Efficient Grain Boundary Suture by Low-cost Tetra-ammonium Zinc Phthalocyanine for Stable Perovskite Solar Cells with Expanded Photo-response

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1 Supporting information for Efficient Grain Boundary Suture by Low-cost Tetra-ammonium Zinc Phthalocyanine for Stable Perovskite Solar Cells with Expanded Photo-response Jing Cao 1,*,, Congping Li 1,, Xudong Lv 1,, Xiaoxia Feng 1,, Ruiqian Meng 1,, Yiying Wu 2,*, Yu Tang 1,* 1 State Key Laboratory of Applied Organic Chemistry, Key Laboratory of Nonferrous Metal Chemistry and Resources Utilization of Gansu Province, College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou , China. 2 Department of Chemistry and Biochemistry, The Ohio State University, 100 West 18th Avenue, Columbus, Ohio 43210, United States caoj@lzu.edu.cn; wu@chemistry.ohio-state.edu; tangyu@lzu.edu.cn [ ] J. Cao, C. P. Li and X. D. Lv contributed equally to this work. Contents 1. Experimental Section 2. Supporting Figures 3. Supporting Tables 4. Supporting References S1

2 Experimental Section Materials: All materials were directly used as received from chemical companies without any further purification unless stated otherwise. The synthesis and purification of methylammonium iodide (MAI) were carried out according to a developed process. [S1] Synthetic route of tetra-ammonium zinc phthalocyanine (ZnPc) Scheme 1 Synthesis route of ZnPc. Compound 1 was prepared according to the reported procedures [S2]. Synthesis of compound ZnPc. A total of 200 mg compound 1 was dissolved in 100 ml dichloromethane, subsequently hydroiodic acid (45%, 1 ml) dropped down to the solution. After stirred at room temperature for 4h, the precipitate was obtained by centrifugation, and then washed with diethyl ether for three times, dried under vacuum at 60 C for 24 h to afford the green solid product (68% yield). HRMS (ESI, m/z): calcd for C 44 H 38 I 2 N 8, ; found [M+H-I] +. Solar Cell Fabrication: Fluorine-doped Tin Oxide (FTO) glass substrates with dimension of 2.0 cm 2.0 cm were patterned by etching with zinc powder and 2 M hydrochloric acid. The substrates were then cleaned in ultrasonic baths of acetone, distilled water and ethanol sequentially. The solution of 0.15 M titanium S2

3 tetraisopropanolate in ethanol was spin coated onto the cleaned FTO glass at a spin speed of 2000 rpm for 30 s to deposit a compact TiO 2 blocking layer. The substrate was heated at 120 C for 15 min, and then sintering at 550 C for 30 min. After cooling down to the room temperature, the obtained film was dipped into the 20 mm TiCl 4 solution at 70 C for 30 min. After dried, a ~200 nm thick mesoporous TiO 2 film was deposited on the prepared compact TiO 2 blocking layer by spin-coating of the TiO 2 paste (Dyesol DSL 18NR-T) with ethanol (1:6, mass ratio), which was followed by annealing at 550 C for 30 min. After cooling down to room temperature, then deposited the perovskite layer, [S3] a mixture of PbI 2, MAI and DMSO in DMF was prepared at room temperature and stirred for 1 h. The perovskite layer was deposited on the mesoporous TiO 2 by the spin-coating the dissolved precursor solution at 4000 rpm for 25 s, then 0.5 ml of diethyl ether was dripped on the rotating substrate in 6 s. The spin-coated film was then annealing at 70 C for 1 min and 100 C for 2 min to form a dense perovskite film. For the post-treatment of perovskite film: as-obtained perovskite film was immersed into IPA solution of ZnPc (0.5 mg/1 ml) for 2 s, and then washed thoroughly with IPA three times to remove physically absorbed ZnPc on the surface of perovskite film. The film was further dried at 100 C for 2 min. After preparation of the perovskite layer, the Co porphyrin/chlorobenzene (30 mg/ml) solution was spin-coated by solution process at 3,000 rpm for 30 s. Finally, an 80-nm thick Au counter electrode was deposited by thermal evaporation under reduced pressure of Torr. The active area was 0.10 cm 2. Device Characterization: The current-voltage characteristics were measured by using a solar simulator (the aperture of cm 2 ) equipped with a Keithley 2400 source meter and 300 W collimated Xenon lamp (Newport) and calibrated with the light intensity to 100 mw cm -2 under simulated AM 1.5G illumination by a certified silicon solar cell. Incident photon-to-electron conversion efficiencies (IPCE) were recorded with a computer-controlled IPCE system (Newport) containing a monochromator, a Xenon lamp and a Keithley multimeter. The system was determined using a certified silicon solar cell and the IPCE data were collected at DC S3

4 mode. XRD patterns were done at an X-ray diffractometer (Rigaku, RINT-2500) with a CuKa radiation source. The surface morphologies were recorded by a SEM field-emission scanning electron microscope (SEM). The Time-resolved photoluminescence (PL) spectra were tested via an Edinburgh Instruments FLS920 spectrometer. The exciting light was used at 495 nm through the film side. S4

5 2. Supporting Figures Figure S1. SEM images of perovskite films (a) without and (b) with ZnPc modification. Figure S2. XRD patterns of ZnPc, perovskite with and without ZnPc modification. Figure S3. (a) Steady PL spectra of perovskite films with and without modification by ZnPc. (b) IPCE of mesoporous PSCs with perovskite with and without modification. S5

6 Figure S4. Structures of Co(II) porphyrin (Co(II)P) and Co(III) porphyrin (Co(III)P). Figure S5. Cross-sectional SEM images of perovskite (a) without and (b) with modification by ZnPc. S6

7 Figure S6. Stabilized power output of PCE and J sc at maximum power point (at 0.93 V bias) as a function of time for the cell under simulated AM 1.5 G solar light condition. Figure S7. The photos of perovskite films with (Right) and without (Left) modification by ZnPc immersed into water solution with different time. S7

8 Figure S8. The photos of perovskite films without (Left) and with (Right) modification by ZnPc tested at 85 C in an N 2 atmosphere with different time. S8

9 3. Supporting Tables Table S1. Photovoltaic parameters of mesoporous PSCs based on perovskite with and without modification by ZnPc obtained in forward (FS) and reverse (RS) scans. Devices J sc /ma cm -2 V oc /V FF/% η/% Rs/Ω cm -2 Perovskite RS FS Modified perovskite RS FS S9

10 4. Supporting References [S1] J. H. Im, C. R. Lee, J. W. Lee, S. W. Park, N. G. Park, Nanoscale 2011, 3, [S2] B. N. Achar, G. M. Fohlen, J. A. Parkers, J. Keshavayya, Polyhedron, 1987, 6, [S3] N. Ahn, D.-Y. Son, I.-H. Jang, S. M. Kang, M. Choi, N.-G. Park, J. Am. Chem. Soc. 2015, 137, S10