Surface-Supported Metal–Organic Framework Thin-Film-Derived

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Functional Inorganic Materials and Devices

Surface-supported metal-organic framework thin film derived transparent CoS @N-doped carbon film as an efficient counter electrode for bifacial dye-sensitized solar cells 1.097

Jinhua Ou, Juan Xiang, Jinxuan Liu, and Licheng Sun ACS Appl. Mater. Interfaces, Just Accepted Manuscript • DOI: 10.1021/acsami.8b21626 • Publication Date (Web): 01 Apr 2019 Downloaded from http://pubs.acs.org on April 1, 2019

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ACS Applied Materials & Interfaces

Surface-supported Metal-organic Framework Thin Film Derived Transparent CoS1.097@N-doped Carbon Film as An Efficient Counter Electrode for Bifacial Dye-sensitized Solar Cells Jinhua Ou,1,3 Juan Xiang,1, * Jinxuan Liu2, * Licheng Sun2,4

Dedicated to Professor Christof Wöll on the occasion of his 60th birthday 1

Chemistry and Chemical Engineering, Central South University, 410083 Changsha,

China. 2

State Key Laboratory of Fine Chemicals, Institute of Artificial Photosynthesis, Dalian

University of Technology, 116024 Dalian, China. 3

Department of Material and Chemical Engineering, Hunan Institute of Technology,

421002, Hengyang, China. 4

Department of Chemistry, KTH Royal Institute of Technology, 110044 Stockholm,

Sweden.

E-mail: [email protected]; [email protected];

KEYWORDS: metal-organic framework thin films; CoS1.097@N-doped carbon film; dye-sensitized solar cells; counter electrode; SURMOF; Electrocatalysis

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ABSTRACT An effective design for counter electrode (CE) catalytic materials with superior catalytic activity, excellent stability, low cost and facile fabrication process is urgently needed for industrialization of dye sensitized solar cells (DSSCs). Herein, we report a facile in-situ method to fabricate transparent CoS1.097 anchored on N-doped carbon film electrode through sulfurization of cobalt-metalloporphyrin metal-organic framework thin film on fluorine doped tin oxide glass. The transparent film as counter electrode in bifacial DSSCs exhibited higher power conversion efficiency (9.11% and 6.64%) respectively from front and rear irradiation than that of Pt (8.04% and 5.87%). The uniformly dispersed CoS1.097 nanoparticles on N-doped carbon film provides large catalytic active area and facilitates the electron transfer, which leads to the excellent catalytic ability of the CoS1.097@N-doped carbon film. In addition, the in-situ preparation of the uniform film with nanosheet structure offers high electrical conductivity and unobstructed access for the diffusion of triiodide to available electroactive sites, resulting in excellent device performance with superior long-term stability over 1000 h under natural conditions.

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1. INTRODUCTION Dye-sensitized solar cells (DSSCs) are one of the devices, which can transform sunlight into electricity and possess the merit of environmental friendliness, simple production process, and high-power conversion efficiency.1-4 A typical DSSC consists of dye molecules loaded photoanode, electrolyte containing redox couple and catalytic materials loaded counter electrode (CE). Tremendous research efforts have been devoted to the development of dye molecules and redox couples in order to improve the power conversion efficiency (PCE).5 Counter electrode plays an important role in transferring electrons from an external circuit to the I3- and I- in the redox electrolyte. Platinum has been widely used as counter electrode due to its outstanding catalytic ability for I- regeneration, but it is scarce and expensive. This restricts its large-scale application in DSSCs.6-7 Therefore, an effective design for counter electrode catalytic materials aiming at fundamental requirements including superior catalytic activity, excellent stability, low cost and facile fabrication process is urgently needed and challengeable for industrialization of DSSCs. Various noble metal-free CE materials have been developed in order to replace Pt in DSSCs, such as carbon materials8-9, transition metal material10-12, metal alloys13, conductive polymers14 or their hybrids15-16. Carbon materials are one of the promising metal-free counter electrode materials with high surface area and high electric conductivity, however their catalytic ability and stability are relatively poor. In addition, transition metal materials including oxides17-18, carbides19, nitrides11 have been designed as CE materials for DSSCs. Hybrid materials are excellent candidates as CE materials for further improving the efficiency and adaptability, which utilize the synergetic effects generated from different components of the hybrid materials.20-21 However, the lack of stability data for these electrode materials restricts further commercial application in DSSCs.7 More importantly, the tedious post-treatment process of CE including mixing with other ancillary materials, spinning slurry and heating treatment limit the practical commercialization of DSSCs.6-7 Thus, an effective 3



design for CE catalytic materials aiming at fundamental requirements including superior catalytic activity, excellent stability, low cost and facile fabrication process is urgently needed for industrialization of DSSCs. In particular, the design of transparent CE catalytic materials is more urgently needed, which can be assembled into the bifacial DSSC and collect sunlight from either of its two sides, and help to reduce the cost of solar to electric energy conversion, facilitating practical application.22-23 Powder metal-organic framework (PMOFs) derived materials such as metal oxide24-25, porous carbon materials26-27 or their composites28 have received substantial attentions because of their advantages in high surface area, conductivity, controllability of composition and morphology originating from their pristine diversiform architectures. PMOFs derived materials have been widely investigated as regards applications in hybrid catalysts29-30, supercapacitors31-32, fuel cells33 and lithium-ion batteries34-35. Recently, surface-anchored metal-organic framework thin film (SURMOF) has been demonstrated to be one of the promising materials for electrical applications, which allows for direct attachment to the electrode surface, unobstructed access to available sites, and controllable film thickness36-39. However, applications using SURMOF derived functional materials as counter electrodes for DSSCs have not been exploited yet. The SURMOF derived materials inherit the advantages of powder MOFs derived materials, and can fulfill the requirements of superior catalytic activity, high electrical conductivity and strong adhesion to conductive substrate to ensure the efficient catalysis of CEs in DSSCs. Herein, for the first time, we report a facile method to prepare the transparent CoS1.097@N-doped carbon film derived from cobalt-metalloporphyin MOF thin film (named PIZA-1) as counter electrode in bifacial DSSCs. The transparent CoS1.097@Ndoped carbon film exhibited remarkable power conversion efficiency (PCE) of 9.11% and 6.64% respectively from front and rear irradiation than Pt (8.04% and 5.87%) and long-term stability (> 1000 h) under the same conditions, which pave the way for development of high-performance Pt-free counter electrode materials. The systematic electrochemical investigations of CoS1.097@N-doped carbon film demonstrated that this 4


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material possesses excellent catalytic performances due to the synergistic effect of numerous catalytic sites within homogeneous CoS1.097 nanoparticles, and strong adhesion and low interfacial contact resistance with substrate.

