Highly luminescent water-dispersible NIR-emitting wurtzite CuInS2

Subscriber access provided by CORNELL UNIVERSITY LIBRARY

Article

Highly luminescent water-dispersible NIR-emitting wurtzite CuInS2/ZnS core/shell colloidal quantum dots Chenghui Xia, Johannes D. Meeldijk, Hans C Gerritsen, and Celso de Mello Donegá Chem. Mater., Just Accepted Manuscript • Publication Date (Web): 22 May 2017 Downloaded from http://pubs.acs.org on May 23, 2017

Just Accepted “Just Accepted” manuscripts have been peer-reviewed and accepted for publication. They are posted online prior to technical editing, formatting for publication and author proofing. The American Chemical Society provides “Just Accepted” as a free service to the research community to expedite the dissemination of scientific material as soon as possible after acceptance. “Just Accepted” manuscripts appear in full in PDF format accompanied by an HTML abstract. “Just Accepted” manuscripts have been fully peer reviewed, but should not be considered the official version of record. They are accessible to all readers and citable by the Digital Object Identifier (DOI®). “Just Accepted” is an optional service offered to authors. Therefore, the “Just Accepted” Web site may not include all articles that will be published in the journal. After a manuscript is technically edited and formatted, it will be removed from the “Just Accepted” Web site and published as an ASAP article. Note that technical editing may introduce minor changes to the manuscript text and/or graphics which could affect content, and all legal disclaimers and ethical guidelines that apply to the journal pertain. ACS cannot be held responsible for errors or consequences arising from the use of information contained in these “Just Accepted” manuscripts.

Chemistry of Materials is published by the American Chemical Society. 1155 Sixteenth Street N.W., Washington, DC 20036 Published by American Chemical Society. Copyright © American Chemical Society. However, no copyright claim is made to original U.S. Government works, or works produced by employees of any Commonwealth realm Crown government in the course of their duties.

Page 1 of 41

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Chemistry of Materials

Highly luminescent water-dispersible NIRemitting wurtzite CuInS2/ZnS core/shell colloidal quantum dots Chenghui Xia,a,b Johannes D. Meeldijk,c Hans C. Gerritsen,b and Celso de Mello Donegaa* a. Condensed Matter and Interfaces, Debye Institute for Nanomaterials Science, Utrecht University, P.O. Box 80000, 3508 TA Utrecht, The Netherlands b. Molecular Biophysics, Debye Institute for Nanomaterials Science, Utrecht University, 3508 TA Utrecht, Netherlands. c. Electron Microscopy Utrecht, Debye Institute for Nanomaterials Science, Utrecht University, 3584 CH Utrecht, Netherlands.

*Corresponding author: E-mail: [email protected]

1 ACS Paragon Plus Environment


1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Page 2 of 41

ABSTRACT. Copper indium sulfide (CIS) QDs are attractive as labels for biomedical imaging since they have large absorption coefficients across a broad spectral range, size- and composition-tunable photoluminescence from the visible to the near-infrared, and low toxicity. However, the application of NIR-emitting CIS QDs is still hindered by large size and shape dispersions and low photoluminescence quantum yields (PLQYs). In this work, we develop an efficient pathway to synthesize highly luminescent NIR-emitting wurtzite CIS/ZnS QDs, starting from template Cu2-xS nanocrystals (NCs), which are converted by topotactic partial Cu+ for In3+ exchange into CIS NCs. These NCs are subsequently used as cores for the overgrowth of ZnS shells (≤ 1 nm thick). The CIS/ZnS core/shell QDs exhibit PL tunability from the first- to the second NIR window (750 - 1100 nm), with PLQYs ranging from 75% (at 820 nm) to 25% (at 1050 nm), and can be readily transferred to water upon exchange of the native ligands for mercaptoundecanoic acid. The resulting water-dispersible CIS/ZnS QDs possess good colloidal stability over at least 6 months and PLQYs ranging from 39% (at 820 nm) to 6% (at 1050 nm). These PLQYs are superior to those of commonly available water-soluble NIR-fluorophores (dyes and QDs), making the hydrophilic CIS/ZnS QDs developed in this work promising candidates for further application as NIR-emitters in bioimaging. The hydrophobic CIS/ZnS QDs obtained immediately after the ZnS shelling are also attractive as fluorophores in luminescent solar concentrators.


