鈣鈦礦太陽能電池效率與鈣鈦礦結構材料層的均勻性、緻密性、覆蓋性以及厚度有關。鈣鈦礦層之製備主要有兩大製程方式，分別為單步驟液相製程法與兩步驟液相製程法。單步驟法是將PbX2 (X = Cl, Br, I) 與CH3NH3X以特定比例溶於特定溶劑中，經由旋轉塗佈法，將鈣鈦礦前驅物沉積至基材上，並藉由退火處理得到鈣鈦礦薄膜。單步驟法雖然能得到連續、緻密性佳的鈣鈦礦薄膜，但對於鈣鈦礦形貌的掌控並不容易，導致元件效率變異性大。而兩步驟法則是藉由旋轉塗佈法，先將PbI2-沉積至基材上，接著第二步將PbI2與CH3NH3I (MAI)反應得到鈣鈦礦薄膜。比起單步法更容易掌控鈣鈦礦的形貌，進而提高元件效率的再現性。但兩步法的缺點在於PbI2與MAI反應後會有體積膨脹效應，PbI2與MAI反應後，會先在表面形成緻密鈣鈦礦層(compact perovskite layer)，材料密度會由PbI2的6.16 g/cm3降至CH3NH3PbI3的4.29g/cm3，導致體積膨脹，此緻密層會阻擋後續MAI擴散至PbI2內部中，造成PbI2轉換成CH3NH3PbI3不完全，因此所形成的鈣鈦礦薄膜會有PbI2殘留的問題，影響元件效能表現。
在本研究中，選用溴摻雜鈣鈦礦材料(CH3NH3PbI3-xBrx)當作吸光層，並且將傳統兩步驟法做進一步改善，發展出混合溶劑浸泡法製備孔洞結構PbX2薄膜，藉由ether/toluene雙成分溶劑對PbX2薄膜造孔，由於具備孔洞性質，可解決傳統兩步法的體積膨脹問題，使反應後的鈣鈦礦薄膜達到低殘留的PbX2，並增加其吸光能力，進而提升元件效率。藉由掃描式電子顯微鏡 (Scanning Electron Microscope, SEM)、X光粉末繞射儀 (X-Ray Diffractometer, XRD)、紫外光/可見光吸收光譜儀(UV-Visible spectrophotometer, UV-Vis)、穩態螢光光譜儀 (Photo Luminescence spectroscopy, PL)、時間解析光激螢光光譜儀(Time-Resolved Photo Luminescence spectroscopy, TR-PL)等材料性質分析，可證實ether/toluene處理之PbX2薄膜，所製備出的鈣鈦礦薄膜結晶性佳、缺陷少、載子壽命較傳統兩步法的製程長。在入射光強度100 mW/cm2¬¬照射下，鈣鈦礦太陽能電池的平均效能指標為: 短路電流(Jsc) = 17.58 mA/cm2 , 開路電壓(Voc) = 1.01 V , 填充因子(Fill Factor , FF) = 0.69 , 轉換效率(Power Conversion Efficiency, PCE) = 12.32 %。相較於傳統兩步法之對照組平均效能指標為: Jsc = 14.88 mA/cm2 , Voc = 0.98 V , FF = 0.68 , PCE = 10.03 %，整體平均效率提升了2.29 %。由入射光子轉換效率量測系統 (Incident Photon Conversion Efficiency, IPCE) 的檢測結果可發現，ether/toluene處理之PbX2薄膜，其所形成的鈣鈦礦太陽能電池的光電轉換效率在可見光範圍(400~800 nm)有顯著提升，最高轉換效率可從原先的65 % 提升至75 %。透過製程參數的最適化，發現PbX2退火溫度由70℃ 提升至100℃ 會有最佳PbX2薄膜孔洞率，形成鈣鈦礦薄膜後會得到大顆粒且連續緻密的鈣鈦礦覆蓋層，因此能夠降低晶界間的缺陷，增加照光後載子的收集率。所獲得的冠軍電池效能指標為: Jsc = 19.26 mA/cm2 , Voc = 1.01V , FF = 0.68, PCE = 13.16 %。

Organo-lead halide perovskite solar cells (PSC) are one of the most promising photovoltaic devices because of their extraordinary power conversion efficiencies. It is known that the performances of perovskite solar cells depend heavily on the uniformity, surface coverage, and thickness of the perovskite active layer. Typically, solution processing of perovskite films in PSCs is carried out using one-step or two-step method. In the one-step method, the perovskite films are directly deposited onto mesoporous metal oxide using a mixture of PbX2 (X = Cl, Br, I) and CH3NH3X in a polar solvent. However, it is difficult to control the morphology of the resulting perovskite layer in the one-step method, leading to a wide fluctuation in photovoltaic performances. In the two-step method, PbI2 is first deposited onto the mesoporous TiO2 scaffold layer. The CH3NH3I (MAI) solution is then introduced to the PbI2 layer to react and form the CH3NH3PbI3 layer. It is much easier to control the morphology of the perovskite layer with the two-step method than with the one-step method. But the main challenge for the two-step method is the volume expansion issue during the formation of the perovskite, leading to incomplete conversion of PbI2, which is detrimental to the photovoltaic performance.
