Determination of the photoluminescence quantum efficiency of silicon nanocrystals by laser-induced deflection

Abstract

The oxidation and passivation of freshly prepared silicon nanocrystals (Si NCs) have been studied by exciting them with a low-fluence violet laser at 406 nm and measuring both the heat generated by nonradiative transitions and the photoluminescence (PL) resulting from radiative charge carrier recombination over a period of 31 days. Laser-induced deflection was employed as a sensitive tool to determine the heat transferred to the phonon bath. The PL quantum efficiency of Si NCs passivated in air was found to develop with a time constant of 8 d from zero to a terminal saturation value of approximately 65%.

Colloidal silicon quantum dots: from preparation to the modification of self-assembled monolayers (SAMs) for bio-applications

“…87,126 In spite of the initial success of this method, strong photoluminescence was detected only in limited cases in subsequent studies, when pyrolysis products were etched with HF, and yield of final product was usually very low. [127][128][129][130][131] Li et al recently advanced this method by first preparing silicon nanoclusters of up to 50 nm, achieved via CO 2 laser induced pyrolysis of SiH 4 gas in an aerosol reactor. 38 This treatment was followed by controlled etching using a mixture containing highly concentrated hydrofluoric acid (HF) (48%) and nitric acid (HNO 3 ).…”

Nanodiamonds and silicon quantum dots: ultrastable and biocompatible luminescent nanoprobes for long-term bioimaging

“…[226][227][228] As shown in Fig. 19 229 the PL quantum efficiency of Si NCs was found to increase, with a time constant of 8 days, from zero to a terminal, saturation value of approximately 65%, as an effect of air oxidation. 229 Luminescent NCs were prepared by doping the silicon matrix with germanium during the synthesis.…”

“…224,225 Huisken et al 226 obtained luminescent particles, but with small PL efficiency, and studied the effect of the aging in air of the hydrogen terminated Si QDs, as well as the effect of surface etching with HF, on the PL features. 19 229 the PL quantum efficiency of Si NCs was found to increase, with a time constant of 8 days, from zero to a terminal, saturation value of approximately 65%, as an effect of air oxidation. 19 229 the PL quantum efficiency of Si NCs was found to increase, with a time constant of 8 days, from zero to a terminal, saturation value of approximately 65%, as an effect of air oxidation.…”

“…19 229 the PL quantum efficiency of Si NCs was found to increase, with a time constant of 8 days, from zero to a terminal, saturation value of approximately 65%, as an effect of air oxidation. 229 Luminescent NCs were prepared by doping the silicon matrix with germanium during the synthesis. 230 Large scale production was achieved by Li et al who designed and optimized a flow reactor, schematized in Fig.…”

“…[226][227][228] As shown in Fig. 229 Luminescent NCs were prepared by doping the silicon matrix with germanium during the synthesis. 229 Luminescent NCs were prepared by doping the silicon matrix with germanium during the synthesis.…”