Page 3 of 41

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


INTRODUCTION

Colloidal semiconductor quantum dots (QDs) have attracted much attention as luminescent probes for bioimaging due to their outstanding optical properties, such as broad absorption spectra, narrow photoluminescence (PL), large absorption cross-sections, high PL quantum yields (PLQYs), and high photostability, which make them superior to organic dyes and fluorescent proteins.1 Moreover, their PL can be tuned throughout the visible to the near-infrared (NIR) spectral window by controlling their composition and size.1 These properties have been translated into higher sensitivity, multiplexed detection (i.e., multiple PL colors upon single excitation wavelength), and longer observation times.1 Colloidal QDs can also be used as multimodal probes, allowing two or more imaging techniques (e.g., MRI and optical) to be combined.2 NIRemitting QDs are of particular interest, since wavelengths in the first and second biological spectral windows (viz. 650-950 nm and 1000-1350 nm, respectively)3 penetrate much deeper in tissue than visible light, while inducing negligible autofluorescence.3-5 However, most currently used NIR-emitting QDs contain highly toxic elements such as Cd, Pb, and As (e.g., CdTe,6-8 CdSe/CdTe,9 Cd3P2,10 InAs,11, 12 PbS,13-15 PbSe16), which severely hinders their application as biolabels. The search for less toxic alternatives is therefore becoming an increasingly relevant topic. Amongst the alternatives, copper indium sulfide (CIS) QDs are particularly promising, since they combine low toxicity17-19 with large absorption coefficients across a broad spectral range and unparalleled PL tunability, spanning a spectral window that covers the PL tunability of CdSe (visible), InP and CdTe/CdSe (visible and first NIR biological window), and PbS (second NIR biological window).20 Nevertheless, to date high PLQYs (≥50%) have only been reported for CIS/ZnS and CIS/CdS core/shell QDs with core diameters below 4 nm and PL up to 750 nm.17-19, 3 ACS Paragon Plus Environment


1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

21-24

Page 4 of 41

Although luminescent CIS QDs larger than 4 nm have also been reported,21, 25-27 their size

and shape dispersion is typically quite large due to the difficulty in balancing the reactivities of multiple precursors (In, Cu, S).20 Partial topotactic Cu+ for In3+ cation exchange (CE) in template Cu2-xS nanocrystals (NCs) has been recently established as an effective strategy to circumvent these limitations,28, 29 allowing the preparation of monodisperse luminescent CIS QDs and NCs of sizes and shapes that would not be easily attainable by direct routes. Interestingly, CIS QDs and NCs obtained by CE adopt the hexagonal wurtzite (WZ) structure, instead of the cubic chalcopyrite (CP) structure typically observed for CIS QDs synthesized by direct routes.28, 29 This creates new opportunities to expand the spectral tunability of CIS QDs, since WZ CIS QDs emit at lower energies than their CP counterparts.30 The PLQY of bare CIS QDs is however low (8), so as to deprotonate the thiol group, thereby ensuring a strong bond between the thiolate head-group and the surface of the CIS/ZnS QDs. However, the high pH will also give rise to the formation of disulfide bonds that may trap the photogenerated hole, resulting in PL quenching.49 To prevent disulfide formation, reducing agents (e.g., sodium borohydride,51 dithiothreitol,52 TCEP49) are commonly added during the phase transfer. In this work, tris-(2carboxyethyl)phosphine hydrochloride (TCEP) was chosen as the reducing agent due to its high efficiency and low contamination during biolabeling.53 The phase transfer was accomplished at pH ~11.6, which resulted in a high concentration of deprotonated MUA thiolate groups that exchanged the native ligands at the surface of CIS/ZnS core/shell QDs, thereby making them hydrophilic (Figure 5). The average Zeta potential of these water-dispersible CIS/ZnS core/shell QDs is about -60 mV (SI Figure S20). The negatively charged surface is attributed to the deprotonation of the carboxyl groups of MUA. This assignment is confirmed by a weak stretching mode of the COOH group at 1720 cm-1 and the appearance of a new band at 1398 cm-1, which is related to the symmetric vibration modes of the COO- group (SI Figure S20).



