一步法和兩步法一直都是以濕式製程製備鈣鈦礦薄膜的主流方法，兩者也都被報導可以製備出高品質的鈣鈦礦薄膜及高效率的元件。然而各研究團隊並未對其所選擇的製備方式詳加說明，使得參考性及重複性不高。再者，縱使兩者都可以達成高效率元件，但不同的製備方式對鈣鈦礦薄膜的特性差異，幾乎沒有被報導過。因此本研究分別利用一步法和兩步法製備出具備19%至20%轉換效率的鈣鈦礦元件，並從一開始的前驅溶液配置到鈣鈦礦的成核機制，以及不同製備方式對鈣鈦礦薄膜特性的影響，逐步地進行討論。
結果發現，由於溶劑溶解前驅物的能力不同，一步法較容易製備出較厚的鈣鈦礦薄膜。同時發現以異丙醇潤洗鈣鈦礦薄膜後，兩步法製程的潤洗液離子含量高於一步法製程，且潤洗後鈣鈦礦薄膜形貌均產生變化。由SEM和AFM的結果發現，一步法製備之鈣鈦礦薄膜中，未反應離子多累積於表面；兩步法製備之鈣鈦礦薄膜中，未反應離子多累積於晶界處，此結果也首次證實鈣鈦礦前驅溶液的配比並不等於鈣鈦礦薄膜實際組成。
實驗結果亦表明製備方式不同可影響鈣鈦礦的長晶過程。一步法的成核較為隨機，薄膜較不均勻且粗糙，導致多重離子鈣鈦礦薄膜內的化學組成較不一致。兩步法則先旋塗形成平坦PbI2基底，再旋塗上有機溶液，反應過程是由上到下逐漸擴散，相比於一步法，兩步法製備之鈣鈦礦縱深元素分布於鈣鈦礦薄膜內和多孔層差異較大。由於先製備PbI2基底較平坦，因此最終形成的鈣鈦礦薄膜粗糙度亦較低，表面能量分布亦較一步法均勻。根據一步法和兩步法所製備鈣鈦礦元件光伏參數之統計數據，兩步法的平均效率與再現性均高於一步法，表示越平坦的表面以及表面能量分布越均勻的薄膜對鈣鈦礦元件的表現有正面的影響。

The one-step method and two-step method are the most commonly used solution processes for perovskite deposition, and both of them have been reported to produce high-quality perovskite films and high-efficiency devices. However, the research teams have little elaboration on the deposition methods they chose, resulting in low reproducibility and low reference value. Even though high-efficiency devices could be obtained by both methods, the difference in the properties of perovskite films made from different methods has rarely been reported. Therefore, this study attempts to use one-step and two-step methods to fabricate perovskite solar cells with the comparable power conversion efficiency from 19% to 20% and then compares the difference in the properties of perovskite films between both methods. The initial precursor solution preparation, perovskite nucleation mechanism, and the influence of different deposition methods on the properties of perovskite films have been discussed gradually.
It shows that it is easier for one-step method to prepare a thicker perovskite film owing to the different solubility of solvent for perovskite precursors. It is also found that after rinsing the perovskite film with IPA, the ion content in the solution after rinsing the perovskite film made from two-step method is higher than that made from one-step method. In addition, the morphology of the perovskite film changes after IPA rinsing. From the result of SEM and AFM, the unreacted ions accumulate on the surface of perovskite film made from one-step method; however, the unreacted ions accumulate at the grain boundary of perovskite film made from two-step method. This result also confirms that the ratio of the perovskite precursor solution is not equal to the actual composition of the perovskite film.
Different deposition methods not only affect the perovskite crystallization process but also influence the uniformity of the perovskite film. The nucleation of the one-step method is relatively random, and the film is relatively uneven and rough leading to inconsistent composition of multiple-ion perovskite film. For the two-step method, a flat PbI2 substrate is firstly formed by spin-coating PbI2 solution, followed by the spin-coating of the organic solution. Because of the top-to-down diffused reaction for the organic compound and PbI2 substrate in the two-step method, the element depth distribution of perovskite is more different from the one-step method. It means that the element composition of the perovskite capping layer and perovskite inside the mesoporous layer is quite different. The preformed PbI2 substrate contributes to low roughness of perovskite film and uniform surface energy distribution. According to the photovoltaic parameters of the devices prepared by one-step and two-step method, the average efficiency and reproducibility of the two-step method are higher than that of the one-step method, which means that low roughness of perovskite film and uniform surface energy distribution are beneficial to the performance of perovskite devices.