In this work, we choose CH3NH3PbI3-xBrx-based perovskites as the active layer and further modify the traditional two-step method in order to address the volume expansion issue of the PbI2 precursor film. Here we develop a solvent soaking method to produce porous PbX2 layers. We use binary mixture organic solvent, diethyl ether and toluene (ether/toluene) to produce porous PbX2, enabling easier MAI solution infiltration into the entire pore space accessing rapidly the interior of the mesoporous PbX2 layer and thus more complete conversion of PbX2 to perovskite. From XRD, UV-Vis, PL, and TR-PL analyses, it is proved that the perovskite films derived from the ether/toluene treatment have better crystallinity, fewer defect states, and longer lifetime than the perovskite films derived from the traditional two-step method. As a result, the average power conversion efficiency was enhanced from 10.03% for the control device up to 12.32% for the ether/toluene treated device under AM 1.5G solar illumination of 100 mW cm-2. From the IPCE data, we found that the highest efficiency was boosted from 65% to 75% in the visible light region as a result of the high quality perovskite layer derived from the ether/toluene treated PbX2 films. Furthermore, by optimizing the processing condition, we found that the increase in the PbX2 annealing temperature from 70℃ up to 100℃ created the optimal fraction of voids in the PbX2 films, leading to larger grains and more dense perovskite capping layer, which can reduce the trap states in the perovskite films and enhance the light harvesting efficiency. The power conversion efficiency of the champion cell is up to 13.16%.

1.Perez, R. and M. Perez, A fundamental look at energy reserves for the planet. The IEA SHC Solar Update, 2009. 50(2).
2.Grätzel, M., Dye-sensitized solar cells. J. Photochem. Photobiol. C: Photochem. Rev., 2003. 4(2): p. 145-153.
3.Burschka, J., N. Pellet, S.-J. Moon, R. Humphry-Baker, P. Gao, M.K. Nazeeruddin, and M. Grätzel, Sequential deposition as a route to high-performance perovskite-sensitized solar cells. Nature, 2013. 499(7458): p. 316-319.
4.Kojima, A., K. Teshima, Y. Shirai, and T. Miyasaka, Organometal halide perovskites as visible-light sensitizers for photovoltaic cells. J. Am. Chem. Soc., 2009. 131(17): p. 6050-6051.
5.Jeon, N.J., H.G. Lee, Y.C. Kim, J. Seo, J.H. Noh, J. Lee, and S.I. Seok, o-Methoxy substituents in spiro-OMeTAD for efficient inorganic–organic hybrid perovskite solar cells. J. Am. Chem. Soc., 2014. 136(22): p. 7837-7840.
6.Xing, G., N. Mathews, S. Sun, S.S. Lim, Y.M. Lam, M. Grätzel, S. Mhaisalkar, and T.C. Sum, Long-range balanced electron-and hole-transport lengths in organic-inorganic CH3NH3PbI3. Science, 2013. 342(6156): p. 344-347.
7.http://www.nrel.gov/ncpv/images/efficiency_chart.jpg.
8.Mei, A., X. Li, L. Liu, Z. Ku, T. Liu, Y. Rong, M. Xu, M. Hu, J. Chen, and Y. Yang, A hole-conductor–free, fully printable mesoscopic perovskite solar cell with high stability. Science, 2014. 345(6194): p. 295-298.
9.Lee, M.M., J. Teuscher, T. Miyasaka, T.N. Murakami, and H.J. Snaith, Efficient hybrid solar cells based on meso-superstructured organometal halide perovskites. Science, 2012. 338(6107): p. 643-647.