2. EXPERIMENTAL 2.1 Materials All chemical reagents were received from Sigma-Aldrich without further purification. Transparent conductive substrate (FTO, fluorine-doped tin oxide: 7Ω/square) was purchased from Mei Jing Yuan glass technology limited company, China. Surlun film was obtained from Seven Colors technology company, China. 2.2 Characterizations X-ray diffraction (XRD) patterns were collected with an X-ray powder diffractometer (D/Max 2400, Japan). X-ray photoelectron spectroscopy (XPS) measurement was performed with a non-monochromatic Al Kα X-ray source and a hemispherical energy analyzer (Escalab 250Xi, Thermo Fisher). UV-visible (UV-vis) spectra were recorded by Agilent spectrophotometer 8453. The morphology characterizations were carried out with scanning electron microscopy (SEM) (Nova. Nano SEM 450, USA) and high-resolution transmission electron microscopy (HRTEM) (Jem-2100F). The infrared (IR) spectra were recorded by using Bruker VERTEX 80 spectrometer. The photovoltaic performances of the fabricated DSSCs were conducted by using a solar simulator (94023A, Newport USA, AM1.5G 100 mw/cm2).

The

electrochemical performance was characterized by an electrochemical analyzer (CHI 660E, Chenghua Shanghai) and a Zennium analyzer system (IM 6, Zahner Germany). The detail measurements conditions were carried out according to previously reported literature. 40 2.3 Preparation of CoS1.097@N-doped carbon film First, the cleaned FTO glass substrates were treated with plasma under ozone for 3 minutes to generate hydroxy groups on FTO surfaces. Second, the cobalt5



metalloporphyin MOF thin film (PIZA-1) was fabricated by liquid-phase epitaxy (LPE) method using a computer-controlled automated dip coater (PTL-MM02-8P, Shengyang kejing Auto-instrument company, China). In brief, the FTO substrates were altanatively immersed into 1 mM cobalt acetate ethanolic solution for 45 s and 0.2 mM [5, 10, 15, 20-(4-carboxyphenyl) porphyrin] (TCPP) ethanolic solution for 45 s at 40 °C, respectively. After each immersion, the FTO susbtrates were dipped into pure ethanol solution for 10 s to get rid of unreacted precursors with subsequent waiting time amounts to be 30 s before immersed into the next precursor solution. The desired PIZA1 film thickness can be achieved by controlling the immersion cycles of FTO substrates in precursor solutions. Last, the as-prepared FTO/PIZA-1 thin film substrate and sulfur powders were placed in a quartz boat and were sulfurized at 500 °C for 2 h under argon atmosphere in a tubular furnace to prepare CoS1.097@N-doped carbon film. As reference, PIZA-1 powder was synthesized according to previously reported method41. 2.4 Fabrication of the DSSCs TiO2 film was fabricated on FTO substrate using commercial TiO2 slurry (P25, Seven color light company, China) by screen-printing method. After that, the film was treated at 500°C for 1h. Subsequently, the obtained FTO/TiO2 photoanode was soaked into an ethanolic solution containing 0.2 mM N719 dye for 24 h. Pt counter electrodes were prepared by the standard literature method.10 In the final step, the TiO2 photoanode and counter electrode were sealed and the electrolyte was injected into the interspace according to previously reported literature method.42

3. RESULTS AND DISCUSSION 3.1 Preparation and Characterization of CoS1.097@N-doped carbon film

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Figure 1. Schematic illustration of preparation process of CoS1.097@N-doped carbon film CE for DSSCs. The in-situ preparation of CoS1.097@N-doped carbon film CE for DSSCs is schematically illustrated in Figure 1. First, the PIZA-1 thin film was prepared by employing previously established liquid-phase epitaxy (LPE) approach via repetition of immersion cycles of functionalized substrates between metal precursor solution (cobalt acetate) and organic ligand solution (5, 10, 15, 20-(4-carboxyphenyl) porphyrin) (Figure S1). In a next step, the CoS1.097@N-doped carbon film was fabricated through sulfidation process by using the PIZA-1 thin film as both template and cobalt precursor, and sulfur powder as sulfur precursor. Finally, the sulphurised PIZA-1 thin film was used as photo cathode and assembled into a standard DSSC. The growth of PIZA-1 thin film on FTO substrate using LPE approach was monitored by using UV-vis spectroscopy. Figure 2a displays UV-vis spectra of PIZA1/FTO and TCPP/FTO. A characteristic feature for free-base porphyrin unit with Soret band and four Q bands was observed. The Soret band (419 nm) and Q bands (519 nm, 552 nm, 594 nm, 654 nm) of PIZA-1 thin film exhibited blue shift compared to the Soret band (422 nm) and Q bands (526 nm, 561 nm, 598 nm, 658 nm) of TCPP/FTO, respectively37, 41. With increasing of immersion cycles from 5 cycle to 15 cycles, the Soret bands and Q bands became more intense, and the intensity of Soret band for PIZA-1 thin film exhibited a linear behavior (Figure 2a inset) with increasing 7



immersion cycles, which indicates the deposition amount of PIZA-1 thin film is uniform between each stacking cycle43-44. Figure S2 displays SEM images of PIZA-1 thin film with 5 cycles, 10 cycles and 15 cycles. It can be seen clearly that the PIZA-1 thin films were successfully deposited on FTO substrate. In order to characterize the morphology and crystalline structure of PIZA-1 thin film, a thicker film with 30 immersion cycles was prepared for XRD, SEM and TEM measurements as shown in Figure 2b and Figure 2c – d, respectively. The deposited PIZA-1 film exhibited a nanosheet-like morphology with a thickness of ~ 20 nm (Figure 2c) and a dimension of ~ 700 nm (Figur2d) and crystalline structure. The pronounced peaks at 5.3°, 6.1°, 7.5° and 12.3° in Figure 2b can be attributed to the (100), (110), (002) and (130) planes, respectively41, 45-47.