1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Page 28 of 41

Figure 5. Schematic illustration of the phase transfer of CIS/ZnS core/shell QDs by ligand exchange using MUA in the presence of TCEP at pH~11.6. The optical properties and morphology of ~5 nm diameter WZ CIS/ZnS core/shell QDs before and after phase-transfer to water are shown in Figure 6. The average size and polydispersity of the QDs are not significantly affected by the phase-transfer procedure (Figure 6b), and the resulting negatively-charged QDs are colloidally stable in water for long periods of time (at least 6 months). The hydrodynamic size of the CIS/ZnS core/shell QDs is 14.2 ± 2.7 nm (SI Figure S20). The absorption spectra of the QDs before and after the transfer are indistinguishable (figure 6a), indicating that they remain intact and that no aggregates are formed, which is also clearly demonstrated by the TEM images (Figure 6b and SI, Figure S21). The PLQY decreases from 75% to 39% after phase-transfer (Figure 6). The PL spectrum also remains essentially the same, apart from a small blue-shift (19 meV) from 820 nm to 810 nm. The origin of this blue-shift is not yet understood, but may be related to the effect of the negative surface charges on the amplitude of


Page 29 of 41

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


the electron wavefunction near the QD surface (assuming that the hole is localized within the core, as discussed above).

Figure 6. (a) Absorption and PL spectra of ∼5 nm CIS/ZnS core/shell QDs before and after phase transfer into water. (b) TEM images and size histograms of CIS/ZnS core/shell QDs before (left) and after (right) ligand exchange (larger area TEM images are given in the SI, Figure S21).

A decrease in PLQY from 26% to 6% upon phase-transfer to water was also observed for 9.2 nm CIS/ZnS core/shell QDs emitting at 1050 nm (SI Figure S22). Reductions in PLQY upon transfer of core/shell QDs to water are commonly observed,17,18,54 and are attributed to insufficient shell quality in part of the QD ensemble.54 In the present case, the drop in the PLQY of the CIS/ZnS core/shell QDs in water may be interpreted as an indication that the ZnS shell in some of the QDs is not yet sufficiently robust to withstand the high pHs required for the ligand exchange. Therefore, it is likely that further improvements in the ZnS shell thickness and quality will lead to higher PLQYs after the phase transfer. Nevertheless, it should be noted that the PLQYs observed in the present work (viz. 39% at 810 nm and 6% at 1030 nm) are rather high for 29 ACS Paragon Plus Environment


1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Page 30 of 41

NIR-emitters in water, and are very competitive with respect to the currently available NIRemitting QDs and dyes (CIS/ZnS QDs: 20% at 800 nm,18 8% at 830 nm,17 Indocyanine green: 12% at 835 nm in DMSO,35 IR-140: 17% at 830 nm,55 ONITCP: 2.3% at 900 nm,55 ODNITCP: 1.4% at 930 nm55). It is worth noting that the stability of the hydrophilic CIS/ZnS core/shell QDs in water is also competitive, since they can be stored in the dark at 4 ˚C for at least 6 months with negligible PL loss. Moreover, these QDs are carboxyl terminated and can thus be easily functionalized with specific proteins or biomacromolecules,8,12,17,18,51,56-58 what makes them promising as NIR-emitting labels for bioimaging.

CONCLUSIONS In conclusion, we have developed a sequential procedure to synthesize highly luminescent waterdispersible NIR-emitting wurtzite CIS/ZnS core/shell QDs. The procedure starts from nearly spherical template Cu2-xS NCs, which are converted into wurtzite CIS QDs with size and shape preservation by topotactic partial Cu+ for In3+ cation exchange at 125 °C. The use of a nearly stoichiometric TOP/In ratio (0.9) ensures that the Cu+-extraction and In3+-incorporation rates remain coupled despite relatively high reaction temperatures, leading to a highly versatile and fast method to obtain CIS QDs in the 3 to 8 nm size range (polydispersity of ~10%). The product CIS QDs can be readily overcoated by a thin (≤1 nm) wurtzite ZnS shell, resulting in CIS/ZnS core/shell QDs with PL tunable from the first to the second NIR-window (750 - 1100 nm) with high PLQYs (e.g. 75 % at 820 nm and 25 % at 1050 nm). These wurtzite CIS/ZnS core/shell QDs are

subsequently

transferred

to

water

upon

exchange

of

the

native

ligands

by

mercaptoundecanoic acid. The resulting water-dispersible CIS/ZnS core/shell QDs have PLQYs ranging from 39 % (at 810 nm) to 6 % (at 1030 nm) and good colloidal stability over at least 6 30 ACS Paragon Plus Environment