10.Docampo, P., J.M. Ball, M. Darwich, G.E. Eperon, and H.J. Snaith, Efficient organometal trihalide perovskite planar-heterojunction solar cells on flexible polymer substrates. Nat. Commun., 2013. 4.
11.Ryu, S., J.H. Noh, N.J. Jeon, Y.C. Kim, W.S. Yang, J. Seo, and S.I. Seok, Voltage output of efficient perovskite solar cells with high open-circuit voltage and fill factor. Energy Environ. Sci., 2014. 7(8): p. 2614-2618.
12.Berhe, T.A., W.-N. Su, C.-H. Chen, C.-J. Pan, J.-H. Cheng, H.-M. Chen, M.-C. Tsai, L.-Y. Chen, A.A. Dubale, and B.-J. Hwang, Organometal halide perovskite solar cells: degradation and stability. Energy Environ. Sci., 2016. 9(2): p. 323-356.
13.Marchioro, A., J.C. Brauer, J. Teuscher, M. Grätzel, and J.-E. Moser. Photoinduced processes in lead iodide perovskite solid-state solar cells. in SPIE NanoScience+ Engineering. 2013. International Society for Optics and Photonics.
14.Zhao, Y. and K. Zhu, Organic–inorganic hybrid lead halide perovskites for optoelectronic and electronic applications. Chem. Soc. Rev., 2016. 45(3): p. 655-689.
15.Leijtens, T., B. Lauber, G.E. Eperon, S.D. Stranks, and H.J. Snaith, The importance of perovskite pore filling in organometal mixed halide sensitized TiO2-based solar cells. J. Phys. Chem. Lett., 2014. 5(7): p. 1096-1102.
16.Zhao, Y., A.M. Nardes, and K. Zhu, Solid-state mesostructured perovskite CH3NH3PbI3 solar cells: charge transport, recombination, and diffusion length. J. Phys. Chem. Lett., 2014. 5(3): p. 490-494.
17.Leijtens, T., G.E. Eperon, S. Pathak, A. Abate, M.M. Lee, and H.J. Snaith, Overcoming ultraviolet light instability of sensitized TiO2 with meso-superstructured organometal tri-halide perovskite solar cells. Nat. Commun., 2013. 4.
18.Im, J.-H., I.-H. Jang, N. Pellet, M. Grätzel, and N.-G. Park, Growth of CH3NH3PbI3 cuboids with controlled size for high-efficiency perovskite solar cells. Nat. Nanotechnol., 2014. 9(11): p. 927-932.
19.Yang, W.S., J.H. Noh, N.J. Jeon, Y.C. Kim, S. Ryu, J. Seo, and S.I. Seok, High-performance photovoltaic perovskite layers fabricated through intramolecular exchange. Science, 2015. 348(6240): p. 1234-1237.
20.Eperon, G.E., S.D. Stranks, C. Menelaou, M.B. Johnston, L.M. Herz, and H.J. Snaith, Formamidinium lead trihalide: a broadly tunable perovskite for efficient planar heterojunction solar cells. Energy Environ. Sci., 2014. 7(3): p. 982-988.
21.Eperon, G.E., V.M. Burlakov, P. Docampo, A. Goriely, and H.J. Snaith, Morphological control for high performance, solution‐processed planar heterojunction perovskite solar cells. Adv. Funct. Mater., 2014. 24(1): p. 151-157.
22.Ahn, N., D.-Y. Son, I.-H. Jang, S.M. Kang, M. Choi, and N.-G. Park, Highly reproducible perovskite solar cells with average efficiency of 18.3% and best efficiency of 19.7% fabricated via Lewis base adduct of lead (II) iodide. J. Am. Chem. Soc., 2015. 137(27): p. 8696-8699.
23.Jung, H.S. and N.G. Park, Perovskite solar cells: from materials to devices. small, 2015. 11(1): p. 10-25.
24.Im, J.-H., H.-S. Kim, and N.-G. Park, Morphology-photovoltaic property correlation in perovskite solar cells: One-step versus two-step deposition of CH3NH3PbI3. APL Mater., 2014. 2(8): p. 081510.
25.Kim, H.-S., S.H. Im, and N.-G. Park, Organolead halide perovskite: new horizons in solar cell research. J. Phys. Chem. C, 2014. 118(11): p. 5615-5625.