Figure 2. (a) The UV-vis spectra of PIZA-1 thin film/FTO and TCPP/FTO. (Inset top: the absorbance versus preparation cycles. Inset bottom: magnifying 480 nm ~ 680 nm of Figure 2d. (b) XRD patterns of stimulated PIZA-1 (black), PIZA-1 power (blue), PIZA-1 film (red). SEM image (c) and TEM image (d) of PIZA-1 thin film with 30 immersion cycles. 8


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The PIZA-1 thin film with 30 immersion cycles was further characterized by infrared spectroscopy and X-ray photoelectron spectroscopy as shown in Figure S3 and S4, respectively. In Figure S3, the stretching band of carboxylate group for PIZA-1 thin film at 1784 cm-1 blue shifted to 1747 cm-1, suggesting the successful coordination between carboxylic acid groups of TCPP and Co atom37. The other detailed band assignments of PIZA-1 film can be found in Table S1. XPS results displayed in Figure S4 further confirmed the formation of PIZA-1 thin film, the peaks at 285 eV, 401 eV, 533 eV corresponded to the C1s, N1s, O1s peaks of TCPP, and the peaks at 782 eV and 798 eV can be assigned to the Co2p41. Further analysis of the XPS results revealed the atomic ratio of Co/N amounts is 0.612, which is in accordance with that of stimulated PIZA-1 (0.625) (Table S2). The as-prepared PIZA-1 thin films (5 cycles, 10 cycles and 15 cycles) were sulfurized by an in-situ approach, the obtained CoS1.097@N-doped carbon film are described as 5-cycle-S, 10-cycle-S, 15-cycle-S. The crystalline structure of the sulfurized PIZA-1 thin films was examined using XRD as shown in Figure S5. The diffraction peaks at 24.2° can be assigned to the (002) planes of carbon and the CoS1.097, which agreed well with the β-CoS1.097 phase (JCPDS NO.19-366)48. The Figure 3a shows the SEM image of 10-cycle-S. After sulfurization the nanosheets of PIZA-1 was transformed into N-doped carbon film embedded with uniformly dispersed approximately 20 nm CoS1.097 nanoparticles. The morphologies of 5-cycle-S and the 15-cycle-S are shown in Figure S6, which exhibits the similar morphology as that of 10-cycle-S. The EDX elemental mapping image of 10-cycle-S in Figure 3b displays a homodispersed C, N, Co, S elements in the N-doped carbon film. The detailed morphology of CoS1.097@N-doped carbon nanocomposite was further characterized by TEM. Figure 3c shows a homogenous dispersion of dark dot, indicating the CoS1.097 nanoparticles were highly confined and uniformly dispersed in the carbon matrix. Moreover, the HRTEM image (Figure 3d) shows a well-defined crystalline lattice with a d spacing of 0.25 nm, which matches well with the (220) plane of CoS1.097, further revealing the formation of highly crystalline CoS1.097 nanoparticles.

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Figure 3. The morphology of CoS1.097@N-doped carbon film (a) SEM image, (b) EDX elemental mapping image, (c) TEM image, (d) HRTEM image. The composition of CoS1.097@N-doped carbon film is further demonstrated by XPS as shown in Figure 4.The C1s peaks can be ascribed to the C=C, C-N and C=O bonds29, 48 and the N1s peaks can be resolved into three types of nitrogen species, i.e. the pyridinic N, pyrrolic N and graphitic N.40 The S2p spectra (Figure 4c) exhibited three characteristic peaks, which are attributed to S 2p3/2 (163.2 eV), S 2p1/2 (164.8 eV) spin-orbit doublet and Co-deficient nonstoichiometric sulfides (161.6 eV)49. The presence of Co-S bond confirmed the formation of cobaltous sulfide. Deconvolution of the Co 2p peaks illustrated the existence of Co 2p3/2 and Co 2p1/2 (Figure 4d), which is consistent with previous literature results.50. During the sulfidation process, the cobalt ions in the PIZA-1 thin film were transformed into CoS1.097 nanoparticles while the nitrogen-rich ligand (TCPP) was in situ carbonized to N-doped carbon, which lead to the formation of uniform CoS1.097@N-doped carbon film on FTO substrate.

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Figure 4. High-resolution XPS spectra of CoS1.097@N-doped carbon film (a) C 1s, (b) N 1s, (c) S 2p, (d) Co 2p. After sulfidation process, the light yellowish PIZA-1 thin film turned shallow black CoS1.097@N-doped carbon film, as shown in Figure 5 (inlet). The transparency of counter electrode has influences on the power conversion efficiencies of bifacial DSSC. Therefore, the optical transparency of CoS1.097@N-doped carbon film with 5-cycle-S, 10-cycle-S and 15-cycle-S was examined using UV-vis spectroscopy (Figure 5), which exceeds 79%, 68% and 52%, respectively. It should be noted that the high transparency is attributed to partially covered FTO surface with the cobalt-metalloporphyrin MOF nanosheets when immersion cycles are less than 15 cycles (Figure S2).

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Figure 5. UV-visible transmittance spectrums of CoS1.097@N-doped carbon film and Pt film (Inset: the first row is the photograph of the PIZA-1 thin film with 5 cycles, 10 cycles, 15 cycles respectively, the second row is the photograph of the CoS1.097@Ndoped carbon film with 5-cycle-S, 10-cycle-S,15-cycle-S respectively.) 3.2 Photovoltaic performance of DSSCs The DSSCs with an architecture consisting of N719 dye loaded porous TiO2 as the photoanodes, CoS1.097@N-doped carbon film as counter electrode and I3-/I- as electrolyte were assembled. The photovoltaic performance of assembled devices was examined by using a solar simulator (AM 1.5). The obtained photocurrent densityvoltage (J-V) curves were shown in Figure 6a and the corresponding photovoltaic parameters were listed in Table 1.

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Figure 6. J-V curves of DSSCs measured in the dark and under illumination of AM 1.5G full sunlight (100 mW cm-2) using various CoS1.097@N-doped carbon film CEs (a) front-side irradiation (b) rear-side irradiation. Stability test of the DSSCs (c)10cycle-S as CE (d) Pt as CE. Table 1. The DSSCs performance using various CoS1.097@N-doped carbon film CEs. [a]

CE

Irradiation

Voc (V)

Jsc (mA∙cm-2)

FF (%)

PCE (%)

