Near-Infrared Light-Activated CuFeSe2 ... - ACS Publications


Publication Date (Web): January 2, 2019 ... develop the near-infrared light-activatable CuFeSe2 hierarchical nanostructures as multifunctional nanomat...
0 downloads 0 Views 664KB Size


Subscriber access provided by Iowa State University | Library

Article

Near-Infrared Light-Activated CuFeSe2 Hierarchical Nanostructures: Synthesis, Characterization, and Growth Mechanism Wenliang Wang, Wenling Feng, Qiao Li, Yutong Zhao, Di Zhao, Zenghao Xia, Wenjian Wang, Shiliang Zhang, Xiaoxia Zheng, and Zhihong Jing Cryst. Growth Des., Just Accepted Manuscript • DOI: 10.1021/acs.cgd.8b01654 • Publication Date (Web): 02 Jan 2019 Downloaded from http://pubs.acs.org on January 8, 2019

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 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 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.

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 22 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

Crystal Growth & Design

Near-Infrared

Light-Activated

Nanostructures:

Synthesis,

CuFeSe2

Characterization,

Hierarchical and

Growth

Mechanism Wenliang Wang,* Wenling Feng, Qiao Li, Yutong Zhao, Di Zhao, Zenghao Xia, Wenjian Wang, Shiliang Zhang, Xiaoxia Zheng and Zhihong Jing School of Chemistry and Chemical Engineering, Qufu Normal University, Qufu 273165, Shandong, P. R. China. * Corresponding author. E-mail: [email protected]; Tel: +86-1565-023-5536. ABSTRACT Near-infrared

light-activated

nanomaterials

are

of

promising

potential

for

phototherapies and biological imaging applications. Despite well-developed syntheses are available for zero dimensional CuFeSe2 nanoparticles, the synthesis of two dimensional CuFeSe2 nanosheets remains a big challenge. Here, we report for the first time the preparation of CuFeSe2 hierarchical nanostructures assembled from nanosheets via a facile cation exchange method. A possible formation mechanism of CuFeSe2 hierarchical nanostructures has been proposed. By carefully optimizing reaction parameters, including growth and exchange times as well as the initial reactant ratios, high-quality CuFeSe2 hierarchical nanostructures are achieved, exhibiting intense photoabsorption region from 400 to 1700 nm. This study sheds light on a new approach to design and develop the near-infrared light-activatable CuFeSe2 hierarchical nanostructures as multifunctional nanomaterials potential for the imaging-guided photothermal therapy of tumors. 1

ACS Paragon Plus Environment

Crystal Growth & Design 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

1. INTRODUCTION Currently, near-infrared (NIR) light-activatable nanomaterials have drawn a great deal of scientific interests due to their composition, size and shape-dependent fascinating properties, and promising applications in phototherapies and biological imaging.1-8 As a minimal invasiveness and highly efficient cancer treatment strategy, NIR light-mediated photothermal therapy (PTT) converts light energy into heat and burns cancer which has attracted enormous attentions in recent years. Furthermore, unlike ultraviolet or visible light, the NIR light bioimaging exhibits numerous advantages, e.g., deeper penetration depth, higher spatial resolution and lower scattering and absorption by tissue and blood.9 To date, a large number of NIR-absorbing nanomaterials have been explored as photothermal agents for the treatment of cancer, such as noble metal nanostructures,4,10,11 carbon-based nanomaterials,12-14 and organic compounds nanoparticles.15-17 However, the relatively high cost, poor dispersibility and/or low photostability suffering from these nanomaterials seriously impede their applications. Thus, developing novel photothermal agent is an imperative requirement for enhancing the NIR-PTT treatment efficacy. The copper-based binary chalcogenides have been regarded as great potential photothermal agents in tumor therapy field due to low cost, facile synthesis, good photostability and so on.18-23 It is well known that the optical absorption range and intensity of semiconductor nanomaterials are closely related to their bandgap energy, size and morphology.24,25 To improve the photothermal conversion efficiency, many efforts have been devoted to broaden and enhance the absorption in the NIR region by 2

ACS Paragon Plus Environment

Page 2 of 22

Page 3 of 22 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

Crystal Growth & Design

regulating the bandgap energy, size and morphology of materials.26,27 Especially, constructing hierarchical nanostructure has been proved as an effective strategy to boost optical absorption ability.28,29 For example, flowerlike CuS superstructures developed by Hu’s group have a significant enhancement of the reflection and absorption capacity due to the outstanding cavity-mirror effect.30 Furthermore, other than achieving excellent results with improved optical absorption capacity, the rational design and fabrication of multifunctional nanomaterials to exert simultaneously the therapeutic and diagnostic functions for imaging-guided synergistic therapy have been vastly desired and explored. The semiconductor CuFeSe2 is able to absorb naturally in the NIR region due to its small bandgap energy.31,32 Besides, CuFeSe2 exhibits good biocompatibility because it is composed of human essential trace elements Cu, Fe, and Se. More importantly, CuFeSe2 has demonstrated interesting magnetic property for magnetic resonance imaging (MRI) to realize the imaging-guided NIR-PTT.32 Based on the above considerations, rational designing and preparing CuFeSe2 nanomaterials as the multifunctional photothermal agents have gained considerable attentions. Recently, sub-5 nm ternary CuFeSe2 nanoparticles with high photothermal conversion efficiency, excellent colloidal stability, and biocompatibility have been prepared by Li’s group.32 Moreover, bioactive glass scaffolds functionalized by CuFeSe2 have been demonstrated by Wang’s and Wu’s groups,33 exhibiting dual functions for tumor therapy and bone reconstruction. However, the morphology of the reported CuFeSe2 is mainly limited in the form of nanoparticles and a facile approach to control the 3

