Predictions for p-Type CH3NH3PbI3 Perovskites - The Journal of

Subscriber access provided by NEW YORK UNIV

Article 3

3

3

Predictions for p-type CHNHPbI Perovskites Tingting Shi, Wan-Jian Yin, and Yanfa Yan J. Phys. Chem. C, Just Accepted Manuscript • DOI: 10.1021/jp508328u • Publication Date (Web): 17 Oct 2014 Downloaded from http://pubs.acs.org on October 18, 2014

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 C 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 19

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

Predictions for p-Type CH3NH3PbI3 Perovskites Tingting Shi, Wan-Jian Yin, and Yanfa Yan* Department of Physics & Astronomy, and Center for Photovoltaics Innovation and Commercialization, The University of Toledo, Toledo, OH 43606, USA *

Corresponding Author: 2801 West Bancroft Street, Toledo, Ohio 43606, USA; email: [email protected]; Tel: (1) 419 530 3918

ABSTRACT

Approaches for doping organic-inorganic CH3NH3PbI3 halide perovskite solar cell materials are investigated by density-functional theory calculations of the extrinsic doping properties of CH3NH3PbI3. Our results reveal that p-type CH3NH3PbI3 halide perovskites can be realized by incorporation of some Group-IA, -IB, or -VIA elements such as Na, K, Rb, Cu, and O at I-rich growth conditions. We further show that n-type CH3NH3PbI3 halide perovskites are more difficult to realize due to the formation for neutral defects or compensation from intrinsic point defects. Our results suggest that non-equilibrium growth conditions and/or processes may be required to produce n-type CH3NH3PbI3 halide perovskites.

KEYWORDS: perovskite; external doping, density functional theory, p-type, n-type

ACS Paragon Plus Environment

1


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 19

INTRODUCTION

Organic-inorganic methylammounium triiodideplumbate CH3NH3PbI3 (MAPbI3)-based halide perovskites have recently emerged as promising solar photovoltaic absorbers.1-14 MAPbI3 perovskite exhibits extremely high optical absorption coefficient and long electron-hole diffusion lengths.10,11,15 It has clearly demonstrated its potential for producing high-efficiency and low-cost thin-film solar cells. The record efficiency of small area MAPbI3-based thin-film solar cells has increased to 17.9%13 from less than 4%1 in four years. However, the current MAPbI3 perovskite thin-film solar cell technology faces challenges for large scale commercialization, primarily due to the use of expensive and unstable hole transport material (HTM)2,2’,7,7’-tetrakis-(N,N-di-p-methoxyphenylamine)9,9’-spirobifluorene (spiroOMeTAD)6,7. MAPbI3 solar cells using non-spiro-OMeTAD HTM layers such as CuSCN16,17, NiO16, and CuI18 or no HTM layers19-22 have exhibited poorer performance than the cells using spiro-OMeTAD HTM layers. An alternative possible approach to achieve low-cost and stable hole transport layers is to dope MAPbI3 p-type. Furthermore, if MAPbI3 can be doped both ptype and n-type, p-n junction based solar cell structures, which have been the case for most inorganic solar cells, may be realized. This could provide new opportunities for fabricating MAPbI3 thin-film solar cells with improved efficiency and stability as compared to current MAPbI3–based thin-film solar cells. In this paper, we present approaches for doping p-type and n-type MAPbI3 revealed by density-functional theory (DFT) investigations of extrinsic doping properties of MAPbI3. Our calculated ionization energies suggest a list of extrinsic dopants that could be shallow donors and acceptors. Group-IA and -IB elements such as Na, K, Rb, and Cu can be both shallow donors


2

Page 3 of 19

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


(when occupy interstitial sites) and shallow acceptors (when occupy Pb site). Group-VIA, elements such as O and S are shallow acceptors when they occupy I sites. Group-IIA elements such as Sr and Ba are shallow donors when they occupy MA sites, but neutral defects when they occupy Pb sites. Group-IIB and -IIIA elements are deep donors. Formation energy calculations reveal that MAPbI3 halide perovskite may be doped more easily p-type than n-type by extrinsic dopants. Group-IA, -IB, and -VIA elements can dope MAPbI3 p-type at I-rich/Pb-poor growth conditions. However, group-II elements cannot dope good n-type CH3NH3PbI3 halide perovskite due to the formation for neutral defects and compensation from intrinsic point defects. Our results suggest that one may need to avoid thermal equilibrium growth conditions or processes to realize n-type MAPbI3 via extrinsic doping.

