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   https://doi.org/10.1021/acsnano.7b06444  

   Shepard, Gabriella D.; Ardelean, Jenny V.; Ajayi, Obafunso A.; Rhodes, Daniel; Zhu, Xiaoyang; Hone, James C.; Strauf, Stefan (September 2017, ACS Nano)
2. Quantum-Cutting Ytterbium-Doped CsPb(Cl _1–x Br _x ) ₃ Perovskite Thin Films with Photoluminescence Quantum Yields over 190%

   https://doi.org/10.1021/acsenergylett.8b01528  

   Kroupa, Daniel M.; Roh, Joo Yeon; Milstein, Tyler J.; Creutz, Sidney E.; Gamelin, Daniel R. (September 2018, ACS Energy Letters)
3. Polysalt ligands achieve higher quantum yield and improved colloidal stability for CsPbBr ₃ quantum dots

   https://doi.org/10.1039/d1nr04753a  

   Wang, Sisi; Du, Liang; Donmez, Selin; Xin, Yan; Mattoussi, Hedi (October 2021, Nanoscale)

   Colloidal lead halide perovskite quantum dots (PQDs) are relatively new semiconductor nanocrystals with great potential for use in optoelectronic applications. They also present a set of new scientifically challenging fundamental problems to investigate and understand. One of them is to address the rather poor colloidal and structural stability of these materials under solution phase processing and/or transfer between solvents. In this contribution, we detail the synthesis of a new family of multi-coordinating, bromide-based polysalt ligands and test their ability to stabilize CsPbBr 3 nanocrystals in polar solutions. The ligands present multiple salt groups involving quaternary cations, namely ammonium and imidazolium as anchors for coordination onto PQD surfaces, along with several alkyl chains with varying chain length to promote solubilization in various conditions. The ligands provide a few key benefits including the ability to repair damaged surface sites, allow rapid ligand exchange and phase transfer, and preserve the crystalline structure and morphology of the nanocrystals. The polysalt-coated PQDs exhibit near unity PLQY and significantly enhanced colloidal stability in ethanol and methanol. 

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4. Picosecond Quantum Cutting Generates Photoluminescence Quantum Yields Over 100% in Ytterbium-Doped CsPbCl ₃ Nanocrystals

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   Milstein, Tyler J.; Kroupa, Daniel M.; Gamelin, Daniel R. (May 2018, Nano Letters)
5. Rovibrational quantum state resolution of the C ₆₀ fullerene

   https://doi.org/10.1126/science.aav2616  

   Changala, P. Bryan; Weichman, Marissa L.; Lee, Kevin F.; Fermann, Martin E.; Ye, Jun (January 2019, Science)

   The unique physical properties of buckminsterfullerene, C 60 , have attracted intense research activity since its original discovery. Total quantum state–resolved spectroscopy of isolated C 60 molecules has been of particularly long-standing interest. Such observations have, to date, been unsuccessful owing to the difficulty in preparing cold, gas-phase C 60 in sufficiently high densities. Here we report high-resolution infrared absorption spectroscopy of C 60 in the 8.5-micron spectral region (1180 to 1190 wave number). A combination of cryogenic buffer-gas cooling and cavity-enhanced direct frequency comb spectroscopy has enabled the observation of quantum state–resolved rovibrational transitions. Characteristic nuclear spin statistical intensity patterns confirm the indistinguishability of the 60 carbon-12 atoms, while rovibrational fine structure encodes further details of the molecule’s rare icosahedral symmetry. 

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