Nanostructured Heterojunction Solar Cells Based on Pb2SbS2I3

Subscriber access provided by University of South Dakota

Letter

Nanostructured Heterojunction Solar Cells Based on Pb2SbS2I3: Linking Lead Halide Perovskites and Metal Chalcogenides Nie Riming, Bohyung Kim, Seung-Tack Hong, and Sang Il Seok ACS Energy Lett., Just Accepted Manuscript • DOI: 10.1021/acsenergylett.8b01332 • Publication Date (Web): 10 Sep 2018 Downloaded from http://pubs.acs.org on September 11, 2018

Just Accepted “Just Accepted” manuscripts have been peer-reviewed and accepted for publication. They are posted online prior to technical editing, formatting for publication and author proofing. The American Chemical Society provides “Just Accepted” as a service to the research community to expedite the dissemination of scientific material as soon as possible after acceptance. “Just Accepted” manuscripts appear in full in PDF format accompanied by an HTML abstract. “Just Accepted” manuscripts have been fully peer reviewed, but should not be considered the official version of record. They are citable by the Digital Object Identifier (DOI®). “Just Accepted” is an optional service offered to authors. Therefore, the “Just Accepted” Web site may not include all articles that will be published in the journal. After a manuscript is technically edited and formatted, it will be removed from the “Just Accepted” Web site and published as an ASAP article. Note that technical editing may introduce minor changes to the manuscript text and/or graphics which could affect content, and all legal disclaimers and ethical guidelines that apply to the journal pertain. ACS cannot be held responsible for errors or consequences arising from the use of information contained in these “Just Accepted” manuscripts.

is published by the American Chemical Society. 1155 Sixteenth Street N.W., Washington, DC 20036 Published by American Chemical Society. Copyright © American Chemical Society. However, no copyright claim is made to original U.S. Government works, or works produced by employees of any Commonwealth realm Crown government in the course of their duties.

Page 1 of 20 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

ACS Energy Letters

Nanostructured Heterojunction Solar Cells Based on Pb2SbS2I3: Linking Lead Halide Perovskites and Metal Chalcogenides Riming Nie, Bohyung Kim, Seung-Tack Hong, and Sang Il Seok* Perovtronics Research Center, Department of Energy Engineering, School of Energy and Chemical Engineering, Ulsan National Institute of Science and Technology (UNIST) , 50 UNIST-gil, Eonyang-eup, Ulju-gun, Ulsan 44919, Republic of Korea AUTHOR INFORMATION Corresponding Author *Correspondence: [email protected]

ABSTRACT: The quaternary chalcogeno-iodides Pb2SbS2I3, comprising group IV and V elements, has attracted significant attention because of its unique semiconducting and ferroelectric properties. However, it has not yet been applied in solar cells. Herein, we report the first fabrication of nanostructured solar cells using Pb2SbS2I3 as a light harvester, prepared through a reaction between antimony sulfide, deposited by chemical bath deposition on mesoporous (mp)-TiO2, and lead iodide under an Ar atmosphere at 300 °C. A power conversion

ACS Paragon Plus Environment

1

ACS Energy Letters 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

Page 2 of 20

efficiency (PCE) of 3.12% under the standard illumination conditions of 100 mW/cm2 was achieved for the Pb2SbS2I3 layer sandwiched between mp-TiO2 and an organic hole conductor. Pb2SbS2I3 cells without encapsulation show good humidity stability over 30 days, retaining about 90% of the initial performance.

TOC GRAPHIC

Earth-abundant Cu2ZnSn(S/Se)4, a quaternary chalcogenide compound, has been actively studied to replace toxic CdTe or expensive In and Ga in Cu(In, Ga)Se2 (CIGS).1-7 However, its efficiency remains very low compared to that of conventional CdTe or CIGS absorber layers. Solar cells employing lead halide perovskites as charge generation layers use pure halides and show efficiencies of >22%.8-13 However, halide perovskite materials have inherently low stability because the ionic bonds between monovalent halide anions and bivalent inorganic cations are weak. Therefore, quaternary compounds in which chalcogenide and halide ions coexist in single crystal structure may be suitable as new solar cell materials offering both efficiency and stability.