Pt

front

0.76 ± 0.02

15.59 ± 0.09

67.89 ± 1.02

8.04 ± 0.08

rear

0.74±0.01

11.38±0.08

69.81±0.96

5.87±0.07

front

0.75 ± 0.02

17.5 ± 0.12

67.69 ± 1.03

8.89 ± 0.11

rear

0.74±0.01

11.95±0.10

70.45±1.05

6.23±0.10

front

0.76 ± 0.01

17.26 ± 0.10

69.42 ± 1.05

9.11 ± 0.09

rear

0.74±0.01

12.42±0.09

72.28±1.02

6.64±0.08

front

0.75 ± 0.01

15.73 ± 0.08

66.74 ± 0.85

7.87 ± 0.07

rear

0.73±0.02

9.74±0.09

69.43±0.93

4.94±0.09

5-cycle-S

10-cycle-S

15-cycle-S

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[a] The standard deviation was calculated with 22 devices using various CEs. Notably, all three DSSCs fabricated with different CoS1.097@N-doped carbon films as CEs exhibited excellent power conversion efficiencies (PCE). In particular, the DSSCs using 10-cycle-S as CE displayed remarkable photovoltaic performance from front irradiation (Jsc = 17.26 mA∙cm-2; Voc = 0.76 V; FF = 69.4; PCE=9.11%). In addition, it exhibited excellent photovoltaic performance from rear irradiation (Jsc = 12.42 mA∙cm-2; Voc = 0.74 V; FF = 72.3; PCE=6.64%). As reference, the DSSC using Pt CE was also measured under the same conditions, which gives a PCE of 8.04% and 5.87%, respectively from front and rear irradiation (front irradiation: Jsc = 15.59 mA∙cm-2, Voc = 0.76 V, FF = 68; rear irradiation: Jsc = 11.38 mA∙cm-2, Voc = 0.74 V, FF = 70;). The reproducibility data of the PCE performance of the devices using as CoS1.097@N-doped carbon film CE can be found in Supporting Information (Figure S7). It is obvious that the DSSCs using CoS1.097@N-doped carbon film as CEs exhibit better performances than that of Pt CE with one exception of the device using 15-cycleS as CE. The IPCE spectra (Figure S8) of the DSSCs with Pt and 10-cycle-S as CE were collected from front-side irradiation and rear-side irradiation. The 10-cycle-S CE based DSSC exhibited a higher IPCE than the cell with a Pt CE, which is in good accordance with the difference of Jsc values. The excellent PCE results from the synergistic catalytic effects of CoS1.097 and N-doped carbon matrix, since the CoS1.097@N-doped carbon film take full advantage of the superior electrocatalytic ability of CoS1.097 nanoparticles31, 51 and the excellent catalytic activity of N-doped carbon matrix film6, 52. The performance using CoS1.097@N-doped carbon film as CEs is impressive by comparison with the previously reported CE materials, including cobalt sulfide-based materials and MOF-derived nanomaterials as listed in Table S3. The long-term stability of DSSCs using CoS1.097@N-doped carbon film as CE was examined as shown in Figure 6b. The photovoltaic parameters of DSSCs with Voc, Jsc, FF and PCE retained 99%, 89%, 97%, 86% of their initial values after 1000 h under natural conditions, respectively. For the purpose of comparison, the long-term stability test of the DSSCs with Pt as CE was tested as shown in Figure 7d. The photovoltaic parameters of DSSCs with Voc, Jsc, FF and PCE retained 99%, 92%, 97%, 88% of their initial values after 1000 h under natural conditions, respectively. The DSSCs using CoS1.097@N-doped carbon film as CE exhibited excellent long-term stability, which is comparable to that of Pt CE. This can be ascribed to the carbon matrix with excellent 14


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corrosion resistance and suitable, uniform isolation to prevent agglomeration of CoS1.097. We further investigated the influence of film thickness on DSSCs photovoltaic performance as shown in Figure S9 and Table S48,

53.

It has been found that the

CoS1.097@N-doped carbon film derived from thicker PIZA-1 film exhibited poor photovoltaic performances compared with those derived from thinner PIZA-1 film (5cycles, 10 cycles). 3.3 Electrochemical characterization As one of the most important components in DSSC, the role of the counter electrode is the reduction of the redox species used as a mediator in regenerating the sensitizer after electron injection. Therefore, the counter materials have important effects on the photovoltaic parameters of DSSC including for FF and Jsc8, 54-56. It has been reported that the use of better catalytic materials as counter electrode will help to achieve a high Jsc and contribute to a higher FF of DSSC57-60. The FF of the DSSCs varies inversely with the series resistances of the CE, which is the sum of the resistance values resulting from the counter electrode, the ionic diffusion in the electrolyte, and the sheet resistance of the conductive substrate 61. Decreasing the series resistance leads to a higher fill factor, thus resulting in greater efficiency. In order to reveal the correlation between cell efficiency and CoS1.097@N-doped carbon film CEs, systematic electrochemical studies including CV, impedance spectroscopy and Tafel-polarization were performed using CoS1.097@N-doped carbon films (5-cycle-S, 10-cycle-S, 15cycle-S) as working electrodes. First, CV experiments using of CoS1.097@N-doped carbon films as working electrodes were carried out to understand the derivations of Jsc and their electrocatalytic activities. Figure 7a displays the CV curves of iodide/triiodide redox species using CoS1.097@N-doped carbon films (5-cycle-S, 10-cycle-S, 15-cycle-S) and Pt as working electrodes.

For all CEs, two pairs of redox peaks are observed and can be described

by reactions (1) and (2),respectively62-63. I3- + 2e

3I-

(1)

3I2 + 2e

2I3-

(2)

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The CE in a DSSC is responsible for catalyzing the reduction of I3− to I−, the characteristics of left pair peaks are at the focus of our analysis. The peak currents and the peak-to-peak separation △Epp are two important parameters to compare catalytic ability of various CEs7,

11, 42.

Both 5-cycle-S and 10-cycle-S possess remarkable

electrochemical catalytic activity for the reduction of I3−, which is better than the Pt electrode based on the peak current densities (Figure 7a) and △Epp value (Table 2). Although the 15-cycle-S CoS1.097@N-doped carbon film exhibits slight larger △Epp inferior to Pt, it still shows good catalytic ability for the reaction (1). In addition, the current density and the △Epp value of 10-cycle-S are almost unchanged after 50 cycles of CV (Figure 7b), which further confirms the excellent electrochemical stability of 10cycle-S.

Figure 7.

(a) CV spectra of various electrodes materials for iodide species. (b) CV

spectra of iodide species with 10-cycle-S after 50 cycles. (c) EIS curves for symmetrical cells using various electrodes materials. (d) Tafel spectra for symmetrical cells using various electrodes materials.