Page 31 of 41

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


months, and are thus promising candidates for in-vivo bioimaging applications. It should be noted that the hydrophobic CIS/ZnS QDs obtained immediately after the ZnS shell overgrowth are also attractive as fluorophores in luminescent solar concentrators due to their large absorption crosssections throughout the UV-visible- NIR spectral range, high PLQYs (75% at 820 nm, which is an ideal wavelength in combination with Si solar cells), and large effective Stokes shifts, which would maximize harvesting of the solar spectrum while minimizing reabsorption losses.59-61

ASSOCIATED CONTENT Supporting Information. PL and absorption spectra of indocyanine green, TEM images and size histograms of Cu2-xS NCs in the 3 to 9.5 nm size range, optical spectra and TEM images of CIS QDs obtained under different synthesis conditions, XRD patterns and EDS spectra of Cu2-xS NCs and CIS QDs obtained by slow and fast CE, EDS spectra of CIS and CIS/ZnS core/shell QDs, representative PL decay curves of CIS QDs and CIS/ZnS QDs, FTIR spectra, TEM images, hydrodynamic size and Zeta potential of CIS/ZnS QDs before and after ligand exchange and phase transfer to water. This material is available free of charge via the Internet at http://pubs.acs.org.

ACKNOWLEDGMENTS Chenghui Xia would like to acknowledge China Scholarship Council (CSC) for financial support (NO. 201406330055). The authors thank Da Wang for TEM measurements, Gang Wang and Donglong Fu for XRD measurements, Ward van der Stam for PL lifetime measurements and suggestions concerning the cation exchange reactions, and Chun-Che Lin and Elleke van Harten 31 ACS Paragon Plus Environment


1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Page 32 of 41

for suggestions regarding the ligand exchange. The authors are also grateful to the Soft Condensed Matter group (Debye Institute for Nanomaterials Science, Utrecht University) for providing access to Fourier transform infrared spectroscopy, Zeta Potential and Dynamic Light Scattering measurements.

REFERENCES (1) Wegner, K. D.; Hildebrandt, N., Quantum Dots: Bright and Versatile in Vitro and in Vivo Fluorescence Imaging Biosensors. Chem. Soc. Rev. 2015, 44, 4792-4834. (2) Skajaa, T.; Zhao, Y.; van den Heuvel, D. J.; Gerritsen, H. C.; Cormode, D. P.; Koole, R.; van Schooneveld, M. M.; Post, J. A.; Fisher, E. A.; Fayad, Z. A.; de Mello Donega, C.; Meijerink, A.; Mulder, W. J. M., Quantum Dot and Cy5.5 Labeled Nanoparticles to Investigate Lipoprotein Biointeractions via Förster Resonance Energy Transfer. Nano Lett. 2010, 10, 51315138. (3) Smith, A. M.; Mancini, M. C.; Nie, S., Bioimaging: Second Window for in Vivo Imaging. Nat. Nanotech. 2009, 4, 710-711. (4) Lim, Y. T.; Kim, S.; Nakayama, A.; Stott, N. E.; Bawendi, M. G.; Frangioni, J. V., Selection of Quantum Dot Wavelengths for Biomedical Assays and Imaging. Mol. Imaging 2003, 2, 50-64. (5) Jacques, S. L., Optical Properties of Biological Tissues: A Review. Phys. Med. Biol. 2013, 58, R37-R61.