2

Page 3 of 20 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

ACS Energy Letters

Many studies have investigated the interesting semiconducting and ferroelectric properties of chalcogen-compound halides combined with metal cations (e.g., Pb, Sb, Sn, and Bi) having ns2 electron configurations.14-19 Because of the distinct bonding preferences of the chalcogenide and halide atoms, unique structures can be formed by the competition among atoms to form stable sites in the crystals of the compounds.17 Hoye et al.20 demonstrated the use of bismuth oxyiodide (BiOI) as a light harvester through theoretical and experimental studies, and the reported sandwiched structure (ITO|NiOx|BiOI|ZnO|Al) between inorganic electron- and hole-transporting layers exhibited the maximum external quantum efficiency (EQE) of 80% with negligible hysteresis. Recently, we also fabricated solar cells employing SbSI as a light harvester; they exhibited the power conversion efficiency (PCE) of 3.05% under standard illumination conditions of 100 mW/cm2.21 Pb2SbS2I3 as a quaternary chalcogenide–halide was first obtained and characterized by Dolgikh et al.,22,

23

who established its isotype with Sn2SbS2I3 and determined its unit cell.

Starosta et al.18 prepared ingots of Pb2SbS2I3 and Sn2SbS2I3 and measured the photoconductivities of the materials to determine their band gaps. Evain et al.19 reported the crystal structures of Pb2SbS2I3 at 100 and 293 K, and performed a comparative modular analysis of their structures to re-examine the crystal chemistry of Pb/Sn/Sb chalcogeno-iodides. The Kanatzidis group17 reported the syntheses and crystal structures of Pb2BiS2I3, Sn2BiS2I3, and Sn2BiSI5, which are n-type semiconductors with direct bandgaps. The bandgaps of these materials vary from 1.2 to 1.6 eV, suitable for solar absorbers, and exhibit high electrical resistivities exceeding 1 MΩ cm. Although many related studies have been performed, no reports on the application of Pb2SbS2I3 in solar cells have yet been published. The bandgap of Pb2SbS2I3 (2.0 eV) 18 is suitable for fabricating tandem solar cells of Pb2SbS2I3 and lead halide perovskites


3


Page 4 of 20

by spin-coating methylammonium iodide (MAI) or formamidinium iodide (FAI) solutions onto Pb2SbS2I3 with excess PbI2. Meanwhile, one method to improve the humidity stability of traditional ABX3 (X=Cl, Br, I) perovskite materials is to incorporate S into perovskite materials, however, it is not easy to replace X with S directly. To keep electric neutrality, one option is to introduce Sb/Bi and S/Se together. Pb2SbS2I3 might be an intermedium to synthesis new perovskite materials (APb2SbS2I4, A= methylammonium (MA), and formamidinium (FA)), which can simultaneously introduce Sb and S into MAPbI3 or FAPbI3. In this study, a Pb2SbS2I3 absorber layer for solar cells was prepared by spin-coating a solution of PbI2 dissolved in N,N-dimethylformamide (DMF) on Sb2S3, which was deposited by chemical bath deposition (CBD) followed by thermal annealing. The formation of Pb2SbS2I3 was confirmed by ultraviolet–visible (UV-Vis) absorption spectroscopy and X-ray diffraction (XRD). Solar cells were fabricated with the configuration of fluorine-doped tin oxide (FTO)/TiO2 blocking layer (bl-TiO2)/mesoporous-TiO2 (mp-TiO2)/Pb2SbS2I3/organic hole-transporting layer (HTL)/Au. The charge recombination phenomena were investigated by impedance measurements. The average activation energies of the trapped electrons in the solar cells were assessed by analyzing the dependence of photocurrent density on the temperature. The PCE of 3.12% under full air mass (AM) 1.5G illumination was achieved when TiO2 and poly[2,6-(4,4bis(2-ethylhexyl)-4H-cyclopenta[2,1-b;3,4-b′]dithiophene)-alt-4,7-(2,1,3-benzothiadiazole)] (PCPDTBT) were used as the electron-transporting layer and HTL, respectively. The nanostructured Pb2SbS2I3-based solar cells without encapsulation showed good humidity stability over 30 days. The preparation process of the Pb2SbS2I3 layer is shown in Figure 1a. The PbI2 solution is spin-coated onto the FTO/bl-TiO2/mp-TiO2/Sb2S3 substrates and annealed in Ar gas, and this


