Hydrothermal synthesis of cadmium selenide quantum dots: effect of reducing agent

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Hydrothermal synthesis of cadmium selenide quantum dots: effect of reducing agent Behzad Karimi1 · Mahdi Shafiee Afarani1   · Amir Masoud Arabi2 Received: 29 March 2020 / Accepted: 11 August 2020 © Springer-Verlag GmbH Germany, part of Springer Nature 2020

Abstract In the present study, CdSe quantum dots were synthesized via hydrothermal method using cadmium chloride and selenium oxide as starting materials, 3-mercaptopropionic acid as a surface modifier, and sodium borohydride, ascorbic acid, trisodium citrate dehydrated, tartaric acid and 2-aminobenzenecarboxylicacid as reducing agents (RAs). The effect of synthesis parameters such as the reducing agent type, synthesis temperature and time, primary pH value, and MPA surface modifier concentration was studied on the photoluminescence properties (PL). Results showed that PL spectra were considerably affected by the type of RA and the synthesis parameters. Moreover, hydrothermal synthesis in the presence of sodium borohydride as a RA with proper synthesis conditions led to the formation of CdSe particles in the quantum dot size range below 5 nm with the bandgap of above 3 eV. Keywords  Reducing agent · CdSe · Surface modifiers · Quantum dots · Hydrothermal method

1 Introduction Quantum dots (QDs) are fluorescent semiconductor nanostructure materials with the characteristic size of about their exciton Bohr radius [1, 2]. The most important advantage of QDs is the bandgap variation with the size, which results in tunable luminescent emission wavelength [1–3]. As a result, numerous investigations have been performed on the synthesis, characterization and application of these materials. Up to now, several QDs with different compositions have been introduced by different researchers such as silicon [4, 5], graphene [6, 7], copper oxide [8, 9], zinc oxide [10, 11], zinc sulfide [12–14], cadmium telluride [15, 16] and cadmium selenide [17, 18], etc. in the form of particles [19], core/ * Mahdi Shafiee Afarani [email protected] * Amir Masoud Arabi [email protected] Behzad Karimi [email protected] 1



Department of Materials Engineering, Faculty of Engineering, University of Sistan and Baluchestan, Zahedan, Iran



Department of Inorganic Pigments and Glazes, Institute for Color Science and Technology (ICST), Tehran, Iran

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shells [20, 21] or composites [22–25]. Cadmium selenide (CdSe) QDs are highly attractive due to their strong luminescence properties and appropriate quantum yield. CdSe quantum dots has been employed in different fields including biological imaging [2, 3], solar cells [1, 26], light-emitting diodes [27, 28], lasers [29, 30] and single-electron transistors [31]. CdSe quantum dots have been synthesized via several techniques including wet chemical [1, 32], sol–gel [33], sonochemical [3, 34], and hydrothermal [35, 36] methods. Hydrothermal method is a technique for one-step synthesis of nanostructure materials. Crystalline phase, particle size and morphology of the particles can be easily controlled by changing reaction temperature and time, pr