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Table 2. The corresponding parameters deduced from the Nyquist plots and CV curves. These parameters were determined by fitting the impedance spectra using the Z-view software. CE

Rs (Ω)

Rct (Ω)

ZN (Ω)

Pt

10.66

3.2

1.24

0.43

5-cycle-S

11.07

2.37

0.453

0.40

10-cycle-S

11.04

1.76

0.383

0.38

15-cycle-S

10.55

4.97

0.323

0.45

△Epp (V)

A symmetric cell using two identical CEs was assembled to investigate the charge transfer and ion diffusion processes with electrochemical impedance spectroscopy (EIS). The obtained data were shown in Figure 7c and the deduced parameters were listed in Table 2. The series resistance (Rs) was deduced from the high-frequency intercept on the real axis.63 The semicircles in the high frequency regions represent the charge-transfer resistance (Rct) and the corresponding constant phase element (CPE), while the semicircles on the right arise from Nernst diffusion impedance (ZN) of the I−/I3− redox couple in the electrolyte64-65. It is obvious that all three CoS1.097@N-doped carbon film CEs (5-cycle-S, 10cycle-S, 15-cycle-S) have similar Rs and ZN with Pt CE. Since the Rs consists of the bulk resistance of CoS1.097@N-doped carbon film, resistance of FTO glass substrate and contact resistance15, 19, the small Rs on CoS1.097@N-doped carbon film should be attributed to the in-situ preparation of the film, which provides better adhesion and lower interfacial contact resistance. The decreased ZN indicates that the diffusion rate of I3- was improved in the CoS1.097@N-doped carbon film involved system due to the well-defined nanosheet structure on carbon film, which offers unobstructed access to available electroactive sites. The Rct decreases in the order of 15-cycle-S > Pt > 5-cycleS > 10-cycle-S. The10-cycle-S CoS1.097@N-doped carbon film with the smallest Rct reveals the best catalytic ability for the reduction of I3-. Therefore, the excellent catalytic ability of the CoS1.097@N-doped carbon film CEs should be ascribed to the 17



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homogeneous and uniform dispersion of CoS1.097 nanoparticles and the in-situ preparation of the uniform N-doped carbon matrix film. The homogeneous and uniform dispersion of CoS1.097 nanoparticles facilitates the electron transfer and provides larger catalytic active area than that of black Pt powder materials. And the in-situ preparation of the uniform N-doped carbon matrix film with nanosheet structure offers high electrical conductivity and unobstructed access to available catalytic sites, resulting in desired performance of DSSCs. Tafel-polarization measurements were performed as shown in Figure 7d. The slope of a tangent to anodic (or cathodic) branches represents the exchange current density (Jo), which is varied inversely with Rct based on formula (3)8, 40, 66. The diffusion limited current (Jlim) observed from the intercept on the Y-axis are associated with the catalytic activity of CEs8, 67. 𝑅𝑇

Jo = 𝑛𝐹𝑅𝑐𝑡

(3)

Where R is the gas constant, F is the Faraday constant, T is the absolute temperature and n is the number of electrons being transferred during the iodide/triiodide redox process. The higher Jo values of 5-cycle-S and 10-cycle-S indicate better catalytic ability for the reduction of I3- to I- than that of Pt, which is consistent with the EIS results. The larger value of Jlim of 5-cycle-S and 10-cycle-S reflect faster ion diffusion rate than Pt, which fairly matches with EIS analysis about the ZN. The results based on CV curves, EIS and Tafel curves demonstrated CoS1.097@N-doped carbon film possess tiny resistance and superior catalytic activity for I3- reduction, which give rise to excellent photovoltaic performance as CEs in DSSCs.

4. CONCLUSION In conclusion, transparent CoS1.097@N-doped carbon film was synthesized directly from cobalt-metalloporphyrin MOFs thin film fabricated on FTO substrate via LPE approach. Compared with previously reported counter electrode materials in DSSCs, the fabrication of CoS1.097@N-doped carbon film does not need tedious posttreatment procedure such as thermal treatment or coating with other ancillary materials. The obtained CoS1.097@N-doped carbon film as CE in DSSCs exhibited higher power 18


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conversion efficiencies (9.11% and 6.64%) than that of Pt (8.04% and 5.87%) respectively from front and rear irradiation, and showed excellent long-term stability, which is a promising low-cost material to replace noble Pt for the commercialization of DSSCs. On the other hand, the established strategy can be generally applied to produce various transition metal compound @carbon film for other application by changing other metal ion-based MOFs film as precursor or substitute sulfur powder with selenium powder, phosphorus powder etc.

ASSOCIATED CONTENT Supporting Information. Schematic illustration of the liquid-phase epitaxy procedure for the fabrication of PIZA-1 thin film FTO substrate (Figure S1); SEM images of FTO and PIZA-1 thin film (Figure S2); IR spectra of PIZA-1 film and TCPP on FTO (Figure S3); XP spectra of PIZA-1 film (Figure S4) ; XRD pattern of CoS1.097@N-doped carbon powder (Figure S5); SEM images of carbon film (Figure S6); Histogram of PCE for 5cycle-S and 10-cycle-S as CE in DSSCs (Figure S7); The IPCE spectra of the DSSCs with Pt and 10-cycle-S as CE (Figure S8); Photovoltaic parameters of DSSCs using CoS1.097@N-doped carbon film CEs with different cycles (Figure S9). Peak assignments of IR spectra for PIZA-1 film and TCPP (Table S1); XPS and atomic percent of PIZA-1 thin film (Table S2). Comparison of photovoltaic performance between the CoS1.097@ N-doped carbon film, cobalt sulfide-based materials and MOFderived nanomaterials (Table S3). The performance of DSSCs using various CEs (Table S4).

ACKNOWLEDGEMENT Financial support from the National the Natural Science Foundation of China (NSFC 21673032, 21573290), the National Key Basic Research Program of China (2014CB744502), the Fundamental Research Funds for the Central Universities (DUT17LK21, DUT18RC(3)055), and the State Key Laboratory of Physical Chemistry of Solid Surfaces, Xiamen University (201812), is gratefully acknowledged. 19



