Synthesis and Characterization of Colloidal CuInS₂ Nanoparticles from a Molecular Single-Source Precursor

Abstract

Thermal decomposition of the molecular single-source precursor (PPh 3 ) 2 CuIn(SEt) 4 in the presence of hexanethiol in dioctylphthalate forms colloidal CuInS 2 at 200 °C. The colloidal solution displays size-dependent quantum confinement behavior in the absorption and photoluminescence spectra. The average size of the nanocrystals can be increased from 2 to 4 nm by raising the reaction temperature from 200 °C to 250 °C. The nanoparticles are capped with hexanethiol ligands; these ligands can be exchanged with trioctylphosphine oxide or pyridine. The nature of the surface-capping ligands has a significant effect on the photoluminescence emission intensity. Investigation of the effect of synthesis parameters and postsynthesis treatments on the optical properties of the nanocrystals leads to the conclusion that the room-temperature emission originates in donor-acceptor defects.

Optimization of the recipe for the synthesis of CuInS2/ZnS nanocrystals supported by mechanistic considerations

“…Until now, the PL QYs of CIS/ZnS in the reach stage have been up to more than 80% [24,25,27,33]. Castro et al [17] reported a difference in the PL QY of two orders of magnitudes when applying different ligands. The strong effect on the optical properties has been assigned to the large number of defects on the surface of nanocrystals that provide a source of defects or unpassivated sites where nonradiative recombination takes place.…”

“…Several independent approaches for CIS synthesis were reported, for example, solvothermal synthesis [16], single-source precursor routes [17], and hot injection techniques [18,19]. An overview of the chemical synthesis methods for CIS or ternary compounds has been published by Kolny-Olesiak and Weller and Aldakov et al [20,21].…”

“…Unlike traditional II-VI group QDs, CIS nanoparticles exhibit broad bandwidth [full-width at half-maximum (FWHM)] of emission and have no obvious band edge absorption [16,17]. Furthermore, the PL peak wavelength of CIS/ZnS has a blue shift compared to CIS QDs [23,24,34].…”

A facile method for the production of SnS thin films from melt reactions

“…In many cases, the uses of SSPs have granted control of both its physical and optical properties that dualsource precursors cannot [9][10][11]. In the last 20 years [12][13][14][15][16][17][18], many SSPs comprised metal (N,N-dialkyldithiocarbamates) [M(S 2 CNR 2 ) n ] have been used to synthesize metal sulfide nanocrystals.…”

Real-Space Mapping of Surface Trap States in CIGSe Nanocrystals Using 4D Electron Microscopy

“…But, when it comes to nanoscale, the presence of multiple trap states and the lack of the knowledge about their ultrafast carrier trapping dynamics limit their efficiency in device-based applications. 16,[23][24][25][26] Various surface passivation techniques, e.g., treatment with different ligands or shelling with higher bandgap materials, have been tried to reduce the detrimental effects of surface-related traps. 24,[27][28][29][30][31][32][33][34][35] However, in order to design more efficient passivation strategies for photoactive materials for any applications, precise knowledge about the surface charge carrier dynamics is a prerequisite.…”