Supplementary Information
Multifunctional naphthol sulfonic salt incorporated in
lead-free 2D tin halide perovskite for red light-emitting diodes
Congcong Gao,† Yuanzhi Jiang,‡ Changjiu Sun,‡ Jingrui Han,† Tingwei He,‡Yanmin Huang,‡ Kaili Yao,† Mei Han,† Xi Wang,† Yunkun Wang,§ Yunan Gao,§
Yongchang Liu,† Mingjian Yuan‡,*and Hongyan Liang†,*
† School of Materials Science and Engineering, Tianjin University, Tianjin 300350, P. R. China. ‡ Key Laboratory of Advanced Energy Materials Chemistry (Ministry of Education), College of
Chemistry, Nankai University, Tianjin, 300071, China
§ State Key Lab for Artificial Microstructure & Mesoscopic Physics, School of Physics, Peking
University, Beijing, 100871, China
*E-mail: [email protected] * E-mail: [email protected]
Contents
Note 1 Experimental Section Note 2 LED device fabrication
Note 3 Device measurements and film characterization
S1. Schematic illustration of crystallization mechanism during the film fabrication process with and without DSAS
S2. SEM images of the PEA2SnI4 films (a) without and (b) with 3 mol.% of the DSAS
molecules, respectively.The pinholes are marked with the blue circles
S3. XPS S 2p spectra of (a) perovskite film with/without DSAS (3 mol.%) and (b) pure DSAS molecules
S4. GIWAXS pattern of the perovskite film without DSAS
S5. XRD spectra of the perovskite film without (a) and with (b) DSAS after 5 days
S6. (a) UV–vis absorption spectra and (b) steady-state PL spectra of perovskite film with/without DSAS (3 mol.%)
S7. Photoluminescence image of with DSAS (3 mol.%) films under UV excitation S8. Luminance (a) and EQE (b) versus voltage characteristics of PeLEDs doped with different amounts of DSAS additives
S9. Lifetime measurement (T50) of (a) without and (b) with DSAS (3 mol.%) PeLEDs
device at a constant voltage of 3.4 V
Table S1 Performance of PeLEDs doped with different amounts of DSAS additives Table S2 Performance summary of similar structure PeLEDs
Note 1 Experimental Section
Materials: Chemicals listed below are commercially available and used without further
purification. PEDOT: PSS (Clevios P VP AL 4083) was purchased from Heraeus. Phenethylammonium iodide (PEAI) (99.999%) was purchased from Greatcell Solar.
Tin (II) iodide (SnI2, 99.999%) was purchased from Alfa Aesar.
2,3-dihydroxynaphthalene-6-sulfonic acid sodium salt (DSAS) (>98.0%)were purchased from Aladdin. DMF (anhydrous, 99.8%), DMSO (anhydrous, >=99.9%) and lithium fluoride (LiF) were purchased from Sigma-Aldrich. 1,3,5-tris(N-phenylbenzimiazole-2-yl)benzene (TPBi) were purchased from Lumtech Corp.
Note 2 LED device fabrication
0.4M precursor solution was prepared by dissolving stoichiometric PEAI and SnI2
and DSAS (3 mol %) in DMF/DMSO (6:1) mixture by stirring at room temperature. The precursor solutions were filtered by 0.45-μm poly (tetrafluroethylene) filters before using. ITO substrates (10 Ω sq-1) were cleaned by standard procedures and then treated
with O2 plasma for 20 min. PEDOT:PSS was then spin-coated on the substrate at 5000
r.p.m. for 30 s, followed by annealing at 150 ℃ for 30 min. Then, the substrates were transferred to a nitrogen-filled glovebox. Different precursor solutions were coated on top of the PEDOT:PSS film via a two-step spin-coating process at 1000 r.p.m for 10 s and then 5000 r.p.m for 60 s. In the course of the second step, 130 μL of chlorobenzene was dropped onto the film, followed by annealing at 110 ℃ for another 15 min. Finally, TPBi (~40 nm), LiF (~1 nm), and Al electrode (~100 nm) were contacted by thermal evaporation.
Note 3 Device measurements and film characterization
All the PeLEDs were measured in a glovebox. A Keithley 2400 source meter coupled with a fiber integration sphere (FOIS-1-FL, QE65 Pro spectrometer) for device performance testing. PeLEDs were measured with a scanning rate of 0.1 V s-1 and a
dwell time of 1 s. The device active area was determined to be 8.57 mm2. Device
UV / Vis / NIR spectrophotometer. SEM images were collected in secondary electron mode by a Hitachi s4800. It was operated at a voltage of 3kV. XRD patterns were obtained using Bruker D8 Advanced diffractometer with Cu Kα radiation (λ = 1.5406 Å). Fourier Transform Infrared Spectroscopy Test with Thermo Scientific Nicolet Is10 Instrument. Ti:Sapphire oscillator and tunable OPO (Coherent Verdi V-10, Mira-HP, and Mira-OPO) pump at 561 nm; laser spot is about 1 µm diameter; the PL was filtered by a 568 nm long pass filter. The XPS spectra were collected by using a Kratos Axis Supra X-ray photoelectron spectrometer. The streak camera was Hamamatsu C5680-04. The steady-state PL of the perovskite films was measured by a fluorescence spectrophotometer (Fluoromax 4, Horiba). The defect density can be deduced from the onset voltage of the trap-filled limit region (VTFL), as shown in Eq.
𝑁𝑡=
2ε0ε𝑟𝑉𝑇𝐹𝐿
𝑞𝐿2
(1). where L is the thickness of perovskite film, εr is the relative dielectric constant, ε0
is the vacuum permittivity, and q is the charge constant. The TRPL decay lifetimes were acquired via a monochromator/spectrograph (Omni-λ300, Zolix) and an oscilloscope (GDS-3354, GWINSTEK).
Figure S1. Schematic illustration of crystallization mechanism during the film
fabrication process with and without DSAS.
Figure S2. SEM images of the PEA2SnI4 films (a) without and (b) with 3 mol.% of
Figure S3. XPS S 2p spectra of (a) perovskite film with/without DSAS (3 mol.%) and
(b) pure DSAS molecules.
Figure S5. XRD spectra of the perovskite film without (a) and with (b) DSAS after 5
days.
Figure S6. (a) UV–vis absorption spectra and (b) steady-state PL spectra of perovskite film with/without DSAS (3 mol.%).
Figure S7. Photoluminescence image of with DSAS (3 mol.%) films under UV excitation.
Figure S8. Luminance (a) and EQE (b) versus voltage characteristics of PeLEDs doped
Figure S9. Lifetime measurement (T50) of (a) without and (b) with DSAS (3 mol.%)
PeLEDs device at a constant voltage of 3.4 V.
Table S1: Performance of PeLEDs doped with different amounts of DSAS additives.
Different amount of DSAS
additives (mol.%) 1.0 2.0 3.0 4.0 5.0 6.0
Max EQE (%) 0.32 0.45 0.72 0.53 0.28 0.17
Max Luminance (cd m-2) 64 81 132 99 50 26
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