On the Rational Design of Core/(Multi)-Crown Type-II Heteronanoplatelets

Savas Delikanli; Betul Canimkurbey; Pedro Ludwig Hernández-Martínez; Farzan Shabani; Ahmet Tarik Isik; Ilayda Ozkan; Iklim Bozkaya; Taylan Bozkaya; Furkan Isik; Emek Goksu Durmusoglu; Merve Izmir; Hakan Akgun; Hilmi Volkan Demir

doi:10.1021/jacs.3c00999

On the Rational Design of Core/(Multi)-Crown Type-II Heteronanoplatelets

J Am Chem Soc. 2023 Jun 7;145(22):12033-12043. doi: 10.1021/jacs.3c00999. Epub 2023 May 9.

Authors

Affiliations

¹ Department of Electrical and Electronics Engineering, Department of Physics, UNAM - Institute of Materials Science and Nanotechnology, Bilkent University, Ankara 06800, Turkey.
² Luminous! Center of Excellence for Semiconductor Lighting and Displays, School of Electrical and Electronic Engineering, Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, School of Materials Science and Engineering, Nanyang Technological University, Singapore 639798, Singapore.
³ Serefeddin Health Services Vocational School, Central Research Laboratory, Amasya University, Amasya 05100, Turkey.

Abstract

Solution-processed two-dimensional nanoplatelets (NPLs) allowing lateral growth of a shell (crown) by not affecting the pure confinement in the vertical direction provide unprecedented opportunities for designing heterostructures for light-emitting and -harvesting applications. Here, we present a pathway for designing and synthesizing colloidal type-II core/(multi-)crown hetero-NPLs and investigate their optical properties. Stoke's shifted broad photoluminescence (PL) emission and long PL lifetime (∼few 100 ns) together with our wavefunction calculations confirm the type-II electronic structure in the synthesized CdS/CdSe_1-xTe_x core/crown hetero-NPLs. In addition, we experimentally obtained the band-offsets between CdS, CdTe, and CdSe in these NPLs. These results helped us designing hetero-NPLs with near-unity PL quantum yield in the CdSe/CdSe_1-xTe_x/CdSe/CdS core/multicrown architecture. These core/multicrown hetero-NPLs have two type-II interfaces unlike traditional type-II NPLs having only one and possess a CdS ending layer for passivation and efficient suppression of stacking required for optoelectronic applications. The light-emitting diode (LED) obtained using multicrown hetero-NPLs exhibits a maximum luminance of 36,612 cd/m² and external quantum efficiency of 9.3%, which outcompetes the previous best results from type-II NPL-based LEDs. These findings may enable designs of future advanced heterostructures of NPLs which are anticipated to show desirable results, especially for LED and lasing platforms.