Precursor non-stoichiometry to enable improved CH3NH3PbBr3 nanocrystal LED performance. Issue 8 (8th February 2018)

• Record Type: Journal Article
• Authors: Chandran, Bevita K.; Veldhuis, Sjoerd A.; Chin, Xin Yu; Bruno, Annalisa; Yantara, Natalia; Chen, Xiaodong; Mhaisalkar, Subodh
• Is Part Of: Physical chemistry chemical physics. Volume 20:Issue 8(2018)
• Page Start: 5918
• Page End: 5925
• Publication Date: 2018-02-08
• Subjects: Chemistry, Physical and theoretical -- Periodicals; 541.3
• DOI: 10.1039/c7cp07827g
• Languages: English
• ISSNs: 1463-9076

Abstract

Abstract : Precursor non-stoichiometry during colloidal CH3 NH3 PbBr3 nanocrystal (NC) synthesis enabled substantial improvements in the LED performance. Abstract : High photoluminescence quantum yields and narrow emission wavelengths, combined with low temperature solution processing, make CH3 NH3 PbBr3 nanocrystals (NCs) favorable candidates for light-emitting applications. Herein, we describe the synthesis of CH3 NH3 PbBr3 NC inks by a convenient room-temperature ligand assisted reprecipitation protocol. We further investigate the effect of modulation of the CH3 NH3 Br : PbBr2 ratio during NC synthesis on the optical properties, crystallinity, particle size distribution and film formation of the NC ink. Subsequently, we fabricate LEDs using these NCs as the emissive layer and the highest efficiency (1.75% external quantum efficiency) and brightness (>2700 cd m −2 ) is achieved for the 1.15 : 1 precursor ratio. It is inferred that the NC surface properties and film coverage are more crucial than the photoluminescence intensity to achieve high device efficiency. Moreover, by separating the NC synthesis and thin film formation processes, we can exert more control during device fabrication, which makes it very promising for scale-up applications.