26.Jeon, N.J., J.H. Noh, W.S. Yang, Y.C. Kim, S. Ryu, J. Seo, and S.I. Seok, Compositional engineering of perovskite materials for high-performance solar cells. Nature, 2015. 517(7535): p. 476-480.
27.Zhang, W., M. Saliba, D.T. Moore, S.K. Pathak, M.T. Hörantner, T. Stergiopoulos, S.D. Stranks, G.E. Eperon, J.A. Alexander-Webber, and A. Abate, Ultrasmooth organic–inorganic perovskite thin-film formation and crystallization for efficient planar heterojunction solar cells. Nat. Commun., 2015. 6.
28.Jeon, N.J., J.H. Noh, Y.C. Kim, W.S. Yang, S. Ryu, and S.I. Seok, Solvent engineering for high-performance inorganic–organic hybrid perovskite solar cells. Nat. Mater., 2014. 13(9): p. 897-903.
29.Liu, D. and T.L. Kelly, Perovskite solar cells with a planar heterojunction structure prepared using room-temperature solution processing techniques. Nat. Photonics, 2014. 8(2): p. 133-138.
30.Zhou, Y., M. Yang, W. Wu, A.L. Vasiliev, K. Zhu, and N.P. Padture, Room-temperature crystallization of hybrid-perovskite thin films via solvent–solvent extraction for high-performance solar cells. J. Mater. Chem. A, 2015. 3(15): p. 8178-8184.
31.Stoumpos, C.C., C.D. Malliakas, and M.G. Kanatzidis, Semiconducting tin and lead iodide perovskites with organic cations: phase transitions, high mobilities, and near-infrared photoluminescent properties. Inorg. Chem., 2013. 52(15): p. 9019-9038.
32.Zhang, T., M. Yang, Y. Zhao, and K. Zhu, Controllable sequential deposition of planar CH3NH3PbI3 perovskite films via adjustable volume expansion. Nano Lett., 2015. 15(6): p. 3959-3963.
33.Harms, H.A., N. Tétreault, N. Pellet, M. Bensimon, and M. Grätzel, Mesoscopic photosystems for solar light harvesting and conversion: facile and reversible transformation of metal-halide perovskites. Faraday Discuss., 2014. 176: p. 251-269.
34.Conings, B., L. Baeten, C. De Dobbelaere, J. D'Haen, J. Manca, and H.G. Boyen, Perovskite‐based hybrid solar cells exceeding 10% efficiency with high reproducibility using a thin film sandwich approach. Adv. Mater., 2014. 26(13): p. 2041-2046.
35.Wu, Y., A. Islam, X. Yang, C. Qin, J. Liu, K. Zhang, W. Peng, and L. Han, Retarding the crystallization of PbI2 for highly reproducible planar-structured perovskite solar cells via sequential deposition. Energy Environ. Sci., 2014. 7(9): p. 2934-2938.
36.Zhang, H., J. Mao, H. He, D. Zhang, H.L. Zhu, F. Xie, K.S. Wong, M. Grätzel, and W.C. Choy, A Smooth CH3NH3PbI3 Film via a New Approach for Forming the PbI2 Nanostructure Together with Strategically High CH3NH3I Concentration for High Efficient Planar‐Heterojunction Solar Cells. Adv. Energy Mater., 2015. 5(23).
37.Liu, T., Q. Hu, J. Wu, K. Chen, L. Zhao, F. Liu, C. Wang, H. Lu, S. Jia, and T. Russell, Mesoporous PbI2 Scaffold for High‐Performance Planar Heterojunction Perovskite Solar Cells. Adv. Energy Mater., 2016. 6(3).
38.El-Henawey, M., R.S. Gebhardt, M. El-Tonsy, and S. Chaudhary, Organic solvent vapor treatment of lead iodide layers in the two-step sequential deposition of CH3NH3PbI3-based perovskite solar cells. J. Mater. Chem. A, 2016. 4(5): p. 1947-1952.
39.Li, F., C. Bao, W. Zhu, B. Lv, W. Tu, T. Yu, J. Yang, X. Zhou, Y. Wang, and X. Wang, Microstructure modulation of the CH3NH3PbI3 layer in perovskite solar cells by 2-propanol pre-wetting and annealing in a spray-assisted solution process. J. Mater. Chem. A, 2016. 4(29): p. 11372-11380.