ACS Paragon Plus Environment

Crystal Growth & Design 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

shape and size has not yet to be achieved although CuFeSe2 nanomaterials have been prepared by various methods.34-36 As is well-known, the morphology of nanomaterials is closely related to their properties. Anisotropic two-dimensional nanostructures often exhibit fascinating properties and promising applications.37,38 Assembly of two-dimensional nanosheets into three-dimensional architectures can not only possess nanosheet individual properties, but also can bring up novel functions.39,40 As for the photothermal agent, the more light is absorbed, the more heat is generated. Inspired by the fact that hierarchical nanostructures can be utilized to improve absorption ability,30 the construction of CuFeSe2 hierarchical nanostructures is expected to broaden and enhance the optical absorption in the NIR region. However, different from the preparation of binary compounds, the reason for the challenging synthesis of the two-dimensional CuFeSe2 nanocrystal is suffering from both its non-layered crystal structure and the reaction between multiple precursors with discrepant reactivities, leading to the poor control of the nanocrystal’s nucleation as well as growth. To the best of our knowledge, three-dimensional CuFeSe2 hierarchical nanostructures assembled from nanosheets have not yet been reported so far. Meanwhile, further applications of CuFeSe2 in the photothermal therapy and biological imaging have been largely hampered due to the scarcity of the CuFeSe2 with various morphologies. Cation exchange reaction has been proved to be a feasible technique, which can be utilized to generate nanomaterials with distinct structures and regulate the composition of as-prepared nanocrystals.41-44 In the present study, the CuFeSe2 4

ACS Paragon Plus Environment

Page 4 of 22

Page 5 of 22 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

Crystal Growth & Design

hierarchical nanostructures have been prepared through a facile solvothermal strategy. The possible growth mechanisms of CuFeSe2 hierarchical nanostructures are discussed. We suggest that the obtained CuFeSe2 hierarchical nanostructures have been subjected to a partial cation exchange reaction based on the replacement of copper by iron ions in the copper selenide crystal lattice. Magnetic measurement reveals that the as-synthesized CuFeSe2 hierarchical structures are ferromagnetic and paramagnetic at 4 and 300 K, respectively. Moreover, the CuFeSe2 hierarchical nanostructures arising from unique architectures exhibit a broad absorption spanning from visible light to near-infrared range. In particular, a strong absorption from 800 to 1700 nm has been observed, suggesting that the CuFeSe2 hierarchical nanostructures may potentially serve as the imaging-guided multifunctional photothermal agents applied in NIR-PTT. 2. EXPERIMENTAL SECTION 2.1 Chemicals. Diphenyl diselenide (Ph2Se2, 98%) and iron acetylacetonate (Fe(acac)3) were purchased from Alfa Aesar. Oleylamine (OAm, 70%) and octadecene (ODE, 90%) were ordered from Aldrich. Anhydrous copper chloride (CuCl), oleic acid (OA), absolute ethanol, toluene, and tetrachloroethylene were obtained from Sinopharm Chemical Reagent Ltd., China. All chemicals were used directly without further purification. 2.2 Preparation of Se- and Fe-precursors. The Se precursor solution was prepared and preheated to 70 °C by mixing 0.0624 g of Ph2Se2 (0.20 mmol) with 1.0 mL of ODE. The Fe precursor solution was prepared by dissolving 0.5298 g of Fe(acac)3 5

ACS Paragon Plus Environment

Crystal Growth & Design 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

(1.50 mmol) in 10.0 mL OAm in a three-neck flask under a nitrogen atmosphere and magnetic stirring, which was heated to 90 °C for 60 min until the Fe(acac)3 completely dissolved. 2.3 Synthesis of typical CuFeSe2 hierarchical nanostructures. In a typical synthesis, CuCl (0.0099 g, 0.10 mmol), 0.2 mL of OA, 0.2 mL of OAm, and 6.0 mL of ODE were added into a three-neck 100 mL round-bottom flask at room temperature. The mixture was first heated to 130 °C for 30 min under a nitrogen flow and magnetic stirring to eliminate water and other low-boiling-point impurities. After that, the mixture was heated to 230 °C. Then the Se precursor solution was transferred into a syringe equipped with a large needle and injected quickly into the flask at 230 °C and maintained at the temperature for 10 min. After 10 min, 1.0 mL Fe precursor solution was immediately injected into the above solution and the reaction mixture was further heated to 255 °C and kept for 90 min with continuous stirring. The reaction was allowed to cool to room temperature naturally. The product was collected by centrifugation (8000 rpm, 3 min) and washed several times with absolute ethanol and toluene. 2.4 Characterization. The as-synthesized samples were characterized by X-ray power diffraction (XRD) performed on a Philips X’pert PRO X-ray diffractometer (Cu Kα, λ = 1.54182 Å) and scanning electron microscopy (SEM, JSM-6700F). The high resolution transmission electron microscopy (HRTEM), selected area electron diffraction (SAED) patterns, high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM), and corresponding energy-dispersive X-ray 6

