School of Electrical and Electronic Engineering, School of Materials Science and Engineering, School of Physical and Mathematical Sciences, The Photonics Institute, LUMINOUS! Centre of Excellence for Semiconductor Lighting & Displays, Shabani, Farzan, Baruj, Hamed Dehghanpour, Delikanli, Savas, Demir, Hilmi Volkan, Delikanlı, Savaş
Colloidal nanoplatelets (NPLs) have emerged as the last class of semiconductor nanocrystals for their potential optoelectronic applications. The heterostructures of these nanocrystals can achieve high photoluminescence quantum yield and enhanced photostability, along with color purity. Such advantages make them a promising candidate for solution-processable light-emitting diodes (LEDs). However, to date, blue-emitting CdSe nanoplatelets (NPLs) exhibit poor photoluminescence quantum yield and also typically suffer from a rolled-up morphology. To mitigate these problems in this work, we propose and demonstrate efficient alloyed 4 ML CdSe1-xSx nanoplatelets having a CdS crown with enhanced photoluminescence quantum yields (up to 60%) in the blue region (462-487 nm). We successfully used these NPLs as an electrically driven active emitter in the blue-emitting NPL-LEDs with a low turn-on voltage of ∼4 V. The Commission Internationale de L'Eclairage (CIE) coordinates of (0.23, 0.14) were obtained for these blue-emitting NPL-LEDs. These emitters could potentially open up the opportunity for full-color displays using these NPL-based blue LEDs in conjunction with the red and green ones. Ministry of Education (MOE) National Research Foundation (NRF) Accepted version This research is supported by the National Research Foundation, Prime Minister’s Office, Singapore under its NRF Investigatorship Award program (NRF-NRFI2016-08) and the Ministry of Education Tier 1 grant (MOE-RG62/20). H.V.D. also gratefully acknowledges the support from TUBA