REFERENCES (1) Gong, J.; Sumathy, K.; Qiao, Q.; Zhou, Z., Review on Dye-Sensitized Solar Cells (Dsscs): Advanced Techniques and Research Trends. Renew. Sust. Energ. Rev. 2017, 68, 234-246. (2) Li, Y.; Pang, A.; Wang, C.; Wei, M., Metal–Organic Frameworks: Promising Materials for Improving the Open Circuit Voltage of Dye-Sensitized Solar Cells. J. Mater. Chem. 2011, 21 (43), 17259. (3) Li, Y.; Chen, C.; Sun, X.; Dou, J.; Wei, M., Metal-Organic Frameworks at Interfaces in Dye-Sensitized Solar Cells. ChemSusChem 2014, 7 (9), 2469-2472. (4) Zhu, G.; Pan, L.; Xu, T.; Sun, Z., One-Step Synthesis of Cds Sensitized Tio₂ Photoanodes for Quantum Dot-Sensitized Solar Cells by Microwave Assisted Chemical Bath Deposition Method. Acs Applied Materials & Interfaces 2011, 3 (5), 1472. (5) Guang, Z.; Xiaojun, W.; Huili, L.; Likun, P.; Hengchao, S.; Xinjuan, L.; Tian, L.; Zhuo, S., Y3al5o12:Ce Phosphors as a Scattering Layer for High-Efficiency Dye Sensitized Solar Cells. Chem. Commun. 2012, 48 (7), 958-960. (6) J.H. Wu; Z. Lan; J.M. Lin; M.L. Huang; Y.F. Huang; L.Q. Fan; G.G. Luo; Y. Lin; Y. Xie; Y.L. Wei, Counter Electrodes in Dye-Sensitized Solar Cells. Chem. Soc. Rev. 2017, 46, 59756024. (7) Yun, S.; Hagfeldt, A.; Ma, T., Pt-Free Counter Electrode for Dye-Sensitized Solar Cells with High Efficiency. Adv. Mater. 2014, 26 (36), 6210-6237. (8) Wu, M.; Lin, X.; Wang, T.; Qiu, J.; Ma, T., Low-Cost Dye-Sensitized Solar Cell Based on Nine Kinds of Carbon Counter Electrodes. Energ. Environ. Sci. 2011, 4 (6), 2308-2315. (9) Zhu, G.; Pan, L.; Lu, T.; Tao, X.; Zhuo, S., Electrophoretic Deposition of Reduced Graphene-Carbon Nanotubes Composite Films as Counter Electrodes of Dye-Sensitized Solar Cells. J. Mater. Chem. 2011, 21 (38), 14869-14875. (10) Gong, F.; Wang, H.; Xu, X.; Zhou, G.; Wang, Z. S., In Situ Growth of Co(0.85)Se and Ni(0.85)Se on Conductive Substrates as High-Performance Counter Electrodes for DyeSensitized Solar Cells. J. Am. Chem. Soc. 2012, 134 (26), 10953-10958. 20


Page 20 of 28

Page 21 of 28 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


(11) Li, G. R.; Song, J.; Pan, G. L.; Gao, X. P., Highly Pt-Like Electrocatalytic Activity of Transition Metal Nitrides for Dye-Sensitized Solar Cells. Energ. Environ. Sci. 2011, 4 (5), 1680-1683. (12) Sun, X.; Dou, J.; Xie, F.; Li, Y.; Wei, M., One-Step Preparation of Mirror-Like Nis Nanosheets on Ito for the Efficient Counter Electrode of Dye-Sensitized Solar Cells. Chem. Commun. 2014, 50 (69), 9869-9871. (13) Peng, S.; Shi, J.; Pei, J.; Liang, Y.; Cheng, F.; Liang, J.; Chen, J., Ni 1− X Pt X ( X =0– 0.08) Films as the Photocathode of Dye-Sensitized Solar Cells with High Efficiency. Nano Res. 2009, 2 (6), 484-492. (14) Trevisan, R.; Döbbelin, M.; Boix, P. P.; Barea, E. M.; Tena-Zaera, R.; Mora-Seró, I.; Bisquert, J., Pedot Nanotube Arrays as High Performing Counter Electrodes for Dye Sensitized Solar Cells. Study of the Interactions among Electrolytes and Counter Electrodes. Adv. Energ. Mater. 2011, 1 (5), 781-784. (15) Wen, Z.; Cui, S.; Pu, H.; Mao, S.; Yu, K.; Feng, X.; Chen, J., Metal Nitride/Graphene Nanohybrids:

General

Synthesis

and

Multifunctional

Titanium

Nitride/Graphene

Electrocatalyst. Adv. Mater. 2011, 23 (45), 5445-5450. (16) Li, G. R.; Wang, F.; Jiang, Q. W.; Gao, X. P.; Shen, P. W., Carbon Nanotubes with Titanium Nitride as a Low-Cost Counter-Electrode Material for Dye-Sensitized Solar Cells. Angew. Chem.

Int. Ed. 2010, 49 (21), 3653-3656.

(17) Zhou, H.; Shi, Y.; Wang, L.; Zhang, H.; Zhao, C.; Hagfeldt, A.; Ma, T., Notable Catalytic Activity of Oxygen-Vacancy-Rich Wo(2.72) Nanorod Bundles as Counter Electrodes for DyeSensitized Solar Cells. Chem. Commun. 2013, 49 (69), 7626-7628. (18) Lin, X.; Wu, M.; Wang, Y.; Hagfeldt, A.; Ma, T., Novel Counter Electrode Catalysts of Niobium Oxides Supersede Pt for Dye-Sensitized Solar Cells. Chem. Commun. 2011, 47 (41), 11489-11491. (19) Wu, M.; Lin, X.; Wang, Y.; Wang, L.; Guo, W.; Qi, D.; Peng, X.; Hagfeldt, A.; Grätzel, M.; Ma, T., Economical Pt-Free Catalysts for Counter Electrodes of Dye-Sensitized Solar Cells. J. Am. Chem. Soc. 2012, 134 (7), 3419-3428. 21



Page 22 of 28

(20) Wen, Z.; Cui, S.; Pu, H.; Mao, S.; Yu, K.; Feng, X.; Chen, J., Metal Nitride/Graphene Nanohybrids:

General

Synthesis

and

Multifunctional

Titanium

Nitride/Graphene

Electrocatalyst. Adv. Mater. 2011, 23 (45), 5445-5450. (21) Liu, G.; Li, X.; Wang, H.; Rong, Y.; Ku, Z.; Xu, M.; Liu, L.; Hu, M.; Yang, Y.; Han, H., An Efficient Thiolate/Disulfide Redox Couple Based Dye-Sensitized Solar Cell with a Graphene Modified Mesoscopic Carbon Counter Electrode. Carbon 2013, 53, 11-18. (22) Bisquert, J., Photovoltaics: The Two Sides of Solar Energy. Nature Photonics 2008, 2 (11), 648-649. (23) Ito, S.; Zakeeruddin, S. M.; Comte, P.; Liska, P.; Kuang, D.; Grätzel, M., Bifacial DyeSensitized Solar Cells Based on an Ionic Liquid Electrolyte. Nature Photonics 2008, 2 (11), 693-698. (24) Han, H.; Guan, B.; Xia, B.; Xiong, W. L., Designed Formation of Co3o4/Nico2o4 DoubleShelled Nanocages with Enhanced Pseudocapacitive and Electrocatalytic Properties. J. Am. Chem. Soc. 2015, 137 (16), 5590-5595. (25) Li, Y.; Che, Z.; Sun, X.; Dou, J.; Wei, M., Metal-Organic Framework Derived Hierarchical Zno Parallelepipeds as an Efficient Scattering Layer in Dye-Sensitized Solar Cells. Chem. Commun. 2014, 50 (68), 9769-9772. (26) Zhang, P.; Sun, F.; Xiang, Z.; Shen, Z.; Yun, J.; Cao, D., Zif-Derived in Situ NitrogenDoped Porous Carbons as Efficient Metal-Free Electrocatalysts for Oxygen Reduction Reaction. Energ. Environ. Sci. 2013, 7 (1), 442-450. (27) Zhang, L.; Su, Z.; Jiang, F.; Yang, L.; Qian, J.; Zhou, Y.; Li, W.; Hong, M., Highly Graphitized Nitrogen-Doped Porous Carbon Nanopolyhedra Derived from Zif-8 Nanocrystals as Efficient Electrocatalysts for Oxygen Reduction Reactions. Nanoscale 2014, 6 (12), 65906602. (28) Zhang, C.; Xiao, J.; Lv, X.; Qian, L.; Yuan, S.; Wang, S.; Lei, P., Hierarchically Porous Co3o4/C Nanowire Arrays Derived from Metal-Organic Framework for High Performance Supercapacitors and Oxygen Evolution Reaction. J.Mater.Chem.A 2016, 4 (42), 13925-13931.

