Synthesis and Characterization of CdSe Colloidal Quantum Dots in Organic Solvent

Abstract

Abstract. In this paper we present experimental results on preparation and characterization of colloidal CdSe quantum dots in organic solvent. CdSe QDs were synthesized following a modifi ed literature method. CdSe QDs were isolated by adding acetone to the cooled solution followed by centrifugation. CdSe QDs have been characterized by UV-Vis absorption and photoluminescent (PL) spectroscopy. The average CdSe particles size estimated from the UV-Vis absorption spectra was found to be in the range 2.28-2.92 nm which is in good agreement with PL measurements.Keywords: colloidal quantum dots, semiconductor, cadmium selenide, nanocrystals, photoluminescence. IntroductionAmong various semiconductor quantum dots (QDs) extensive research efforts have been developed over the last decade in the case of CdSe QDs because of their attractivity for various application in optoelectronics, photonics, medicine, etc. [1][2][3]. In spite of the problems related to the toxicity of Cd compounds, the possibility of tuning of the optical parameters of CdSe QDs makes them very attractive for technological development as well as for optoelectronics and biomedical applications. The size of QDs can be easily controlled by different ways, for example by variation of the reaction time, or the temperature of the solvents, by variation of the concentration of the reaction solvents, etc. This means a relatively simply and convenient technology for controlling the optical parameters of the nanocompozite structures for practical exploitation. For example, PL emission from colloidal CdSe quantum dots can be adjusted in a relatively wide spectral range from 465 to 670 nm [2]. The technology makes it possible to prepare different sized nanocrystals with high PL effi ciency and narrow PL band, while PL emission may cover a narrow spectral band, tuned from blue to read and even up to near infrared. Control and improvement of optical properties of CdSe quantum dots remain on the agenda of research in the fi eld of nanotechnology.

CdSe quantum dots enhancing blue emission of nematic liquid crystals

“…The sharp and intense first exciton absorption peak and the emission peak of the synthesized CdSe QDs are observed at 503 nm and 526 nm, respectively. This attributed to the very narrow and highly mono-dispersed size distribution [2]. The size of the CdSe QDs was estimated using CdSe sizing curve [14] as in equation (1…”

“…Quantum dots (QDs) have unique qualities such as a narrow luminescence peak and a high quantum yield, and are used in solar cells, light emitting devices, and optical molecular sensor systems [1]. Because of its appealing features, cadmium selenium (CdSe) QDs have got a lot of attention in recent decades among the various QDs [2]. Moreover, it has size-dependent optical properties because of its quantum confinement effects, admirable nonlinear optical properties, application in an optoelectronic due to a broad range of optical transmission [1,3], and biomedical applications [4].…”

“…Moreover, it has size-dependent optical properties because of its quantum confinement effects, admirable nonlinear optical properties, application in an optoelectronic due to a broad range of optical transmission [1,3], and biomedical applications [4]. Despite the toxicity of cadmium (Cd), the ability to tune optical characteristics of CdSe QDs makes them a promising candidate for optoelectronics and biological sensors [2]. The size of QDs can be tuned by adjusting the quantity of reaction solvents and varying the temperature [2].…”

“…Despite the toxicity of cadmium (Cd), the ability to tune optical characteristics of CdSe QDs makes them a promising candidate for optoelectronics and biological sensors [2]. The size of QDs can be tuned by adjusting the quantity of reaction solvents and varying the temperature [2].…”