Enhanced Optoelectronic Performance on the (110) Lattice Plane of

Jan 23, 2017 - Advanced Research Center for Optics, Shandong University, Jinan ... However, the lack of optimizations in energy harvest, transportatio...
0 downloads 0 Views 1MB Size
Subscriber access provided by UB + Fachbibliothek Chemie | (FU-Bibliothekssystem)

Letter

Enhanced Optoelectronic Performance on (110) Lattice Plane of MAPbBr3 Single Crystal Zhiyuan Zuo, Jianxu Ding, Ying Zhao, Songjie Du, Yongfu Li, Xiaoyuan Zhan, and Hongzhi Cui J. Phys. Chem. Lett., Just Accepted Manuscript • Publication Date (Web): 23 Jan 2017 Downloaded from http://pubs.acs.org on January 23, 2017

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 free 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 accessible to all readers and 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.

The Journal of Physical Chemistry Letters 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 18

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

The Journal of Physical Chemistry Letters

Enhanced Optoelectronic Performance on (110) Lattice Plane of MAPbBr3 Single Crystal †

††

††

††



††

Zhiyuan Zuo ‡*, Jianxu Ding § *, Ying Zhao , Songjie Du , Yongfu Li *, Xiaoyuan Zhan , Hongzhi Cui †

††

Advanced Research Center for Optics, Shandong University, Shandanan Road, Jinan 250100,

China. §

State Key Laboratory of Mining Disaster Prevention and Control Co-founded by Shandong

Province and the Ministry of Science and Technology, Shandong University of Science and Technology, Qingdao 266590, China. ‡

State Key Laboratory of Crystal Materials, Shandong University, Shandanan Road, Jinan

250100, China. ††

College of Materials Science and Engineering, Shandong University of Science and

Technology, Qingdao 266590, China.

Corresponding Authors *Email: [email protected], [email protected], [email protected].

ACS Paragon Plus Environment

1

The Journal of Physical Chemistry 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 18

ABSTRACT: Hybrid organic-inorganic lead halide perovskites have attracted significant attentions due to their impressive optoelectronic properties. MAPbX3(MA= CH3NH3+, X= Cl, Br or I.), the most popular member of this family, has been recognized as an important next generation optoelectronic materials contender and remarkable progresses have been achieved in both thin film and single crystal. However, lacking of optimizations in energy harvest, transportation, carrier extraction and process compatibility are hindering their future development. In this study, a triangle prism MAPbBr3 single crystal exposing (100) and (110) crystallographic planes were successfully synthesized and optoelectronic performances of these two lattice planes were systematically explored by employing a planar Metal-Semiconductor-Metal (MSM) devices. Compared to the device fabricated on (100) plane, a 153.33% enhancement of responsivity was achieved under 10 µW irradiation and 10 V bias on (110) plane. Finally, possible mechanism for such an enhancement was discussed based on the different defects migration behaviors of (100) and (110) planes.

TOC GRAPHICS

ACS Paragon Plus Environment

2

Page 3 of 18

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

The Journal of Physical Chemistry Letters

Over the past several years, hybrid organic-inorganic lead halide perovskites, especially MAPbX3, have been intensively investigated due to their extraordinary optoelectronic properties such as high photon absorption efficiency,1 outstanding carrier lifetime,2, 3 and excellent carrier diffusion ability 4 etc. Meanwhile, energy band gap of MAPbX3 materials can be tuned continuously over a broad range by changing the ratio of halogen elements and component like III-V compound semiconductors. Further taking low fabrication cost and facile preparation into account, MAPbX3 materials will show great potential applications in the fields of photovoltaic, water photolysis, laser, luminescence and photo-detection etc.5-10 Since MAPbBr3 in MAPbX3 family shows effective optical absorption ability across the visible spectra band,11, 12 this advantage reveals great application potential in light emitting devices13 and photo-detectors.14 Additionally, MAPbBr3 shows better thermal and chemical stabilities than MAPbI3 which makes it more competitive in visible range optoelectronic applications. Single crystals are more ideal for optoelectronic device fabrication than polycrystalline films as serious comprehensive influence caused by lattice orientation, surface states and grain boundariesinpolycrystallinematerials.15-17 Polycrystalline films are made up by crystal grains with different lattice orientation exhibit different properties according to the anisotropy of crystals. So performances of devices fabricated by using polycrystalline films are degraded by the irregular orientation structures. Furthermore, high surface defects densities and grain boundaries provide more recombination centers which can increase the recombination probability of the excited carriers. As a result, the internal quantum efficiency (IQE) of photodetecting devices is limited. In contrast, devices made from MAPbBr3 singlefilm18 and crystals possess much better performances than those fabricated using polycrystalline films.19A prime example is that diffusion length of carrier obtained from MAPbBr3 single crystal exceeding 10

