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Hybrid perovskites are a series of solution-processable materials for photovoltaic devices. To achieve better performance and stability, interface passivation is an effective method. So far, the most commonly used passivators are organic amines, which can tailor perovskite into a lower-dimensional structure (Ruddlesden-Popper perovskite). Here, we select a biimizole (BIM) molecule as a new passivator for perovskite. The BIM based single layer perovskite has a more rigid structure. And multi-layered structure cannot be formed due to large lattice mismatching and structural rigidity. By inducing the excess MAI (methanaminium iodide) into the lattice, the layered structure is maintained, and half of the BIM molecules are replaced by MA (methylamine). The mixed layered structure is distorted, because of the difference in size between two kinds of cations. We then investigate passivation effect of BIM on perovskite solar cells. By carefully controlling the feed ratio in precursor solutions, we fabricate solar cells with different passivation structures. We find that the introduction of BIM can cause V octo increase generally, indicating that MAPbI 3is well passivated. The peak at 7.5° and 15° in X-ray diffraction pattern are corresponding to a two-dimensional (2D) phase with a shorter layer distance. There are no peaks at lower degrees, so that no multi-layered structure is formed in the film either. We suppose that a dual-phase 2D-3D (where 3D represents three-dimensional) structure is formed in the perovskite film. To explain the passivation effect of the two 2D structures, we investigate their lattice matching towards MAPbI 3. The distorted 2D structure is well matched with (110) face of o-MAPbI 3, and the mismatching rate is lower 1% in the two directions. On the other hand, the BIM based 2D structure cannot well match with (–110) face of o-MAPbI 3, nor with (001) face of c-MAPbI 3. We also consider that the less rigidity of distorted structure contributes to better passivation. As a result, we achieve a BIM passivated perovskite solar cell with a power conversion efficiency up to 14%. This work paves a new way to the interface engineering of perovskite solar cells.
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Keywords:
- perovskite/
- solar cell/
- two-dimensional structure
[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] -
组成 投料摩尔比(BIMI2:MAI:PbI2) BIM0.2MA0.8PbI3.2(BIMPbI4:MAPbI3= 0.2 : 0.8) 0.2 : 0.8 : 1 BIM0.1MA0.9PbI3.1(BIMPbI4:MAPbI3= 0.1 : 0.9) 0.1 : 0.9 : 1 BIM0.2MAPbI3.4(MA2BIMPb2I8:MAPbI3= 0.1 : 0.8) 0.2 : 1 : 1 BIM0.1MAPbI3.2(MA2BIMPb2I8:MAPbI3= 0.05 : 0.9) 0.1 : 1 : 1 组成 开路电压Voc/V 短路电流Jsc/ mA·cm–2 填充因子FF/% 转换效率η/% BIM0.2MA0.8PbI3.2 1.08 8.90 45.8 4.41 BIM0.1MA0.9PbI3.1 1.01 15.90 67.6 10.89 BIM0.2MAPbI3.4 1.07 14.72 66.1 10.46 BIM0.1MAPbI3.2 1.08 17.25 75.12 14.06 二维晶面 晶格间距/Å (横向, 纵向) 钝化晶面 晶格间距/Å (横向, 纵向) 失配率 (横向, 纵向) MA2BIMPb2I8(002) 6.25, 6.38 正交MAPbI3(110) 6.26, 6.32 0.16%, 0.95% BIMPbI4(002) 6.45, 6.45 正交MAPbI3(–110) 6.32, 6.26 2.06%, 3.04% 立方MAPbI3(001) 6.31, 6.31 2.22%, 2.22% 参数 取值 Compound MA2BIMPb2I8 Formula weight 1628.6 Temperature/K 249.99 Crystal system orthorhombic Space group Pmna a/Å 12.5016(7) b/Å 6.3876(4) c/Å 18.8380(12) α/(°) 90.00 β/(°) 90.00 γ/(°) 90.00 Volume/Å3 1504.31(16) Z 4 ρcalc/g·cm–3 5.581 μ/mm–1 46.218 F(000) 2086.0 Radiation Mo Kα(λ= 0.71073) 2θrange for data collection/(°) 6.38 to 52.72 Index ranges –15 ≤h≤ 15, –7 ≤k≤ 7, –23 ≤l≤ 23 Reflections collected 12046 Independent reflections 1608 [Rint = 0.0780, Rsigma = 0.0442] Data/restraints/parameters 1608/0/64 Goodness-of-fit onF2 1.039 FinalRindexes [I≥ 2σ(I)] R1 = 0.0485,wR2 = 0.1043 FinalRindexes [all data] R1 = 0.0767,wR2 = 0.1171 Largest diff. peak/hole/e·Å–3 3.45/–2.09 组成 类型/层数 Voc/V Jsc/mA·cm-2 FF/% η/% (PEA)2(MA)3Pb4I13 RP (4) 1.16 14.7 77 12.1[22] (BA)2MA3Pb4I13 RP (4) 0.99 18.43 75.2 13.8[16] (BEA)2MA3Pb4I13 RP (4) 1.01 20.63 78.0 16.1[16] (BYA)2MA3Pb4I13 RP (4) 1.01 19.53 76.4 15.1[16] (PEA)2MA3Pb4I13 RP (4) 1.14 18.78 62 13.41[23] BA2MA4Pb5I16 RP (5) 0.99 11.67 72.1 8.32[24] PA2MA4Pb5I16 RP (5) 1.13 18.89 49 10.41[14] (BA)2(MA)3Pb4I13 RP (4) 1.06 16.6 70.9 12.5[25] 3AMP(MA)3Pb4I13 DJ (4) 1.06 10.17 67.6 7.33[26] 3AMP(MA0.75FA0.25)3Pb4I13 DJ (4) 1.09 13.69 81.04 12.04[27] (PDMA)FA2Pb3I10 DJ (3) 0.84 11.48 72.1 7.11[28] BzDA(Cs0.05MA0.15FA0.8)9Pb10(I0.93Br0.07)31 DJ (10) 1.02 21.5 71 15.6[29] BIM0.2MAPbI3.4 4 1.07 14.72 66.1 10.46 BIM0.1MAPbI3.2 9 1.08 17.25 75.1 14.06 -
[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]
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