40.Li, S., P. Zhang, H. Chen, Y. Wang, D. Liu, J. Wu, H. Sarvari, and Z.D. Chen, Mesoporous PbI2 assisted growth of large perovskite grains for efficient perovskite solar cells based on ZnO nanorods. J. Power Sources, 2017. 342: p. 990-997.
41.Zhang, J., G. Zhai, W. Gao, C. Zhang, Z. Shao, F. Mei, J. Zhang, Y. Yang, X. Liu, and B. Xu, Accelerated formation and improved performance of CH3NH3PbI3-based perovskite solar cells via solvent coordination and anti-solvent extraction. J. Mater. Chem. A, 2017. 5(8): p. 4190-4198.
42.Liang, K., D.B. Mitzi, and M.T. Prikas, Synthesis and characterization of organic− inorganic perovskite thin films prepared using a versatile two-step dipping technique. Chem. Mater., 1998. 10(1): p. 403-411.
43.Yang, S., Y.C. Zheng, Y. Hou, X. Chen, Y. Chen, Y. Wang, H. Zhao, and H.G. Yang, Formation mechanism of freestanding CH3NH3PbI3 functional crystals: in situ transformation vs dissolution–crystallization. Chem. Mater., 2014. 26(23): p. 6705-6710.
44.Fu, Y., F. Meng, M.B. Rowley, B.J. Thompson, M.J. Shearer, D. Ma, R.J. Hamers, J.C. Wright, and S. Jin, Solution growth of single crystal methylammonium lead halide perovskite nanostructures for optoelectronic and photovoltaic applications. J. Am. Chem. Soc., 2015. 137(17): p. 5810-5818.
45.Lanford, O.E. and S.J. Kiehl, The solubility of lead iodide in solutions of potassium iodide-complex lead iodide ions. J. Am. Chem. Soc., 1941. 63(3): p. 667-669.
46.Kawamura, Y., H. Mashiyama, and K. Hasebe, Structural study on cubic–tetragonal transition of CH3NH3PbI3. J. Phys. Soc. Jpn., 2002. 71(7): p. 1694-1697.
47.Smith, I.C., E.T. Hoke, D. Solis‐Ibarra, M.D. McGehee, and H.I. Karunadasa, A layered hybrid perovskite solar‐cell absorber with enhanced moisture stability. Angew. Chem., 2014. 126(42): p. 11414-11417.
48.Han, Y., S. Meyer, Y. Dkhissi, K. Weber, J.M. Pringle, U. Bach, L. Spiccia, and Y.-B. Cheng, Degradation observations of encapsulated planar CH3NH3PbI3 perovskite solar cells at high temperatures and humidity. J. Mater. Chem. A, 2015. 3(15): p. 8139-8147.
49.Habisreutinger, S.N., T. Leijtens, G.E. Eperon, S.D. Stranks, R.J. Nicholas, and H.J. Snaith, Carbon nanotube/polymer composites as a highly stable hole collection layer in perovskite solar cells. Nano Lett., 2014. 14(10): p. 5561-5568.
50.Zhou, H., Q. Chen, G. Li, S. Luo, T.-b. Song, H.-S. Duan, Z. Hong, J. You, Y. Liu, and Y. Yang, Interface engineering of highly efficient perovskite solar cells. Science, 2014. 345(6196): p. 542-546.
51.Tress, W., N. Marinova, T. Moehl, S. Zakeeruddin, M.K. Nazeeruddin, and M. Grätzel, Understanding the rate-dependent J–V hysteresis, slow time component, and aging in CH3NH3PbI3 perovskite solar cells: the role of a compensated electric field. Energy Environ. Sci., 2015. 8(3): p. 995-1004.
52.Shao, Y., Z. Xiao, C. Bi, Y. Yuan, and J. Huang, Origin and elimination of photocurrent hysteresis by fullerene passivation in CH3NH3PbI3 planar heterojunction solar cells. Nat. Commun., 2014. 5.
53.Wu, C.-G., C.-H. Chiang, Z.-L. Tseng, M.K. Nazeeruddin, A. Hagfeldt, and M. Grätzel, High efficiency stable inverted perovskite solar cells without current hysteresis. Energy Environ. Sci., 2015. 8(9): p. 2725-2733.
54.Heo, J.H., H.J. Han, D. Kim, T.K. Ahn, and S.H. Im, Hysteresis-less inverted CH3NH3PbI3 planar perovskite hybrid solar cells with 18.1% power conversion efficiency. Energy Environ. Sci., 2015. 8(5): p. 1602-1608.