ACS Paragon Plus Environment

3

The Journal of Physical Chemistry 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 4 of 18

µm19 while the value in polycrystalline film was hundreds of nanometers.20 The obvious benefit is that, longer carrier diffusion length and lifetime will promote the extraction efficiency of photon excited electron-hole pairs. Systematical comparisons of transport properties between free-standing crystal, integrated single crystal film and polycrystalline film had been listed by Schmidt et al.21Although previous results revealed the importance of lattice orientation uniformity, optoelectronic performances on particular crystallographic planes are still uncharted and sufficient studies on the optoelectronic application of single crystal MAPbBr3 are still highly demanded. A triangle prism MAPbBr3 single crystal with (100) and (110) crystallographic planes had been prepared by controlling the orientation of seed crystal and growth conditions. Gold interdigital electrodes were fabricated on (100) and (110) planes to harvest different optoelectronic performances. Then optical and electrical analysis was performed and further studies on photocurrent, responsivity and time response were carried out on both planes to compare the optoelectronic performances. Figure 1a presents the schematic illustration of MAPbBr3 single crystal preparation process. MAPbBr3 single crystal can be easily obtained by using the falling temperature method due to the reversible temperature solubility character in DMF. By finely tuning solution concentration and growth temperature, large size crystals of high quality can be obtained. Figure 1b displays the photo of single crystal with triangular prism shape grown at optimized conditions by controlling the orientation of seed crystal. The size of the single crystal reaches 5 mm × 5 mm × 7 mm and different lattice plane indexes are indicated in Figure 1c.The red plane are perpendicular to green plane which can be recognized as (100) and (010) lattice plane respectively. The biggest plane represent the (110) lattice plane of MAPbBr3 single crystal.

ACS Paragon Plus Environment

4

Page 5 of 18

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

The Journal of Physical Chemistry Letters

Powder X-ray diffraction (XRD) pattern of the ground crystals demonstrates pure perovskite cubic MAPbBr3 crystal structure as shown in Figure 1d. By fitting the powder XRD data, the space group can be assigned toPm3m and the unit cell parameters are determined to be a=0.5919 nm. The XRD results shows that the crystal parameters are in good agreement with the previous reported data22 and calculated result. Detailed experimental introduction can be found in Supporting Information.

ACS Paragon Plus Environment

5

The Journal of Physical Chemistry 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 6 of 18

Figure 1.Depiction of MAPbBr3 single crystal. (a) Schematic representation of the single crystal growth process with a triangular prism seed crystal. (b) Photos of triangular prism MAPbBr3 single crystal. (c) Lattice plane index of different exposed surfaces on triangular prism MAPbBr3 single crystal. (d) Experimental and calculated XRD patterns of MAPbBr3 single crystal powder.

The absorption and photoluminescence (PL) spectrums are shown in Figure 2. From the absorption curve we can obtain the valence band maximum to the conduction band minimum (VBM to CBM) transition of MAPbBr3 single crystal is located around 578 nm (Original absorption spectrum is shown in Figure S4), and the energy band gap (Eg) of 2.15 eV can be obtained. The value of Eg is smaller than the typical value (2.30 ± 0.10eV) reported before.22, 23 A narrower energy band gap will be an advantage in its optoelectronic application due to the expansion of active wavelength band. The strongest absorbance appeared at 520 nm and no significant defect level absorption can be observed except normal Urbach tail24 while the photon energy goes less than 2.15 eV. PL spectrum had been obtained under 405 nm excitation illumination using a xenon lamp and the CBM to VBM recombination peak located at 535 nm and obvious emission band caused by deep defect levels can be observed from 585 nm to 750 nm. There are at least three primary types of defect recombination and the central emission wavelengths are 584 nm (2.12 eV), 645 nm (1.92 eV) and 700 nm (1.77 eV) respectively, which are correspond to the defect emissions reported by Atourkia et al.25 Recombinations contributed by the defect levels are probably due to the native vacancies rather than antisite defects because antisite defects in hybrid organic-inorganic lead halide perovskites are usually shallow defects.26 As there is no significant absorption in this wavelength range, the electrons filled in the deep defect levels should come from the conduction band. And one possible recombination path is from CBM to deep defect levels inside the band gap, while the other is from deep defect levels to

