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

verfasst von

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.

Organisationseinheit(en)

Institut für Physikalische Chemie und Elektrochemie
PhoenixD: Simulation, Fabrikation und Anwendung optischer Systeme

Externe Organisation(en)

Eberhard Karls Universität Tübingen
Universite de Technologie de Troyes

Typ

Artikel

Journal

ACS Applied Materials and Interfaces

Band

11

Seiten

48271-48280

Anzahl der Seiten

10

ISSN

1944-8244

Publikationsdatum

26.12.2019

Publikationsstatus

Veröffentlicht

Peer-reviewed

Ja

ASJC Scopus Sachgebiete

Werkstoffwissenschaften (insg.)

Elektronische Version(en)

https://doi.org/10.1021/acsami.9b18236 (Zugang: Geschlossen)