4

Page 5 of 20 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

ACS Energy Letters

process is repeated to finally form the Pb2SbS2I3 layer. If MAI or FAI were added into Pb2SbS2I3, we might obtain new materials (eg., MAPb2SbS2I4 or FAPb2SbS2I4), which can simultaneously introduce Sb and S into methylammonium lead iodide (MAPbI3) or formamidinium lead iodide (FAPbI3). This part will be addressed in the future work. Figure 1b shows the UV-Vis absorption spectra for Pb2SbS2I3 layers prepared using 0.05, 0.10, and 0.20 mol/L PbI2 solutions. Regardless of concentration, all samples show similar spectra. Furthermore, the absorption coefficients of the Pb2SbS2I3 layers (inset in Figure 1b) are comparable to those of other indirect-bandgap solar absorbers.24 However, at a very low PbI2 concentration of 0.03 mol/L, Sb2S3 cannot fully transform into Pb2SbS2I3, and absorption of the remaining Sb2S3 is observed (Figure S1). The corresponding Tauc plots are shown in Figure 1c. The Pb2SbS2I3 films exhibit the bandgap of approximately 2.19 eV, which matches well with orange appearance of Pb2SbS2I3 film (the inset in Figure 1c). The bandgap is slightly larger than that reported previously,18 which was determined from the spectral dependence of the photoelectric current. The transport properties of the Pb2SbS2I3 films were evaluated by measuring their charge carrier lifetimes using time-resolved photo-luminescence (TRPL) via time-correlated single-photon counting (TCSPC). The PL decay was fitted by a simple exponential equation: ି௫

y = ‫ܣ‬ଵ ∗ exp ቀ ቁ + ‫ݕ‬଴ ௧ భ

(1)

where y is the PL intensity, A1 is a pre-exponential factor, t1 is the time constant, and y0 is a constant. As shown in Figure 1d, the bulk lifetime is 8.47 ns, which is >1 ns, indicating the potential use of Pb2SbS2I3 as a light harvester.25 The XRD patterns (Figure 1e) show that regardless of PbI2 concentration, all peaks observed from the films show good agreement with


5


Page 6 of 20

the reported Pb2SbS2I3 orthorhombic phase (JCPDS No. 39-0660). The Pb2SbS2I3 film prepared by 0.10 mol/L PbI2 was stored in ambient conditions (relative humidity of ~50%) at room temperature for one month, and the diffraction peak positions remained unchanged over time (Figure S2).

Figure 1. a) The preparation process, b) UV-Vis absorption spectrum, c) Tauc plots, d) the timeresolved photoluminescence (TRPL) spectrum and e) XRD patterns of the Pb2SbS2I3 layer prepared at various concentration PbI2 solutions on glass/mp-TiO2 substrates. The insets in b)


6

Page 7 of 20 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

ACS Energy Letters

and c) are the absorption coefficient and the photograph of the Pb2SbS2I3 film prepared by using the 0.10 mol/L PbI2 solution. The TRPL spectrum was fitted by a simple exponential mode. The main peaks of TiO2 in e) were marked as “T”. The standard Pb2SbS2I3 (JCPDS No. 39-0660) structure file is plotted as the dark column. To investigate the morphologies of the Pb2SbS2I3 films, field-emission scanning electron microscopy (FESEM) was used. Figure S3 a–d show FESEM surface images of the Pb2SbS2I3 films prepared using 0.05, 0.10, and 0.20 mol/L PbI2 solutions. The morphologies of all Pb2SbS2I3 samples are similar to that of Sb2S3, indicating that spin-coating of the PbI2 solution does not change the morphology and that the distribution of Pb2SbS2I3 on the mp-TiO2 is uniform. To apply Pb2SbS2I3 in solar cells, PCPDTBT used as the HTL was deposited onto mpTiO2/Pb2SbS2I3 to form the nanostructured device configuration, and the distribution of Pb2SbS2I3 on the mp-TiO2 was investigated by FESEM equipped with energy-dispersive X-ray (EDX) spectrometry. Figure S3e shows the cross-sectional FESEM image of the Pb2SbS2I3based solar cells where Pb2SbS2I3 was prepared using the 0.10 mol/L PbI2 solution. In the crosssectional FESEM images, four distinct layers, the FTO, bl-TiO2, mp-TiO2/Pb2SbS2I3/HTL, and Au layers, are visible. The line EDX profile (Figure S3f) and EDX mapping data (Figure S3g–k) show the uniform distribution of Pb2SbS2I3. The energy level diagram of the device was investigated. Figures S4a and b show the secondary electron cutoff regions and the highest occupied molecular orbital (HOMO) regions, respectively, of the ultraviolet photoelectron spectroscopy (HeI UPS)-obtained spectra for Pb2SbS2I3; the samples used were the same as those used for XPS. The Fermi levels (EF) of Pb2SbS2I3 prepared using 0.05, 0.10, and 0.20 mol/L PbI2 are 5.06, 5.00, and 5.00 eV, respectively, and the corresponding valence-band maxima (VBMs) are located 1.80, 1.30, and


