A molecularly engineered hole-transporting material for efficient perovskite solar cells

Transcription

1 ARTICLE NUMBER: DOI: /NENERGY A molecularly engineered hole-transporting material for efficient perovskite solar cells Michael Saliba, Simonetta Orlandi, Taisuke Matsui, Sadig Aghazada, Marco Cavazzini, Juan-Pablo Correa-Baena, Peng Gao, Rosario Scopelliti, Edoardo Mosconi, Klaus H. Dahmen, Filippo De Angelis, Antonio Abate, Anders Hagfeldt, Gianluca Pozzi, Michael Graetzel and Mohammad Khaja Nazeeruddin Supplementary Note 1 NATURE ENERGY 1

2 DOI: /NENERGY Supplementary Figure 1. 1 H NMR of FDT 2 NATURE ENERGY

3 DOI: /NENERGY SUPPLEMENTARY INFORMATION Supplementary Figure 2. 1 H NMR of FDT (aromatic region) NATURE ENERGY 3

4 DOI: /NENERGY Supplementary Figure C NMR of FDT 4 NATURE ENERGY

5 DOI: /NENERGY SUPPLEMENTARY INFORMATION Supplementary Figure C NMR of FDT (aromatic region) NATURE ENERGY 5

6 DOI: /NENERGY Supplementary Figure 5. 1 H- 13 C HSQC of FDT 6 NATURE ENERGY

7 DOI: /NENERGY SUPPLEMENTARY INFORMATION Supplementary Figure 6. ESI-QTOF (the peak at m/z + = is related to the (M+Na) + adduct.) NATURE ENERGY 7

8 DOI: /NENERGY Supplementary Figure 7. ESI-QTOF (Calculated and experimental molecular mass distribution due to isotope distribution.) 8 NATURE ENERGY

9 DOI: /NENERGY SUPPLEMENTARY INFORMATION Supplementary Figure 8. (a) Thermogravimetric analysis (TGA) of FDT (circles) and spiroometad (squares). FDT retains 95% of its initial weight (dashed line) at 400 C and for SpiroOMeTAD at 445 C. (b) Differential scanning calorimetry of FDT (circles) and spiro-ometad (squares). For FDT (spiro-ometad), a melting temperature of 200 C (245 C) and a glass transition at 110 C (120 C) can be observed. NATURE ENERGY 9

10 DOI: /NENERGY Supplementary Note 2 The XRD data of FDT in Figure 1c matches well with the chemical structure. This suggests that the crystal structure mimics that of Spiro-OMeTAD with half of it replaced by planar cyclopentadithiophene (CPDT) 1. The central tetrahedral sp 3 hybridized carbon induce a spiro conformation out of the two orthogonally interconnected moieties, the dihedral angle of which is measured to be o. This value is slightly smaller than that of spiro-ometad (89.94 o ) due to the decreased steric hindrance of the unsubstituted CPDT. (Figure SX) This effect is also reflected in the close face to face intermolecular distance (4 ) which is within the limit of - interactions as indicated by the blue dashed line 2. The face to face distance between to upper half of the molecules is measured to be 5.47 In contrast, due to the highly sterically hindered geometry, no direct face to face contacts is observed from spiro-ometad crystals which was reported by Ganesan and co-workers 1. FDT was found to crystallize in the triclinic space group P-1 (2). Supplementary Figure 9. The diffraction data of FDT were measured at low temperature [100(2) K] using Mo Ka radiation on a Bruker APEX II CCD diffractometer equipped with a kappa geometry goniometer. The dataset was reduced by EvalCCD 3 and then corrected for absorption 4. The crystal structure was solved and refined by SHELX 5. The crystal structure was refined using full-matrix leastsquares based on F 2 with all non hydrogen atoms anisotropically defined. Hydrogen atoms were placed in calculated positions by means of the riding model. Pseudo merohedral twinning was found in the last stages of refinement and treated by the TWINROTMAT algorithm of PLATON 6, obtaining one BASF value: 0.511(5). A summary of the crystallographic data, the data collection parameters, and the refinement parameters are given in Supplementary Table NATURE ENERGY

11 DOI: /NENERGY SUPPLEMENTARY INFORMATION Supplementary Figure 10. Dihedral angle between the two planar moieties of FDT. NATURE ENERGY 11

12 DOI: /NENERGY Supplementary Table 1. Crystallographic parameters of FDT and spiro-ometad FDT spiro-ometad 5 Empirical formula C 49 H 38 N 2 O 4 S 2 C 81 H 68 N 4 O 8 Formula weight Crystal color, habit Colorless, needle Crystal system triclinic Colorless, needle triclinic a, Å (5) (7) b, Å (11) (7) c, Å (19) (9), deg (6) (4), deg (7) (4), deg (5) (4) V, Å (29) calc, g/cm Space group P -1 P -1 Z value 2 2 Temperature, K 100 (2) 140 no. of reflections measured no. of variables Residuals: R; wr , , NATURE ENERGY