55.Noh, J.H., S.H. Im, J.H. Heo, T.N. Mandal, and S.I. Seok, Chemical management for colorful, efficient, and stable inorganic–organic hybrid nanostructured solar cells. Nano Lett., 2013. 13(4): p. 1764-1769.
56.Yang, M., T. Zhang, P. Schulz, Z. Li, G. Li, D.H. Kim, N. Guo, J.J. Berry, K. Zhu, and Y. Zhao, Facile fabrication of large-grain CH3NH3PbI3-xBrx films for high-efficiency solar cells via CH3NH3Br-selective Ostwald ripening. Nat. Commun., 2016. 7.
57.Jang, D.M., K. Park, D.H. Kim, J. Park, F. Shojaei, H.S. Kang, J.-P. Ahn, J.W. Lee, and J.K. Song, Reversible halide exchange reaction of organometal trihalide perovskite colloidal nanocrystals for full-range band gap tuning. Nano Lett., 2015. 15(8): p. 5191-5199.
58.Zhang, F., B. Yang, X. Mao, R. Yang, L. Jiang, Y. Li, J. Xiong, Y. Yang, R. He, and W. Deng, Perovskite CH3NH3PbI3-xBrx Single Crystals with Charge-Carrier Lifetimes Exceeding 260 μs. ACS Appl. Mater. Interfaces, 2017. 9(17): p. 14827-14832.
59.Yi, C., X. Li, J. Luo, S.M. Zakeeruddin, and M. Grätzel, Perovskite photovoltaics with outstanding performance produced by chemical conversion of bilayer mesostructured lead halide/TiO2 films. Adv. Mater., 2016.
60.Xie, Y., F. Shao, Y. Wang, T. Xu, D. Wang, and F. Huang, Enhanced performance of perovskite CH3NH3PbI3 solar cell by using CH3NH3I as additive in sequential deposition. ACS Appl. Mater. Interfaces, 2015. 7(23): p. 12937-12942.
61.Noel, N.K., A. Abate, S.D. Stranks, E.S. Parrott, V.M. Burlakov, A. Goriely, and H.J. Snaith, Enhanced photoluminescence and solar cell performance via lewis base passivation of organic–inorganic lead halide perovskites. ACS nano, 2014. 8(10): p. 9815-9821.
62.Zuo, L., S. Dong, N. De Marco, Y.-T. Hsieh, S.-H. Bae, P. Sun, and Y. Yang, Morphology Evolution of High Efficiency Perovskite Solar Cells via Vapor Induced Intermediate Phases. J. Am. Chem. Soc., 2016. 138(48): p. 15710-15716.
63.Yuan, S., Z. Qiu, C. Gao, H. Zhang, Y. Jiang, C. Li, J. Yu, and B. Cao, High-Quality Perovskite Films Grown with a Fast Solvent-Assisted Molecule Inserting Strategy for Highly Efficient and Stable Solar Cells. ACS Appl. Mater. Interfaces, 2016. 8(34): p. 22238-22245.
64.Kim, Y.H., H. Cho, J.H. Heo, T.S. Kim, N. Myoung, C.L. Lee, S.H. Im, and T.W. Lee, Multicolored Organic/Inorganic Hybrid Perovskite Light‐Emitting Diodes. Adv. Mater., 2015. 27(7): p. 1248-1254.
65.Dar, M.I., M. Abdi‐Jalebi, N. Arora, M. Grätzel, and M.K. Nazeeruddin, Growth Engineering of CH3NH3PbI3 Structures for High‐Efficiency Solar Cells. Adv. Energy Mater., 2016. 6(2).
66.Kim, H.-S., C.-R. Lee, J.-H. Im, K.-B. Lee, T. Moehl, A. Marchioro, S.-J. Moon, R. Humphry-Baker, J.-H. Yum, and J.E. Moser, Lead iodide perovskite sensitized all-solid-state submicron thin film mesoscopic solar cell with efficiency exceeding 9%. Sci. Rep., 2012. 2: p. 591.
67.Correa‐Baena, J.P., M. Anaya, G. Lozano, W. Tress, K. Domanski, M. Saliba, T. Matsui, T.J. Jacobsson, M.E. Calvo, and A. Abate, Unbroken Perovskite: Interplay of Morphology, Electro‐optical Properties, and Ionic Movement. Adv. Mater., 2016. 28(25): p. 5031-5037.