On the rational design of core/(multi)-crown type-II heteronanoplatelets

• Main Authors: Delikanli, Savas, Canimkurbey, Betul, Hernández-Martínez, Pedro Ludwig, Shabani, Farzan, Isik, Ahmet Tarik, Ozkan, Ilayda, Bozkaya, Iklim, Bozkaya, Taylan, Isik, Furkan, Durmusoglu, Emek Goksu, Izmir, Merve, Akgun, Hakan, Demir, Hilmi Volkan
• Other Authors: School of Electrical and Electronic Engineering
• Format: Article
• Language: English
• Published: 2023
• Subjects: Engineering::Electrical and electronic engineering; Heteronanoplatelet; Light Emitting Diodes
• Online Access: https://hdl.handle.net/10356/170561
• Institution: Nanyang Technological University

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/CdSe1-xTex 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/CdSe1-xTex/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.