13 DOI: /NENERGY SUPPLEMENTARY INFORMATION Supplementary Figure 11. Perspective views of FDT along different axis and the S-S short contacts. NATURE ENERGY 13

14 DOI: /NENERGY Voltage (V) Supplementary Figure 12. Best performing current-voltage scans collected under AM 1.5 simulated sunlight for FDT (open circles) and spiro-ometad (solid squares) on mixed perovskite, MAPbI 3 and MAPbBr 3. The extracted performance parameters are presented in Supplementary Table 2. The voltage scan rate was 10 mv s -1 and no device preconditioning, such as light soaking or forward voltage bias applied for a long time, was applied before starting the measurement. The full hysteresis loop (forward and backward scan) for each scan is listed in Supplementary Table NATURE ENERGY

15 DOI: /NENERGY SUPPLEMENTARY INFORMATION Supplementary Table 2. Short circuit current-density (J sc ), open-circuit voltage (V oc ), fill factor (FF) and power conversion efficiency (PCE) of the best performing FDT and spiro-ometad device with mixed perovskite, MAPbI 3 and MAPbBr 3 as extracted from Supplementary Figure 12. Devices were masked with a metal aperture of 0.16 cm 2 to define the active area. No device preconditioning, such as light soaking or forward voltage bias applied for long time, was applied before starting the measurement. HTM perovskite Jsc (ma cm -2 ) Voc (mv) FF PCE (%) Light Intensity (mw cm -2 ) FDT mixed spiro FDT MAPbI spiro FDT MAPbBr spiro NATURE ENERGY 15

16 DOI: /NENERGY Supplementary Table 3. Short circuit current-density (J sc ), open-circuit voltage (V oc ), fill factor (FF) and power conversion efficiency (PCE) of the best performing FDT and spiro-ometad device on mixed perovskite, MAPbI 3 and MAPbBr 3 as extracted from Supplementary Figure 12 (full hysteresis loop). The curves were recorded at a scanning rate of 10 mv s 1 from forward bias (FB) to the short circuit condition (SC), and the other way around. Devices were masked with a metal aperture of 0.16 cm 2 to define the active area. No device preconditioning, such as light soaking or forward voltage bias applied for long time, was applied before starting the measurement. HTM/perovskite Scan direction J sc (ma cm -2 ) V oc (mv) FF PCE (%) FDT/mixed FB to SC SC to FB spiro/mixed FB to SC SC to FB FDT/MAPbI 3 FB to SC SC to FB spiro/mapbi 3 FB to SC SC to FB FDT/MAPbBr 3 FB to SC SC to FB spiro/mapbbr 3 FB to SC SC to FB NATURE ENERGY

17 DOI: /NENERGY SUPPLEMENTARY INFORMATION Supplementary Figure 13. Device statistics of FDT and spiro-ometad devices of at least 41 devices. NATURE ENERGY 17

18 DOI: /NENERGY Supplementary Figure 14. Performance parameters of FDT and spiro-ometad devices measured after 60 days. Solar cells were stored under dry conditions. 18 NATURE ENERGY

19 DOI: /NENERGY SUPPLEMENTARY INFORMATION Supplementary Note 3 The lab synthesis costs of FDT were estimated on the base of a model originally proposed by Osedach et al. 7 Such a model has been recently applied by Petrus et al to the synthesis of other hole transporting materials. 8 For every synthetic step the actual amounts of reactants, catalysts, reagents, solvents and materials for workup and purification required to obtain 1 gram of FDT are reported (Tables S4, S5 and S6). However, the use of 1 g of drying agent (MgSO 4 ) was assumed to be required to obtain 1 g of the (intermediate) product. The price per kg of the commercially available chemicals and the cost per kg of the homemade intermediates 2,7-dibromo-9H-fluoren-9-one and bis(4-methoxyphenyl)amine were multiplied by the quantities that are required for the synthesis. The costs thus obtained were summed up affording an estimation of the direct material cost for FDT (34.43 /g = $/g, Table S4), in analogy with what was reported in the literature. 7,8 However, since this figure does not take into account several important parameters (e.g. energy consumption, waste treatment and labor), it was multiplied by a factor of 1.5 to get a more realistic estimation of lab synthesis costs of ~60 $/g as reported in the main text (38.85 x 1.5 = $/g). NATURE ENERGY 19