7


Page 8 of 20

1.35 eV below EF, respectively. Combining these results and the bandgaps acquired from the Tauc plot (Figure 1c), the energy levels of the prepared Pb2SbS2I3 are shown in Figure S4c. The conduction-band minima (CBM) and VBMs of Pb2SbS2I3 prepared using 0.05, 0.10, and 0.20 mol/L PbI2 are 4.67 eV and 6.86 eV, 4.11 eV and 6.30 eV, and 4.16 eV and 6.35 eV, respectively. For the 0.05 mol/L sample, the CBM of Pb2SbS2I3 is slightly lower than that of TiO2, indicating that electrons from Pb2SbS2I3 are not easily transferred to TiO2; thus, more electrons recombine with holes in Pb2SbS2I3, yielding higher charge recombination. The different band structure of the 0.05 mol/L film can be attributed to the surface composition change of Pb2SbS2I3. The EDX line scan profile (Figure S5) of the Pb2SbS2I3 solar cells fabricated using 0.05-mol/L PbI2 shows the decrease of Pb2SbS2I3 on the top of mp-TiO2. The effect of the PbI2 concentration on the device performance was investigated. Figure 2a shows the photo-current density–voltage (J–V) curves of the fabricated Pb2SbS2I3-based solar cells, and the device performances are summarized in Table 1. The cells fabricated using the 0.10-mol/L PbI2 solution exhibits the highest PCE of 2.77%, accompanied by a short-circuit current (JSC) of 7.60 mA/cm2, an open-circuit voltage (VOC) of 0.62V, and a fill factor (FF) of 58.8%.


8

Page 9 of 20 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

ACS Energy Letters

Figure 2. a) J-V curves and b) Nyquist plots under standard illumination conditions (100 mW/cm2) of air mass 1.5 global (AM 1.5 G), c) the series resistance (Rs), the charge-transfer resistance (Rct) and the electron lifetime (τ) extracted from the impedance curves and d) J-V curves of the Pb2SbS2I3 devices prepared by using 0.05, 0.10 and 0.20 mol/L PbI2 solutions, respectively. The inset in b) is an equivalent circuit used to fit impedance curves. Figure 2b presents the Nyquist plots of the Pb2SbS2I3-based solar cells fabricated using 0.05, 0.10, and 0.20 mol/L PbI2 solutions. The Nyquist plots are fitted by an equivalent circuit (inset in Figure 2b). Figure 2c shows the series resistance (Rs), charge-transfer resistance (Rct), and electron lifetime (τ) extracted from the impedance curves. The cells fabricated using 0.10-mol/L PbI2 solutions exhibit low Rs, the highest Rct, and the largest τ, agreeing well with their best


9


Page 10 of 20

overall device performance. The cells fabricated using 0.10 mol/L PbI2 solutions also show the lowest dark-current densities (Figure 2d). Table 1. JSC, VOC, FF and PCE acquired from Figure 2a. Concentration JSC (mol/L)[a] (mA/cm2)

[a]

VOC (V)

FF (%)

PCE (%)