ACS Paragon Plus Environment

Page 6 of 22

Page 7 of 22 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

Crystal Growth & Design

spectroscope (EDX) mapping analyses were performed on a JEOL JEM-ARF200F TEM/STEM with a spherical aberration corrector. X-ray photoelectron spectroscopy (XPS) was performed using an ESCALAB MK II with Mg Kα as the excitation source. The magnetic measurements on powder samples enclosed in a medical cap were carried out with a superconducting quantum interference device. Optical absorption

spectra

were

recorded

on

a

spectrophotometer

(Shimadzu

Solidspec-3700DUV) at room temperature. 3. RESULTS AND DISCUSSION On the basis of the mentioned experimental details, the typical preparation of CuFeSe2 hierarchical nanostructures has been first demonstrated via a facile hot-injection strategy. The phase and shape of the as-fabricated CuFeSe2 hierarchical nanostructures are characterized by XRD and SEM, respectively. As shown in Figure 1a, the diffraction peaks at 16.2°, 28.1°, 32.6°, 36.5°, 46.6°, 49.6°, 55.2°, 67.9°, 70.4°, and 75.0° match well with (100), (112), (200), (210), (220), (214), (312), (400), (410), and (332) planes of the standard data of tetragonal phase CuFeSe2 (JCPDS No. 81-1959),32,35 respectively. No additional impurity peak and peak splitting have been observed, indicating the nonexistence of the possibility of phase separation in the preparation of CuFeSe2 hierarchical nanostructures. Furthermore, the diffraction peaks are intense and sharp, demonstrating its highly crystalline nature. These results confirm that high purity CuFeSe2 hierarchical nanostructures have been successfully synthesized. Subsequently, the morphologies of the products are investigated by SEM. As displayed in Figure 1b, the observed CuFeSe2 hierarchical nanostructures are 7

ACS Paragon Plus Environment

Crystal Growth & Design 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

assembled by many two-dimensional hexagonal nanosheets. The average thickness and side length of individual nanosheet are ~ 50 nm and ~ 400 nm, respectively.

Figure 1. (a) XRD pattern of the as-synthesized CuFeSe2 hierarchical nanostructures along with standard JCPDS No. 81-1959 for reference. (b) SEM image of the as-synthesized CuFeSe2 hierarchical nanostructures consisting of hexagonal nanosheets as building blocks. The crystal microstructure and composition of as-synthesized CuFeSe2 hierarchical nanostructures are investigated by HRTEM, SAED, and EDX. As can be seen in Figure 2a, the interplanar distances for the CuFeSe2 nanosheet crystalline are 0.32 nm, corresponding to (112) and (1-12) planes of tetragonal phase CuFeSe2.32 Here, the observed (112) plane is consistent with the intensive (112) diffraction peak in the XRD pattern (Figure 1a). Meanwhile, as shown in Figure 2b, the observed regular symmetric diffraction spots of the corresponding SAED pattern in the [20-1] zone axis further reveal the single-crystalline nature of CuFeSe2 hierarchical nanostructures. To gain more information on the elemental composition and distribution of CuFeSe2 hierarchical nanostructures, STEM-EDX elemental mapping and line scan have been conducted. As shown in Figures 2c and 2d, these results of the co-existence of Cu, Fe, and Se in CuFeSe2 hierarchical nanostructures demonstrate the homogeneous 8

ACS Paragon Plus Environment

Page 8 of 22

Page 9 of 22 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

Crystal Growth & Design

distribution of the three elements with the Cu:Fe:Se ratio close to the expected 1:1:2 (Figure S1).

Figure 2. (a) HRTEM image of the CuFeSe2 hierarchical nanostructures, and (b) the corresponding SAED pattern. (c) HAADF-STEM image and STEM-EDX elemental mappings of the CuFeSe2 hierarchical nanostructures. (d) STEM-EDX line scan of one single CuFeSe2 nanosheet, and the inset is the corresponding STEM image. The composition and chemical bonding state of the CuFeSe2 hierarchical nanostructures have been further investigated by XPS analysis, where the survey and high-resolution spectra have been displayed in Figures 3a-d. As shown in Figure 3a, the typical survey spectrum also verifies the presence of Cu, Fe, and Se elements (Cu:Fe:Se=10.03:9.86:19.78) in CuFeSe2 hierarchical nanostructures in addition to the C and O elements from surface ligands. As shown in Figure 3b, two peaks of core level spectrum of Cu 2p located at 931.8 and 951.6 eV with a binding energy splitting of 19.8 eV can be indexed to Cu 2p3/2 and Cu 2p1/2, respectively, demonstrating the 9

ACS Paragon Plus Environment

Crystal Growth & Design 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

formation of Cu+.45,46 Similarly, the Fe 2p core level peaks located at 710.7 eV and 723.3 eV confirm the presence of Fe3+ (Figure 3c).32,35 The Se 3d core level peak at 53.7 eV is in agreement with the reported Se2- (Figure 3d).47-49 Therefore, the XPS analyses reveal that the valence states of Cu, Fe, and Se are +1, +3, and -2, respectively, further demonstrating the formation of CuFeSe2.