COMPUTATIONAL DETAILS The defect calculations were based on a (4×4×4) host supercell with the Γ point. The supercell contains 768 atoms. With this large supercell size, both conduction band maximum (VBM) and conduction band minimum (CBM) are folded to the Γ point. Our test calculations indicate that the use of (4×4×4) host supercell with the Γ point provides reliable results. The DFT calculations were performed using VASP code23 with the standard frozen-core projector augmented-wave (PAW) method. The cut-off energy for basis functions was 400 eV. The general gradient approximation (GGA) was used for exchange-correlation.24.25 Atomic positions are relaxed until all the forces on atoms are below 0.05 eV/Å. The effect of spin-orbital coupling (SOC) in MAPbI3 due to strong relativistic effect of Pb has been discussed in literature26-29. However, the band gap errors of using GGA and non-SOC are cancelled with each other in occurrence30. For


3


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 19

the cubic cell structure with a lattice constant of 6.39Å, the calculated band gap is 1.538 eV. Therefore, the GGA band gap is close to the experimental band gap without underestimation. Because the use of large supercell size of 768 atoms makes calculations with SOC not possible, SOC was not considered in our calculations. It is noted that the main characteristics of the conduction and valence band of MAPbI3 produced by SOC and non-SOC DFT calculations do not change significantly. We have also calculated the electronic density of states of MAPbI3 using non-SOC GGA calculations and SOC plus hybrid functional calculations (Fig. S1), no significant differences on the valence and conduction bands have been found. Because the defect levels, especially the shallow acceptor/donor levels, are mostly derived from either valence or conduction bands, it is reasonable to expect that the calculated shallow energy levels using nonSOC should not exhibit significant errors. The errors for deep levels could be large, but these defects are not important for doping. In formation energy calculations, the equilibrium growth condition of MAPbI3 should be considered so that the chemical potentials of MA (µMA), Pb (µPb), and I (µI) satisfy the relation of µMA + µPb + 3µI = ∆H(MAPbI3) = -5.26 eV . To exclude the possible secondary phases of PbI2 and MAI (rock-salt phase), the chemical potentials of MA, Pb, and I (µMA, µPb, and µI) are constrained, which are related to growth conditions. In our defect calculations, we have considered two chemical potential combinations that are related to two representative growth conditions: I-rich/Pb-poor (µMA= −2.87 eV, µPb= −2.39 eV, µI= 0 eV) and I-poor/Pb-rich (µMA= −1.68 eV, µPb= 0 eV, µI= −1.19 eV). The details of these chemical points can be found in our previous publication.31 The calculation of transition energies and formation energies of defects followed the methods described in literature.32,33 The chemical potentials of considered dopant elements must satisfy


4

Page 5 of 19

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


additional constrains to exclude the formation of dopant-related secondary phases. For example, for doping using group-IA elements such as Na, K, and Rb, we exclude the possible secondary phases of NaI, KI, and RbI. Therefore, the following constrains must also be satisfied: µNa + µI < ∆H(NaI) = -2.59 eV, µK + µI < ∆H(KI) = -3.01 eV, and µRb + µI < ∆H(RbI) = -3.03 eV. Similar constrains are considered for excluding the formation of other possible dopant-related secondary phases, for examples, CuI, SrI2, BaI2, SbI3, BiI3, PbO, PbS, PbSe, and PbTe.

