The Nobel Prize in Chemistry 2023 has been awarded to

• Moungi G. Bawendi, Massachusetts Institute of Technology (MIT), Cambridge, MA, USA,
• Louis E. Brus, Columbia University, New York, NY, USA, and
• Alexei Ekimov, Nanocrystals Technology Inc., New York, NY, USA,

for “the discovery and synthesis of quantum dots” [1].

 

Research

Quantum Dots

It has long been known that, in theory, nanoparticles could show size-dependent quantum effects, but few people believed that this knowledge would be put to practical use. This year’s Laureates have succeeded in producing particles so small that their properties are determined by quantum phenomena. The particles, which are called quantum dots, are of great importance in nanotechnology.

Quantum dots constitute a new class of materials that differs from both molecular and bulk materials. They have the same composition as bulk materials, but their properties can be tuned using a single parameter, the particle’s size. For example, the optical absorption and emission of CdSe quantum dots can be tuned across nearly the entire visible range of the optical spectrum.

 

Quantum Dots in a Glass Matrix

Around 1980, Alexei Ekimov succeeded in creating size-dependent quantum effects in colored glass [2–4]. The color came from copper chloride nanoparticles. By varying the temperature and duration of heat treatment during the production of the glass, the average size of CuCl particles could be controlled. Ekimov demonstrated that the particle size affected the color of the glass via quantum effects [5–7].

 

Colloidal Quantum Dots

Louis Brus was the first scientist in the world to prove size-dependent quantum effects in particles floating freely in a fluid [8,9]. In 1983, he investigated CdS crystallites prepared in solution, and found that there were differences between fresh and aged particles—the latter recrystallized to form larger particles. The larger aged particles featured an excitation spectrum like that expected for bulk CdS; the fresh, smaller particles showed a blue shift.

 

Improved Synthesis of Quantum Dots

In 1993, Moungi Bawendi revolutionized the chemical production of quantum dots, resulting in high-quality particles [10], which are necessary for applications. The synthesis begins with the injection of organometallic precursors for the desired nanoparticles into a hot solvent and immediate pyrolysis. This results in abrupt supersaturation and in a nucleation that takes place at a well-defined moment. The injection is accompanied by a sudden drop in temperature and dilution of the precursors such that growth stops.

After reheating to the desired growth temperature, a slow growth and annealing process takes place in a coordinating solvent that helps to stabilize the resulting colloidal dispersion. Finally, particles can be selected using purification and size-dependent precipitation to obtain monodisperse nanoparticles.

 

Applications

Quantum dots now illuminate computer monitors and television screens based on QLED technology (quantum-dot light-emitting diodes). They are also used for biomedical imaging. In the future, they could contribute, e.g., to flexible electronics, tiny sensors, thinner solar cells, and encrypted quantum communication.

 

Laureates

Moungi G. Bawendi, born in 1961 in Paris, France, studied chemistry at Harvard University, Cambridge, MA, USA, and received his Ph.D. from the University of Chicago, IL, USA. As a postdoctoral fellow, he worked with Louis Brus at AT&T Bell Laboratories. In 1990, he joined the faculty of MIT, becoming an Associate Professor in 1995 and a Full Professor in 1996.

Among his many honors, he received the Raymond and Beverly Sackler International Prize in Chemistry (“Physical Sciences”) in 2001, the Ernest Orlando Lawrence Prize in 2006, and the American Chemical Society (ACS) Award in Colloid Chemistry in 2010. He has been a Sloan Research Fellow since 1994, a member of the American Academy of Arts and Sciences since 2004, and a member of the National Academy of Sciences since 2007.

 

Louis E. Brus, born in 1943 in Cleveland, OH, USA, studied chemistry at Rice University, Houston, TX, USA, and received his Ph.D. in chemical physics from Columbia University, New York, NY, USA, in 1969. From 1969 to 1973, he conducted research at the U.S. Naval Research Laboratory (NRL), Washington, D.C., and then at Bell Laboratories until 1996. He has been a Professor at Columbia University since 1996.

Among his many honors, he received the Irving Langmuir Prize in Chemical Physics from the American Physical Society in 2001, the Chemistry of Materials Prize from the ACS in 2005, and the Welch Award in Chemistry in 2013. He has been a member of the American Physical Society since 1980, the American Academy of Arts and Sciences since 1998, and the National Academy of Sciences since 2004.