Figure 3. XPS spectra of the as-synthesized CuFeSe2 hierarchical nanostructures. (a) Survey spectrum, (b) Cu 2p core level spectrum, (c) Fe 2p core level spectrum, and (d) Se 3d core level spectrum. In order to investigate the magnetic properties of CuFeSe2 hierarchical nanostructures, magnetic measurements have been performed by employing a superconducting quantum interference device. Figure 4 displays the field-dependent magnetization curve of the resultant CuFeSe2 hierarchical nanostructures at 4 and 300 K, respectively. It is observed that CuFeSe2 hierarchical nanostructures exhibit paramagnetic characteristics at 300 K.35 Moreover, with the decreasing of temperature 10

ACS Paragon Plus Environment

Page 10 of 22

Page 11 of 22 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

Crystal Growth & Design

from 300 to 4 K, the coercivity sharply increases from 10 to 18611 Oe, indicating that CuFeSe2 hierarchical nanostructures undergo a transition from paramagnetism to ferromagnetism.32 Therefore, the CuFeSe2 hierarchical nanostructures have the potential to be used as a contrast agent for MRI.

Figure 4. M−H curves of the CuFeSe2 hierarchical nanostructures recorded at 4 and 300 K. To explore the possible growth mechanism of CuFeSe2 hierarchical nanostructures, a series of experimental investigations and structural determinations have been carried out. As shown in Figure 5, the as-prepared product has been characterized when the reaction time maintained 10 min at 230 °C after Se-precursor injection. The crystal phase of the resultant product is analyzed by XRD in Figure 5a. The observed several diffraction peaks located at 27.2°, 31.5°, 45.0°, 53.3°, and 65.4° can be indexed to the (111), (200), (220), (311), and (400) planes of the cubic phase of Cu2-xSe (JCPDS No. 06−0680).50 As shown in Figure 5b, the EDX spectrum suggests that the 11

ACS Paragon Plus Environment

Crystal Growth & Design 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

corresponding atomic ratio of Cu:Se is about 1.89:1, which is in accordance with the nonstoichiometric composition of Cu2−xSe. The morphology of the as-prepared product is examined by SEM in Figure 5c. Obviously, the detected Cu2-xSe hierarchical nanostructures are assembled from two-dimensional nanosheets. To further gain detailed information on the crystal structure of the Cu2-xSe hierarchical nanostructures, HRTEM technique is carried out. As shown in Figure 5d, a lattice spacing of 0.33 nm can be well indexed to the interplanar spacing of the (111) plane of the cubic Cu2-xSe.51 Meanwhile, as shown in Figure 5d, the observed regular symmetric diffraction spots of the corresponding SAED pattern (inset) are well consistent with the single-crystalline nature of Cu2-xSe hierarchical nanostructures. Based on the above analyses, the formation of Cu2-xSe hierarchical nanostructures has been confirmed in the first stage of Se-precursor injection.

Figure 5. (a) XRD pattern, (b) EDX spectrum, (c) SEM image, and (d) HRTEM image and SAED pattern (inset) of the product prepared at 230 °C for 10 min after Se-precursor injection. 12

ACS Paragon Plus Environment

Page 12 of 22

Page 13 of 22 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

Crystal Growth & Design

Given the fact that high temperature is in favor of cation diffusion and tends to result in the formation of homogeneous alloy,52,53 the reaction temperature has been raised to 255 °C after Fe-precursor injection. In order to further understand the formation of CuFeSe2 hierarchical nanostructures, the products have been characterized by XRD as a function of reaction time. As shown in Figure 6a, a fraction of tetragonal CuFeSe2 has already been observed when the reaction time is 5 min although the as-prepared products are mainly cubic Cu2−xSe. With the prolongation of the reaction time to 30 min (Figure 6b), the characteristic diffraction peaks intensity of CuFeSe2 is becoming stronger. When the reaction time is further increased to 60 min (Figure 6c), Cu2−xSe still exits although CuFeSe2 has become dominant. Finally, pure phase of CuFeSe2 with tetragonal structure has been successfully prepared when the reaction time is extended to 90 min. Furthermore, the purity of the phase can also be influenced by the ratio of precursors. As shown in Figure S2, although the morphology without obvious change, the obtained products are CuFeSe2 nanocrystals mixed with byproducts of Cu2−xSe nanocrystals when the precursor molar ratio of Cu:Fe:Se is set to 1:1:4. On the basis of the above experimental investigations and structural determinations, the formation of CuFeSe2 hierarchical nanostructures can be proposed as shown in Figure 7.

13

ACS Paragon Plus Environment

Crystal Growth & Design 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

Figure 6. XRD patterns of the sample synthesized at 255 °C for (a) 5 min, (b) 30 min, (c) 60 min, respectively.

