Absorptance Of PbS Quantum Dots Thin Film Deposited On Trilayer MoS2

¹Department of Electrical and Computer Engineering, School of Engineering and Applied Science,The George Washington University, Washington, D.C. 20052, USA

²Department of Chemistry, National University of Singapore, 3 Science Drive 3, 117543, Singapore

Adv. Mater. Lett., 2015, 6 (11), pp 936-940

DOI: 10.5185/amlett.2015.6094

Publication Date (Web): Oct 26, 2015

Copyright © IAAM-VBRI Press

E-mail: simsek@gwu.edu

Abstract

We have studied the optical absorptance of lead sulfide (PbS) quantum dot (QD) coated thin crystalline layered material (TCLM) experimentally and numerically. Starting with the synthesis, fabrication and characterizations, a sample of PbS QDs deposited on trilayer molybdenum disulphide (MoS₂) thin film has been probed locally using a reflection spectrometer set-up. Since transmittance is needed to calculate the absorbtance of the QD film/TCLM sample, we run a set of simulations using a 3D finite-difference time-domain full-wave electromagnetic solver. Based on the agreement between experimental and numerical results for the reflectance spectra, which verifies the accuracy of our QD and TCLM modelling, we have calculated the absorptance. Unlike metal nanoparticle decorated TCLMs in which metal nanoparticles act like induced dipoles and enhance the absorptance, here we have not observed the similar effect; rather we have found that the absorptance of QD film/TCLM sample is almost equal to the summation of QDs’ and TCLM’s individual absorptance in the wavelength range of 450-800 nm.

Keywords

Quantum dots, PbS, MoS_2, TMDC, absorption.