to correlation
Chemical Society Reviews 43:1287–1310 (2013)

12. Mark W.B. Wilson, Akshay Rao, Bruno Ehrler, and Richard H. Friend
Singlet Exciton fission in polycrystalline pentacene: From photophysics toward devices
Accounts of Chemical Research 46(6):1330–1338 (2013)
*Cited more than 100 times

11. Andrey D. Poletayev, Jenny Clark, Mark W.B. Wilson, Akshay Rao, Yoshitaka Makino, Shu Hotta, and Richard H. Friend
Triplet Dynamics in Pentacene Crystals: Applications to Fission-Sensitized Photovoltaics
Advanced Materials 26(6):919–924 (2013)

10. Bruno Ehrler, Brian J.Walker, Marcus L. Böhm, Mark W.B. Wilson, Yana Vaynzof, Richard H. Friend, and Neil C. Greenham
In situ measurement of exciton energy in hybrid singlet-fission solar cells
Nature Communications 3:1019 (2012)
*Cited more than 100 times

9. Simon Gélinas, James Kirkpatrick, Ian A. Howard, Kerr Johnson, Mark W.B. Wilson, Giuseppina Pace, Richard H. Friend, and Carlos Silva
Recombination dynamics of charge pairs in a push-pull polyfluorene-derivative
The Journal of Physical Chemistry B 117(16):4649–4653 (2012)

8. Bruno Ehrler, Mark W.B. Wilson, Akshay Rao, and Richard H. Friend
Singlet exciton fission-sensitized infrared quantum dot solar cells
Nano Letters 12(2):1053–1057 (2012)
*Cited more than 100 times

7. Mark W.B. Wilson, Akshay Rao, Jenny Clark, R. Sai Santosh Kumar, Daniele Brida, Giulio Cerullo, and Richard H. Friend
Ultrafast dynamics of exciton fission in polycrystalline pentacene
Journal of the American Chemical Society 133(31):11830–11833 (2011)
*Cited more than 200 times

6. Richard H. Friend, Matthew Phillips, Akshay Rao, Mark W.B. Wilson, Zhe Li, and
Christopher R. McNeill
Excitons and charges at organic semiconductor heterojunctions
Faraday Discussions 155:339–348 (2011)

5. Akshay Rao, Mark W.B. Wilson, Sebastian Albert-Seifried, Riccardo Di Pietro, Richard H. Friend
Photophysics of pentacene thin films: The role of exciton fission and heating effects
Physical Review B 84(19):195411 (2011)

4. Akshay Rao†, Mark W.B. Wilson†, Justin M. Hodgkiss, Sebastian Albert-Seifried, Heinz Bässler, and Richard H. Friend
Exciton fission and charge generation via triplet excitons in pentacene/C60 bilayers
Journal of the American Chemical Society 132(36):12698–12703 (2010)
†These authors contributed equally.
*Cited more than 200 times, highlighted in a ‘News & Views’ in Nature Materials

3. Yee-Fan Xiao, Tam Q. Nhan, Mark W.B. Wilson, and James M. Fraser
Saturation of the Photoluminescence at Few-Exciton Levels in a Single-Walled Carbon Nanotube under Ultrafast Excitation
Physical Review Letters 104(1):1–4 (2010)

2. Natalie O.V. Plank, Ian A. Howard, Akshay Rao, Mark W.B. Wilson, Caterina Ducati,
Rajaram Sakharam Mane, James S. Bendall, Rami R.M. Louca, Neil C. Greenham, Hidetoshi Miura, Richard H. Friend, Henry J. Snaith, and Mark E. Welland
Efficient ZnO Nanowire Solid-State Dye-Sensitized Solar Cells Using Organic Dyes and Core-Shell Nanostructures
The Journal of Physical Chemistry C 113(43):18515-18522 (2009)

1. Jack Barnes, Brent Carver, James M. Fraser, Gianluca Gagliardi, Hans-Peter Loock, Zhaobing Tian, Mark W.B. Wilson, Scott Yam, and Oksana Yastubshak
Loss determination in microsphere resonators by phase-shift cavity ring-down measurements
Optics Express 16(17):13158–13167 (2008)