Tunable structural and optical properties of CuInS
2 colloidal quantum dots as photovoltaic absorbers.
RSC Adv 2021;
11:21351-21358. [PMID:
35478826 PMCID:
PMC9034010 DOI:
10.1039/d1ra03659a]
[Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2021] [Accepted: 06/09/2021] [Indexed: 11/30/2022] Open
Abstract
Facile phase selective synthesis of CuInS2 (CIS) nanostructures has been an important pursuit because of the opportunity for tunable optical properties of the phases, and in this respect is investigated by hot-injection colloidal synthesis in this study. Relatively monodispersed colloidal quantum dots (3.8–5.6 nm) of predominantly chalcopyrite structure synthesized at 140, 180 and 210 °C over 60 minutes from copper(ii) hexafluoroacetylacetonate hydrate and indium(iii) diethyldithiocarbamate precursors exhibit temperature-dependent structural variability. The slightly off-stoichiometric quantum dots are copper-deficient in which copper vacancies , indium interstitials , indium–copper anti-sites and surface trapping states are likely implicated in broad photoluminescence emission with short radiative lifetimes, τ1, τ2, and τ3 of 1.5–2.1, 7.8–13.9 and 55.2–70.8 ns and particle-size dependent tunable band gaps between 2.25 and 2.32 eV. Further structural and optical tunability (Eg between 2.03 and 2.28 eV) is achieved with possible time-dependent wurtzite to chalcopyrite phase transformation at 180 °C likely involving a dynamic interplay of kinetic and thermodynamic factors.
We report the facile hot-injection colloidal synthesis of near-stoichiometric CuInS2 quantum dots at varying reaction times and temperatures which exhibit both optical and structural tunability with implications for enhanced photovoltaic utility.![]()
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