ACS Paragon Plus Environment

6

Page 7 of 18

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

The Journal of Physical Chemistry Letters

the VBM. The existence of such deep level defects will play a very important role in the photocurrent performances, as will be discussed systematically in the following contents.

Figure 2.The absorption and photoluminescence spectrums of MAPbBr3 single crystal.

Photocurrent, responsivity and external quantum efficiency (EQE) are the key parameters to evaluate a photo-detecting device. To obtain these data of (100) and (110) lattice planes shown in Figure 3, planar gold interdigital electrodes were fabricated on both of the two planes in this pseudo-cubic single crystal. By applying this type of electrodes, most carriers will be restricted to transport along certain different lattice directions. Figure 3a and 3b shows the dark and photocurrents obtained from (100) and (110) plane respectively by using a 405 nm laser diode (LD). Same results in logarithmic coordinate format are shown in lower left. During the

ACS Paragon Plus Environment

7

The Journal of Physical Chemistry 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 8 of 18

measurements, lower dark current acquired on (110) plane is 1.93×10-7 A, in contrast to 3.45×107

A on (100) plane at the same voltage of 10 V and the value of photocurrents on (110) plane is

larger than those on (100) plane while the LD output beyond 40 µW. The different transport performances of these two planes are more significant in the logarithmic coordinate figures. For (100) plane (lower left inset of Figure 3a), the tendencies of both dark current and photocurrents show mainly linear features even the applied voltages reach to 10 V and which can be described as ohmic regime showing a linear principle between voltage and current. 27

Figure 3.Photocurrents, responsivities and EQEs of the devices on (100) and (110) lattice planes of MAPbBr3 single crystal. (a) and (b) reveal the photo responses of (100) and (110) plane respectively and the lower left insets in both of (a) and (b) show the same data using logarithmic

ACS Paragon Plus Environment

8

Page 9 of 18

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

The Journal of Physical Chemistry Letters

coordinate. Responsivities and EQEs of devices on (100) and (110) planes are plotted in (c) and (d) respectively. Simple diagrams of device design and fabrication location are inserted to the lower part of (c) and (d), and basic work function sketch of the devices is shown in the upper left of (d).

Linear increase can also be seen in results of (110) plane (lower left inset of Figure 3b) at lower applied voltage range. However, non-linear features are significant for both dark current and photocurrents while the applied voltages are larger than 2.10 V. This non-linear part meets the current feature of traps-filled-limit (TFL) condition28 and increases abruptly. The voltage value of the inflexion point can be recognized as VTFL:



 = 2

Where e stands for the elementary charge, Nt stands for the trap density of the crystal, l is the distance between the neighboring contact fingers. ε is the relative dielectric constant of MAPbBr3, and ε0 is the vacuum permittivity. As can be seen from the figure, VTFL shows a decrease trend while the LD outputs grow larger. This phenomenon is probably caused by the interactions between the incident photons and the filled/trapped carriers. Despite the trap filling carriers driven by the applied voltage, photon excited carriers will also be active trap states fillers. The responsivities R and EQEs can be calculated by using:

R=

 −   ∙ 

and:

ACS Paragon Plus Environment

9

The Journal of Physical Chemistry 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

EQE =

Page 10 of 18

! ∙ ℎ#

$

where IPC and Idark are photocurrents measured under illumination and dark, respectively. Pirra stands for irradiation power density and S is the effective area of the detector. c is the speed of light and λ stands for the wavelength of irradiation.29 Responsivity reveals the ratio of photon excited current to irradiation flux and EQEs can be obtained from responsivity by changing the ratio of current/incident light power to electron quantity/photon quantity in order to evaluate the photon-current conversion ability of our devices on different lattice planes. As the illumination wavelength was fixed to 405 nm during all the measurements in this study, responsivities and EQEs told the same story for devices on both (100) and (110) planes, which are shown together in Figure 3c and 3d. We can get a conclusion that responsivities and EQEs depend sensitively on the applied voltage and incident laser power density and increase with the applied voltages. For original linear data, please see Figure S5, S6 and S7. Furthermore, irradiation power density also remarkably affect the responsivities and EQEs and significant decreases appeared when the voltage exceeds 8.00 V under stronger irradiations. For the detailed numerical results, the highest values of responsivity and EQE obtained from device on (100) plane is 0.015 A/W and 0.046% respectively under 9.84 V bias when the irradiation power is 10 µW. While for the (110) device, the highest values of responsivity and EQE is 0.038 A/W and 0.113% respectively.