Figure 7. A schematic illustration of formation mechanism of CuFeSe2 hierarchical nanostructures by using a partial cation exchange strategy. The optical properties of Cu2−xSe and CuFeSe2 hierarchical nanostructures are investigated by measuring UV-vis-NIR absorption spectra. As shown in Figure 8, Cu2−xSe hierarchical nanostructures exhibit an absorption peak in visible region owing to the direct band gap, and the peak in NIR region can be attributed to the localized surface plasmon resonance stemming from the copper-defect-induced free carriers.18,54-57 As for CuFeSe2 hierarchical nanostructures, they possess a broad and strong photoabsorption range from visible to NIR region (400-1700 nm) arising from 14

ACS Paragon Plus Environment

Page 14 of 22

Page 15 of 22 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

Crystal Growth & Design

both the small band gap of 0.57 eV (Figure S3) and unique structure-induced cavity-mirror effect.30 Hopefully, the intense NIR photoabsorption of CuFeSe2 hierarchical nanostructures may open up opportunities for the promising potential in NIR imaging-guided NIR-PTT for tumor.

Figure 8. UV-vis-NIR absorption spectra of Cu2−xSe and CuFeSe2 hierarchical nanostructures dispersed in tetrachloroethylene. 4. CONCLUSIONS In summary, it is the first time that CuFeSe2 hierarchical nanostructures assembled from nanosheets are successfully synthesized by using a partial cation exchange strategy. Starting from the preparation of corresponding Cu2−xSe hierarchical nanostructures as templates, a subsequent partial cation exchange with Fe3+ leads to the formation of ternary CuFeSe2. By carefully regulating reaction parameters, pure phase CuFeSe2 with hierarchical nanostructures is achieved. The magnetic and optical results reveal that the CuFeSe2 hierarchical nanostructures have great potential to be 15

ACS Paragon Plus Environment

Crystal Growth & Design 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

served as the multifunctional photothermal agents for MRI and NIR dual-modal imaging-guided NIR-PTT of tumors. Future work will focus on the optimization of these CuFeSe2 hierarchical nanostructures for their phototherapies and biological imaging applications ■ ASSOCIATED CONTENT Supporting Information. EDX spectrum and band gap of the as-synthesized CuFeSe2 hierarchical nanostructures. XRD pattern and SEM image of the CuFeSe2 nanocrystals synthesized at 255 °C for 90 min with molar ratio of 1:1:4 for Cu:Fe:Se in feedstock. This material is available free of charge via the Internet at http://pubs.acs.org. ■ AUTHOR INFORMATION Corresponding Author *E-mail: [email protected] ORCID Wenliang Wang: 0000-0001-5919-1807 Notes The authors declare no competing financial interest. ■ ACKNOWLEDGMENT This work was supported by National Natural Science Foundation of China (No. 21805163), the Doctoral Foundation of Shandong Province (No. ZR2016BB20, ZR2017BB055), Laboratory Open Foundation of Qufu Normal University (sk201722) and Innovative Training Program of Qufu Normal University (2018A049). 16

ACS Paragon Plus Environment

Page 16 of 22

Page 17 of 22 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

Crystal Growth & Design

■ REFERENCES (1) Zhang, Z.; Wang, J.; Chen, C. Near-Infrared Light-Mediated Nanoplatforms for Cancer Thermo-Chemotherapy and Optical Imaging. Adv. Mater. 2013, 25, 3869-3880. (2) Melancon, M. P.; Zhou, M.; Li, C. Cancer Theranostics with Near-Infrared Light-Activatable Multimodal Nanoparticles. Acc. Chem. Res. 2011, 44, 947-956. (3) Chen, M.-C.; Lin, Z.-W.; Ling, M.-H. Near-Infrared Light-Activatable Microneedle System for Treating Superficial Tumors by Combination of Chemotherapy and Photothermal Therapy. ACS Nano 2015, 10, 93-101. (4) Vijayaraghavan, P.; Liu, C. H.; Vankayala, R.; Chiang, C. S.; Hwang, K. C. Designing Multi-Branched Gold Nanoechinus for NIR Light Activated Dual Modal Photodynamic and Photothermal Therapy in the Second Biological Window. Adv. Mater. 2014, 26, 6689-6695. (5) Pu, K.; Shuhendler, A. J.; Jokerst, J. V.; Mei, J.; Gambhir, S. S.; Bao, Z.; Rao, J. Semiconducting polymer nanoparticles as photoacoustic molecular imaging probes in living mice. Nat. Nanotechnol. 2014, 9, 233-239. (6) Cheng, L.; Wang, C.; Feng, L.; Yang, K.; Liu, Z. Functional Nanomaterials for Phototherapies Of Cancer. Chem. Rev. 2014, 114, 10869-10939. (7) Fan, W.; Yung, B.; Huang, P.; Chen, X. Nanotechnology for Multimodal Synergistic Cancer Therapy. Chem. Rev. 2017, 117, 13566-13638. (8) Mao, F.; Wen, L.; Sun, C.; Zhang, S.; Wang, G.; Zeng, J.; Wang, Y.; Ma, J.; Gao, M.; Li, Z. Ultrasmall Biocompatible Bi2Se3 Nanodots for Multimodal Imaging-Guided Synergistic Radiophotothermal Therapy against Cancer. ACS Nano 2016, 10, 11145-11155. (9) Hong, G.; Antaris, A. L.; Dai, H. Near-infrared fluorophores for biomedical imaging. Nat. Biomed. Eng. 2017, 1, 0010. (10) Kumar, A.; Kim, S.; Nam, J.-M. Plasmonically Engineered Nanoprobes for Biomedical Applications. J. Am. Chem. Soc. 2016, 138, 14509-14525. (11) Bi, C.; Chen, J.; Chen, Y.; Song, Y.; Li, A.; Li, S.; Mao, Z.; Gao, C.; Wang, D.; Möhwald, H. Realizing a Record Photothermal Conversion Efficiency of Spiky Gold Nanoparticles in the Second Near-Infrared Window by Structure-Based Rational Design. Chem. Mater. 2018, 30, 2709-2718. (12) Hong, G.; Diao, S.; Antaris, A. L.; Dai, H. Carbon Nanomaterials for Biological Imaging and Nanomedicinal Therapy. Chem. Rev. 2015, 115, 10816-10906. (13) Kumar, S.; Rani, R.; Dilbaghi, N.; Tankeshwar, K.; Kim, K.-H. Carbon nanotubes: a novel material for multifaceted applications in human healthcare. Chem. Soc. Rev. 2017, 46, 158-196. (14) Liang, C.; Diao, S.; Wang, C.; Gong, H.; Liu, T.; Hong, G.; Shi, X.; Dai, H.; Liu, Z. Tumor Metastasis Inhibition by Imaging-Guided Photothermal Therapy with Single-Walled Carbon Nanotubes. Adv. Mater. 2014, 26, 5646-5652. (15) Zha, Z.; Yue, X.; Ren, Q.; Dai, Z. Uniform Polypyrrole Nanoparticles with High Photothermal Conversion Efficiency for Photothermal Ablation of Cancer Cells. Adv. Mater. 2013, 25, 777-782. 17