0.05

6.22

0.54

51.5

1.73

0.10

7.60

0.62

58.8

2.77

0.20

5.41

0.49

49.8

1.32

The concentration of the PbI2 solution. To further elucidate the mechanisms underlying the various recombination rates, we

investigated the role of trap states in the device. The J–V characteristics were measured at different temperatures to determine the effect of trap states on the device performance. The solar cells used to test films of each concentration were randomly chosen, rather than using optimized cells. Figure S6 shows the J–V characteristics measured in the dark and under standard AM 1.5 G illumination conditions (100 mW/cm2) of the Pb2SbS2I3 solar cells fabricated using 0.05, 0.10, and 0.20 mol/L PbI2 solutions. Compared to that of the dark-current density, the dependence of the photocurrent density on temperature is smaller. The average activation energy of the trapped electrons can be calculated by using the Richardson–Dushman equation:26, 27 ∆ಶ

J ∝ ݁ ିೖ೅

(2)

where ∆E, k, and T are the electron activation energy, Boltzmann constant, and absolute temperature, respectively. Figure 3a-c show the effects of the temperature on the dark- and photocurrent density. The slope can be used to calculate ∆E. Under dark conditions, ∆E for the Pb2SbS2I3 solar cells fabricated using 0.05, 0.10, and 0.20 mol/L PbI2 solutions are 0.14, 0.15,


10

Page 11 of 20 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

ACS Energy Letters

and 0.21 eV, respectively. Under dark conditions, the device fabricated with the 0.10 mol/L PbI2 solution shows a larger activation energy than that with 0.05 mol/L, possibly because the dark current under short-circuit conditions is affected by noise. The corresponding ∆E under illumination are 0.07 eV (0.05 mol/L), 0.06 eV (0.10 mol/L), and 0.15 eV (0.20 mol/L). The activation energy under illumination represents the averaged energetic depth of shallow traps. These results show that compared to those with 0.05 and 0.20 mol/L, the performance of the cell fabricated using 0.10 mol/L PbI2 solution depends less on traps, indicating that traps have smaller roles in the device performance, which agrees well with the cells showing the lowest recombination rates. Figure 3d shows the role of traps in the devices. After light harvesting, electrons and holes are transferred to the corresponding transporting layers via processes 1 and 2, respectively. If there are sub-bandgap states in Pb2SbS2I3, some electrons are trapped via process 3. The electrons in TiO2 may be transferred back to trap states (process 4), while the electrons trapped in sub-bandgap states may be recombined with the holes in PCPDTBT (process 5). All these processes increase electron–hole recombination, thus; it is important to reduce the trap density in the device.


11


Page 12 of 20

Figure 3. a)-c) Dependence of dark and photo current density at short-circuit conditions on temperature of Pb2SbS2I3 solar cells deposited by using 0.05, 0.10 and 0.20 mol/L PbI2 solutions at temperatures of 25, 50, 75, 100, 125, 150oC and cooling to 25oC, respectively. d) Schematic diagrams of energy levels for the device to describe the role of trap states. To further improve the PCE, various experimental parameters were optimized, including the spin-coating speed of the PbI2 solution, the thickness of mp-TiO2, and the CBD deposition time for Sb2S3 (Tables S1 to S3, Figures S7 to S9). The optimum conditions for fabricating the Pb2SbS2I3-based solar cells were 0.10 mol/L PbI2 solution, 1000 rpm spin-coating speed, 300 °C annealing temperature, 2.5 h CBD, and a 1300-nm-thick mp-TiO2 layer. The J–V curves measured in dark conditions and under standard AM 1.5 G illumination (100 mW/cm2), as well


12

Page 13 of 20 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

ACS Energy Letters

as the incident photon conversion efficiency (IPCE) spectrum, of the most efficient cell are shown in Figure 4a and 4b. A PCE of 3.12% is obtained, accompanied by JSC of 8.79 mA/cm2, VOC of 0.61 V, and FF of 58.2%. The IPCE spectrum is slightly broader than the absorption spectrum (Figure 1b), which can be attributed to the additional absorption of PCPDTBT.28 To separate the photovoltaic activities of Pb2SbS2I3 and PCPDTBT, cells with the configuration of FTO/BL-TiO2/mp-TiO2/PCPDTBT/PEDOT:PSS/Au were also fabricated. These cells showed very poor PCE, indicating that Pb2SbS2I3, rather than PCPDTBT, has the dominant role in the light-harvesting process (Figure S10).

