Investigation of the size–property relationship in CuInS₂quantum dots

Abstract

aIn this work we investigated fundamental properties of CuInS 2 quantum dots in dependence of the particle size distribution (PSD). Size-selective precipitation (SSP) with acetone as poor solvent was performed as an adequate post-processing step. Our results provide deep insight into the correlation between particle size and various optical characteristics as bandgap energy, absorption and emission features and the broadness of the emission signal. These structure-property relationships are only achieved due to the unique combination of different analytical techniques. Our study reveals that the removal of 10 wt% of smallest particles from the feed results in an enhancement of the emission signal. This improvement is ascribed to a decreased quenching of the emission in larger particles. Our results reveal the impact of PSDs on the properties and the performance of an ensemble of multicomponent QDs and anticipate the high potential of controlling PSDs by well-developed post-processing.

Size-Dependent Band-Gap and Molar Absorption Coefficients of Colloidal CuInS2 Quantum Dots

“…51 and Akdas et al . 56 used the Scherrer’s diameter determined from powder X-ray diffraction. The E 1 values were also determined by using different methods ( e.g ., extrapolation of Tauc plots in ref (55), double-tangent method in ref (51)).…”

“…g ., Cu 2 S–CIS). 40 Moreover, CIS QDs produced by direct synthesis are typically trigonal-pyramidal in shape, 52−55 further complicating the determination of their sizes and introducing ambiguities, since “diameter” becomes an ill-defined quantity, leading different authors to use different metrics for the QD size ( e.g ., average edge length, 55 average diagonal length, 52 Scherrer’s diameter determined from powder X-ray diffraction 51,56 ).…”

2D analysis of polydisperse core–shell nanoparticles using analytical ultracentrifugation

“…Spherical shape of these NPs was previously demonstrated by image analysis using TEM. 22, 23 In contrast to ZnO, these NPs have a thicker organic shell of about 1 nm. 22 In our previous work, resolution with respect to the simultaneous determination of size and effective density was severely limited because the c(s, D) analysis was employed.…”

“…22, 23 In contrast to ZnO, these NPs have a thicker organic shell of about 1 nm. 22 In our previous work, resolution with respect to the simultaneous determination of size and effective density was severely limited because the c(s, D) analysis was employed. 22 c(s) analysis was further used to determine the PSD but this approach incurred drawbacks due to the assumption of a constant effective NP density.…”

“…Batch synthesis of the CuInS 2 QDs was performed in a 50 ml three-necked round bottom flask using a Schlenk line. 21, 22 1-ODE was degassed minimum 30 min prior to synthesis. CuAc (81 mg, 0.66 mmol), InAc 3 (193 mg, 0.66 mmol), 1-DDT (1.5 ml, 6.3 mmol) and 1-ODE (14 ml) were added into the flask and degassed by pulling vacuum for 10 min, followed by N 2 bubbling for 1 min.…”