 

Alexei I. Ekimov, born in 1945 in the former USSR, received his Ph.D. in physics in 1974 from the Ioffe Physical-Technical Institute in Leningrad, USSR. Since 1999, Alexei Ekimov has lived and worked in the USA, currently, he is at Nanocrystals Technology Inc., New York, NY, USA.

Among many other honors, he received the USSR State Prize in Physics and Technology in 1975, the Alexander von Humboldt Prize in 2006 for his work on quantum dots, and the R. W. Wood Prize in 2006, shared with Louis Brus and Alexander Efros. He holds several patents.

 

References

[1] nobelprize.org

[2] A. L. Efros, L. E. Brus, Nanocrystal Quantum Dots: From Discovery to Modern Development, ACS Nano 2021, 15, 6192–6210. https://doi.org/10.1021/acsnano.1c01399

[3] A. Ekimov, A. A. Onushchenko, V. Tsekhomskii, Exciton light absorption by CuCl microcrystals in glass matrix, Sov. Glass Phys. Chem. 1980, 6, 511-512.

[4] V. V. Golubkov, A. Ekimov, A. A. Onushchenko, V. Tsekhomskii, Growth kinetics of CuCl microcrystals in a glassy matrix, Fizika i Khimiya Stekla 1980, 7, 397-40

[5] A. Ekimov, A. A. Onushchenko, Quantum Size Effect in Three-Dimensional Microscopic Semiconductor Crystals, JETP Lett. 1981, 34, 345-349.

[6] A. Ekimov, A. A. Onushchenko,  Quantum Size Effect in the Optical Spectra of Semiconductor Micro-Crystals, Sov. Phys. Semicond. 1982, 16, 775-778.

[7] A. Ekimov, A. A. Onushchenko, A. G. Plyukhin, A. L. Efros, Size Quantization of Excitons and Determination of Their Energy-Spectrum Parameters in CuCl, Sov. Phys. JETP 1985, 61, 891−897.

[8] L. E. Brus, A simple model for the ionization potential, electron affinity, and aqueous redox potentials of small semiconductor crystallites, J. Chem. Phys. 1983, 79, 5566–5571. https://doi.org/10.1063/1.445676

[9] R. Rossetti, J. L. Ellison, J. M. Gibson, L. E. Brus, Size effects in the excited electronic states of small colloidal CdS crystallites, J. Chem. Phys. 1984, 80, 4464–4469. https://doi.org/10.1063/1.447228

[10] C. B. Murray, D. J. Norris, M. G. Bawendi, Synthesis and characterization of nearly monodisperse CdE (E = sulfur, selenium, tellurium) semiconductor nanocrystallites, J. Am. Chem. Soc. 2002, 115, 8706–8715. https://doi.org/10.1021/ja00072a025

 

Selected Publications

Selected Publications of Moungi G. Bawendi

• C. Chen, X. Luo, A. E. K. Kaplan, M. G. Bawendi, R. J. Macfarlane, M. Bathe, Ultrafast dense DNA functionalization of quantum dots and rods for scalable 2D array fabrication with nanoscale precision, Sci. Adv. 2023. https://doi.org/10.1126/sciadv.adh8508
• J. J. Yoo, G. Seo, M. R. Chua, T. G. Park, Y. Lu, F. Rotermund, Y.-K. Kim, C. S. Moon, N. J. Jeon, J.-P. Correa-Baena, V. Bulović, S. S. Shin, M. G. Bawendi, J. Seo, Efficient perovskite solar cells via improved carrier management, Nature 2021, 590,  587–593. https://doi.org/10.1038/s41586-021-03285-w
• Ha. S. Choi, W. Liu, P. Misra, E. Tanaka, J. P. Zimmer, B. I. Ipe, M. G. Bawendi, J. V. Frangioni, Renal clearance of quantum dots, Nat. Biotechnol. 2007, 25, 1165–1170. https://doi.org/10.1038/nbt1340
• C.-H. M. Chuang, P. R. Brown, V. Bulović, M. G. Bawendi, Improved performance and stability in quantum dot solar cells through band alignment engineering, Nat. Mater. 2014, 13, 796–801. https://doi.org/10.1038/nmat3984
• Y. Shirasaki, G. J. Supran, M. G. Bawendi, V. Bulović, Emergence of colloidal quantum-dot light-emitting technologies, Nat. Photonics 2013, 7,  13–23. https://doi.org/10.1038/nphoton.2012.328
• O. Chen, J. Zhao, V. P. Chauhan, J. Cui, C. Wong, D. K. Harris, H. Wei, H.-S. Han, D. Fukumura, R. K. Jain, M. G. Bawendi, Compact high-quality CdSe–CdS core–shell nanocrystals with narrow emission linewidths and suppressed blinking, Nat. Mater. 2013, 12,  445–451. https://doi.oirg/10.1038/nmat3539