Figure 4. a) J-V curves under dark conditions and standard illumination conditions (100 mW/cm2) of air mass 1.5 global (AM 1.5 G) and b) EQE spectrum of the most efficient Pb2SbS2I3 solar cell. c) Histogram of device efficiencies from the 34 devices fabricated independently. d) Moisture stability tests in ambient condition with a 50% relative humidity at room temperature, e) photo-stability tests under standard AM 1.5G illumination with a xenon


13


Page 14 of 20

lamp including UV radiation and f) thermal stability test at 85oC of the un-encapsulated Pb2SbS2I3 based solar cells.

JSC was calculated by integrating the overlap of the external quantum efficiency (EQE) spectrum with the standard AM 1.5 G solar photon flux as 8.03 mA/cm2, which is in agreement with that measured from the J–V curves. The distributions of the cell PCEs were also investigated; as shown in Figure 4c, a normal distribution and an average PCE of 1.96% are obtained. To test the stability under humidity, light exposure, and elevated temperatures, the unencapsulated cells were stored in ambient conditions with 50% humidity at room temperature, illuminated under standard illumination conditions (100 mW/cm2) of AM 1.5 G including UV radiation, and at 85 °C in air under 40% relative humidity in the dark, respectively. The test results show that the Pb2SbS2I3-based solar cells exhibit comprehensive good stability (Figure 4d-f). Even if the cells stored under various severe conditions, they retained close to 90% of the initial performance. In summary, we fabricated the first nanostructured heterojunction solar cells based on Pb2SbS2I3. Pb2SbS2I3 was prepared through multiple cycles of spin-coating and thermal annealing of a PbI2 solution on Sb2S3, as deposited by the CBD method. Through analyzing impedance measurements and the role of traps in the devices, solar cells fabricated using the 0.10 mol/L PbI2 solution exhibited the lowest recombination and the smallest dependence on traps. The best performing solar cells exhibited the PCE of 3.12%. Pb2SbS2I3 cells without encapsulation show good humidity stability over 30 days. This work demonstrates the applicability of quaternary chalcogenide–halides of group IV and V elements in solar cells.


14

Page 15 of 20 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

ACS Energy Letters

ASSOCIATED CONTENT Supporting Information. The Supporting Information is available free of charge on the ACS Publications website at DOI: Experimental section, surface FESEM images, EDX line and mapping data, secondary electron cutoff region and enlarged highest occupied molecular orbital (HOMO) region of HeI UPS spectra, J–V characteristics measured in the dark and under standard illumination conditions at various temperature, J–V curves under various experiment conditions, and stability tests.

AUTHOR INFORMATION Corresponding Authors *E-mail: [email protected] Notes The authors declare no competing financial interest. ACKNOWLEDGMENTS This work was supported by the National Research Foundation of Korea (NRF) grant funded by the Korea government (MSIT) (2018R1A3B1052820). This work was also financially supported by a project (1.180043.01) of UNIST.


