Supporting Information

Transcription

1 Supporting Information Air-Stable Surface-Passivated Perovskite Quantum Dots for Ultra-Robust, Single- and Two-Photon-Induced Amplified Spontaneous Emission Jun Pan,, Smritakshi P. Sarmah,, Banavoth Murali,, Ibrahim Dursun, Wei Peng, Manas R. Parida, Jiakai Liu, Lutfan Sinatra, Noktan Alyami, Chao Zhao, Erkki Alarousu, Tien Khee Ng, δ Boon S. Ooi, δ Osman M. Bakr *, and Omar F. Mohammed*, Solar and Photovoltaics Engineering Research Center, Advanced Nanofabrication, Imaging and Characterization Core Labs, δ Photonics Laboratory, Computer, Electrical, and Mathematical Sciences and Engineering (CEMSE), King Abdullah University of Science and Technology (KAUST), Thuwal , Kingdom of Saudi Arabia AUTHOR INFORMATION J. P., S. S., B.M. contributed equally to this work. Corresponding Author *Osman M. Bakr, *Omar F. Mohammed, 1

2 Supporting information Contents: 1) Figure-S1 2) Figure-S2 3) Figure-S3 4) Figure-S4 5) Figure-S5 6) Figure-S6 7) Figure-S7 8) Figure-S8 9) Figure-S9 10) Figure-S10 11) Figure-S11 12) Table-S1 13) Table-S2 2

3 Figure S1. TEM images and corresponding size distributions of sample 1 (a, d), sample 2 (b, e), and sample 3 (c, f) QDs. 3

4 Figure S2. Normalized PL emission peaks of CsPbBr 3 QDs of various sizes. 4

5 Figure S3. a) Absorption and emission spectra of the untreated QD sample and the treated QD with various amounts of sulfur; the beam width was fixed at 1 nm for the 367 nm excitation. b) Corresponding PLQY. 5

6 Figure S4. a) Energy-filtered TEM RGB image of sulfur-treated CsPbBr 3 QD networks. b) EF- TEM image at the same location as panel a, with lead mapping. c) EF-TEM mapping of sulfur. d) Size distribution of QDs after treatment. EF-TEM characterization was performed on sulfur-treated NCs. Elemental mapping was carried out for lead and sulfur. Results indicate a high correlation between lead and sulfur (Fig. S4 b, c), suggesting that sulfur was indeed present on the NCs as a capping layer rather than as a PbS shell. 6

7 Figure S5. XRD patterns of the untreated and treated samples. 7

8 Figure S6. Photographs of treated (left) and untreated sample (right) (a) without and (b) under UV light irradiation. Both the treated and untreated samples were washed with 1-butanol, centrifuged and placed under vacuum. The color varied and the luminescence was improved with the applied treatment. X-ray fluorescence (XRF) was used to analyze the major elements of the sample. The Cs:Pb:Br ratio was approximately 1:2:5 for the untreated sample (see Table S2), confirming the instability of the inorganic perovskite, which is consistent with the XRD pattern (Figure S5). The elemental ratio of the treated sample obtained by XRF analysis is not reasonable, perhaps because the sulfur K line (2.307 kev) is very close to the lead M line (2.42 kev) and because hybrid ion pair ligand passivation was performed. However, the XRD pattern (Figure S5) of the treated sample corresponds to cubic phase CsPbBr 3, indicating high stability in air (60% humidity in the lab, KAUST, Saudi Arabia). 8

9 Figure S7. FTIR spectra of untreated CsPbBr 3 QDs in toluene and treated sample in octane. The peak at 1680 cm 1 is associated with the (C=O) stretching of the original oleate ligand. 9

10 Figure S8. SEM image of a) CsPbBr 3 QDs thin film. The inset shows a high-resolution image. b) Cross-sectional SEM image is showing the thickness of the film used for lasing. An ITO film was used as a reference specimen for SEM to avoid charging effects. 10

11 Figure S9. Threshold behavior of passivated CsPbBr 3 QDs film before and 4 months after passivation. 11

12 Figure S10. Time-correlated single photon counting data (TCSPC) of CsPbBr 3 QD film. 12

13 Figure S11. Kinetics of nanosecond transient absorption spectroscopy of CsPbBr 3 QD film excited at 350 nm (blue dots) and 760 nm (dark yellow dots). 13

14 Table S1. Elemental analysis results sample Sample weight (mg) N (%) C (%) H (%) S (%) CsPbBr Treated CsPbBr The molar ratio of N, C and H in treated sample is about 1: 26: 56, which is in consistent with that of didodecyldimethylammonium ion, confirmed the formation of ion pair ligand. Table S2. X-ray fluorescence (XRF) results of untreated sample Elem. Line Mass[%] 3sigma Atomic[%] 35 Br K Cs K Pb L