ACS Paragon Plus Environment

Crystal Growth & Design 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

(16) Cheng, L.; Yang, K.; Chen, Q.; Liu, Z. Organic Stealth Nanoparticles for Highly Effective in Vivo Near-Infrared Photothermal Therapy of Cancer. ACS Nano 2012, 6, 5605-5613. (17) Jung, H. S.; Verwilst, P.; Sharma, A.; Shin, J.; Sessler, J. L.; Kim, J. S. Organic molecule-based photothermal agents: an expanding photothermal therapy universe. Chem. Soc. Rev. 2018, 47, 2280-2297. (18) Zhang, S.; Sun, C.; Zeng, J.; Sun, Q.; Wang, G.; Wang, Y.; Wu, Y.; Dou, S.; Gao, M.; Li, Z. Ambient Aqueous Synthesis of Ultrasmall Pegylated Cu2-xSe Nanoparticles as a Multifunctional Theranostic Agent for Multimodal Imaging Guided Photothermal Therapy of Cancer. Adv. Mater. 2016, 28, 8927-8936. (19) Mou, J.; Li, P.; Liu, C.; Xu, H.; Song, L.; Wang, J.; Zhang, K.; Chen, Y.; Shi, J.; Chen, H. Ultrasmall Cu2-xS Nanodots for Highly Efficient Photoacoustic Imaging-Guided Photothermal Therapy. Small 2015, 11, 2275-2283. (20) Wang, S.; Riedinger, A.; Li, H.; Fu, C.; Liu, H.; Li, L.; Liu, T.; Tan, L.; Barthel, M. J.; Pugliese, G. Plasmonic Copper Sulfide Nanocrystals Exhibiting Near-Infrared Photothermal and Photodynamic Therapeutic Effects. ACS Nano 2015, 9, 1788-1800. (21) Li, W.; Zamani, R.; Rivera Gil, P.; Pelaz, B.; Ibáñez, M.; Cadavid, D.; Shavel, A.; Alvarez-Puebla, R. A.; Parak, W. J.; Arbiol, J. CuTe Nanocrystals: Shape and Size Control, Plasmonic Properties, and Use as SERS Probes and Photothermal Agents. J. Am. Chem. Soc. 2013, 135, 7098-7101. (22) Zhang, S.; Huang, Q.; Zhang, L.; Zhang, H.; Han, Y.; Sun, Q.; Cheng, Z.; Qin, H.; Dou, S.; Li, Z. Vacancy engineering of Cu2-xSe nanoparticles with tunable LSPR and magnetism for dual-modal imaging guided photothermal therapy of cancer. Nanoscale 2018, 10, 3130-3143. (23) Zhang, H.; Wang, T.; Qiu, W.; Han, Y.; Sun, Q.; Zeng, J.; Yan, F.; Zheng, H.; Li, Z.; Gao, M. Monitoring the Opening and Recovery of the Blood-Brain Barrier with Noninvasive Molecular Imaging by Biodegradable Ultrasmall Cu2-xSe Nanoparticles. Nano Lett. 2018, 18, 4985-4992. (24) Ray, P. C. Size and Shape Dependent Second Order Nonlinear Optical Properties of Nanomaterials and Their Application in Biological and Chemical Sensing. Chem. Rev. 2010, 110, 5332-5365. (25) Ross, M. B.; Mirkin, C. A.; Schatz, G. C. Optical Properties of One-, Two-, and Three-Dimensional Arrays of Plasmonic Nanostructures. J. Phys. Chem. C 2016, 120, 816-830. (26) Shen, S.; Wang, Q. Rational Tuning the Optical Properties of Metal Sulfide Nanocrystals and Their Applications. Chem. Mater. 2012, 25, 1166-1178. (27) Shanmugam, V.; Selvakumar, S.; Yeh, C.-S. Near-infrared light-responsive nanomaterials in cancer therapeutics. Chem. Soc. Rev. 2014, 43, 6254-6287. (28) Xiao, Z.; Xu, C.; Jiang, X.; Zhang, W.; Peng, Y.; Zou, R.; Huang, X.; Liu, Q.; Qin, Z.; Hu, J. Hydrophilic bismuth sulfur nanoflower superstructures with an improved photothermal efficiency for ablation of cancer cells. Nano Res. 2016, 9, 1934-1947. (29) Huang, X.; Zhang, W.; Guan, G.; Song, G.; Zou, R.; Hu, J. Design and Functionalization of the NIR-Responsive Photothermal Semiconductor Nanomaterials 18