RESULTS AND DISCUSSIONS Because of the use of large supercell, the calculations of defects are very time demanding. In this paper, we have only considered the dopants that may introduce singly charged defect states, because defects with multiple charges usually produce deep levels. We have considered groupIA and -IB elements including K, Na, Rb, and Cu on interstitial sites (Nai, Ki, Rbi, and Cui) as donors and on Pb sites (NaPb, KPb, RbPb, and CuPb) as acceptors. We have considered group-IIA and -IIB elements including Sr, Ba, Zn, and Cd on MA site (SrMA, BaMA, ZnMA, and CdMA) as donors and on Pb site (SrPb, BaPb, ZnPb, and CdPb) as neutral defects. We have considered groupIIIA elements, Al, Ga, and In, and group VA elements, Sb and Bi, on Pb sites (AlPb, GaPb, InPb, SbPb, and BiPb) as potential donors. We have considered O, S, Se, and Te on I sites (OI, SI, SeI, and TeI) as potential acceptors.


5


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 19

Fig. 1. Calculated transition energy levels of identified shallow donors (a) and shallow acceptors (b). The incorporation of most shallow donor defects such as SrMA, BaMA, Cui, Nai, Ki favors Ipoor/Pb-rich growth conditions. Whereas the incorporation of some shallow acceptor defects such as NaPb, KPb, RbPb, CsPb, CuPb favors the I-rich/Pb-poor growth conditions, others shallow acceptor defects such as OI, SI, and SeI favors I-poor/Pb-rich growth conditions. (see details in discussions of formation energy calculations below)

The calculated transition energy levels of identified shallow donors are shown in Figure 1(a). The transition energy levels are referenced to the CBM of CH3NH3PbI3. It shows that interstitial group-IA and -IB elements, Nai, Ki, Rbi, and Cui, are shallow donors. Group-IIA elements such as Sr and Ba at MA sites are also shallow donors. They are neutral defects when they occupy Pb sites. Our calculations revealed that ZnMA, CdMA, AlPb, GaPb, and InPb are deep donors. Therefore, these dopants will not be considered further in this paper. BiPb and SbPb are shallow donors with transition energy levels of -0.17 eV and -0.19 eV, respectively. The calculated transition energy levels of the identified shallow acceptors are shown in Figure 1(b). The transition energy levels are referenced to the VBM of CH3NH3PbI3. The calculated transition energy levels of NaPb, KPb, RbPb, and CuPb are -0.026 eV, 0.014 eV, 0.020 eV, and 0.084 eV, respectively. The calculated transition energy levels for OI, SI, SeI, and TeI are


6

Page 7 of 19

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


-0.076 eV, 0.021eV, 0.070eV, and 0.128eV, respectively. The negative transition energies for NaPb and OI mean that their levels are below the VBM, indicating spontaneous ionizations.

Fig. 2. Calculated formations energies of defects formed by group-IA and -IB elements as functions as the Fermi levels at (a) I-rich/Pb-poor and (b) I-poor/Pb-rich conditions. The intrinsic defects with the lowest formation energies are shown as the dashed line. The vertical dotted lines indicate the Fermi level pinning. The Fermi levels are referenced to the VBM.

While the calculated transition energy levels show that many of the considered dopants produce shallow donors and acceptors, the extrinsic doping properties of MAPbI3 rely on the positions of Fermi levels, which are determined by the formation of all defects including intrinsic and extrinsic defects. To evaluate the extrinsic doping properties of MAPbI3, we have calculated