15


Page 16 of 20

REFERENCES (1) Todorov,T. K.; Tang, J.; Bag, S.; Gunawan, O.; Gokmen, T.; Zhu, Y.; Mitzi, D. B. Beyond 11% Efﬁciency: Characteristics of State-of-The-Art Cu2ZnSn(S, Se)4 Solar Cells. Adv. Energy Mater. 2013, 3, 34-38. (2) Wang, W.; Winkler, M. T.; Gunawan, O.; Gokmen, T.; Todorov, T. K.; Zhu, Y.; Mitzi, D. B. Device Characteristics of CZTSSe Thin-Film Solar Cells with 12.6% Efficiency. Adv. Energy Mater. 2014, 4, 1301465. (3) Cao, Y.; Denny Jr., M. S.; Caspar, J. V.; Farneth, W. E.; Guo, Q.; Ionkin, A. S.; Johnson, L. K.; Lu, M.; Malajovich, I.; Radu, D.; et al. High-Efficiency SolutionProcessed Cu2ZnSn(S, Se)4 Thin-Film Solar Cells Prepared from Binary And Ternary Nanoparticles. J. Am. Chem. Soc. 2012, 134, 15644-15647. (4) Kim, J.; Hiroi, H.; Todorov, T. K.; Gunawan, O.; Kuwahara, M.; Gokmen, T.; Nair, D.; Hopstaken, M.; Shin, B.; Lee, Y. S.; et al. High Efficiency Cu2ZnSn (S, Se)4 Solar Cells by Applying A Double In2S3/CdS Emitter. Adv. Mater. 2014, 26, 7427-7431. (5) Yang, W.; Duan, H.-S.; Bob, B.; Zhou, H.; Lei, B.; Chung, C.-H.; Li, S.-H.; Hou, W. W.; Yang, Y. Novel Solution Processing of High-Efficiency Earth-Abundant Cu2ZnSn(S, Se)4 Solar Cells, Adv. Mater. 2012, 24, 6323-6329. (6) Miskin, C. K.; Yang, W.-C.; Hages, C. J.; Carter, N. J.; Joglekar, C. S.; Stach, E. A.; Agrawal, R. 9.0% Efficient Cu2ZnSn (S, Se)4 Solar Cells from Selenized Nanoparticle Inks, Prog Photovolt: Res Appl. 2015, 23, 654-659. (7) Yang, K. J.; Sim, J. H.; Son, D. H.; Kim, Y. I.; Kim, D. H.; Nam, D.; Cheong, H. S.;


16

Page 17 of 20 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

ACS Energy Letters

Kim, S. Y.; Kim, J. H.; Kang, J. K. Precursor Designs for Cu2ZnSn(S, Se)4 Thin-Film Solar Cells, Nano energy 2017, 35, 52-61. (8) Heo, J. H.; Im, S. H.; Noh, J. H.; Mandal, T. N.; Lim, C.-S.; Chang, J. A.; Lee, Y. H.; Kim, H.-J.; Sarkar, A.; Nazeeruddin, M. K et al. Efficient Inorganic–Organic Hybrid Heterojunction Solar Cells Containing Perovskite Compound And Polymeric Hole Conductors, Nat. Photonics 2013, 7, 486-491. (9) Jeon, N. J.; Noh, J. H.; Kim, Y. C.; Yang, W. S.; Ryu, S.; Seok, S. I. Solvent Engineering for High-Performance Inorganic–Organic Hybrid Perovskite Solar Cells, Nat. Mater. 2014, 13, 897-903. (10)

Jeon, N. J.; Noh, J. H.; Yang, W. S.; Kim, Y. C.; Ryu, S.; Seo, J.; Seok, S. I.

Compositional Engineering of Perovskite Materials for High-Performance Solar Cells, Nature 2015, 517, 476-480. (11)

Yang, W. S.; Noh, J. H.; Jeon, N. J.; Kim, Y. C.; Ryu, S.; Seo, J.; Seok, S. I.

High-Performance Photovoltaic Perovskite Layers Fabricated Through Intramolecular Exchange, Science 2015, 348, 1234-1237. (12)

Bi, D.; Tress, W.; Dar, M. I.; Gao, P.; Luo, J.; Renevier, C.; Schenk, K.; Abate,

A.; Giordano, F.; Correa Baena, J.-P.; et al. Efficient Luminescent Solar Cells Based on Tailored Mixed-Cation Perovskites, Sci. Adv. 2016, 2, e1501170. (13)

Yang, W. S.; Park, B.-W.; Jung, E. H.; Jeon, N. J.; Kim, Y. C.; Lee, D. U.; Shin,

S. S.; Seo, J.; Kim, E. K.; Noh, J. H.; et al. Iodide Management in FormamidiniumLead-Halide–Based Perovskite Layers for Efficient Solar Cells, Science 2017, 356,


17


Page 18 of 20

1376-1379. (14)

Fenner, J.; Mootz, D. The Crystal Structure of Gold Telluride Iodide AuTel, J.