ACS Paragon Plus Environment

10

Page 11 of 18

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

The Journal of Physical Chemistry Letters

Figure 4.Time-dependent photocurrents and the swiching times. (a) and (b) show five continues on-off cicles under different applied voltages of the devices on (100) plane and (110) plane respectively. (c) and (d) provide detail response times of (100) and (110) facet devices while different voltages were applied.

Time depended photocurrents measurements were carried out with the aim to compare switching characteristics of the two devices at different applied voltages (Figure 4 a to d). The switch features of the devices were measured by employing a high frequency light emitting diode (LED) with a fixed 0.31 mW cm−2 illumination density and a dominant wavelength of 462 nm (Figure 4a and 4b). The highest on/ off ratio of ~36 was achieved under 10.00 V bias from (100) facet

ACS Paragon Plus Environment

11

The Journal of Physical Chemistry 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 12 of 18

device while ~55 from the device on (110) plane. Figure 4 (c) and (d) shows the rise and decay times of the two devices and no significant correlations between different devices and applied voltages were found from the results. Although single crystals can provide better crystalline quality, significant defects emission contents were still seen in the PL results. Organo halide perovskites are prone to defect formation due to their weak thermal stability.30 As antisites incline to split into the respective interstitials and vacancies spontaneously31 in organo halide perovskites, so interstitial defects and vacancies are the most probable defects in our crystal.32 Previous reports reveal that vacancies and halogen interstials can be driven to migrate with fairly low activation energies in the organo halide perovskites and their favorite paths is the diagonal of the (100), (010) and (001) plane.33 As MAPbBr3 crystal belongs to pseudo-cubic structure, the direction of electric field applied to the device on (110) surface coincide with the defects’ favorite migration path. Moreover, except Pb vacancies, the activation energies of the defects are less than 1.00 eV33 (VPb activation energy is larger than 2.00 eV),34 then interstials and vacancies can be easily driven by the photons emitted from the LD (3.06 eV) and the applied voltage. The major types of diffusible ions MA+ and halogen vacancies will move to appropriate electrodes until blocked by the metal contacts.35Then the vacancy density in the area far away from the metal contacts will be decreased compare to the original condition. This means that a much lower Br- vacancy density can be obtained except the area around electrodes. As the conduction band are mainly contributed by the 6p of Pb and X ions inMAPbX3materials, 31 perfect Br- configuration can improve the transportation performance of electrons in conductive bands. Furthermore, low Br- vacancy density also means less recombination centers, less carrier traps and less scattering while the carriers drifting to the electrodes. All the benefits above are more remarkable in (110) lattice plane than (100) due to

ACS Paragon Plus Environment

12

Page 13 of 18

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

The Journal of Physical Chemistry Letters

the efficient ion migration process on (110) surface. Finally, when the electrons move close to the electrodes, non-radiative recombination process will be suppressed continuously by the builtin electrical field which is induced by the piled ion charges36 and more excited electrons will survive from the non-radiative recombination loss. Previous research works have achieved rather fascinating results in photo-detection related areas based on both MAPbBr3 films and single crystals. Although it has been proved that higher performances can be obtained in single crystals rather than using polycrystalline films, but the advantages of polycrystalline films such as can be easily integrated to typical chip processes, large wafer size and low cost are still of great attractions. In our study, performances of different MAPbBr3 lattice planes have been systematically investigated and lower dark current combined with higher photocurrents were obtained on the (110) plane. The greatest improvement of responsivity obtained from (110) facet device is 153.33% and possible mechanism was discussed based on ion transportation features of organic-inorganic lead halide perovskites. ASSOCIATED CONTENT ACKNOWLEDGMENT This work was financially supported by the National Key Research Project (2016YFB0401802), Fund of State Key Laboratory of Crystal Materials in Shandong University (No. KF1504), Fundamental Research Funds of Shandong University, Scientific Research Foundation of Shandong University of Science and Technology for Recruited Talent (No. 2014RCJJ001), National Natural Science Foundation of China (No. 51202131), SDUST Research Fund and Joint Innovative Canter for Safe and Effective Mining Technology and Equipment of Coal Resources, Shandong Province (No. 2014JQJH102).