Page 33 of 41

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


(6) Cai, W.; Shin, D.-W.; Chen, K.; Gheysens, O.; Cao, Q.; Wang, S. X.; Gambhir, S. S.; Chen, X., Peptide-Labeled Near-Infrared Quantum Dots for Imaging Tumor Vasculature in Living Subjects. Nano Lett. 2006, 6, 669-676. (7) Zhang, W.; Zhang, H.; Feng, Y.; Zhong, X., Scalable Single-Step Noninjection Synthesis of High-Quality Core/Shell Quantum Dots with Emission Tunable from Violet to Near Infrared. ACS Nano 2012, 6, 11066–11073. (8) Wang, J.; Lu, Y.; Peng, F.; Zhong, Y.; Zhou, Y.; Jiang, X.; Su, Y.; He, Y., Photostable Water-Dispersible NIR-emitting CdTe/CdS/ZnS Core-Shell-Shell Quantum Dots for HighResolution Tumor Targeting. Biomaterials 2013, 34, 9509-9518. (9) Pan, H.; Zhang, P.; Gao, D.; Zhang, Y.; Li, P.; Liu, L.; Wang, C.; Wang, H.; Ma, Y.; Cai, L., Noninvasive Visualization of Respiratory Viral Infection Using Bioorthogonal Conjugated Near-Infrared-Emitting Quantum Dots. ACS Nano 2014, 8, 5468–5477. (10) Miao, S.; Hickey, S. G.; Rellinghaus, B.; Waurisch, C.; Eychmüller, A., Synthesis and Characterization of Cadmium Phosphide Quantum Dots Emitting in the Visible Red to NearInfrared. J. Am. Chem. Soc. 2010, 132, 5613–5615. (11) Allen, P. M.; Liu, W.; Chauhan, V. P.; Lee, J.; Ting, A. Y.; Fukumura, D.; Jain, R. K.; Bawendi, M. G., InAs(ZnCdS) Quantum Dots Optimized for Biological Imaging in the NearInfrared. J. Am. Chem. Soc. 2010, 132, 470-471. (12) Zimmer, J. P.; Kim, S. W.; Ohnishi, S.; Tanaka, E.; Frangioni, J. V.; Bawendi, M. G., Size Series of Small Indium Arsenide-Zinc Selenide Core-Shell Nanocrystals and Their Application to In Vivo Imaging. J. Am. Chem. Soc. 2006, 128, 2526-2527.



1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Page 34 of 41

(13) Hines, M. A.; Scholes, G. D., Colloidal PbS Nanocrystals with Size-Tunable Near-Infrared Emission: Observation of Post Synthesis self-Narrowing of the Particle Size Distribution. Adv. Mater. 2003, 15, 1844-1849. (14) Pichaandi, J.; Abel, K. A.; Johnson, N. J. J.; van Veggel, F. C. J. M., Long-Term Colloidal Stability and Photoluminescence Retention of Lead-Based Quantum Dots in Saline Buffers and Biological Media through Surface Modification. Chem. Mater. 2013, 25, 2035-2044. (15) Justo, Y.; Geiregat, P.; van Hoecke, K.; Vanhaecke, F.; Donega, C. d. M.; Hens, Z., Optical properties of PbS/CdS core/shell quantum dots. J. Phys. Chem. C 2013, 117, 2017120177. (16) Shuhendler, A. J.; Prasad, P.; Chan, H. K. C.; Gordijo, C. R.; Soroushian, B; Kolios, M.; Yu, K.; O'Brien, P. J.; Rauth, A. M. ; Wu, X. Y., Hybrid Quantum Dot-Fatty Ester Stealth Nanoparticles: Toward Clinically Relevant in Vivo Optical Imaging of Deep Tissue. ACS Nano 2011, 5, 1958-1966. (17) Li, L.; Daou, T. J.; Texier, I.; Chi, T. T. K.; Liem, N. Q.; Reiss, P., Highly Luminescent CuInS2/ZnS Core/Shell Nanocrystals: Cadmium-Free Quantum Dots for In Vivo Imaging. Chem. Mater. 2009, 21, 2422–2429. (18) Pons, T.; Pic, E.; Lequeux, N.; Cassette, E.; Bezdetnaya, L.; Guillemin, F.; Marchal, F.; Dubertret, B., Cadmium-Free CuInS2/ZnS Quantum Dots for Sentinel Lymph Node Imaging with Reduced Toxicity. ACS Nano 2010, 4, 2531–2538.