ACS Paragon Plus Environment

Page 18 of 22

Page 19 of 22 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

Crystal Growth & Design

for Cancer Theranostics. Acc. Chem. Res. 2017, 50, 2529-2538. (30) Tian, Q.; Tang, M.; Sun, Y.; Zou, R.; Chen, Z.; Zhu, M.; Yang, S.; Wang, J.; Wang, J.; Hu, J. Hydrophilic Flower-Like CuS Superstructures as an Efficient 980 nm Laser-Driven Photothermal Agent for Ablation of Cancer Cells. Adv. Mater. 2011, 23, 3542-3547. (31) Hamdadou, N.; Morsli, M.; Khelil, A.; Bernede, J. Fabrication of n-and p-type doped CuFeSe2 thin films achieved by selenization of metal precursors. J. Phys. D: Appl. Phys. 2006, 39, 1042-1049. (32) Jiang, X.; Zhang, S.; Ren, F.; Chen, L.; Zeng, J.; Zhu, M.; Cheng, Z.; Gao, M.; Li, Z. Ultrasmall Magnetic CuFeSe2 Ternary Nanocrystals for Multimodal Imaging Guided Photothermal Therapy of Cancer. ACS Nano 2017, 11, 5633-5645. (33) Dang, W.; Li, T.; Li, B.; Ma, H.; Zhai, D.; Wang, X.; Chang, J.; Xiao, Y.; Wang, J.; Wu, C. A bifunctional scaffold with CuFeSe2 nanocrystals for tumor therapy and bone reconstruction. Biomaterials 2018, 160, 92-106. (34) Lu, Q.; Hu, J.; Tang, K.; Deng, B.; Qian, Y.; Li, Y. The synthesis of CuFeSe2 through a solventothermal process. J. Cryst. Growth 2000, 217, 271-273. (35) Wang, W.; Jiang, J.; Ding, T.; Wang, C.; Zuo, J.; Yang, Q. Alternative Synthesis of CuFeSe2 Nanocrystals with Magnetic and Photoelectric Properties. ACS Appl. Mater. Interfaces 2015, 7, 2235-2241. (36) Delgado, J.; De Delgado, G. D.; Quintero, M.; Woolley, J. The crystal structure of copper iron selenide, CuFeSe2. Mater. Res. Bull. 1992, 27, 367-373. (37) Nasilowski, M.; Mahler, B.; Lhuillier, E.; Ithurria, S.; Dubertret, B. Two-Dimensional Colloidal Nanocrystals. Chem. Rev. 2016, 116, 10934-10982. (38) Chen, Y.; Fan, Z.; Zhang, Z.; Niu, W.; Li, C.; Yang, N.; Chen, B.; Zhang, H. Two-Dimensional Metal Nanomaterials: Synthesis, Properties, and Applications. Chem. Rev. 2018, 118, 6409-6455. (39) Joshi, R. K.; Schneider, J. J. Assembly of one dimensional inorganic nanostructures into functional 2D and 3D architectures. synthesis, arrangement and functionality. Chem. Soc. Rev. 2012, 41, 5285-5312. (40) Vogel, N.; Retsch, M.; Fustin, C.-A.; del Campo, A.; Jonas, U. Advances in Colloidal Assembly: the Design of Structure and Hierarchy in Two and Three Dimensions. Chem. Rev. 2015, 115, 6265-6311. (41) De Trizio, L.; Manna, L. Forging Colloidal Nanostructures via Cation Exchange Reactions. Chem. Rev. 2016, 116, 10852-10887. (42) Lox, J. F.; Dang, Z.; Dzhagan, V. M.; Spittel, D.; Martín-García, B.; Moreels, I.; Zahn, D. R.; Lesnyak, V. Near-Infrared Cu-In-Se-Based Colloidal Nanocrystals via Cation Exchange. Chem. Mater. 2018, 30, 2607-2617. (43) Fenton, J. L.; Steimle, B.; Schaak, R. E. Exploiting Crystallographic Regioselectivity to Engineer Asymmetric Three-Component Colloidal Nanoparticle Isomers using Partial Cation Exchange Reactions. J. Am. Ceram. Soc. 2018, 140, 6771-6775. (44) Akkerman, Q. A.; Genovese, A.; George, C.; Prato, M.; Moreels, I.; Casu, A.; Marras, S.; Curcio, A.; Scarpellini, A.; Pellegrino, T. From Binary Cu2S to Ternary Cu-In-S and Quaternary Cu-In-Zn-S Nanocrystals with Tunable Composition via 19

