A novel sustainable and green mechanochemical route from a (HSiO1.5)n polymer to emissive silicon nanocrystals. Issue 35 (11th August 2022)

• Record Type: Journal Article
• Authors: Xu, Yuping; Xin, Yunzi; Kato, Kunihiko; Shirai, Takashi
• Is Part Of: Journal of materials chemistry. Volume 10:Issue 35(2022)
• Page Start: 12588
• Page End: 12601
• Publication Date: 2022-08-11
• Subjects: Materials -- Periodicals; Chemistry, Analytic -- Periodicals; Optical materials -- Research -- Periodicals; Electronics -- Materials -- Research -- Periodicals; 543.0284
• DOI: 10.1039/d2tc02352k
• Languages: English
• ISSNs: 2050-7526

Abstract

Abstract : A novel, sustainable and green strategy to transform the (HSiO1.5 ) n polymer into functional Si NCs via a room-temperature mechanochemical process without H2 supply. Abstract : Thermal-induced pyrolysis of the hydrogen silsesquioxane ((HSiO1.5 ) n ) polymer has often been applied as a popular straightforward method for the synthesis of silicon nanocrystals (Si NCs), in which the need for high temperature (>1100 °C) and continuous H2 supply during the time-consuming pyrolysis and cooling processes are the main drawbacks. Herein, we offer a sustainable and green alternative to conventional thermal transformations from the (HSiO1.5 ) n polymer to emissive Si NCs via a room-temperature mechanochemical process with zero H2 supply. Along with the systematic monitoring of the chemical structure change of the (HSiO1.5 ) n polymer under altered mechanochemical conditions and the detailed characterizations of both solid-state and gas phase products, we derived a novel reaction mechanism from (HSiO1.5 ) n polymer to Si NCs via a mechanochemical route distinct from conventional thermal pyrolysis. It was found that the in-vessel produced H2 via the cleavage of the Si–H bond in (HSiO1.5 ) n molecule facilitates the generation of Si radicals and formation of resultant Si NCs, while the remaining Si–O–Si network transformed into a SiO2 -like matrix through the collapse of the raw (HSiO1.5 ) n structure and bond redistribution during the mechanochemical process. As a practical application, emissive free-standing Si NCs were successfully prepared via further matrix removal by chemical etching and surface passivation by 1-decene. The prepared Si NCs exhibit photoluminescence in the red-light wavelength region and an absolute quantum yield of 9.8%, whose value is comparable to that synthesized by the conventional thermal pyrolysis method. The novel and facile mechnochemical route developed in the present work opens a new avenue for the smart synthesis of functional nanomaterials.