Page 35 of 41

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


(19) Speranskaya, E. S.; Sevrin, C.; De Saeger, S.; Hens, Z.; Goryacheva, I. Y.; Grandfils, C., Synthesis of Hydrophilic CuInS2/ZnS Quantum Dots with Different Polymeric Shells and Study of Their Cytotoxicity and Hemocompatibility. ACS Appl. Mater. Interfaces 2016, 8, 7613-7622. (20) van der Stam, W.; Berends, A. C.; de Mello Donega, C., Prospects of Colloidal Copper Chalcogenide Nanocrystals. Chemphyschem 2016, 17, 559-581. (21) Zhong, H.; Lo, S. S.; Mirkovic, T.; Li, Y.; Ding, Y.; Li, Y.; Scholes, G. D., Noninjection Gram-Scale Synthesis of Monodisperse Pyramidal CuInS2 Nanocrystals and Their SizeDependent Properties. ACS Nano 2010, 4, 5253–5262. (22) Chuang, P. H.; Lin, C. C.; Liu, R. S., Emission-Tunable CuInS2/ZnS Quantum Dots: Structure, Optical Properties, and Application in White Light-Emitting Diodes with High Color Rendering Index. ACS Appl. Mater. Interfaces 2014, 6, 15379-15387. (23) Li, L.; Pandey, A.; Werder, D. J.; Khanal, B. P.; Pietryga, J. M.; Klimov, V. I., Efficient Synthesis of Highly Luminescent Copper Indium Sulfide-Based Core/Shell Nanocrystals with Surprisingly Long-Lived Emission. J. Am. Chem. Soc. 2011, 133, 1176-1179. (24) Xia, C.; Cao, L.; Liu, W.; Su, G.; Gao, R.; Qu, H.; Shi, L.; He, G., One-step Synthesis of Near-infrared Emitting and Size Tunable CuInS2 Semiconductor Nanocrystals by Adjusting Kinetic Variables. CrystEngComm 2014, 16, 7469–7477. (25) Panthani, M. G.; Akhavan, V.; Goodfellow, B.; Schmidtke, J. P.; Dunn, L.; Dodabalapur, A.; Barbara, P. F.; Korgel, B. A., Synthesis of CuInS2, CuInSe2, and Cu(InxGa1-x)Se2 (CIGS) Nanocrystal “Inks” for Printable Photovoltaics. J. Am. Chem. Soc. 2008, 130, 16770–16777.



1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Page 36 of 41

(26) Leach, A. D. P.; Mast, L. G.; Hernández-Pagán, E. A.; Macdonald, J. E., Phase Dependent Visible to Near-Infrared Photoluminescence of CuInS2 Nanocrystals. J. Mater. Chem. C 2015, 3, 3258-3265. (27) Xie, R.; Rutherford, M.; Peng, X., Formation of High-Quality I-III-VI Semiconductor Nanocrystals by Tuning Relative Reactivity of Cationic Precursors. J. Am. Chem. Soc. 2009, 131, 5691-5697. (28) van der Stam, W.; Berends, A. C.; Rabouw, F. T.; Willhammar, T.; Ke, X.; Meeldijk, J. D.; Bals, S.; de Mello Donega, C., Luminescent CuInS2 Quantum Dots by Partial Cation Exchange in Cu2–xS Nanocrystals. Chem. Mater. 2015, 27, 621-628. (29) van der Stam, W.; Bladt, E.; Rabouw, F. T.; Bals, S.; de Mello Donega, C., Near-Infrared Emitting CuInSe2/CuInS2 Dot Core/Rod Shell Heteronanorods by Sequential Cation Exchange. ACS Nano 2015, 9, 11430–11438. (30) Leach, A. D. P.; Shen, X.; Faust, A.; Cleveland, M. C.; La Croix, A. D.; Banin, U.; Pantelides, S. T.; Macdonald, J. E., Defect Luminescence from Wurtzite CuInS2 Nanocrystals: Combined Experimental and Theoretical Analysis. J. Phys. Chem. C 2016, 120, 5207-5212. (31) Berends, A. C.; Rabouw, F. T.; Spoor, F. C. M.; Bladt, E.; Grozema, F. C.; Houtepen, A. J.; Siebbeles, L. D. A.; de Mello Donegá, C., Radiative and Nonradiative Recombination in CuInS2 Nanocrystals and CuInS2-Based Core/Shell Nanocrystals. J. Phys. Chem. Lett. 2016, 7, 3503-3509. (32) Akkerman, Q. A.; Genovese, A.; George, C.; Prato, M.; Moreels, I.; Casu, A.; Marras, S.; Curcio, A.; Scarpellini, A.; Pellegrino, T.; Manna, L.; Lesnyak, V., From Binary Cu2S to Ternary