7


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 19

the formation energies of the above-preselected dopants with shallow transition energies under two representative growth conditions: I-rich/Pb-poor and I-poor/Pb-rich. Figures 2(a) and 2(b) show the calculated formation energies as functions of Fermi levels for group-IA and -IB dopants at I-rich/Pb-poor and I-poor/Pb-rich growth conditions, respectively. The chemical potentials for Na, K, Rb, and Cu are constrained to avoid the formation of secondary phases of NaI, KI, RbI, and CuI. The calculated formation enthalpies are -2.59 eV, 3.01eV, -3.03eV and -0.33 eV for NaI, KI, RbI, and CuI, respectively. The dashed line shows the intrinsic defects with the lowest formation energies. It is seen that at I-rich/Pb-poor condition (Fig. 2(a)), the formation energies of acceptors of NaPb, KPb, RbPb, and CuPb are much lower than that of the donors, Nai, Ki, Rbi, and Cui. Therefore, for doping with Na, K, Rb, and Cu, the dopants will mostly occupy Pb sites and dope CH3NH3PbI3 p-type. The compensation from intrinsic donor defect, MAi, is very weak. For Na and K doping, the Fermi levels are pinned below the VBM, indicating degenerate p-type doping. For Cu doping, the Fermi level is pinned by the CuPb (0/-1) transition, which is about 0.09 eV above the VBM. For Rb doping, the Fermi level is pinned at about 0.06 eV above the VBM by RbPb and MAi. At I-poor/Pb-rich growth condition (Fig. 2(b)), the formation energies of donor defects are still higher than that of the intrinsic donor defects (MAi and MAI). Therefore, the compensations are between intrinsic donor defects and the extrinsic acceptor defects. For Na, K, and Rb doping, the Fermi levels are pinned at 1.02eV, 1.26eV, and 1.31 eV by NaPb, KPb, RbPb and MAi, respectively. For Cu doping, the Fermi level is pinned by the intrinsic defects, MAi and VPb. Our results reveal that doping using group-IA and -IB elements would not lead to better n-type doing than the intrinsic defects at Ipoor/Pb-rich growth condition. However, they can produce good p-type MAPbI3 at I-rich/Pbpoor conditions.


8

Page 9 of 19

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


Fig. 3. The calculated formation energies as functions of Fermi levels for group-IIA at Irich/Pb-poor (a) and I-poor/Pb-rich (b), showing that the formation energies of SrMA and BaMA are generally higher than that of SrPb and BaPb, and intrinsic defects VPb (Pb vacancy) and MAi.

Figure 3(a) and 3(b) show the calculated formation energies as functions of Fermi levels for group-IIA dopants at I-rich/Pb-poor and I-poor/Pb-rich conditions, respectively. It is seen that the formation energies of SrMA and BaMA are in general higher than that of SrPb and BaPb, and intrinsic defects VPb (Pb vacancy) and MAi. This may be due to a couple of reasons. It is known that the fully-occupied s orbital of Pb2+ has strong antibonding coupling with I p orbital. The s-p antibonding coupling is energetically unfavorable.15,31,34,35 When a Pb is substituted by a Sr2+ or Ba2+ that does not have fully occupied s orbital, the energetically unfavorable s-p antibonding coupling is eliminated, leading to energetically favorable substitutions. Another possible reason is that Sr and Ba are isovalent to Pb. While SrMA and BaMA introduce electrons to the conduction


9


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 10 of 19

band, SrPb and BaPb do not. Furthermore, SrPb and BaPb may introduce less lattice strain than SrMA and BaMA due to less size mismatch. Therefore group-IIA elements are not expected to produce better n-type MAPbI3 than intrinsic defects though these dopants can produce very shallow donor levels.

Fig. 4. The calculated formation energies as functions of Fermi levels for Sb and Bi at (a) Irich/Pb-poor and (b) I-poor/Pb-rich.

The doping using Sb and Bi at I-rich/Pb-poor condition is strongly compensated by the formation of VPb as shown in Fig. 4(a). The Fermi levels are pinned at 0.16eV and 0.19 eV above the VBM, respectively. Therefore, Sb and Bi doping at I-rich/Pb-poor conditions cannot lead to n-type MAPbI3. At I-poor/Pb-rich condition, the Fermi level is pinned by the intrinsic defects,


10

Page 11 of 19

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


MAi and VPb as shown in Fig. 4(b). Therefore, Sb and Bi doping is not expected to produce better n-type MAPbI3 than the intrinsic n-type under thermal equilibrium growth conditions.

Fig. 5. Calculated formations energies of defects formed by group-VI elements as functions as the Fermi levels at (a) I-rich/Pb-poor and (b) I-poor/Pb-rich.

