ARTICLE NUMBER: 1118 DOI: 1.138/NENERGY.21.118 Designing ternary blend bulk heterojunction solar cells with reduced carrier recombination and fill factor of 77% Nicola Gasparini 1, Xuechen Jiao 2, Thomas Heumueller 1, Derya Baran 1, Gebhard J. Matt 1, Stefanie Fladischer 1,3, Erdmann Spiecker 3, Harald Ade 2, Christoph J. Brabec 1, and Tayebeh Ameri 1 1 Institute of Materials for Electronics and Energy Technology (I-MEET), Friedrich- Alexander-University Erlangen-Nuremberg, Martensstraße 7, 918 Erlangen, Germany 2 Department of Physics, North Carolina State University, 21 Stinson Drive, Raleigh, NC 279, USA 3 Center for Nanoanalysis and Electron Microscopy (CENEM), Friedrich-Alexander- University Erlangen-Nuremberg, Cauerstraße, 918 Erlangen, Germany Bavarian Center for Applied Energy Research (ZAE Bayern), Haberstrasse 2a, 918 Erlangen, Germany NATURE ENERGY www.nature.com/natureenergy 1
DOI: 1.138/NENERGY.21.118.8 8 7.7 7 V oc (V) J sc (ma cm -2 ).. PTB7:PC7BM +1% Si-PCPDTBT +1% Si-PCPDTBT +2% Si-PCPDTBT +2% Si-PCPDTBT +% Si-PCPDTBT Si-PCPDTBT:PC7BM 17 1 1 1 13 12 PTB7:PC7BM +1% Si-PCPDTBT +1% Si-PCPDTBT +2% Si-PCPDTBT +2% Si-PCPDTBT +% Si-PCPDTBT:PC7BM PTB7:PC7BM +1% Si-PCPDTBT +1% Si-PCPDTBT +2% Si-PCPDTBT +2% Si-PCPDTBT +% Si-PCPDTBT:PC7BM Supplementary Figure 1. Photovoltaic parameters. Trend of the photovoltaic parameters for the BHJ solar cells studied in this work. FF [%] (%) 9. 9. 8. 8. 7. 7....... 3. 3. PTB7:PC7BM +1% Si-PCPDTBT +1% Si-PCPDTBT +2% Si-PCPDTBT +2% Si-PCPDTBT +% Si-PCPDTBT:PC7BM 2 NATURE ENERGY www.nature.com/natureenergy
DOI: 1.138/NENERGY.21.118 SUPPLEMENTARY INFORMATION J (A cm -2 ) a) 3 2 1 Bilayer: ITO/PEDOT/Si-PCPDTBT/PTB7/MoOx/Ag J (A cm -2 ) 1 1 1.1.1 1E-3 1E- 1E- -1-8 - - -2 2 8 V (V) J (A cm -2 ) -8 - - -2 2 8 ITO/PEDOT/Si-PCPDTBT/MoOx/Ag V (V) b) c) 3 2 1-1 -2-3 - - - -8 - - -2 2 8 V (V) ITO/PEDOT/PTB7/MoOx/Ag 3 2 1-1 -2-3 - - - -8 - - -2 2 8 Supplementary Figure 2 Hole-only devices a) Bilayer hole-only devices and proposed charge transfer / transport mechanism. The fabrication of the hole-only bilayer devices is made by first coating Si-PCPDTBT from a 2 mg/ml solution in chlorobenzene and then depositing PTB7 from a 1 mg/ml solution in toluene. Hole-only pristine Si-PCPDTBT b) andptb7 c) devices J (A cm -2 ) V (V) NATURE ENERGY www.nature.com/natureenergy 3
DOI: 1.138/NENERGY.21.118 J (ma cm -2 ) - -1-1 -2-2 PTB7:PC 7 BM PTB7:Si-PCPDTBT:PC 7 BM.8:.1:1. J sc =1.1 ma cm -2 FF=9% V oc =.72V eff=.% J sc =1.3 ma cm -2 FF=72% V oc =.7V eff=8.2%..2...8 V (V) Supplementary Figure 3. J-V characteristics for thick devices. Current density-voltage characteristics of PTB7:PC 7 BM (a), PTB7:Si-PCPDTBT:PC7BM (.8:.1:1.) with 1 nm active layer thickness. NATURE ENERGY www.nature.com/natureenergy