22


Page 23 of 28 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


(29) Zhong, H. X.; Wang, J.; Zhang, Y. W.; Xu, W. L.; Xing, W.; Xu, D.; Zhang, Y. F.; Zhang, X. B., Zif-8 Derived Graphene-Based Nitrogen-Doped Porous Carbon Sheets as Highly Efficient and Durable Oxygen Reduction Electrocatalysts. Angew. Chem.Int.Ed. 2014, 53 (51), 14459-14463. (30) Yu, X.; Feng, Y.; Guan, B.; Lou, X. W. D.; Paik, U., Carbon Coated Nickel Phosphides Porous Nanoplates for Highly Efficient Oxygen Evolution Reaction. Energ. Environ. Sci. 2016, 9 (4), 1246-1250. (31) Yu, X. Y.; Yu, L.; Lou, X. W., Metal Sulfide Hollow Nanostructures for Electrochemical Energy Storage. Adv. Energ. Mater. 2016, 6 (3), 333-347. (32) Yu, X. Y.; Yu, L.; Wu, H. B.; Lou, X. W., Formation of Nickel Sulfide Nanoframes from Metal-Organic Frameworks with Enhanced Pseudocapacitive and Electrocatalytic Properties. Angew. Chem. Int. Ed. 2015, 127 (18), 5331-5335. (33) Chen, J. E.; Fan, M. S.; Chen, Y. L.; Deng, Y. H.; Kim, J. H.; Alamri, H. R.; Alothman, Z. A.; Yamauchi, Y.; Ho, K. C.; Wu, K. C. W., Prussian Blue‐Derived Synthesis of Hollow Porous Iron Pyrite Nanoparticles as Platinum‐Free Counter Electrodes for Highly Efficient Dye ‐Sensitized Solar Cells. Chemistry 2017, 23 (54), 1-6. (34) Hu, H.; Zhang, J.; Guan, B.; Lou, X. W., Unusual Formation of Cose@Carbon Nanoboxes, Which Have an Inhomogeneous Shell, for Efficient Lithium Storage. Angew. Chem. Int. Ed. 2016, 128 (33), 9666-9670. (35) Chen, Y. M.; Yu, L.; Lou, X. W., Hierarchical Tubular Structures Composed of Co3o4 Hollow Nanoparticles and Carbon Nanotubes for Lithium Storage. Angew.Chem.Int. Ed. 2016, 55 (20), 5990-5993. (36) Kornienko, N.; Zhao, Y.; Kley, C. S.; Zhu, C.; Kim, D.; Lin, S.; Chang, C. J.; Yaghi, O. M.; Yang, P., Metal-Organic Frameworks for Electrocatalytic Reduction of Carbon Dioxide. J. Am. Chem. Soc. 2015, 137 (44), 14129-14135.

23



Page 24 of 28

(37) Ahrenholtz, S. R.; Epley, C. C.; Morris, A. J., Solvothermal Preparation of an Electrocatalytic Metalloporphyrin Mof Thin Film and Its Redox Hopping Charge-Transfer Mechanism. J. Am. Chem. Soc. 2014, 136 (6), 2464-2472. (38) Liu, J.; Wöll, C., Surface-Supported Metal-Organic Framework Thin Films: Fabrication Methods, Applications, and Challenges. Chem. Soc. Rev. 2017,

(7), 5681-6076.

(39) Shen, D.; Pang, A.; Li, Y.; Dou, J.; Wei, M., Metal-Organic Frameworks at Interfaces of Hybrid Perovskite Solar Cells for Enhanced Photovoltaic Properties. Chem. Commun. 2018, 54 (10), 1253-1256. (40) Ou, J.; Gong, C.; Wang, M.; Xiang, J.; Liu, J., Highly Efficient Zif-8/Graphene Oxide Derived N-Doped Carbon Sheets as Counter Electrode for Dye-Sensitized Solar Cells. Electrochim. Acta 2018, 286, 212-218. (41) Li, D. J.; Gu, Z. G.; Vohra, I.; Kang, Y.; Zhu, Y. S.; Zhang, J., Epitaxial Growth of Oriented Metalloporphyrin Network Thin Film for Improved Selectivity of Volatile Organic Compounds. Small 2017, 13 (17), 17-25. (42) Ou, J.; Gong, C.; Xiang, J.; Liu, J., Noble Metal-Free Co@N-Doped Carbon Nanotubes as Efficient Counter Electrode in Dye-Sensitized Solar Cells. Sol. Energy 2018, 174, 225-230. (43) Makiura, R.; Motoyama, S.; Umemura, Y.; Yamanaka, H.; Sakata, O.; Kitagawa, H., Surface Nano-Architecture of a Metal-Organic Framework. Nat. Mater. 2010, 9 (7), 565-571. (44) So, M. C.; Jin, S.; Son, H. J.; Wiederrecht, G. P.; Farha, O. K.; Hupp, J. T., Layer-byLayer Fabrication of Oriented Porous Thin Films Based on Porphyrin-Containing MetalOrganic Frameworks. J. Am. Chem. Soc. 2013, 135 (42), 15698-15701. (45) Kosal, M. E.; Chou, J. H.; Wilson, S. R.; Suslick, K. S., A Functional Zeolite Analogue Assembled from Metalloporphyrins. Nat. Mater. 2002, 1 (2), 118-121. (46) Xu, G.; Yamada, T.; Otsubo, K.; Sakaida, S.; Kitagawa, H., Facile "Modular Assembly" for Fast Construction of a Highly Oriented Crystalline Mof Nanofilm. J. Am. Chem. Soc. 2012, 134 (40), 16524-16527.

