Complete Colloidal Synthesis of Cu<sub>2</sub>SnSe<sub>3</sub> Nanocrystals with Crystal Phase and Shape Control

Wang, Jianjun; Liu, Pai; Seaton, Colin C.; Ryan, Kevin M.

doi:10.1021/ja501591n

Cited by 78 publications

(102 citation statements)

References 60 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The final Cu 0.66 Sn 0.33 Se NCs exhibited a main peak at 179 cm –1 and three minor peaks at 205, 228, and 245 cm –1 , in good agreement with literature data for the Cu 2 SnSe 3 phase. 37,38 The appearance and the progressive shift of the Cu 0.66 Sn 0.33 Se Raman modes that followed the entrance of Sn 4+ ions inside the Cu 2- x Se NCs support the formation of solid Cu 2–4 y Sn y Se solutions as intermediate phases.…”

Section: Resultsmentioning

confidence: 88%

“…This is most likely due to the very low Raman scattering efficiency of this phase, as already observed recently by Izquierdo-Roca et al 36 Starting from the pristine Cu 2- x Se NCs, already at the very early stages of the Cu + → Sn 4+ exchange (for example when the composition was Cu 1.85 Sn 0.07 Se, as measured by elemental analysis via ICP) a broad peak at about 185 cm –1 was observed (see Figure 1c). This peak appears to be related to the main mode of the Cu 0.66 Sn 0.33 Se phase, 37,38 albeit blue-shifted by few cm –1 from that mode. Upon increasing the amount of Sn 4+ ions incorporated in the Cu 2- x Se NCs (for example at a composition corresponding to Cu 1.20 Sn 0.19 Se), all peaks traceable to the Raman modes of the Cu 2 SnSe 3 phase were observed, although almost all of them were slightly blue-shifted from those modes.…”

Section: Resultsmentioning

confidence: 89%

See 1 more Smart Citation

Sn Cation Valency Dependence in Cation Exchange Reactions Involving Cu_2-xSe Nanocrystals

et al. 2014

View full text Add to dashboard Cite

We studied cation exchange reactions in colloidal Cu2-xSe nanocrystals (NCs) involving the replacement of Cu+ cations with either Sn2+ or Sn4+ cations. This is a model system in several aspects: first, the +2 and +4 oxidation states for tin are relatively stable; in addition, the phase of the Cu2-xSe NCs remains cubic regardless of the degree of copper deficiency (that is, “x”) in the NC lattice. Also, Sn4+ ions are comparable in size to the Cu+ ions, while Sn2+ ones are much larger. We show here that the valency of the entering Sn ions dictates the structure and composition not only of the final products but also of the intermediate steps of the exchange. When Sn4+ cations are used, alloyed Cu2–4ySnySe NCs (with y ≤ 0.33) are formed as intermediates, with almost no distortion of the anion framework, apart from a small contraction. In this exchange reaction the final stoichiometry of the NCs cannot go beyond Cu0.66Sn0.33Se (that is Cu2SnSe3), as any further replacement of Cu+ cations with Sn4+ cations would require a drastic reorganization of the anion framework, which is not possible at the reaction conditions of the experiments. When instead Sn2+ cations are employed, SnSe NCs are formed, mostly in the orthorhombic phase, with significant, albeit not drastic, distortion of the anion framework. Intermediate steps in this exchange reaction are represented by Janus-type Cu2-xSe/SnSe heterostructures, with no Cu–Sn–Se alloys.

show abstract

Section: Resultsmentioning

confidence: 88%

Section: Resultsmentioning

confidence: 89%

Sn Cation Valency Dependence in Cation Exchange Reactions Involving Cu_2-xSe Nanocrystals

et al. 2014

View full text Add to dashboard Cite

show abstract

“…Ternary copper tin chalcogenides (CTAs; A=S, Se, Te) have a large variety of stable phases, among which Cu 2 SnA 3 is the most studied. Several reports show that the capping ligands present in the reaction mixture have a crucial impact on the crystal structure of the resulting CTS or CTSe NCs . For example, cubic and wurtzite crystal structures have been reported by Ryan and co‐workers upon using elemental selenium at elevated temperatures and diphenyl diselenide, respectively (Figure ) .…”