 

Selected Publications of Louis E. Brus

• A. Raja, L. E. Brus, Non-local dielectric effects in nanoscience featured, J. Chem. Phys. 2023, 159, 020901. https://doi.org/10.1063/5.0150293
• Y. Guo, O. Yaffe, T. D. Hull, J. S. Owen, D. R. Reichman, L. E. Brus, Dynamic emission Stokes shift and liquid-like dielectric solvation of band edge carriers in lead-halide perovskites, Nat. Commun. 2019. https://doi.org/10.1038/s41467-019-09057-5
• T. J. S. Evans, A. Schlaus, Y. Fu, X. Zhong, T. L. Atallah, M. S. Spencer, L. E. Brus, Song Jin, X.-Y. Zhu, Continuous-Wave Lasing in Cesium Lead Bromide Perovskite Nanowires, Adv. Opt. Mater.  2017. https://doi.org/10.1002/adom.201700982
• A. Raja, A. Chaves, J. Yu, G. Arefe, H. M. Hill, A. F. Rigosi, T. C. Berkelbach, P. Nagler, C. Schüller, T. Korn, C. Nuckolls, J. Hone, L. E. Brus, T. F. Heinz, D. R. Reichman, A. Chernikov, Coulomb engineering of the bandgap and excitons in two-dimensional materials, Nat. Commun. 2017. https://doi.org/10.1038/ncomms15251
• C. Lee, H. Yan, L. E. Brus, T. F. Heinz, J. Hone, S. Ryu, Anomalous Lattice Vibrations of Single- and Few-Layer MoS₂, ACS Nano 2010, 4, 5, 2695–2700. https://doi.org/10.1021/nn1003937
• Y.-J. Yu, Y. Zhao, Su. Ryu, L. E. Brus, K. S. Kim, P. Kim, Tuning the Graphene Work Function by Electric Field Effect, Nano Lett. 2009, 9(10), 3430–3434. https://doi.org/10.1021/nl901572a

 

Selected Publications of A. Ekimov

• D. M. Hoffman, B. K. Meyer, A. I. Ekimov, I. A. Merkulov, A. L. Efros, M. Rosen, G. Couino, T. Gacoin, J. P. Boilot, Giant internal magnetic fields in Mn doped nanocrystal quantum dots, Solid State Commun. 2000, 114, 547–550. https://doi.org/10.1016/S0038-1098(00)00089-2
• A. A. Sirenko, V. I. Belitsky, T. Ruf, M. Cardona, A. I. Ekimov, C. Trallero-Giner,, Spin-flip and acoustic-phonon Raman scattering in CdS nanocrystals, Phys. Rev. B 1998, 58, 2077–2087. https://doi.org/10.1103/PhysRevB.58.2077
• A. I. Ekimov, I. A. Kudryavtsev, Al. L. Efros, T. V. Yazeva, F. Hache, M. C. Schanne-Klein, A. V. Rodina, D. Ricard, C. Flytzanis, Absorption and intensity-dependent photoluminescence measurements on CdSe quantum dots: assignment of the first electronic transitions, J. Opt. Soc. Am. B 1993, 10, 100. https://doi.org/10.1364/JOSAB.10.000100
• D. I. Chepic, A. L. Efros, A. I. Ekimov, M. G. Ivanov, V. A. Kharchenko, I. A. Kudriavtsev, T. V. Yazeva, Auger ionization of semiconductor quantum drops in a glass matrix, J. Lumin. 1990, 47, 113–127. https://doi.org/10.1016/0022-2313(90)90007-X
• A. I. Ekimov, A. L. Efros, A. A. Onushchenko, Quantum size effect in semiconductor microcrystals, Solid State Commun. 1985, 56, 921–624. https://doi.org/10.1016/S0038-1098(85)80025-9

 

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