Sun-Like White Light Emitting Diodes Based on. Zero-Dimensional Organic Metal Halide Hybrids

Transcription

1 Supporting Information Sun-Like White Light Emitting Diodes Based on Zero-Dimensional Organic Metal Halide Hybrids Michael Worku, Yu Tian, Chenkun Zhou, Sujin Lee, Quinton Meisner, Yan Zhou, Biwu Ma * Materials Science and Engineering Program, Florida State University, Tallahassee, FL, 32306, USA Department of Chemical and Biomedical Engineering, FAMU-FSU College of Engineering, Tallahassee, FL, 32310, USA Department of Chemistry and Biochemistry, Florida State University, Tallahassee, FL, 32306, USA * bma@fsu.edu (Biwu Ma) Experimental Methods Materials: Tin (II) bromide (SnBr2), antimony(iii) chloride (SbCl3,.95 %), manganese(ii) bromide (MnBr2, 98%), tetraphenylphosphonium chloride (Ph4PCl, 98 %), tetraphenylphosphonium bromide (Ph4PBr, 97 %), N,N -dimethyl ethylenediamine (C4N2H14, %), hydrobromic acid (48 wt.% in H2O) were purchased from Sigma-Aldrich. Dichloromethane (DCM,.9%), dimethylformamide (DMF,.8%) and diethyl ether S-1

2 ((C2H5)2O, anhydrous) were purchased from VWR. Acetone (HPLC grade) was purchased from EMD Millipore. All reagents and solvents were used without further purification unless otherwise stated. Solution growth of 0D metal halide bulk materials: Yellow light emitting (C4N2H14Br )4SnBr6 crystals were prepared following the reported procedure35 by diffusing DCM to DMF solution of SnBr2 and C4N2H14Br2 overnight. Red light emitting (Ph4P)2SbCl5 crystals were prepared following the reported procedure by diffusing (C2H5)2O to DMF solution of SbCl3 and Ph4PCl overnight.37 Green light emitting (Ph4P)2MnBr4 crystals were prepared following a revised procedure38 by diffusing 12 ml (C2H5)2O to 4 ml DMF solution of 2 mmol Ph4PBr and 1 mmol MnBr2 at room temperature for overnight. The crystals were washed with (C2H5)2O and dried under reduced pressure. Fabrication of white LEDs: Simulation and optimization of the white light spectra were conducted using the Osram-Sylvania LED Color Calculator. The single crystal phosphors were hand-ground using mortar and pestle. They were then proportioned and mixed with a two-part polydimethylsiloxane (PDMS) EI-1184, purchased from Dow-Corning, at a concentration of 25 mg ml-1. The mixture gel was placed in a polytetrafluoroethylene (PTFE) mold and cured at 100 C for 30 minutes, under ambient atmosphere. The phosphor layer was subsequently attached to an Opulent Americas LST1-01G01-UV nm UV-LED. Characterization: Steady-state emission and excitation of phosphors was collected using a Horiba JY Fluoromax-4 Fluorometer. The temperature dependent photoluminescence spectra were measured on a Varian Cary Eclipse Fluorescence Spectrometer with a Water 4 Position Multicell Holder Accessory attached to a Julabo F12-EC Refrigerated/Heating Circulator filled with ethylene glycol-water mixture (3:2). The photoluminescence quantum efficiencies (PLQEs) of the phosphors and phosphor-polymer composites were measured in a Hamamatsu Quantaurus-QY Absolute PL quantum yield spectrometer at an excitation wavelength of 365 S-2

3 nm. The Electroluminescence spectra, current dependence and thermal stability measurements of the white LEDs were collected on an Ocean Optics USB4000 Miniature Fiber Optic Spectrometer in combination with a Keithley 2400 source-meter. Efficiency measurements were conducted using Keithley 2400 source-meter, a Newport 818-UV photodetector and a Newport multi-function optical meter. An Edmund Optics deep-dyed Polyethylene terephthalate (PET) UV filter was used during efficiency measurement to remove contribution to photocurrent from the UV-LED. Figure S1. Absorption spectra of phosphors S-3

4 Table S1. Photophysical property of phosphors summary Materials λ exc λ emi FWHM Stokes PLQE (nm) (nm) (nm) Shift (nm) (%) BAM:Eu (Ph 4 P) 2 MnBr 4 280, 365, (C 4 N 2 H 14 Br) 4 SnBr (Ph 4 P) 2 SbCl Figure S2. PLQE comparison of single crystal versus ball-milled 0D hybrids S-4

5 Table S2. Photometric results of simulated white light CCT CRI (R a ) CQS R9 CIE (x, y) (0.4355, ) (0.3811, ) 5000 (0.3458, ) (0.3217, ) Figure S3. Temperature dependent emission of (a) BAM:Eu 2+, (b) (Ph 4 P) 2 MnBr 4, (c) (C 4 N 2 H 14 Br ) 4 SnBr 6, and (d) (Ph 4 P) 2 SbCl 5. S-5

6 Figure S4. CIE 1931 diagram of (a) chromaticity points of emission under forward bias current variation from 10 ma to 20 ma; (b) chromaticity points of devices aged at 85 C for 0, 24, 48, 72 and 96 hours. Figure S5. Voltage versus current efficiency and luminous efficiency of prototype device. S-6