Hybrid nanospheres of silica covalently containing yellow-emitting cationic iridium(III) complex: preparation and application in white light-emitting diodes

Haoju Li; Jing Qin; Shanglan Xian; Huaijun Tang; Yuxiang Jiao; Meifang Zhang; Long Wang; Qiang Zhou; Zhengliang Wang

doi:10.1039/d3dt03763k

Hybrid nanospheres of silica covalently containing yellow-emitting cationic iridium(III) complex: preparation and application in white light-emitting diodes

Dalton Trans. 2024 Feb 27;53(9):4080-4087. doi: 10.1039/d3dt03763k.

Authors

Haoju Li^{1

2}, Jing Qin¹, Shanglan Xian¹, Huaijun Tang¹, Yuxiang Jiao¹, Meifang Zhang³, Long Wang¹, Qiang Zhou¹, Zhengliang Wang¹

Affiliations

¹ Key Laboratory of Green-Chemistry Materials in University of Yunnan Province, National and Local Joint Engineering Research Center for Green Preparation Technology of Biobased Materials, School of Chemistry & Environment, Yunnan Minzu University, Kunming, 650500, P. R. China. tanghuaijun@sohu.com.
² School of Materials and Energy, Guangdong University of Technology, No. 100 Waihuan Xi Road, Guangzhou Higher Education Mega Center, Guangzhou 510006, China.
³ Institute of Carbon Neutral New Energy Research, Yuzhang Normal University, Nanchang 330031, China. mfzhang@whu.edu.cn.

PMID: 38314631
DOI: 10.1039/d3dt03763k

Abstract

A yellow-emitting cationic iridium(III) complex [(dfppy)₂Ir(TBD)]PF₆ (TBD: N⁴,N^4'-bis(3-(triethoxysilyl)propyl)-[2,2'-bipyridine]-4,4'-dicarboxamide; dfppy: 2-(2,4-difluorophenyl)pyridine) containing hydrolysable alkoxysilanes was synthesized. Then, a series of silica-based hybrid nanospheres with diameters of around 400 nm was prepared via the hydrolysis of this complex together with tetraethyl orthosilicate (TEOS, a silica source). When the amount of the complex used was 5.0 wt%, hybrid nanospheres showed the best photoluminescence (PL) properties, relative to the PL quantum yield of pure solid [(dfppy)₂Ir(TBD)]PF₆ (12.7%), that of hybrid nanospheres increased to 26.2%. Moreover, the thermal decomposition temperature (T_d) of pure solid [(dfppy)₂Ir(TBD)]PF₆ was 331 °C, the T_d of the complex in hybrid nanospheres increased to 447 °C. However, the yellow light emission was almost unchanged and was still located at 500-750 nm with a maximum wavelength (λ_em,max) of 577 nm. Under the excitation of blue-emitting chips (λ_em,max ≈ 455 nm), cold/neutral/warm white light-emitting diodes (WLEDs) with good luminous quality can all be fabricated using these hybrid nanospheres as phosphors in epoxy resin at different blending concentrations. Compared with two or three iridium(III) complexes being contained in silica-based particles as phosphors as described in literatures, in this study, silica-based hybrid nanospheres covalently containing only one yellow-emitting cationic iridium(III) complex as phosphors provide a more effective and simpler method for preparation high-performance WLEDs.