DOI: 1.138/NENERGY.21.118 SUPPLEMENTARY INFORMATION Current density (ma cm -2 ) Current density (ma cm -2 ) Current density (ma cm -2 ) - -1-1 a) PTB7:PC 7 BM 1:1. -2 -.2..2...8 1. - -1-1 b) Voltage (V) PTB7:Si-PCPDTBT:PC 7 BM.8:.1:1. 1 mw cm -2 97 mw cm -2 88 mw cm -2 7 mw cm -2 mw cm -2 7 mw cm -2 3 mw cm -2 31 mw cm -2 2 mw cm -2 17 mw cm -2 8 mw cm -2 2 mw cm -2 1 mw cm -2.8 mw cm -2-2 -.2..2...8 1. c) - -1-1 Voltage (V) PTB7:Si-PCPDTBT:PC 7 BM.7:.2:1. 1 mw cm -2 97 mw cm -2 88 mw cm -2 7 mw cm -2 mw cm -2 7 mw cm -2 3 mw cm -2 31 mw cm -2 2 mw cm -2 17 mw cm -2 8 mw cm -2 2 mw cm -2 1 mw cm -2.8 mw cm -2-2 -.2..2...8 1. Voltage (V) 1 mw cm -2 97 mw cm -2 88 mw cm -2 7 mw cm -2 mw cm -2 7 mw cm -2 3 mw cm -2 31 mw cm -2 2 mw cm -2 17 mw cm -2 8 mw cm -2 2 mw cm -2 1 mw cm -2.8 mw cm -2 Supplementary Figure. Light-intensity dependent current voltage measurements. Current density-voltage characteristics of PTB7:PC 7 BM (a), PTB7:Si-PCPDTBT:PC 7 BM NATURE ENERGY www.nature.com/natureenergy
DOI: 1.138/NENERGY.21.118 (.8:.1:1.) (b) and PTB7:Si-PCPDTBT:PC 7 BM (.7:.2:1.) (c) solar cells under different illumination intensities. 1 J ph (ma cm -2 ) 1 PTB7:PC 7 BM PTB7:Si-PCPDTBT:PC 7 BM.8:.1:1. PTB7:Si-PCPDTBT:PC 7 BM.7:.2:1..1.1 1 V eff (V) Supplementary Figure. Photocurrent density as a function of the effective voltage. Photocurrent density of PTB7:PC7BM, PTB7:Si-PCPDTBT:PC7BM (.8:.1:1.) and PTB7:Si-PCPDTBT:PC7BM (.7:.2:1.) solar cells as a function of the effective voltage under 1 sun illumination. NATURE ENERGY www.nature.com/natureenergy
DOI: 1.138/NENERGY.21.118 SUPPLEMENTARY INFORMATION a) Normalized Photovoltage (V) b) Normalized Photovoltage (V) b) Normalized Photovoltage (V) 1. suns PTB7:PC 2.8 suns 7 BM 1:1. 2.3 suns 1. suns.8 1 sun. suns.2 suns...2.. 2.x1 -.x1 -.x1-8.x1-1.x1-1..8...2 1..8...2 Time (s) PTB7:Si-PCPDTBT:PC 7 BM.8:.1:1... 2.x1 -.x1 -.x1-8.x1-1.x1 - Time (s) PTB7:Si-PCPDTBT:PC 7 BM.7:.2:1... 2.x1 -.x1 -.x1-8.x1-1.x1 - Time (s) suns 2.8 suns 2.3 suns 1. suns 1 sun. suns.2 suns suns 2.8 suns 2.3 suns 1. suns 1 sun. suns.2 suns.. 2.x1 -.x1 - Supplementary Figure. Transient photovoltage and charge extraction measurements. Transient photovoltage (a,b,c) and charge extraction (d,e,f) traces of PTB7:PC 7 BM, PTB7:Si-PCPDTBT:PC 7 BM (.8:.1:1.) and PTB7:Si-PCPDTBT:PC 7 BM (.7:.2:1.) solar cells as a function of light intensity. d) Current density (ma cm -2 ) e) Current density (ma cm -2 ) f)current density (ma cm-2)...2.. 2.x1 -.x1 -.x1-8.x1-1.x1 -...2.. 2.x1 -.x1 -.x1-8.x1-1.x1 -...2 PTB7:PC 7 BM 1:1. Time (s) PTB7:Si-PCPDTBT:PC 7 BM.8:.1:1. Time (s) PTB7:Si-PCPDTBT:PC 7 BM.7:.2:1. Time (s) suns 2.8 suns 2.3 suns 1. suns 1 sun. suns.2 suns suns 2.8 suns 2.3 suns 1. suns 1 sun. suns.2 suns suns 2.8 suns 2.3 suns 1. suns 1 sun. suns.2 suns NATURE ENERGY www.nature.com/natureenergy 7