24


Page 25 of 28 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


(47) Biemmi, E.; Scherb, C.; Bein, T., Oriented Growth of the Metal Organic Framework Cu3(Btc)2(H2o)3·Xh2o Tunable with Functionalized Self-Assembled Monolayers. J. Am. Chem. Soc. 2007, 129 (26), 8054-8055. (48) Cao, F.; Zhao, M.; Yu, Y.; Chen, B.; Huang, Y.; Yang, J.; Cao, X.; Lu, Q.; Zhang, X.; Zhang, Z., Synthesis of Two-Dimensional Cos1.097/Nitrogen-Doped Carbon Nanocomposites Using Metal–Organic Framework Nanosheets as Precursors for Supercapacitor Application. J. Am. Chem. Soc. 2016, 138 (22), 6924-6927. (49) Wu, R.; Wang, D. P.; Kumar, V.; Zhou, K.; Law, A. W.; Lee, P. S.; Lou, J.; Chen, Z., Mofs-Derived

Copper

Sulfides

Embedded

within

Porous

Carbon

Octahedra

for

Electrochemical Capacitor Applications. Chem. Commun. 2015, 51 (15), 3109-3112. (50) Liu, S.; Wang, J.; Wang, J.; Zhang, F.; Liang, F.; Wang, L., Controlled Construction of Hierarchical Co1−Xs Structures as High Performance Anode Materials for Lithium Ion Batteries. Crystengcomm 2013, 16 (5), 814-819. (51) Lin, J. Y.; Liao, J. H.; Wei, T. C., Honeycomb-Like Cos Counter Electrodes for Transparent Dye-Sensitized Solar Cells. Electrochem. Solid-State Lett. 2011, 14, 4-8. (52) Sun, X.; Li, Y.; Dou, J.; Shen, D.; Wei, M., Metal-Organic Frameworks Derived Carbon as a High-Efficiency Counter Electrode for Dye-Sensitized Solar Cells. J. Power Sources 2016, 322, 93-98. (53) Murakami, T. N.; Kay, A.; Ito, S.; Wang, Q.; Nazeeruddin, M. K.; Bessho, T.; Liska, P.; Baker, R. H.; Comte, P.; Pechy, P., Highly Efficient Dye-Sensitized Solar Cells Based on Carbon Black Counter Electrodes. J. Electrochem. Soc. 2006, 153 (12), A2255-A2261. (54) Huang, Q.-H.; Ling, T.; Qiao, S.-Z.; Du, X.-W., Pyrite Nanorod Arrays as an Efficient Counter Electrode for Dye-Sensitized Solar Cells. J. Mater. Chem. A 2013, 1 (38), 1182811833. (55) Wang, H.; Feng, Q.; Gong, F.; Li, Y.; Zhou, G.; Wang, Z.-S., In Situ Growth of Oriented Polyaniline Nanowires Array for Efficient Cathode of Co(Iii)/Co(Ii) Mediated Dye-Sensitized Solar Cell. J. Mater. Chem. A 2013, 1 (1), 97-104.

25



(56) Murakami, T. N.; Grätzel, M., Counter Electrodes for Dsc: Application of Functional Materials as Catalysts. Inorganica Chimica Acta 2008, 361 (3), 572-580. (57) Wang, G.; Xing, W.; Zhuo, S., Application of Mesoporous Carbon to Counter Electrode for Dye-Sensitized Solar Cells. Journal of Power Sources 2009, 194 (1), 568-573. (58) Lee, B.; Buchholz, B. D.; Chang, R. P. H., An All Carbon Counter Electrode for Dye Sensitized Solar Cells. Energy & Environmental Science 2012, 5 (5), 6941-6952. (59) Ramasamy, E.; Lee, W. J.; Dong, Y. L.; Song, J. S., Spray Coated Multi-Wall Carbon Nanotube Counter Electrode for Tri-Iodide Reduction in Dye-Sensitized Solar Cells. Electrochem. Commun. 2008, 10 (7), 1087-1089. (60) Lin, J.-Y.; Liao, J.-H., Mesoporous Electrodeposited-Cos Film as a Counter Electrode Catalyst in Dye-Sensitized Solar Cells. J. Electrochem. Soc. 2012, 159 (2), D65-D71. (61) Sj, L., Correlation between Dye-Sensitized Solar Cell Performance and Internal Resistance Using Electrochemical Impedance Spectroscopy. J. Phys. Chem. Biophys. 2015, 5 (3), 181189. (62) Chen, T. Y.; Huang, Y. J.; Li, C. T.; Kung, C. W.; Vittal, R.; Ho, K. C., Metal-Organic Framework/Sulfonated Polythiophene on Carbon Cloth as a Flexible Counter Electrode for Dye-Sensitized Solar Cells. Nano Energy 2017, 32, 19-27. (63) Hou, Y.; Wang, D.; Yang, X. H.; Fang, W. Q.; Zhang, B.; Wang, H. F.; Lu, G. Z.; Hu, P.; Zhao, H. J.; Yang, H. G., Rational Screening Low-Cost Counter Electrodes for Dye-Sensitized Solar Cells. Nat. Commun. 2013, 4 (3), 1583-1591. (64) Xu, X.; Huang, D.; Cao, K.; Wang, M.; Zakeeruddin, S. M.; Grätzel, M., Electrochemically Reduced Graphene Oxide Multilayer Films as Efficient Counter Electrode for Dye-Sensitized Solar Cells. Sci. Rep. 2013, 3 (12), 1489-1496. (65) Xin, X.; He, M.; Han, W.; Jung, J.; Lin, Z., Low-Cost Copper Zinc Tin Sulfide Counter Electrodes for High-Efficiency Dye-Sensitized Solar Cells. Angew. Chem. Int. Ed. 2011, 50 (49), 11739-11742.

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(66) Hui, W.; Kai, S.; Franklin, T.; Stacchiola, D. J.; Yun Hang, H., 3d Honeycomb-Like Structured Graphene and Its High Efficiency as a Counter-Electrode Catalyst for DyeSensitized Solar Cells. Angew. Chem. Int. Ed. 2013, 125 (35), 9380-9384. (67) Xie, Z.; Cui, X.; Xu, W.; Wang, Y., Metal-Organic Framework Derived Coni@Cnts Embedded Carbon Nanocages for Efficient Dye-Sensitized Solar Cells. Electrochim. Acta 2017, 229, 361-370.

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Surface-Supported Metal–Organic Framework Thin-Film-Derived

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