Section: Ternary Copper Chalcogenidesmentioning

confidence: 99%

Prospects of Colloidal Copper Chalcogenide Nanocrystals

2016

View full text Add to dashboard Cite

Over the past few years, colloidal copper chalcogenide nanocrystals (NCs) have emerged as promising alternatives to conventional Cd and Pb chalcogenide NCs. Owing to their wide size, shape, and composition tunability, Cu chalcogenide NCs hold great promise for several applications, such as photovoltaics, lighting and displays, and biomedical imaging. They also offer characteristics that are unparalleled by Cd and Pb chalcogenide NCs, such as plasmonic properties. Moreover, colloidal Cu chalcogenide NCs have low toxicity, potentially lower costs, and excellent colloidal stability. This makes them attractive materials for the large-scale deployment of inexpensive, sustainable, and environmentally benign solution-processed devices. Nevertheless, the synthesis of colloidal Cu chalcogenide NCs, especially that of ternary and quaternary compositions, has yet to reach the same level of mastery as that available for the prototypical Cd chalcogenide based NCs. This review provides a concise overview of this rapidly advancing field, sketching the state of the art and highlighting the key challenges. We discuss recent developments in the synthesis of size-, shape-, and composition-controlled NCs of Cu chalcogenides, with emphasis in strategies to circumvent the limitations arising from the need to precisely balance the reactivities of multiple precursors in synthesizing ternary and quaternary compositions. In this respect, we show that topotactic cation-exchange reactions are a promising alternative route to complex multinary Cu chalcogenide NCs and hetero-NCs, which are not attainable by conventional routes. The properties and potential applications of Cu chalcogenide NCs and hetero-NCs are also addressed.

show abstract

“…3 During the synthesis of multicomponent copper chalcogenides, we have observed that the temperature range for the growth of WZ phase is 220−280°C and for ZB growth is 255−310°C. 37 If the nucleation temperature is higher (>280°C) than the growth temperature then the resulting nanocrystals tend to have the 3-D morphology with a tetrahedrally coordinated ZB core and WZ derived arms. Contrary to this, when the nucleation is achieved at a much lower temperature (<220°C) with the growth at higher temperatures, 1-D linear structures are formed having a WZ core and two ZB-derived tips on either end.…”

Section: The Journal Of Physical Chemistry Lettersmentioning

confidence: 99%

“…Wang et al discovered that the use of copper chloride (Cu(I)Cl) (highly reactive Cu source) along with tin chloride as metal precursors provided optimal control over separation of nucleation and growth events to form polytypic Cu 2 SnSe 3 tetrapod and linear heterostructures. 37 Coughlan et al for CZTS polytypic nanocrystals reported that the combination of metal chlorides as precursors along with OLA prompts the growth of biphasic heterostructures. 38 We have observed lately that by separating out the role of precursor and ligand species, it is possible to tune the shape and phases of complex polytypic structures.…”

Section: The Journal Of Physical Chemistry Lettersmentioning

confidence: 99%

Occurrence of Polytypism in Compound Colloidal Metal Chalcogenide Nanocrystals, Opportunities, and Challenges