ACS Paragon Plus Environment

13

The Journal of Physical Chemistry 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 14 of 18

Supporting Information. All the experimental details about crystal synthesis and measurements can be found in the supporting information. This material is available free of charge via http://pubs.acs.org. REFERENCES (1) Green, M. A.; Ho-Baillie, A; Snaith, H. J. The Emergence of Perovskite Solar Cells. Nat. Photon. 2014, 8, 506-514. (2) Dong, Q. F.; Fang, Y. J.; Shao, Y. C.; Mulligan, P.; Qiu, J.; Cao, L.; Huang, J. S. Electron-hole Diffusion Lengths >175 µm in Solution-grown CH3NH3PbI3 Single Crystals. Science 2015, 347, 967-970. (3) Saidaminov, M. I.; Abdelhady, A. L.; Murali, B.; Alarousu, E.; Burlakov, V. M.; Peng, W.; Dursun, I.; Wang, L. F.; He, Y.; Maculan, G. et al. High-quality Bulk Hybrid Perovskite Single Crystals Within Minutes by Inverse Temperature Crystallization. Nat. Commun. 2015, 6, 7586. (4) Stranks, S. D.; Eperon, G. E.; Grancini, G.; Menelaou, C.; Alcocer, M. J. P.; Leijtens, T.; Herz, L. M.; Petrozza, A.; Snaith, H. J. Electron-Hole Diffusion Lengths Exceeding 1 Micrometer in an Organometal Trihalide Perovskite Absorber. Science 2013, 342, 341344. (5) Yang, W. S.; Noh, J. H.; Jeon, N. J.; Kim, Y. C.; Ryu, S. C.; Seo, J. G.; Seok, S. L. Highperformance Photovoltaic Perovskite Layers Fabricated through Intramolecular Exchange. Science 2015, 348, 1234-1237. (6) Luo, J. S.; Im, J. H.; Mayer, M. T.; Schreier, M.; Nazeeruddin, M. K.; Park, N. G.; Tilley, S. D.; Fan, H. J.; Grätzel, M. Water Photolysis at 12.3% Efficiency via Perovskite Photovoltaics and Earth-abundant Catalysts. Science 2014, 345, 1593-1596.

ACS Paragon Plus Environment

14

Page 15 of 18

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

The Journal of Physical Chemistry Letters

(7) Dou, L. T.; Yang, Y.; You, J. B.; Hong, Z. R.; Chang, W. H.; Li, G.; Yang, Y. Solutionprocessed Hybrid Perovskite Photodetectors with High Detectivity. Nat. Commun. 2014, 5, 5404. (8) Noh, J. H.; Im, S. H.; Heo, J. H.; Mandal, T. N.; Seok, S. L. Chemical Management for Colorful, Efficient, and Stable Inorganic–Organic Hybrid Nanostructured Solar Cells. Nano Lett. 2013, 13, 1764-1769. (9) Xing, G. C.; Mathews, N.; Lim, S. S.; Yantara, N.; Liu, X. F.; Sabba, D.; Grätzel, M.; Mhaisalkar, S.; Sum, T. C. Low-temperature Solution-processed Wavelength-tunable Perovskites for Lasing. Nat. Mater. 2014, 13, 476-480. (10) Wang, L.; Yuan, G. D.; Duan, R. F.; Huang, F.; Wei, T. B.; Liu, Z. Q.; Wang, J. X.; Li, J. M. Tunable Bandgap in Hybrid Perovskite CH3NH3Pb(Br3−yXy) Single Crystals and Photodetector Applications. AIP Adv. 2016, 6, 045115. (11) Wolf, S. D.; Holovsky, J.; Moon, S. J.; Löper, P.; Niesen, B.; Ledinsky, M.; Haug, F. J.; Yum, J. H.;Ballif, C. Organometallic Halide Perovskites: Sharp Optical Absorption Edge and Its Relation to Photovoltaic Performance. J. Phys. Chem. Lett. 2014, 5, 1035-1039. (12) Maculan, G.; Sheikh, A. D.; Abdelhady, A. L.; Saidaminov, M. I.; Haque, M. A.; Murali, B.; Alarousu, E.; Mohammed, O. F.; Wu, T.; Bakr, O. M. CH3NH3PbCl3 Single Crystals: Inverse Temperature Crystallization and Visible-Blind UV-Photodetector. J. Phys. Chem. Lett. 2015, 6, 3781-3786. (13) Tan, Z. K.; Moghaddam, R. S.; Lai, M. L.; Docampo, P.; Higler, R.; Deschler, F.; Price, M.; Sadhanala, A.; Pazos, L. M.; Credgington, D.; et al. Bright Light-emitting Diodes Based on Organometal Halide Perovskite. Nat. Nanotech. 2014, 9, 687-692. (14) Fang, Y. J.; Dong, Q. F.; Shao, Y. C.; Yuan, Y. B.; Huang, J. S. Highly Narrowband Perovskite Single-crystal Photodetectors Enabled by Surface-charge Recombination. Nat. Photon. 2015, 9, 679-686.