Figures 5(a) and 5(b) reveal the calculated formation energies as functions of Fermi levels for group-VIA elements on I sites at I-rich/Pb-poor and I-poor/Pb-rich conditions, respectively. The chemical potentials for O, S, Se, and Te are constrained to avoid the formation of secondary phases of PbO, PbS, PbSe, and PbTe. The calculated formation enthalpies are -2.96 eV, -1.16 eV, -1.25eV and -0.96eV for PbO, PbS, PbSe, and PbTe, respectively. The dashed lines show the intrinsic defects with the lowest formation energies. At I-rich/Pb-poor growth condition (Fig. 5(a)), the doping of OI is pinned by MAi at the VBM. An interstitial O atom binds to two H


11


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 19

atoms of a MA molecule. Like O in Si, O interstitials in MAPbI3 do not produce any gap states and therefore are neutral defects. The results suggest that doping with O should lead to better ptype MAPbI3 than the doping of intrinsic defects at I-rich/Pb-poor conditions. However, for S, Se, and Te doping, the formation energies of SI, SeI, and TeI are much higher than the formation energy of intrinsic acceptor, VPb. Therefore, the p-type conductivity will be determined by the intrinsic defects. At I-poor/Pb-rich condition, the doping is strongly compensated by the formation of intrinsic point defects. Therefore, doping using group-VIA elements leads to p-type MAPbI3 at I-rich/Pb-poor growth condition, but n-type at I-poor/Pb-rich condition.

Fig. 6. Calculated total DOS and partial DOS for acceptors of OI, SI, SeI, and TeI. The DOS of the acceptors are enlarged by 500 times.


12

Page 13 of 19

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


Our calculated total density of states (DOS) and partial DOS (Fig. 6) for group-VIA acceptors of OI, SI, SeI, and TeI support the above conclusion that O should lead to better p-type type MAPbI3 than other group-VIA elements. It is seen clearly that the O p state is very delocalized with strong coupling to the valence band of MAPbI3. However, the p states of S, Se, and Te show clear narrow peaks, indicating strong localization. The trend is consistent with the trend of the energy position of the atomic p-orbitals of the O, S, Se, and Te.

4. CONCLUSION We have studied the doping properties of MAPbI3 perovskite with extrinsic dopants including group-IA, -IB, -IIA, -IIB, -IIA, -VA, and –VIA elements. We found that show that MAPbI3 perovskite may be doped more easily p-type than n-type by extrinsic dopants. Our results suggest that good p-type MAPbI3 may be produced by doping with external elements including Na, K, Rb, Cu and O at I-rich/Pb-poor growth conditions. Group-IIA elements such as Sr and Ba and group-VA elements such as Sb and Bi can produce shallow donor levels, but they cannot lead to good n-type MAPbI3 due to the formation for neutral defects and compensation from intrinsic point defects. Our results imply that non-equilibrium growth conditions may be needed to dope MAPbI3 for good n-type conductivities.

ACKNOWLEDGMENT This research used the resources of the Ohio Supercomputer Center and the National Energy Research Scientific Computing Center, which is supported by the Office of Science of the U.S.


13


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 19

Department of Energy under Contract No. DE-AC02-05CH11231. Y.Y. acknowledges the support of the Ohio Research Scholar Program.

SUPPORTING INFORMATION: Additional calculations and density of states. This information is available free of charge via the Internet at http://pubs.acs.org.

REFERENCES (1) Kojima, A.; Teshima, K.; Shirai, Y.; Miyasaka, T. Organometal Halide Perovskites as Visible-Light Sensitizers for Photovoltaic Cells. J. Amer. Chem. Soc. 2009, 131, 60506051. (2) Im, J. H.; Lee, C. R.; Lee, J. W.; Park, S. W.; Park, N.-G. Efficient Perovskite QuantumDot-Sensitized Solar Cell. Nanoscale 2011, 3, 4088-4093. (3) Kim, H.-S.; Lee, C.-R.; Im, J. H.; Lee, K. B.; Moehl, T.; Marchioro, A.; Moon, S. J .; Humphry-Baker, R.; Yum, J. H.; Moser, J. E.; et al. Lead Iodide Perovskite Sensitized All-Solid-State Submicron Thin Film Mesoscopic Solar Cell with Efficiency Exceeding 9%. Sci. Rep. 2012, 2, 591. (4) Chung, I.; Lee, B.; He, J. Q.; Chang, R. P. H., Kanatzidis, M. G. All-Solid-State DyeSensitized Solar Cells with High Efficiency. Nature 2012, 485, 486-489. (5) Lee, M. M.; Teuscher, J.; Miyasaka, T.; Murakami, T. N.; Snaith, H. J. Efficient Hybrid Solar Cells Based on Meso-Superstructured Organometal Halide Perovskites. Science 2012, 338, 643-647.


