Multifold Emission Enhancement in Nanoimprinted Hybrid Perovskite Metasurfaces

Transcription

1 Supporting Information for: Multifold Emission Enhancement in Nanoimprinted Hybrid Perovskite Metasurfaces Sergey V. Makarov, Valentin Milichko, Elena V. Ushakova, Mikhail Omelyanovich,,* Andrea Cerdan Pasaran $, Ross Haroldson, Balasubramaniam Balachandran, * Honglei Wang *, Walter Hu, * Yuri S. Kivshar,, and Anvar A. Zakhidov,,& Department of Nanophotonics and Metamaterials, Department of Optical Physics and Modern Natural Science, ITMO University, St. Petersburg , Russia * Department of Radio Science and Engineering, Aalto University, Helsinki 13000, Finland Nonlinear Physics Centre, Australian National University, Canberra ACT 2601, Australia Department of Physics, *Department of Engineering, University of Texas at Dallas, Richardson, TX 75080, USA, $ Universidad de Guanajuato, División de Ciencias Naturales y Exactas, Noria Alta s/n, Guanajuato, Gto , México. & National University of Science and Technology MISIS, Moscow, , Russia 1

2 1. Photoluminescence stability tests Long-term stability of photoluminescence (PL) is a crucial property of ligh-emitting metasurface of halide perovskite. In order to improve the PL stability, we create a tri-cation composition Cs 0.05 (MA 0.17 FA 0.83 )Pb(I 0.83 Br 0.17 ) 3 and compare it with standard MAPbI 3. As shown in Fig.S1, after 3000 hours of lying in ambient conditions, the mixed perovskite preserves high mobility of photogenerated carriers, whereas MAPbI 3 degrades completely, exhibiting decay time of PL around few nanoseconds. Figure S1. (a) Time resolved photoluminescence and (b) optical image of the Cs 0.05 (MA 0.17 FA 0.83 )Pb(I 0.83 Br 0.17 ) 3 (red curve) and MAPbI 3 (blue curve). 2

3 2. Large scale metasurface In Fig.S2 we demonstrate an example of nanoimprinted halide perovskite metasurface with area 1 cm 2. The metasurface represents homogeneous array with some defects on the periphery due to some imperfections during nanoimprinting process. Figure S2. Optical image of the imprinted perovskite metasurface made of nanoholes. Side length of the square is equal to 1 cm. 3. Grain size analysis by means of atomic force microscopy Morphologies of halide perovskite before and after nanoimprint process are shown in Fig.S3. We use an atomic force microscope stage (SmartSPM AIST-NT) and a micrometer stage (3-axis flexure stage Thorlabs MBT616D). Our AFM-images show that the initial film represents rough surface with amplitude around 50 nm, whereas the surface of nanoimprinted grating has highfrequency roughness less than 10 nm and large-scale defects around 1 µm. We believe that the large-scale defects are originated from residual stress during the nanoimprint process and can be eliminated by optimizing the temperature-pressure regime. Figure S3. AFM images of perovskite film before (a) and after (b) nanoimprint lithography. 3

4 4. Composition study of tri-cation organohalide perovskite by energy dispersive analysis (EDS). In order to study the element composition of tri-cation mixed perovskite we carry out EDS analysis for nanoimprinted [Figs. S4(a,b)] and initial [Fig.S4(c)] film deposited on silicon substrate. Although Cs line was superimposed on iodine line and sensitivity of C and N detection is quite low, one can evaluate roughly the relative concentrations of basic elements: Cs, Pb, I, and Br. The resulting tables in Figs.S4-S5 show that our assymtion on concentration of elements after the perovskite synthesis is correct within uncertainty of the EDS technique. Fig. S4. The EDS spectra of the nanoimprinted (as nanograting) sample of mixed cation perovskite Cs α FA β MA γ Pb(I x Br y ) 3. The relative composition ratios of atoms is shown below the spectra. 4

5 Fig. S5. The EDS spectra of the nanoimprinted (as nanoholes) sample of mixed cation perovskite Cs α FA β MA γ Pb(I x Br y ) 3. The relative composition ratios of atoms is shown below the spectra. 5

6 Fig. S6. The EDS spectra of the reference, non-nanoimprinted sample of standard reference perovskite MAPbI 3. The relative composition ratios of atomic weights is shown below the spectra. 5. The structural characterization of nanoimprinted samples of mxed cation perovskite by X-ray diffraction (XRD) and its evolution with accelerated degradaton According to Figure S7, the nanogratings show the strongest peak of residual PbI 2, indicating that after nanoimprint lithography (NIL) process the largest interface of stripes in nanogratings degrades quickly at surface with formation of PbI 2. This effect is smaller for NIL holes, and smallest for flat control. Note that the control and reference MAPbI 3 samples are both nonimprinted. 6

7 Fig. S7. XRD of the different types of nanoimprinted samples: nanoholes, stripes (nanogratings) versus control, non-imprinted sample of Cs 0.05 (MA 0.17 FA 0.83 )Pb(I 0.83 Br 0.17 ) 3 and compared to reference MAPbI 3 (blue color). Degradation tests for perovskite with different compositions are shown in Figure S8. The control and reference samples are both non-imprinted. All the XRD lines of mixed cations show no changes, while MAPbI 3 reference shows degradation mostly in 310 line. The increased crystallinity of perovskite is clearly shown in the X-ray diffraction patterns improvement (see Figure S9). 7

8 a b Fig. S8. XRD lines dynamics with time of degradation for the different types of nanoimprinted (a) mixed (cation perovskite samples: nanoholes, stripes (nanogratings) versus (b) control, non-imprinted sample of Cs 0.05 (MA 0.17 FA 0.83 )Pb(I 0.83 Br 0.17 ) 3 and compared to reference MAPbI 3 (blue color). 8

9 Figure S9: X-ray diffraction of reference MAPbI 3 non-imprinted film and nano-imprinted film using a nanograting mold over an area of 1 cm 2. Comparison of XRD line full-width at half-maximum (FWHM) narrowing upon nanoimprinting in reference standard MAPbI 3 perovskites (in which the crystallite size increases upon NIL process from 68.3 nm to nm) to similar effect of grain increase with NIL in tri-cation perovskite (in which crystallite size increase is a smaller effect) but the overall stability of structure with time is larger, as evident from Figs.S7-S8. 9

10 Fig. S10. XRD spectra for (110) line of mixed (a) and MAPbI 3 (b) perovskite films. 10