ACS Paragon Plus Environment

15

The Journal of Physical Chemistry 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 16 of 18

(15) Yang, D.; Yang, R. X.; Zhang, J.; Yang, Z.; Liu, S. Z.; Li, C. High Efficiency Flexible Perovskite Solar Cells Using Superior Low Temperature TiO2. Energ. Environ. Sci. 2015, 8, 3208-3214. (16) Unger, E. L.; Hoke, E. T.; Bailie, C. D.; Nguyen, W. H.; Bowring, A. R.; Heumuller, T.; Christoforo, M. G.;McGehee, M. D. Hysteresis and Transient Behavior in Current– voltage Measurements of Hybrid-perovskite Absorber Solar Cells. Energ. Environ. Sci. 2014, 7, 3690-3698. (17) Snaith, H. J.; Abate, A.; Ball, J. M.; Eperon, G. E.; Leijtens, T.; Noel, N. K.; Stranks, S. D.; Wang, T. W.; Wojciechowski, K.; Zhang, W. Anomalous Hysteresis in Perovskite Solar Cells. J. Phys. Chem. Lett. 2014, 5, 1511-1515. (18) Peng, W.; Wang, L. F.; Murali, B.; Ho, K. T.; Bera, A.; Cho, N.; Kang, C. F.; Burlakov, V. M.; Pan, J.; Sinatra, L. et al. Solution-Grown Monocrystalline Hybrid Perovskite Films for Hole-Transporter-Free Solar Cells. Adv. Mater. 2016, 28, 3383-3390. (19) Shi, D.; Adinolfi, V.; Comin, R.; Yuan, M. J.; Alarousu, E.; Buin, A.; Chen, Y.; Hoogland, S.; Rothenberger, A.; Katsiev, K. et al. Low Trap-state Density and Long Carrier Diffusion in Organo Lead Trihalide Perovskite Single Crystals. Science 2015, 347, 519-522. (20) Kedem, N.; Brenner, T. M.; Kulbak, M.; Schaefer, N.; Levcenko, S.; Levine, I.; AbouRas, D.; Hodes, G.; Cahen, D. Light-Induced Increase of Electron Diffusion Length in a p-n Junction Type CH3NH3PbBr3 Perovskite Solar Cell. J. Phys. Chem. Lett. 2015, 6, 2469-2476. (21) Schmidt, L. C.; Pertegás, A.; Carrero, S. G.; Malinkiewicz, O.; Agouram, S.; Espallargas, G. M.; Bolink, H. J.; Galian, R. E.; Prieto, J. P. Nontemplate Synthesis of CH3NH3PbBr3 Perovskite Nanoparticles. J. Am. Chem. Soc. 2014, 136, 850−853. (22) Schulz, P.; Edri, E.; Kirmayer, S.; Hodes, G.; Cahen, D.; Kahn, A. Interface Energetics in Organo-metal Halide Perovskite-based Photovoltaic Cells. Energ. Environ. Sci. 2014, 7, 1377-1381.