14

Page 15 of 19

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


(6) Burschka, J.; Pellet, N.; Moon, S. J.; Humphry-Baker, R.; Gao, P.; Nazeeruddin, M. K.; Gratzel, M. Sequential Deposition as a Route to High-Performance PerovskiteSensitized Solar Cells. Nature 2013, 499, 316-319. (7) Liu, M. Z.; Johnston, M. B.; Snaith, H. J. Efficient Planar Heterojunction Perovskite Solar Cells by Vapour Deposition. Nature 2013, 501, 395-398. (8) Noh, J. H.; Im, S. H.; Heo, J. H.; Mandal, T. N.; Seok, S. I. Chemical Management for Colorful, Efficient, and Stable Inorganic–Organic Hybrid Nanostructured Solar Cells. Nano Letters 2013, 13, 1764-1769. (9) Park, N. G. Organometal Perovskite Light Absorbers Toward a 20% Efficiency LowCost Solid-State Mesoscopic Solar Cell. J. Phys. Chem. Lett. 2013, 4, 2423-2429. (10) Xing, G. C.; Mathews, N.; Sun, S. Y.; Lim, S. S.; Lam, Y. M.; Gratzel, M.; Mhaisalkar, S.; Sum, T. C. Long-Range Balanced Electron- and Hole-Transport Lengths in OrganicInorganic CH3NH3PbI3. Science 2013, 342, 344-347. (11) 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, 341-344. (12) Chen, Q.; Zhou, H.; Hong, Z.; Luo, S.; Duan, H.-S.; Wang, H.-H.; Liu, Y.; Li, G.; Yang, Y. Planar Heterojunction Perovskite Solar Cells via Vapor-Assisted Solution Process. J. Am. Chem. Soc. 2014, 136, 622-625. (13) http://www.nrel.gov/ncpv/images/efficiency_chart.jpg (accessed on October 13, 2014)


15


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 19

(14) 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, doi:10.1038/nmat4014. (15) Yin, W.-J.; Shi, T.; Yan, Y. Unique Properties of Halide Perovskite Solar Cell Materials. Adv. Mater. 2014, 26, 4653-4658. (16) Subbiah, A. S.; Halder, A.; Ghosh, S.; Mahuli, N.; Hodes, G.; Sarkar, S.K. Inorganic Hole Conducting Layers for Perovskite-Based Solar Cells. J. Phys. Chem. Lett. 2014, 5, 1748-1753. (17) Qin, P.; Tanaka, S.; Ito, S.; Tetrault, N.; Manabe, K.; Nishino, H.; Nazeeruddin, M.K.; Gratzel, M. Inorganic Hole Conductor-Based Lead Halide Perovskite Solar Cells with 12.4% Conversion Efficiency. Nat. Comm. 2014, 5, 3834. (18) Christians, J.A.; Fung, R.C.M.; Kamat, P.V. An Inorganic Hole Conductor for OrganoLead Halide Perovskite Solar Cells. Improved Hole Conductivity with Copper Iodide. J. Am. Chem Soc. 2014, 136, 758-764. (19) Laban, W. A.; Etgar L. Depleted Hole Conductor-Free Lead Halide Iodide Heterojunction Solar Cells. Energy Environ. Sci. 2013, 6, 3249-3253. (20) Aharon, S.; Gamliel, S.; Cohen, B. El; Etgar, L. Depletion Region Effect of Highly Efficient Hole Conductor Free CH3NH3PbI3 Perovskite Solar Cells. Phys. Chem. Chem. Phys. 2014, 16, 10512–10518. (21) Shi, J.; Dong, J.; Lv, S.; Xu, Y.; Zhu, L.; Xiao, J.; Xu, X.; Wu, H.; Li, D.; Luo, Y.; et al. Hole-Conductor-Free Perovskite Organic Lead Iodide Heterojunction Thin-Film Solar Cells: High Efficiency and Junction Property. Appl. Phys. Lett. 2014, 104, 063901.


