Syntheses and characterization of Schiff base ligands and their Ir (III) complexes as coating for phosphor-converted LEDs

Author(s)

Canisares, Felipe S. M. ^{[1, 2, 3]} ; Bispo-Jr, Airton G. ; Pires, Ana M. ^{[2, 3, 4]} ; Lima, Sergio A. M. ^{[2, 3]}

Affiliation

^[1] Sao Paulo State Univ UNESP, Inst Chem, Araraquara, SP - Brazil

^[2] Sao Paulo State Univ Unesp, Sch Technol & Sci, R Roberto Simonsen 305, BR-19060900 Presidente Prudente, SP - Brazil

^[3] Sao Paulo State Univ UNESP, Inst Biosci Humanities & Exact Sci, Sao Jose Do Rio Preto, SP - Brazil

^[4] Bispo-Jr, Jr., Airton G., Sao Paulo State Univ Unesp, Inst Chem, Araraquara, SP - Brazil

• Document type: Journal article
• Source: OPTIK; v. 219, OCT 2020.
• Web of Science Citations: 1

Abstract

Ir(III) complexes find several applications in light conversion molecular devices (LCMD) such as in solid-state lighting (SSL). Although, a couple of blue or green-emitting Ir(III) complexes are found so far, there is a lack of near-UV-to-red downshifting converter Ir(III) complexes to be used as coatings of near-UV-excited white-light-emitting diodes (WLEDs). Thus, in this study, we introduce the syntheses of two ligands named as 2-(((3-methyl-1-phenyl-1H-pyrazol-5-yl)imino)methyl)phenol (BS1) and 5-(diethylamino)-2-(((3-methyl-1-phenyl-1H-pyrazol-5-yl)imino)methyl)phe nol (BS2) and their use to synthesize two new red-emitting iridium complexes, Ag{[}Ir(ppz)(2)(BS1)] and Ag{[}Ir(ppz)(2)(BS2)]. BS1 and BS2 structures were deeply investigated theoretically and experimentally, and they display emission in the yellow and green spectral region under UV excitation, respectively. Ag{[}Ir(ppz)(2)(BS1)] and Ag{[}Ir(ppz)(2)(BS2)] features emission characterized by a broadband centered with color coordinates of (0.659;0.337) and (0.612;0.380), respectively, both in the red spectral region, with 100 % of color purity. To demonstrate their application in SSL, BS1 and Ag{[}Ir(ppz)(2)(BS1)] were used to coat commercial near-UV-emitting LEDs (395 nm). The radiant stability of the prototypes overseen for 24 h attests that the emission intensity of the Ag{[}Ir(ppz)(2)(BS1)]-LED prototype decreases only 10 %, confirming that the complex matches with the desired photostability and qualifying this complex to be used as coatings of near-UV excited white-light-emitting diodes. (AU)

• FAPESP's process: 12/13876-9 - Optical and Structural effects of Eu(III) doping ion concentration in the Ba2SiO4 host lattice synthesized via sol-gel method
• Grantee: Airton Germano Bispo Júnior
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• FAPESP's process: 15/03400-5 - Synthesis and characterization of lanthanide complexes with carboxylic acid ligands
• Grantee: Felipe da Silva Manrique Canisares
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• FAPESP's process: 16/20421-9 - Tricolor devices based on Ba2SiO4:Eu3+ e/ou Tb3+: sol-gel synthesis and eletrophoretic deposition for W-LEDs application
• Grantee: Airton Germano Bispo Júnior
• Support Opportunities: Scholarships in Brazil - Doctorate (Direct)
• FAPESP's process: 15/10394-1 - LBL luminescent thin films of rare earth doped Ba2SiO4 obtained via sol-gel for white LED application
• Grantee: Airton Germano Bispo Júnior
• Support Opportunities: Scholarships in Brazil - Master