ACS Paragon Plus Environment

16

Page 17 of 18

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

The Journal of Physical Chemistry Letters

(23) Grancini, G.; Kandada, A. R. S.; Frost, J. M.; Barker, A. J.; Bastiani, D. M.; Gandini,M.; Marras, S.; Lanzani, G.; Walsh, A.; Petrozza, A. Role of Microstructure in the Electron– hole Interaction of Hybrid Lead Halide Perovskites. Nat. Photon. 2015, 9, 695-701. (24) Dow, J. D.; Redfield, D. Toward a Unified Theory of Urbach's Rule and Exponential Absorption Edges. Phys. Rev. B 1972, 5, 594-610. (25) Atourkia, L.; Vegab, E.; Maríb, B.; Mollarb, M.; Ahsainec, H. A.; Bouabida, K.; Ihlal, A. Role of the Chemical Substitution on the Structural and Luminescence Properties of the Mixed Halide Perovskite Thin MAPbI3− xBrx(0 ≤ x ≤ 1) Films. Appl. Surf. Sci. 2016, 371, 112-117. (26) Yin, W. J.; Shi, T. T.; Yan, Y. F. Unusual Defect Physics in CH3NH3PbI3 Perovskite Solar Cell Absorber. Appl. Phys. Lett. 2014, 104, 063903. (27) Rose, A. Space-charge-limited Currents in Solids. Phys. Rev. 1955, 97, 1538-1544. (28) Bube, R. H. Trap Density Determination by Space-Charge-Limited Currents. J. Appl. Phys. 1962, 33, 1733-1737. (29) Lian, Z. P.; Yan, Q. F.; Lv, Q. R.; Wang, Y.; Liu, L. L.; Zhang, L. J.; Pan, S. L.; Li, Q.; Wang, L. D.; Sun, J. L. High-Performance Planar-Type Photodetector on (100) Facet of MAPbI3 Single Crystal. Sci. Rep. 2015, 5, 16563. (30) Shao, Y. C.; Xiao, Z. G.; Bi, C.; Yuan, Y. B.;Huang, J. S. Origin and Elimination of Photocurrent Hysteresis by Fullerene Passivation in CH3NH3PbI3 Planar Heterojunction Solar Cells. Nat. Commun. 2014, 5, 5784. (31) Du, M. H. Efficient Carrier Transport in Halide Perovskites: Theoretical Perspectives. J. Mater. Chem. A 2014, 2, 9091-9098. (32) Agiorgousis, M. L.; Sun, Y. Y.; Zeng, H.; Zhang, S. B. Strong Covalency-Induced Recombination Centers in Perovskite Solar Cell Material CH3NH3PbI3. J. Am. Chem. Soc. 2014, 136, 14570-14575.

ACS Paragon Plus Environment

17

The Journal of Physical Chemistry 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 18 of 18

(33) Azpiroz, J. M.; Mosconi, E.; Bisquert, J.; De Angelis, F. Defects Migration in Methyl Ammonium Lead Iodide and their Role in Perovskite Solar Cells Operation. Energ. Environ. Sci. 2015, 8, 2118-2127. (34) Eames, C.; Frost, J. M.; Barnes, P. R. F.; O’Regan, B. C.; Walsh, A.; Islam, M. S. Ionic Transport in Hybrid Lead Iodide Perovskite Solar Cells. Nat. Commun. 2015, 6, 7497. (35) Yuan, Y. B.; Chae, J. S.; Shao, Y. C.; Wang, Q.; Xiao, Z. G.; Centrone, A.; Huang, J. S. Photovoltaic Switching Mechanism in Lateral Structure Hybrid Perovskite Solar Cells. Adv. Energ. Mater. 2015, 5, 1500615. (36) Tress, W.; Marinove, N.; Inganäs, O.; Nazeeruddin, M. K.; Zakeeruddin, S. M.; Graetzel, M. Predicting the Open-Circuit Voltage of CH3NH3PbI3 Perovskite Solar Cells Using Electroluminescence and Photovoltaic Quantum Efficiency Spectra: the Role of Radiative and Non-Radiative Recombination. Adv. Energ. Mater. 2014, 5, 1400812.

AUTHOR INFORMATION Corresponding Authors Email: [email protected] Phone: 86-531-88369769 Email: [email protected] Phone: 86-531-86057921 Email: [email protected] phone: 86-531-88366853 Notes The authors declare no competing financial interests.

ACS Paragon Plus Environment

18