SUPPLEMENTARY INFORMATION

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1 Supplementary Information Efficient inorganic-organic hybrid heterojunction solar cells containing perovskite compound and polymeric hole conductors Jin Hyuck Heo, Sang Hyuk Im, Jun Hong Noh, Tarak N. Mandal, Choong-Sun Lim, Jeong Ah Chang,Yong Hui Lee, Hi-jung Kim, Arpita Sarkar, Md. K. Nazeeruddin, Michael Grätzel, and Sang Il Seok Intensity (a.u) (a) θ (degree) 5 6 Weight (%) 12 (b) Weight Derivertive weight 26 % Temperature ( o C) Deriv. Weight (%/ o C) Fig. S1. (a) XRD pattern and (b) TGA spectrum of CH 3 NH 3 PbI 3 perovskite crystal. NATURE PHOTONICS Macmillan Publishers Limited. All rights reserved.

2 Fig. S2. XPS (X-ray photoelectron spectroscopy) depth profile of each element. Acquisition with a K-Alpha (Thermo Scientific, UK) system by using a microfocused (4 µm, 72 W) Al Ka X ray beam with a photoelectron take off angle of 9. A dual-beam charge neutralizer (1 V Ar + and 3 V electron beams) was used to compensate for the charge-up effect. The etching rate was.5 nm/s. In XPS profile analysis, it is difficult to detect carbon contents originated from only PTAA as the CH 3 NH 3 PbI 3 deposited onto mp-tio 2 also contains carbons. However, we can justify by comparing depth profile of exclusive I ions in CH 3 NH 3 PbI 3 and that of total carbon contents. As can be seen in XPS profile below, depth profile caused by I3d 5 remained almost constant to the bottom (around 6 nm) while the XPS intensity of carbon 1s is considerlably reduced with the depth. Thus, we conclude that PTAA was mostly located on the surface of the TiO 2 /CH 3 NH 3 PbI 3 composites. The peaks of I and Pb element at early etching time (< 1s = 5 nm-thickness) are attributed to the CH 3 NH 3 PbI 3 overlayer. 2 NATURE PHOTONICS Macmillan Publishers Limited. All rights reserved.

3 Fig. S3. Energy dispersive X-ray spectra (EDS) mapping of each element. NATURE PHOTONICS Macmillan Publishers Limited. All rights reserved.

4 Fig. S4. Energy level diagram of the corresponding materials used in our devices. Fig. S5. Transfer curve of top contact CH 3 NH 3 PbI 3 TFT device. Inset = schematic illustration of TFT device. TFT device for the above was fabricated as follows. For top contact TFT device, we thermally grew 3 nm-thick SiO 2 as a gate (G) dielectric layer on a heavily doped n-type (1) Si wafer (.5 Ω cm). After UV/ozone treatment of SiO 2 /Si wafer, we spin-coated 1 wt.% of CH 3 NH 3 PbI 3 / γ-butyrolactone on SiO 2 /Si wafer at 3 rpm for 12 s. The Cr/Au (5 nm/6 nm) source (S) and drain (D) electrodes were deposited by thermal evaporation through a shadow mask with a channel length (5 µm) a channel width (3 µm). The transfer curve of CH 3 NH 3 PbI 3 TFT device was recorded by using a semiconductor parametric analyser and a source meter (Keithley 24). 4 NATURE PHOTONICS Macmillan Publishers Limited. All rights reserved.

5 As shown in Fig. S4, the CH 3 NH 3 PbI 3 behaves like ambipolar semiconductor. The hole transporting mobility calculated from the transfer and output characteristics was ~ 1-5 cm 2 /Vs. The field-effect mobility 1, µ (cm 2 /Vs) are calculated from the transconductance using a below equation. Where I DS is the drain-source current, V G is the applied gate voltage, W and L are the channel width and length and C i is the gate capacitance per unit area. Fig. S6. Photoluminescence (PL) spectra of mp-tio 2 /CH 3 NH 3 PbI 3, mp-tio 2 / CH 3 NH 3 PbI 3 /PTAA, mp-al 2 O 3 /CH 3 NH 3 PbI 3, and mp-al 2 O 3 /CH 3 NH 3 PbI 3 /PTAA model films. Excitation = 6 nm-wavelength. NATURE PHOTONICS Macmillan Publishers Limited. All rights reserved.

6 (a) (b) 5 µm 1 µm (c) (d) 5 µm 5 nm (e) (f) 5 µm 5 nm Fig. S7. SEM surface images and its magnified image at a tilted angle of CH 3 NH 3 PbI 3 coated on (a,b) TiO 2 -nm, (c,d) TiO 2 6-nm, and (e,f) TiO 2 1-nm. 6 NATURE PHOTONICS Macmillan Publishers Limited. All rights reserved.

7 Table S1. The highest occupied molecular orbital (HOMO) energy level, and charge carrier mobility of PTAA and spiro-ometad. Summary of device parameters obtained from the best cell consisting of FTO/bl-TiO 2 /6 nm-thick mp-tio 2 /CH 3 NH 3 PbI 3 /PTAA/Au, and FTO/bl-TiO 2 /6 nm-thick mp-tio 2 /CH 3 NH 3 PbI 3 /spiro-ometad/au, with overlayer thickness between HTM and Au. HTM PTA A Fig. S8. J-V curve extended from -.5 V to 1.5 V in V oc, for mp- spiro- OMe TAD HOMO energy level (-ev) Charge Carrier Mobility (cm 2 /V s) J SC (ma/ cm 2 ) V OC (V) FF (%) η (%) R S (Ω cm 2 ) HTM overlayer thickness (nm) 5.2 a 4 1-3, b ~ a 4 1-5, c ~5 a: HOMO energy levels determined by Photo Electron Spectroscopy in Air (PESA). (Ref. 2) b: Hole mobility calculated using a standard thin film transistor model from field effect transistor. (Ref. 3) c: hole mobility values measured by using the space charge limited current (SCLC) method. (Ref. 3) 1 C urrent density ( m A /c m 2 ) Voltag e (V) NATURE PHOTONICS Macmillan Publishers Limited. All rights reserved.

8 TiO 2 /CH 3 NH 3 PbI 3 /PTAA/Au. 8 NATURE PHOTONICS Macmillan Publishers Limited. All rights reserved.

9 Counts (a) J sc (ma/cm 2 ) Counts Counts 2 18 (b) (c) FF (%) V oc (mv) Fig. S9. A histogram for each value of (a) Jsc, (b) Voc and (c) F.F of 1 samples from 6 nm-thick mp-tio 2 /CH 3 NH 3 PbI 3 /PTAA/Au. References 1. Horowitz, G. Field-effect transistors based on short organic molecules. J. Mater. Chem., 9, (1999) 2. Zhang, W., Smith, J., Hamilton, R., Heeney, M., Kirkpatrick, J., Song, K., Watkins, S. E., Anthopoulos, T. & McCulloch, I. Systematic improvement in charge carrier mobility of air stable triarylamine copolymers. J. Am. Chem. Soc. 131, (29). 3. Leijtens, T., Ding, I-K., Giovenzana, T., Bloking, J. T., McGehee, M. D. & Sellinger, A. Glass transition temperatures and high solubility for application in solid-state dyesensitized solar cells. ACS Nano 6, (212). NATURE PHOTONICS Macmillan Publishers Limited. All rights reserved.