Page 37 of 41

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


Cu-In-S and Quaternary Cu-In-Zn-S Nanocrystals with Tunable Composition via Partial Cation Exchange. ACS Nano 2015, 9, 521-531. (33) Wang, Y.; Hu, Y.; Zhang, Q.; Ge, J.; Lu, Z.; Hou, Y.; Yin, Y., One-pot Synthesis and Optical Property of Copper(I) Sulfide Nanodisks. Inorg. Chem. 2010, 49, 6601-6608. (34) Tamang, S.; Beaune, G.; Texier, I.; Reiss, P., Aqueous Phase Transfer of InP/ZnS Nanocrystals Conserving Fluorescence and High Colloidal Stability. ACS Nano 2011, 5, 9392– 9402. (35) Benson, R. C.; Kues, H. A., Fluorescence Properties of Indocyanine Green as Related to Angiography. Phys. Med. Biol. 1978, 23, 159-163. (36) Mu, L.; Wang, F.; Sadtler, B.; Loomis, R. A.; Buhro, W. E., Influence of the Nanoscale Kirkendall Effect on the Morphology of Copper Indium Disulfide Nanoplatelets Synthesized by Ion Exchange. ACS Nano 2015, 9, 7419-7428. (37) Pearson, R. G. Absolute Electronegativity and Hardness: Application to Inorganic Chemistry Inorg. Chem. 1988, 27, 734–740. (38) Donega, C. d. M. Synthesis and Properties of Colloidal Heteronanocrystals. Chem. Soc. Rev. 2011, 40, 1512–1546. (39) Boles, M. A.; Ling, D.; Hyeon, T.; Talapin, D. V., The Surface Science of Nanocrystals. Nature Mater. 2016, 15, 141-153. (40) Leach, A. D. P.; Macdonald, J. E., Optoelectronic Properties of CuInS2 Nanocrystals and Their Origin. J. Phys. Chem. Lett. 2016, 7, 572-583.



1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Page 38 of 41

(41) Donega, C. d. M.; Koole, R., Size Dependence of the Spontaneous Emission Rate and Absorption Cross Section of CdSe and CdTe Quantum Dots. J. Phys. Chem. C 2009, 113, 65116520. (42) De Trizio, L.; Prato, M.; Genovese, A.; Casu, A.; Povia, M.; Simonutti, R.; Alcocer, M. J. P.; D'Andrea, C.; Tassone, F.; Manna, L., Strongly Fluorescent Quaternary Cu-In-Zn-S Nanocrystals Prepared from Cu1-xInS2 Nanocrystals by Partial Cation Exchange. Chem. Mater. 2012, 24, 2400-2406. (43) Park, J.; Kim, S. -W., CuInS2/ZnS Core/Shell Quantum Dots by Cation Exchange and Their Blue-Shifted Photoluminescence. J. Mater. Chem. 2011, 21, 3745-3750. (44) Nam, D. -E.; Song, W. -S.; Yang, H., Facile, Air-Insensitive Solvothermal Synthesis of Emission-Tunable CuInS2/ZnS Quantum Dots With High Quantum Yields. J. Mater. Chem. 2011, 21,18220-18226. (45) Groeneveld, E.; Witteman, L.; Lefferts, M.; Ke, X.; Bals, S.; van Tendeloo, G.; Donega, C. d. M., Tailoring ZnSe-CdSe Colloidal Quantum Dots via Cation Exchange: From Core/Shell to Alloy Nanocrystals. ACS Nano 2013, 7, 7913-7930. (46) Shabaev, A.; Mehl, M. J.; Efros, A. L. Energy Band Structure of CuInS2 and Optical Spectra of CuInS2 Nanocrystals. Phys. Rev. B 2015, 92, 035431. (47) Knowles, K. E.; Nelson, H. D.; Kilburn, T. B.; Gamelin, D. R. Singlet–Triplet Splittings in the Luminescent Excited States of Colloidal Cu+:CdSe, Cu+:InP, and CuInS2 Nanocrystals: Charge-Transfer Configurations and Self-Trapped Excitons. J. Am. Chem. Soc. 2015, 137, 13138–13147.