20 DOI: /NENERGY Supplementary Table 4. Materials quantities and cost for the synthesis of FDT. a Chemical Weight reagent (g/g) Weight solvent (g/g) Weight workup (g/g) Price of Chemical ( /kg) Chemical cost ( /g product) 2,3-Dibromothiophene Bromothiophene Mg Pd(dppf) 2 Cl Et 2 O Et 2 O MgSO Bromo-2,2'-bithiophene 1.01 NBS AcOH CHCl CH 2 Cl NaHCO MgSO Petroleum ether ,5,5'-Tribromo- 2,2'bithiophene 1.53 Chlorotrimethylsilane n-buli (1.6M solution) Et 2 O Et 2 O MgSO Hexanes Silica gel Bromo ,5'bis(trimethylsilyl)- 2,2'bithiophene (1) 2,7-dibromo-9H-fluoren b 9one n-buli (1.6M solution) THF Et 2 O NH 4 Cl MgSO Petroleum ether CH 2 Cl Silica gel Cost per step ( /step) NATURE ENERGY

21 DOI: /NENERGY SUPPLEMENTARY INFORMATION 9-(5,5'-Bis(trimethylsilyl)- [2,2'-bithiophen]-3-yl)2,7- dibromo-9h-fluoren9-ol (2) 1.25 FeCl CHCl3 c 166 d Petroleum ether CHCl Silica gel ',7'-Dibromospiro 0.76 [cyclopenta [2,1- b:3,4b']dithiophene- 4,9'fluorene] (3) Bis(4-methoxy e phenyl)amine t Bu 3 P (1M solution) Pd 2 (dba) NaO t Bu Toluene Et 2 O MgSO Hexanes AcOEt Silica gel Total a See Supplementary Note 1 b See Supplementary Table 5 c Stabilized with amylene. The solvent recovered by evaporation under reduced pressure has been reused in more than five subsequent runs affording constant yields of product 3. d g of solvent has been used to produce 1.70 g of 3 in five subsequents cyclization runs, each one performed on 0.56 g of starting material 2. e See Supplementary Table 6 NATURE ENERGY 21

22 DOI: /NENERGY Supplementary Table 5. Materials quantities and cost for the synthesis of 2,7-dibromo-9H-fluoren- 9one. 9 Chemical Weight reagent (g/g) Weight solvent (g/g) Weight workup (g/g) Price of Chemical ( /kg) Chemical cost ( /g product) Cost per step ( /step) Fluoren-9-one Br H 2 O MeOH Total NATURE ENERGY

23 DOI: /NENERGY SUPPLEMENTARY INFORMATION Supplementary Table 6. Materials quantities and cost for the synthesis of bis(4methoxyphenyl)amine. 9 Chemical Weight reagent (g/g) Weight solvent (g/g) Weight workup (g/g) Price of Chemical ( /kg) Chemical cost ( /g product) Cost per step ( /step) 1-Iodo- 4methoxybenzene tert-butyl carbamate CuI K 3 PO N 1,N 2 - Dimethylethane1,2- diamine Toluene Toluene MgSO Petroleum ether tert-butyl 1.13 bis(4methoxyphenyl) carbamate CF 3 COOH Total NATURE ENERGY 23

24 DOI: /NENERGY Supplementary References 1 Ganesan, P. et al. A simple spiro-type hole transporting material for efficient perovskite solar cells. Energ Environ Sci 8, , (2015). 2 Avasthi, K., Shukla, L., Kant, R. & Ravikumar, K. Folded conformations due to arene interactions in dissymmetric and symmetric butylidene-linker models based on pyrazolo[3,4d]pyrimidine, purine and 7-deazapurine. Acta crystallographica. Section C, Structural chemistry 70, , (2014). 3 Duisenberg, A. J. M., Kroon-Batenburg, L. M. J. & Schreurs, A. M. M. An intensity evaluation method: EVAL-14. J Appl Crystallogr 36, , (2003). 4 Blessing, R. H. An Empirical Correction for Absorption Anisotropy. Acta Crystallogr A 51, 3338, (1995). 5 Sheldrick, G. M. A short history of SHELX. Acta Crystallogr A 64, , (2008). 6 Spek, A. L. Structure validation in chemical crystallography. Acta Crystallogr D 65, , (2009). 7 Osedach, T. P., Andrew, T. L. & Bulovic, V. Effect of synthetic accessibility on the commercial viability of organic photovoltaics. Energ Environ Sci 6, , (2013). 8 Petrus, M. L., Bein, T., Dingemans, T. J. & Docampo, P. A low cost azomethine-based hole transporting material for perovskite photovoltaics. J Mater Chem A 3, , (2015). 9 Zhang, X., Han, J. B., Li, P. F., Ji, X. & Zhang, Z. Improved, Highly Efficient, and Green Synthesis of Bromofluorenones and Nitrofluorenones in Water. Synthetic Commun 39, , (2009). 24 NATURE ENERGY