16

Page 17 of 19

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


(22) Mei, A.; Li, X.; Liu, L.; Ku, Z.; Liu, T.; Rong Y.; Xu, M.; Hu, M.; Chen, J.; Yang, Y.; et al. A Hole-Conductor–Free, Fully Printable Mesoscopic Perovskite Solar Cell with High Stability. Science 2014, 345, 295-298. (23) Kresse G.; Furthmuller, J. Efficient Iterative Schemes for ab initio Total-Energy Calculations Using a Plane-Wave Basis Set. Phy. Rev. B 1996, 54, 11169-11186. (24) Blochl, P. E. Projector Augmented-Wave Method. Phys. Rev. B 1994, 50, 17953-17979. (25) Kresse, G.; Joubert, D. From Ultrasoft Pseudopotentials to the Projector AugmentedWave Method. Phys. Rev. B 1999, 59, 1758-1775. (26) Even, J.; Pedesseau, L.; Dupertuis, M.-A.; Jancu, J.-M.; Katan, C. Electronic Model for Self-Assembled Hybrid Organic/Perovskite Semiconductors: Reverse Band Edge Electronic States Ordering and Spin-Orbit Coupling. Phys. Rev. B 2012, 86, 205301205304. (27) Even, J.; Pedesseau, L.; Jancu, J.-M.; Katan, C. Importance of Spin–Orbit Coupling in Hybrid Organic/Inorganic Perovskites for Photovoltaic Applications. J. Phys. Chem. Lett. 2013, 4, 2999-3005. (28) Umari, P.; Mosconi, E.; De Angelis, F. Relativistic GW Calculations on CH3NH3PbI3 and CH3NH3SnI3 Perovskites for Solar Cell Applications. Sci. Rep. 2014, 4, DOI: 10.1038/srep04467. (29) Menéndez-Proupin, E.; Palacios, P.; Wahnón, P.; Conesa, J. C., Self-Consistent Relativistic Band Structure of the CH3NH3PbI3 Perovskite. Phys. Rev. B 2014, 90, 045207.


17


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 19

(30) Mosconi, E.; Amat, A.; Nazeeruddin, M. K.; Gratzel, M.; De Angelis, F. First-Principles Modeling of Mixed Halide Organometal Perovskites for Photovoltaic Applications. J. Phy. Chem. C 2013, 117, 13902-13913. (31) Yi, W.-J.; Shi, T.; Yan, Y., Unusual Defect Physics in CH3NH3PbI3 Perovskite Solar Cell Absorber. Appl. Phys. Lett. 2014, 104, 063903. (32) Wei, S.-H. Overcoming the Doping Bottleneck in Semiconductors. Computational Mater. Sci. 2004, 30, 337-348. (33) Yan, Y.; Wei, S.-H. Doping Asymmetry in Wide-Bandgap Semiconductors: Origins and Solutions. Phys. Stat. Sol. (b) 2008, 245, 641-652. (34) Brivo, F.; Walker, A. B.; Walsh, A. Structural and Electronic Properties of Hybrid Perovskites for High-Efficiency Thin-Film Photovoltaics from First-Principles. APL Materials 2013, 1, 042111. (35) Wang, Y.; Gould, T.; Dobson, J.; Zhang, H.; Yan, H.; Yao, X.; Zhao, H. Phys. Density Functional Theory Analysis of Structural and Electronic Properties of Orthorhombic Perovskite CH3NH3PbI3. Chem. Chem. Phys. 2014, 16, 1424-1429.


18

Page 19 of 19

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


TOC GRAPHICS


19

Predictions for p-Type CH3NH3PbI3 Perovskites - The Journal of

Recommend Documents