Fast, Infrared-Active Optical Transistors Based on Dye-Sensitized CdSe Nanocrystals

authored by

Krishan Kumar, Quan Liu, Jonas Hiller, Christine Schedel, Andre Maier, Alfred Meixner, Kai Braun, Jannika Lauth, Marcus Scheele

Abstract

We report an optically gated transistor composed of CdSe nanocrystals (NCs), sensitized with the dye zinc β-tetraaminophthalocyanine for operation in the first telecom window. This device shows a high ON/OFF ratio of 6 orders of magnitude in the red spectral region and an unprecedented 4.5 orders of magnitude at 847 nm. By transient absorption spectroscopy, we reveal that this unexpected infrared sensitivity is due to electron transfer from the dye to the CdSe NCs within 5 ps. We show by time-resolved photocurrent measurements that this enables fast rise times during near-infrared optical gating of 47 ± 11 ns. Electronic coupling and accelerated nonradiative recombination of charge carriers at the interface between the dye and the CdSe NCs are further corroborated by steady-state and time-resolved photoluminescence measurements. Field-effect transistor measurements indicate that the increase in photocurrent upon laser illumination is mainly due to the increase in the carrier concentration while the mobility remains unchanged. Our results illustrate that organic dyes as ligands for NCs invoke new optoelectronic functionalities, such as fast optical gating at sub-bandgap optical excitation energies.

Organisation(s)

Institute of Physical Chemistry and Electrochemistry
PhoenixD: Photonics, Optics, and Engineering - Innovation Across Disciplines

External Organisation(s)

University of Tübingen
Universite de Technologie de Troyes

Type

Article

Journal

ACS Applied Materials and Interfaces

Volume

11

Pages

48271-48280

No. of pages

10

ISSN

1944-8244

Publication date

26.12.2019

Publication status

Published

Peer reviewed

Yes

ASJC Scopus subject areas

Materials Science(all)

Electronic version(s)

https://doi.org/10.1021/acsami.9b18236 (Access: Closed)