DOI: 1.138/NENERGY.21.118 1 a) b) Material Contrast 1 1 3 1 2 PTB7:PC 7 BM Si-PCPDTBT:PC 7 BM PTB7:Si-PCPDTBT 28 282 28 28 288 29 Energy (ev) Supplementary Figure 7. R-SoXS profiles. a) Material contrast as a function of photon energy between different components. As shown in figure S9, the material contrast of PTB7:PC 7 BM and Si-PCPDTBT:PC 7 BM are comparable under 28.2 ev. Thus, the integrated scattering intensity (ISI) under 28.2 ev for PTB7:PC 7 BM, PTB7:Si-PCPDTBT:PC 7 BM (.8:.1:1.) and PTB7:Si- PCPDTBT:PC 7 BM (.7:.2:1.) should be comparable given that relative average composition variation does not change along blends with different Si-PCPDTBT amount. b) Lorentz corrected and normalized R-SoXS profiles for PTB7:PC 7 BM, PTB7:Si- PCPDTBT:PC 7 BM (.8:.1:1.) and PTB7:Si-PCPDTBT:PC 7 BM (.7:.2:1.) films under 27 ev. 8 NATURE ENERGY www.nature.com/natureenergy
DOI: 1.138/NENERGY.21.118 SUPPLEMENTARY INFORMATION a) b) c) d) e) f) Supplementary Figure 8. TEM images. Elemental maps based on energy filtered TEM (EFTEM) imaging of sulfur (S L edge, top row) and carbon (C K edge, bottom row) of PTB7:PC 7 BM (a,d), PTB7:Si-PCPDTBT:PC 7 BM (.8:.1:1.) (b,e) and PTB7:Si- PCPDTBT:PC 7 BM (.7:.2:1.) (c,f), respectively. The scale bar represents nm in all images. NATURE ENERGY www.nature.com/natureenergy 9
DOI: 1.138/NENERGY.21.118 Intensity.1.1 1% Si-PCPDTBT 2% Si-PCPDTBT 2 2 7.1 Si-PCPDTBT (1) 2 3 7 PCBM Q vector [A -1 ] 1 Circular Horizontal Vertical Si-PCPDTBT (1) 2 3 Intensity 2.1 2.1 7.1 Si-PCPDTBT (1) 2 3 7 PCBM Q vector [A -1 ] 1 Circular Horizontal Vertical Si-PCPDTBT (1) 2 3 Supplementary Figure 9. Normalized 1D GIWAXS profiles. Normalized 1D profiles along circular, horizontal and vertical sectors for PTB7:Si-PCPDTBT:PC7BM (.8:.1:1.) and PTB7:Si-PCPDTBT:PC7BM (.7:.2:1.). 1 NATURE ENERGY www.nature.com/natureenergy
DOI: 1.138/NENERGY.21.118 SUPPLEMENTARY INFORMATION Supplementary Figure 1. SIMS data. SIMS ion yield as a function of sputtering time for (a) PTB7:Si-PCPDTBT:PC7BM (.8:.1:1.) and (b) PTB7:Si-PCPDTBT:PC7BM (.7:.2:1.). Supplementary Table 1. SIMS analysis. Summary of mass fraction at the interface between active layer and cathode electrode. PTB7:Si- PCPDTBT:PC 7 BM CN - (Si- PCPDTBT) F - (PTB7) C7 - (PC 7 BM).8:.1:1. 13% 2% 7%.7:.2:1. 29% 11% % NATURE ENERGY www.nature.com/natureenergy 11
DOI: 1.138/NENERGY.21.118 a) b) Current density (ma cm -2 ) - -1-1 PTB7-th:PC 7 BM 1:1..8 mw cm -2 1 mw cm -2 2 mw cm -2 8 mw cm -2 17 mw cm -2 2 mw cm -2 31 mw cm -2 3 mw cm -2 7 mw cm -2 mw cm -2 7 mw cm -2 88 mw cm -2 97 mw cm -2 1 mw cm -2-2..2...8 1. Voltage (V) Current density (ma cm -2 ) - -1-1 -2 PTB7-th:Si-PCPDTBT:PC 7 BM.9:.1:1..8 mw cm -2 1 mw cm -2 2 mw cm -2 8 mw cm -2 17 mw cm -2 2 mw cm -2 31 mw cm -2 3 mw cm -2 7 mw cm -2 mw cm -2 7 mw cm -2 88 mw cm -2 97 mw cm -2 1 mw cm -2..2...8 1. Voltage (V) Supplementary Figure 11. J-V characteristics of PTB7-th based devices. Current densityvoltage characteristics of PTB7-th:PC 7 BM (a) and PTB7-th:Si-PCPDTBT:PC 7 BM (.9:.1:1.) (b) solar cells under different illumination intensities. 