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) 1..8.6.4.2 (a). 1 2 3 4 2θ (degree) 5 6 Weight (%) 12 (b) 1 8 6 4 2 Weight Derivertive weight 26 % 1 2 3 4 5 Temperature ( o C) 1 8 6 4 2 Deriv. Weight (%/ o C) Fig. S1. (a) XRD pattern and (b) TGA spectrum of CH 3 NH 3 PbI 3 perovskite crystal. NATURE PHOTONICS www.nature.com/naturephotonics 1 213 Macmillan Publishers Limited. All rights reserved.
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 www.nature.com/naturephotonics 213 Macmillan Publishers Limited. All rights reserved.
Fig. S3. Energy dispersive X-ray spectra (EDS) mapping of each element. NATURE PHOTONICS www.nature.com/naturephotonics 3 213 Macmillan Publishers Limited. All rights reserved.
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 www.nature.com/naturephotonics 213 Macmillan Publishers Limited. All rights reserved.
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 www.nature.com/naturephotonics 5 213 Macmillan Publishers Limited. All rights reserved.
(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 www.nature.com/naturephotonics 213 Macmillan Publishers Limited. All rights reserved.
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 16.5.997 72.7 12. 5.4 ~3 5.11 a 4 1-5, c 16.7.855 58.8 8.4 12.7 ~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 ) 5-5 - 1-15 - 2-25 -.5..5 1. 1.5 Voltag e (V) NATURE PHOTONICS www.nature.com/naturephotonics 7 213 Macmillan Publishers Limited. All rights reserved.
TiO 2 /CH 3 NH 3 PbI 3 /PTAA/Au. 8 NATURE PHOTONICS www.nature.com/naturephotonics 213 Macmillan Publishers Limited. All rights reserved.
Counts 35 3 25 2 15 1 5 (a) 1 11 12 13 14 15 16 17 18 19 2 J sc (ma/cm 2 ) Counts Counts 2 18 (b) 16 14 12 1 8 6 4 2 8 85 9 95 1 15 11 2 18 (c) 16 14 12 1 8 6 4 2 5 55 6 65 7 75 8 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, 221 226 (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, 1814 1815 (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, 1455 1462 (212). NATURE PHOTONICS www.nature.com/naturephotonics 9 213 Macmillan Publishers Limited. All rights reserved.