ACS Paragon Plus Environment

Crystal Growth & Design 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

Partial Cation Exchange. ACS Nano 2015, 9, 521-531. (45) Wang, W.; Feng, W.; Ding, T.; Yang, Q. Phosphine-Free Synthesis and Characterization of Cubic-Phase Cu2SnTe3 Nanocrystals with Optical and Optoelectronic Properties. Chem. Mater. 2015, 27, 6181-6184. (46) Li, B.; Yuan, F.; He, G.; Han, X.; Wang, X.; Qin, J.; Guo, Z. X.; Lu, X.; Wang, Q.; Parkin, I. P. Ultrasmall CuCo2S4 Nanocrystals: All-in-One Theragnosis Nanoplatform with Magnetic Resonance/Near-Infrared Imaging for Efficiently Photothermal Therapy of Tumors. Adv. Funct. Mater. 2017, 27, 1606218. (47) Wang, J.-J.; Wang, Y.-Q.; Cao, F.-F.; Guo, Y.-G.; Wan, L.-J. Synthesis of Monodispersed Wurtzite Structure CuInSe2 Nanocrystals and Their Application in High-Performance Organic-Inorganic Hybrid Photodetectors. J. Am. Chem. Soc. 2010, 132, 12218-12221. (48) Wang, W.; Ding, T.; Chen, G.; Zhang, L.; Yu, Y.; Yang, Q. Synthesis of Cu2SnSe3-Au heteronanostructures with optoelectronic and photocatalytic properties. Nanoscale 2015, 7, 15106-15110. (49) Chen, X. Q.; Li, Z.; Dou, S. X. Ambient Facile Synthesis of Gram-Scale Copper Selenide Nanostructures from Commercial Copper and Selenium Powder. ACS Appl. Mater. Interfaces 2015, 7, 13295-13302. (50) Chen, H.; Zou, R.; Wang, N.; Chen, H.; Zhang, Z.; Sun, Y.; Yu, L.; Tian, Q.; Chen, Z.; Hu, J. Morphology-selective synthesis and wettability properties of well-aligned Cu2-xSe nanostructures on a copper substrate. J. Mater. Chem. 2011, 21, 3053-3059. (51) Wang, Y.; Zhukovskyi, M.; Tongying, P.; Tian, Y.; Kuno, M. Synthesis of Ultrathin and Thickness-Controlled Cu2-xSe Nanosheets via Cation Exchange. J. Phys. Chem. Lett. 2014, 5, 3608-3613. (52) Ramasamy, P.; Kim, M.; Ra, H.-S.; Kim, J.; Lee, J.-S. Bandgap tunable colloidal Cu-based ternary and quaternary chalcogenide nanosheets via partial cation exchange. Nanoscale 2016, 8, 7906-7913. (53) Song, J.; Ma, C.; Zhang, W.; Li, X.; Zhang, W.; Wu, R.; Cheng, X.; Ali, A.; Yang, M.; Zhu, L. Bandgap and Structure Engineering via Cation Exchange: from Binary Ag2S to Ternary AgInS2, Quaternary AgZnInS Alloy and AgZnInS/ZnS Core/Shell Fluorescent Nanocrystals for Bioimaging. ACS Appl. Mater. Interfaces 2016, 8, 24826-24836. (54) Zhu, J.; Li, Q.; Bai, L.; Sun, Y.; Zhou, M.; Xie, Y. Metastable Tetragonal Cu2Se Hyperbranched Structures: Large-Scale Preparation and Tunable Electrical and Optical Response Regulated by Phase Conversion. Chem.-Eur. J. 2012, 18, 13213-13221. (55) Agrawal, A.; Cho, S. H.; Zandi, O.; Ghosh, S.; Johns, R. W.; Milliron, D. J. Localized Surface Plasmon Resonance in Semiconductor Nanocrystals. Chem. Rev. 2018, 118, 3121-3207. (56) Kriegel, I.; Jiang, C.; Rodríguez-Fernández, J.; Schaller, R. D.; Talapin, D. V.; Da Como, E.; Feldmann, J. Tuning the Excitonic and Plasmonic Properties of Copper Chalcogenide Nanocrystals. J. Am. Chem. Soc. 2012, 134, 1583-1590. (57) Liu, X.; Wang, X.; Zhou, B.; Law, W. C.; Cartwright, A. N.; Swihart, M. T. 20

ACS Paragon Plus Environment

Page 20 of 22

Page 21 of 22 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

Crystal Growth & Design

Size‐Controlled Synthesis of Cu2‐xE (E=S, Se) Nanocrystals with Strong Tunable Near-Infrared Localized Surface Plasmon Resonance and High Conductivity in Thin Films. Adv. Funct. Mater. 2013, 23, 1256-1264.

21

ACS Paragon Plus Environment

Crystal Growth & Design 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 22 of 22

For Table of Contents Use Only

Near-Infrared

Light-Activated

Nanostructures:

Synthesis,

CuFeSe2

Characterization,

Hierarchical and

Growth

Mechanism Wenliang Wang,* Wenling Feng, Qiao Li, Yutong Zhao, Di Zhao, Zenghao Xia, Wenjian Wang, Shiliang Zhang, Xiaoxia Zheng and Zhihong Jing

CuFeSe2 hierarchical nanostructures exhibiting a broad and strong photoabsorption range from visible to NIR region are successfully synthesized for the first time by using a partial cation exchange strategy.

22

ACS Paragon Plus Environment