Photoconductivity of CdTe Nanocrystal-Based Thin Films: Te(2-) Ligands Lead To Charge Carrier Diffusion Lengths Over 2 μm

Ryan W Crisp; Rebecca Callahan; Obadiah G Reid; Dmitriy S Dolzhnikov; Dmitri V Talapin; Garry Rumbles; Joseph M Luther; Nikos Kopidakis

doi:10.1021/acs.jpclett.5b02252

Photoconductivity of CdTe Nanocrystal-Based Thin Films: Te(2-) Ligands Lead To Charge Carrier Diffusion Lengths Over 2 μm

J Phys Chem Lett. 2015 Dec 3;6(23):4815-21. doi: 10.1021/acs.jpclett.5b02252. Epub 2015 Nov 20.

Authors

Ryan W Crisp^{1

2}, Rebecca Callahan^{1

3}, Obadiah G Reid⁴, Dmitriy S Dolzhnikov⁵, Dmitri V Talapin⁵, Garry Rumbles¹, Joseph M Luther¹, Nikos Kopidakis¹

Affiliations

¹ National Renewable Energy Laboratory , Golden, Colorado 80401, United States.
² Department of Physics, Colorado School of Mines , Golden, Colorado 80401, United States.
³ Department of Chemistry and Biochemistry, University of Colorado , Boulder, Colorado 80309, United States.
⁴ Renewable and Sustainable Energy Institute, University of Colorado at Boulder , Boulder, Colorado 80309, United States.
⁵ Department of Chemistry, University of Chicago , Chicago, Illinois 60637, United States.

PMID: 26571095
DOI: 10.1021/acs.jpclett.5b02252

Abstract

We report on photoconductivity of films of CdTe nanocrystals (NCs) using time-resolved microwave photoconductivity (TRMC). Spherical and tetrapodal CdTe NCs with tunable size-dependent properties are studied as a function of surface ligand (including inorganic molecular chalcogenide species) and annealing temperature. Relatively high carrier mobility is measured for films of sintered tetrapod NCs (4 cm(2)/(V s)). Our TRMC findings show that Te(2-) capped CdTe NCs show a marked improvement in carrier mobility (11 cm(2)/(V s)), indicating that NC surface termination can be altered to play a crucial role in charge-carrier mobility even after the NC solids are sintered into bulk films.

Keywords: CdTe; nanocrystal; photoconductivity.

Publication types

Research Support, U.S. Gov't, Non-P.H.S.