Size-Dependent Charge Collection in Junctions Containing Single-Size and Multi-Size Arrays of Colloidal CdSe Quantum Dots

Abstract

This paper describes the electrical characteristics of junctions composed of three-dimensional arrays of colloidal CdSe quantum dots (QDs) with tin-doped indium oxide (ITO)/poly(3,4-ethylenedioxy-thiophene):poly(styrenesulfonate) (PEDOT:PSS) and eutectic Ga-In (EGaIn) electrodes. It focuses on a comparison of junctions containing QDs of one size to those of arrays containing QDs of multiple sizes. This comparison makes it possible to estimate the relative contributions of transport across various interfaces (e.g., between the QDs and between the QDs and the electrodes) to the observed electrical characteristics of the junction and to evaluate the dependence of these contributions on the locations of various sizes of QDs within the junction. The junctions were diodes, and their turn-on voltage depended on the size of the QDs next to the PEDOT:PSS. We describe this dependence using a Marcus model to estimate the barrier for charge transfer induced by the difference in energies between the orbitals of the QDs and the valence band of PEDOT:PSS.

Charge transport in mixed CdSe and CdTe colloidal nanocrystal films

“…The top electrode was a eutectic gallium-indium solder ͑EGaIn͒. 19 The film treatment employed in this paper is postdeposition cap exchange with butylamine. 5 For the butylamine cap exchange, the NC film was soaked in a 0.1 M solution of butylamine in acetonitrile for 2 min.…”

Effect of different aqueous synthesis parameters on the size of CdSe nanocrystals

“…Semiconductor nanoparticles (NP) have been the subject of intensive studies due to their size-dependent electronic and optical properties and their potential applications in biological labelling, microelectronics and optical communication [1][2][3][4][5][6]. There are two major effects in NP properties which are responsible for these size variations.…”

Facile fabrication of CdSe/CdS quantum dots and their application on the screening of colorectal cancer

“…The first is the organometallic synthetic route using TOPO (trioctylphosphine oxide) or TOP (trioctylphosphine) as stabilizing reagents (Tonti et al 2004;Weiss et al 2008). As the CdSe QDs synthesized in organic solvents are insoluble in the aqueous phase and incompatible with biological systems, before tumor marker detection they are usually transferred to water-soluble QDs transferring reagents, such as thiols or amphiphilic polymers (Larson et al 2003).…”