Molecular hybrids of CdSe semiconductor nanocrystals with terthiophene carboxylic acid or its polymeric analogue

Abstract

Hybrid materials consisting of CdSe nanocrystals (CdSe NCs) and 7-(4,4″-dioctyl-2,2′:5′,2″-terthiophene-3′-yl)heptanoic acid (TTHA) or its high molecular analogue—poly(7-(4,4″-dioctyl-2,2′:5′,2″-terthiophene-3′-yl)heptanoic acid) (PTTHA) have been prepared from TOPO capped NCs via ligand exchange. Detailed spectroscopic and spectroelectrochemical (UV–vis–NIR, Raman) studies of these hybrids enabled us to determine the alignment of the HOMO and LUMO levels of their components. Since, for NCs of 3.7 nm, the alignment of the energy levels in both hybrids is staggered, the elaborated new materials are of potential use in photovoltaic devices. In the CdSe–PTTHA hybrid material a uniform distribution of the NCs within the polymer matrix is evidenced by TEM images. This is caused by strong interactions between nanocrystals surface and coordinating carboxylic function of the polymer.