Insights of Crystal Growth, Nucleation Density, and Shape Modulations in the Formation of I–V–VI Ternary Semiconductor Nanoplatelet Photoelectrocatalysts

Abstract

Ternary semiconductor nanocrystals remained one of the leading electronic nanomaterials for optoelectronics, catalysis, and photovoltaic applications. Among these, while the chemistry of formation of group I−III−VI nanocrystals was extensively studied, group I−V−VI nanostructures were less explored. Considering Cu 3 BiS 3 ternary nanostructures as a case study, herein, the insight mechanism of formation of exclusive ternary platelets, their nucleation density-controlled length and shape tunability, and the dissolution process of initially formed copper sulfides for providing monomers during growth are studied and reported. These are performed by controlling reactions with tuning the compositions of precursors, varying the solvent volume, and also tuning the reaction temperature. The active monomerdriven shape modulations in 2D platelets, which are unique in ternary materials, were correlated with controlled directional growths of these nanostructures. Finally, these were also explored as catalysts for photoelectrochemical water reduction and performances were related to the copper-deficient nanostructures.

Two-dimensional copper based colloidal nanocrystals: synthesis and applications

“…54 Introduction of transition metals, group IV and group V elements into Cu-chalcogenide 2D NCs resulted in the following compositions of CuSbS 2 , Cu 3 SbS 3 , Cu 3 BiS 3 , Cu 2 SnS 3 , Cu 2 SnSe 3 , Cu 2 GeS 3 , CuFeS 2 , Cu 2 SnZnSe 4 , Cu 2 GeZnSe 4 , etc . 22,37,55–61 More recently, metal halides of Cu with compositions of Cs 3 Cu 2 I 5 , Cs 3 Cu 2 Br 5 and Rb 2 CuX 3 (X = Cl, Br) have also been synthesised. 35,62 Among the metallic Cu 2D NCs seeded growth materialised NCs with PdCu and PdPtCu compositions.…”

“…Among the other semiconductor NCs are multinary CuInS 2 nanodiscs, nanosheets, CuSbS 2 nanosheets, and Cu 3 BiS 3 nanoplatelets using heat-up and hot-injection approaches. 21,52,55,56,70 Initial approaches for synthesising CuInS 2 were based on the heat-up of the metal precursor and S source. But extension of the elemental composition to quaternary by the introduction of Ga and Se required a more controlled hot-injection approach where cation and anion introduction windows can be separated based on the injection temperature.…”

“…For group V based NCs, heat up techniques are based on the decomposition of diethyldithiocarbamate precursors of metals. 55,56 Using the cation exchange of Cu 2− x S and Cu 2− x Se 2D templates several heterostructures and multinary nanoplates with more complex compositions involving Au, Ag, Cd, Zn, Hg, Pb, Pd, In, Ga, Fe, Sn, and Ge have also been achieved in recent times. 61 The recent addition to the ion exchange series is the anion exchange of the Cu 3− x P template for the materialisation of Cu 3 P 1− x S x nanorings.…”

Morphology Controlled Synthesis of Composition Related Plasmonic CuCdS Alloy Nanocrystals

“…Cu-based ternary semiconductor nanocrystals are of great scientific interest for applications in solar cells (Rivest et al, 2011 ), light-emitting devices (LEDs) (Yoon et al, 2019 ; Li et al, 2020 ), biological imaging (Meng et al, 2017 ), photo-catalytic (Zhao et al, 2016 ), photoelectric detectors because of their low-toxicity, tunable band gaps, and high absorption coefficients (Pejova et al, 2020 ). Especially, ternary nanocrystals based on Cu 1.94 S, with localized surface plasmon resonance due to the large number of copper vacancies, have been widely demonstrated for photoelectrochemical water reduction and solar cells due to their high concentration of free charge carriers (Liu et al, 2017 ; Bai et al, 2020 ; Bera et al, 2020 ; Zhu et al, 2020 ). Developing the size-, shape-, and composition-controlled composite nanocrystals is a significant strategy to regulate their energy level position, carrier concentration, and photoluminescence quantum yield for the improvement of device performance.…”

“…Interestingly, these ternary nanocrystals possessed the alloyed nanostructure instead of a heterostructure. And they revealed enhanced photocatalytic activities toward photoelectrochemical water reduction, owing to their tailored optical band gaps, energy level alignments, and shape affecting (Bera et al, 2020 ; Zhu et al, 2020 ). Therefore, further exploiting new methods to synthesize highly crystallized transition-metal and II-VI alloyed nanostructures still worth systematical study.…”