Singh

Ryan

2015

J. Phys. Chem. Lett.

View full text Add to dashboard Cite

This Perspective will look at the occurrence of polytypism in colloidal nanocrystals of metal chalcogenides. The low energy barrier between growth in wurtzite and zincblende crystal phases allows the occurrence of both in a single particle which has a dramatic influence on shape control. To date, various strategies have been employed to understand and control this phenomenon leading to a range of particle shapes across a wide range of semiconductor compositions from the archetypal cadmium selenide to the more recently studied compound copper chalcogenide nanocrystals such as dicopper− zinc−tin tetrasulfide and copper indium gallium selenide systems. The Perspective will also look at the control factors for polytypism in colloidal nanocrystals and the impact of polytypism on end-use applications. P olytypism can be defined as the occurrence of two crystal polymorphic forms within the same particle. 1 It is generally prevalent in tetrahedrally coordinated IV, III−V, and II−VI semiconductors crystals due to large atom stacking freedom, among which hexagonal wurtzite (WZ) and cubic zincblende (ZB) are two very commonly observed polymorphs. 2 The (111) plane of the cubic ZB lattice structure can interface well with the (002) plane of the hexagonal WZ structure, allowing for ease of transition between growth in either phase to create polytypes. 3 This allows for the nucleation of a particle in one crystal phase with the subsequent transition to growth in another crystal phase leading to shape morphologies that are not possible in single crystal systems.For example, branched 3-D morphologies are obtained when the nucleation takes place in ZB with subsequent growth in WZ (Figure 1). The faceting of the ZB seed is such that it has eight {111} crystalline facets that each can serve as nucleation points for subsequent transition to growth of WZ. The formation of tetrapod nanocrystals are obtained when the four {111} ZB facets (more reactive facets compared to other four {111} ZB facets) allow the epitaxial growth of wurtzite pods. Octapod nanocrystals are obtained when all the eight {111} ZB facets serve as nucleation facets for epitaxial growth of WZ pods under suitable conditions (Figure 1a). Branched polytypes of this form with nucleation in ZB and then subsequent growth in WZ have been observed with, tetrapods of CdSe, 5−7 CdTe, 7−9 CdS, 10,11 ZnSe, 12,13 ZnTe, 14 and multipods of CdSe/CdS 3,5,15 and CdSe/CdTe. 3 Polytypes arising from nucleation in the WZ phase with subsequent growth in ZB are always linear 1-D structures. 16 In WZ, there are only two opposite {002} facets that can allow transition to epitaxial growth of ZB tips. Additionally, the reactivity of + (002) facet differs from that of − (002) facet which gives access to localize the ZB tip selectively on one or both ends of the WZ core (Figure 1b). 4 Figure 1. Schematic illustration of the polytypic nanocrystal growth with different morphology. Adapted with permission from ref 4.

show abstract

Complete Colloidal Synthesis of Cu₂SnSe₃ Nanocrystals with Crystal Phase and Shape Control

Abstract: Bradford Scholars -how to deposit your paper Overview Copyright check• Check if your publisher allows submission to a repository.• Use the Sherpa RoMEO database if you are not sure about your publisher's position or email openaccess@bradford.ac.uk.

Cited by 78 publications

References 60 publications

Sn Cation Valency Dependence in Cation Exchange Reactions Involving Cu_2-xSe Nanocrystals

Sn Cation Valency Dependence in Cation Exchange Reactions Involving Cu_2-xSe Nanocrystals

Prospects of Colloidal Copper Chalcogenide Nanocrystals

Occurrence of Polytypism in Compound Colloidal Metal Chalcogenide Nanocrystals, Opportunities, and Challenges

Contact Info

Product

Resources

About

Complete Colloidal Synthesis of Cu2SnSe3 Nanocrystals with Crystal Phase and Shape Control

Abstract: Bradford Scholars -how to deposit your paper Overview Copyright check• Check if your publisher allows submission to a repository.• Use the Sherpa RoMEO database if you are not sure about your publisher's position or email openaccess@bradford.ac.uk.

Cited by 78 publications

References 60 publications

Sn Cation Valency Dependence in Cation Exchange Reactions Involving Cu2-xSe Nanocrystals

Sn Cation Valency Dependence in Cation Exchange Reactions Involving Cu2-xSe Nanocrystals

Prospects of Colloidal Copper Chalcogenide Nanocrystals

Occurrence of Polytypism in Compound Colloidal Metal Chalcogenide Nanocrystals, Opportunities, and Challenges

Contact Info

Product

Resources

About

Complete Colloidal Synthesis of Cu₂SnSe₃ Nanocrystals with Crystal Phase and Shape Control

Sn Cation Valency Dependence in Cation Exchange Reactions Involving Cu_2-xSe Nanocrystals

Sn Cation Valency Dependence in Cation Exchange Reactions Involving Cu_2-xSe Nanocrystals