Page 39 of 41

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


(48) Knowles, K. E.; Hartstein, K. H.; Kilburn, T. B.; Marchioro, A.; Nelson, H. D.; Whitham, P. J.; Gamelin, D. R. Luminescent Colloidal Semiconductor Nanocrystals Containing Copper: Synthesis, Photophysics, and Applications. Chem. Rev. 2016, 116, 10820-10851. (49) Tamang, S.; Beaune, G.; Texier, I.; Reiss, P., Aqueous Phase Transfer of InP/ZnS Nanocrystals Conserving Fluorescence and High Colloidal Stability. ACS Nano 2011, 5, 93929402. (50) Pong, B.-K.; Trout, B. L.; Lee, J.-Y., Modified Ligand-Exchange for Efficient Solubilization of CdSe/ZnS Quantum Dots in Water: A Procedure Guided by Computational Studies. Langmuir 2008, 24, 5270-5276. (51) Susumu, K.; Mei, B. C.; Mattoussi, H., Multifunctional Ligands Based on Dihydrolipoic Acid and Polyethylene Glycol to Promote Biocompatibility of Quantum Dots. Nat. Protoc. 2009, 4, 424-436. (52) Pathak, S.; Davidson, M. C.; Silva, G. A., Characterization of the Functional Binding Properties of Antibody Conjugated Quantum Dots. Nano Lett. 2007, 7, 1839-1845. (53) Getz, E. B.; Xiao, M.; Chakrabarty, T.; Cooke, R.; Selvin, P. R., A Comparison between the Sulfhydryl Reductants Tris(2-carboxyethyl)phosphine and Dithiothreitol for Use in Protein Biochemistry. Anal. Biochem. 1999, 273, 73-80. (54) Liu, W.; Hak, S. C.; Zimmer, J. P.; Tanaka, E.; Frangioni, J. V.; Bawendi, M., Compact Cysteine-Coated CdSe(ZnCdS) Quantum Dots for in Vivo Applications. J. Am. Chem. Soc. 2007, 129, 14530-14531.



1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Page 40 of 41

(55) Rurack, K.; Spieles, M., Fluorescence Quantum Yields of a Series of Red and NearInfrared Dyes Emitting at 600−1000 nm. Anal. Chem. 2011, 83, 1232-1242. (56) Hong, G.; Robinson, J. T.; Zhang, Y.; Diao, S.; Antaris, A. L.; Wang, Q.; Dai, H., In Vivo Fluorescence Imaging with Ag2S Quantum Dots in the Second Near-Infrared Region. Angew. Chem. Int. Ed. Engl. 2012, 51, 9818-9821. (57) Yong, K. T.; Ding, H.; Roy, I.; Law, W. C.; Bergey, E. J.; Maitra, A.; Prasad, P. N., Imaging Pancreatic Cancer Using Bioconjugated InP Quantum Dots. ACS Nano 2009, 3, 502– 510. (58) Zhang, Y.; Hong, G.; Zhang, Y.; Chen, G.; Li, F.; Dai, H.; Wang, Q., Ag2S Quantum Dot: A Bright and Biocompatible Fluorescent Nanoprobe in the Second Near-Infrared Window. ACS Nano 2012, 6, 3695–3702. (59) Krumer, Z.; Pera, S. J.; van Dijk-Moes, R. J. A. ; Zhao, Y.; de Brouwer, A. F. P.; Groeneveld, E.; van Sark, W. G. J. H. M.; Schropp, R. E. I.; de Mello Donega, C. Sol. Energy Mater. Sol. Cells 2013, 111, 57–65. (60) Knowles, K. E.; Kilburn, T. B.; Alzate, D. G.; McDowall, S.; Gamelin, D. R., Bright CuInS2/CdS Nanocrystal Phosphors for High-Gain Full-Spectrum Luminescent Solar Concentrators. Chem. Commun. 2015, 51, 9129–9132. (61) Meinardi, F.; McDaniel, H.; Carulli, F.; Colombo, A.; Velizhanin, K. A.; Makarov, N. S.; Simonutti, R.; Klimov, V. I.; Brovelli, S., Highly Efficient Large-Area Colourless Luminescent Solar Concentrators Using Heavy-Metal-Free Colloidal Quantum Dots. Nat. Nanotechnol. 2015, 10, 878–885.


Page 41 of 41

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


Table of Contents Graph


Highly luminescent water-dispersible NIR-emitting wurtzite CuInS2

Recommend Documents