Miniband Formation in Superlattices of Colloidal Quantum Dots and Conductive Polymers

Abstract

We study the bound states and quasi-bound states in a 3- dimensional superlattice formed by an alternating structure of colloidal quantum dots and conductive polymers. Calculations of transmission coefficient of injected holes and electrons vs. their energy, by means of a transfer-matrix implementation1, are performed. In this study, TiO2, CdSe, CdS and GaN quantum dots are investigated as in a 1-dimensional array of ten quantum dots, interspersed in conductive polymers PDCTh and MEH- PPV. These compound semiconductor quantum dots are selected in view of their potential applications in single-photon detectors, solar cells, etc.2,3 Discrete energy levels in such periodic nanoscale structures form minibands;4 moreover, for injection energies close to the barrier height, these minibands have substantial width and large transmission coefficients implying that they may be used to improve the charge transport efficiency in previously-identified c lasses of electronic and optoelectronic devices incorporating ensembles of colloidal quantum dots embedded in conductive polymers.