Solid State Chem. 1978, 24, 367-369. (15)

Alpen, U. V.; Fenner, J.; Predel, B.; Rabenau, A.; Schluckebier, G. Telluride

Halides of Copper With High Ionic Partial Conductivity. Z. Anorg. Allg. Chem. 1978, 438, 5-14. (16)

Carkner, P. M.; Haendler, H. M. The Crystal Structure of Copper Bromide

Telluride, J. Solid State Chem. 1976, 18, 183-189. (17)

Islam, S. M.; Malliakas, C. D.; Sarma, D.; Maloney, D. C.; Stoumpos, C. C.;

Kontsevoi, O. Y.; Freeman, A. J.; Kanatzidis, M. G. Direct Gap Semiconductors Pb2BiS2I3, Sn2BiS2I3, and Sn2BiSI5. Chem. Mater. 2016, 28, 7332–7343. (18)

Starosta, V. I.; Kroutil, J.; Benes, L.; Preparation and Fundamental Physical

Properties of Sn2SbS2I3 and Pb2SbS2I3 compounds. Cryst. Res. Technol.1990, 25, 14391442. (19)

Doussier, C.; Moelo, Y.; Leone, P.; Meerschaut, A.; Evain, M. Crystal Structure

of Pb2SbS2I3, and Re-examination of The Crystal Chemistry within The Group of (Pb/Sn/Sb) Chalcogeno-Iodides, Solid State Science 2007, 9, 792-803. (20)

Hoye, R. L. Z.; Lee, L. C.; Kurchin, R. C.; Huq, T. N.; K. Zhang, H. L.;

Sponseller, M.; Nienhaus, L.; Brandt, R. E.; Jean, J.; Polizzotti, J. A.; et al. Strongly Enhanced Photovoltaic Performance and Defect Physics of Air-Stable Bismuth


18

Page 19 of 20 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

ACS Energy Letters

Oxyiodide (BiOI), Adv. Mater. 2017, 29, 1702176. (21)

Nie, R. M.; Yun, H.-S.; Paik, M.-J.; Mehta, A.; Park, B.-W.; Choi, Y. C.; Seok,

S. I. Efficient Solar Cells Based on Light-Harvesting Antimony Sulfoiodide, Adv. Energy Mater. 2018, 8, 1701901. (22)

Dolgikh, V. A. New Chalkogen-Halogenides of the Type M2SbS2I3. Izv.

Akad. Nauk SSSR, Neorg. Mater. 1985, 21, 1211-1214. (23)

Dolgikh, V. A. Preparation of Single Crystals and Dielectric Properties of

Sn2SbS2I3, and Pb2SbS2I3. Izv. Akad. Nauk SSSR, Neorg. Mater. 1985, 21, 1215-1218. (24)

Ganose, A. M.; Savory, C. N.; Scanlon, D. O. Beyond Methylammonium Lead

Iodide: Prospects for The Emergent Field of ns2 Containing Solar Absorbers, Chem. Commun. 2017, 53, 20-44. (25)

Jaramillo, R.; Sher, M.-J.; Ofori-Okai, B. K.; Steinmann, V.; Yang, C.;

Hartman, K.; Nelson, K. A.; Lindenberg, A. M.; Gordon, R. G.; Buonassisi, T. Transient Terahertz Photoconductivity Measurements of Minority-Carrier Lifetime in Tin Sulfide Thin Films: Advanced Metrology for An Early Stage Photovoltaic Material, J. Appl. Phys. 2016, 119, 35101. (26)

Deng, X.; Zheng, L.; Yang, C.; Li, Y.; Yu, G.; Cao, Y. Polymer Photovoltaic

Devices Fabricated with Blend MEHPPV and Organic Small Molecules. J. Phys. Chem. B 2004, 108, 3451-3456. (27)

Nie, R.; Deng, X.; Feng, L.; Hu, G.; Wang, Y.; Yu, G.; Xu, J. Highly Sensitive


19


Page 20 of 20

and Broadband Organic Photodetectors with Fast Speed Gain and Large Linear Dynamic Range at Low Forward Bias, Small 2017, 13, 1603260. (28)

Chang, J. A.; Im, S. H.; Lee, Y. H.; Kim. H.-J.; Lim, C.-S.; Heo, J. H.; Seok, S.

I. Panchromatic Photon-Harvesting by Hole-Conducting Materials in Inorganic– Organic Heterojunction Sensitized-Solar Cell Through the Formation of Nanostructured Electron Channels, Nano Lett. 2012, 12, 1863-1867.


20

Nanostructured Heterojunction Solar Cells Based on Pb2SbS2I3

Recommend Documents