8 a) b) FF (%) 8 7 7 PTB7:PC 7 BM PTB7:Si-PCPDTBT:PC 7 BM.8:.1:1. 1 1 1 Light Intensity (mw cm -2 ) FF (%) 8 7 7 PTB7-th:PC 7 BM PTB7-th:Si-PCPDTBT:PC 7 BM.8:.1:1. 1 1 1 Light Intensity (mw cm -2 ) Supplementary Figure 12. Fill Factor vs light intensity trend of ternary devices. PTB7- based devices (a) and PTB7-th-based devices (b). 12 NATURE ENERGY www.nature.com/natureenergy
DOI: 1.138/NENERGY.21.118 SUPPLEMENTARY INFORMATION EQE (%) 8 7 3 2 1 PTB7:-th:PC 7 BM 1:1. PTB7-th:Si-PCPDTBT:PC 7 BM.9:.1:1. 7 8 (nm) Supplementary Figure 13. EQE curves of PTB7-th based devices. External quantum efficiency curves of PTB7-th-based (a) and PBTZT-stat-BDTT-8-based binary and ternary devices (b). Supplementary Table 2. Photovoltaic parameters of PTB7-th based devices. Photovoltaic device parameters of binary and ternary inverted solar cells under 1 sun illumination (1 mw cm -2 ). The values presented in parenthesis are the averaged values measured from 2 devices. V oc J sc FF (V) (ma cm -2 ) (%) (%) PTB7-th:PC 7 BM 1:1..78 (.78±.1) PTB7-th:Si- PCPDTBT:PC 7 BM.7.9:.1:1. (.72±.1) 1.93 (1.±.8) 1.83 (1.22±.1).78 (.8±1.3) 7.99 (7.1±.98) 8.32 (8.1±.17) 9.8 (8.89±.19) NATURE ENERGY www.nature.com/natureenergy 13
DOI: 1.138/NENERGY.21.118 Supplementary Methods Duel beam dynamic SIMS. Duel beam dynamic SIMS was employed to provide high depth resolution and chemical resolution simultaneously, where Bi+ is employed as primary ion and Cs+ is used to do sputtering. F-, C7- and CN- were chosen as representatives for PTB7, PC 7 BM and Si-PCPDTBT respectively due to they are unique to each component. The ion counts as a function of sputtering time are ploted in figure S9 (a) and (b). Note that the sputtering time is normalized by the total sputtering time, which is set identical to both blends. At the top (t/tmax=), F- (PTB7) and CN-(Si-PCPDTBT) rich layers are formed, competing with C7-(PC 7 BM). In the middle region (.1<t/tmax<.), CN-(Si-PCPDTBT) is weaker than F- (PTB7) in 1% Si-PCPDTBT, while CN-(Si-PCPDTBT) is stronger than F- (PTB7) in 2% Si-PCPDTBT. At the bottom (t/tmax=.8). CN- (Si-PCPDTBT) shows a peak and F- (PTB7) shows a dip, while PC 7 BM remains constant in both samples. Due to the fact that different secondary ions are not sensitive to the primary ion with the same degree of sensitivity, the ion yield from figure S1 (a) and (b) does not provide direct information about component amount. In order to quantify the amount of each component, the total ion yield across the whole thickness is normalized by the nominal component ratio in each blend. Figure S1 (c) and (d) demonstrate the integrated ion yield along with sputtering time. Thereafter, the normalized mass plot against sputtering time is obtained and shown in Figure in the main text. 1 NATURE ENERGY www.nature.com/natureenergy