摘要 i
Abstract ii
致謝 iv
目錄 v
圖目錄 vii
表目錄 xii
第一章 緒論 1
1-1 前言 1
1-2 太陽能電池的原理 2
1-3 太陽能電池的發展 2
第二章 文獻回顧 5
2-1 鈣鈦礦太陽能電池之簡介 5
2-1-1 鈣鈦礦的起源與材料 5
2-1-2 鈣鈦礦太陽能電池的發展 6
2-1-3 鈣鈦礦太陽能電池的結構 11
2-1-4 鈣鈦礦太陽能電池的工作原理 13
2-2 鈣鈦礦薄膜製備方式 14
2-2-1 一步法(One-step method) 15
2-2-2 兩步法(Two-step method) 16
2-2-3 熱蒸鍍法(Thermal evaporation method) 20
2-2-4 蒸氣輔助溶液製程(Vapor-assisted solution process, VASP) 21
2-3 提高鈣鈦礦太陽能電池效率的手段 22
2-3-1 組成工程(Compositional Engineering) 22
2-3-2 鈍化效應(Passivation Effect) 31
2-4 研究目的與動機 40
第三章 實驗方法與儀器分析 41
3-1 實驗藥品與材料 41
3-2 實驗儀器與分析設備 43
3-2-1 紫外光臭氧清洗系統(UV Ozone cleaning system) 44
3-2-2 X光繞射儀(X-Ray Diffractometer, XRD) 44
3-2-3 紫外光-可見光光譜儀(Ultraviolet-visible spectrometer, UV-vis) 45
3-2-4 光致放光光譜(Photoluminescence spectra, PL) 46
3-2-5 表面電位顯微鏡(Kelvin Probe Force Microscopy, KPFM) 47
3-2-6 二次離子質譜分析(Secondary Ion Mass Spectrometer, SIMS) 48
3-2-7 太陽光模擬器(Solar simulator)與電流密度-電壓曲線 48
3-3 實驗步驟與方法 52
3-3-1 基板預處理到多孔結構層之製備 52
3-3-2 一步法製備多重離子鈣鈦礦流程 53
3-3-3 兩步法製備多重離子鈣鈦礦流程 54
3-3-4 電洞傳輸層及金背電極製備 54
第四章 實驗結果與討論 56
4-1 鈣鈦礦元件效率之改善 56
4-1-1 以一步法製備鈣鈦礦元件效率改善 56
4-1-2 以兩步法製備鈣鈦礦元件效率改善 63
4-1-3 最大輸出功率追蹤(Maximum Power Point Tracking, MPPT) 66
4-1-4 鈣鈦礦薄膜厚度比較 71
4-2 鈣鈦礦組成配比之探討 78
4-2-1 鈦礦前驅物配比之探討 78
4-2-2 鈣鈦礦前驅物與鈣鈦礦實際組成之探討 81
4-3 一步法和兩步法製備之鈣鈦礦薄膜性質綜合比較 89
4-3-1 鈣鈦礦表面形貌與XRD分析 89
4-3-2 鈣鈦礦薄膜表面粗糙度分析 91
4-3-3 鈣鈦礦表面功函數分析 92
4-3-4 鈣鈦礦縱深元素分布分析 95
第五章 結論 98
第六章 未來展望 102
參考文獻 103
附錄A 109

參考文獻
[1] (2010). Available: http://www.hydrogenambassadors.com/background/global-energy-flows.php
[2] D. M. Chapin, C. Fuller, and G. Pearson, "A new silicon p‐n junction photocell for converting solar radiation into electrical power," Journal of Applied Physics, vol. 25, no. 5, pp. 676-677, 1954.
[3] (2020). Available: https://www.nrel.gov/pv/cell-efficiency.html
[4] A. Kojima, K. Teshima, Y. Shirai, and T. Miyasaka, "Organometal halide perovskites as visible-light sensitizers for photovoltaic cells," Journal of the American Chemical Society, vol. 131, no. 17, pp. 6050-6051, 2009.
[5] Y. Chen, L. Zhang, Y. Zhang, H. Gao, and H. Yan, "Large-area perovskite solar cells–a review of recent progress and issues," RSC advances, vol. 8, no. 19, pp. 10489-10508, 2018.
[6] Z. Li, M. Yang, J.-S. Park, S.-H. Wei, J. J. Berry, and K. Zhu, "Stabilizing perovskite structures by tuning tolerance factor: formation of formamidinium and cesium lead iodide solid-state alloys," Chemistry of Materials, vol. 28, no. 1, pp. 284-292, 2016.
[7] G. E. Eperon, 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 & Environmental Science, vol. 7, no. 3, pp. 982-988, 2014.
[8] W. Shockley, "The Shockley-Queisser limit," J. Appl. Phys, vol. 32, pp. 510-519, 1961.
[9] J.-H. Im, C.-R. Lee, J.-W. Lee, S.-W. Park, and N.-G. Park, "6.5% efficient perovskite quantum-dot-sensitized solar cell," Nanoscale, vol. 3, no. 10, pp. 4088-4093, 2011.
[10] H.-S. Kim et al., "Lead iodide perovskite sensitized all-solid-state submicron thin film mesoscopic solar cell with efficiency exceeding 9%," Scientific reports, vol. 2, no. 1, pp. 1-7, 2012.
[11] M. M. Lee, J. Teuscher, T. Miyasaka, T. N. Murakami, and H. J. Snaith, "Efficient hybrid solar cells based on meso-superstructured organometal halide perovskites," Science, vol. 338, no. 6107, pp. 643-647, 2012.
[12] J. Burschka et al., "Sequential deposition as a route to high-performance perovskite-sensitized solar cells," Nature, vol. 499, no. 7458, pp. 316-319, 2013.
[13] M. Liu, M. B. Johnston, and H. J. Snaith, "Efficient planar heterojunction perovskite solar cells by vapour deposition," Nature, vol. 501, no. 7467, pp. 395-398, 2013.
[14] N. J. Jeon, 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," Nature materials, vol. 13, no. 9, pp. 897-903, 2014.
[15] H. Zhou et al., "Interface engineering of highly efficient perovskite solar cells," Science, vol. 345, no. 6196, pp. 542-546, 2014.
[16] N. J. Jeon et al., "Compositional engineering of perovskite materials for high-performance solar cells," Nature, vol. 517, no. 7535, pp. 476-480, 2015.
[17] M. Saliba et al., "Cesium-containing triple cation perovskite solar cells: improved stability, reproducibility and high efficiency," Energy & environmental science, vol. 9, no. 6, pp. 1989-1997, 2016.
[18] W. S. Yang et al., "Iodide management in formamidinium-lead-halide–based perovskite layers for efficient solar cells," Science, vol. 356, no. 6345, pp. 1376-1379, 2017.
[19] C. Ma and N.-G. Park, "A Realistic Methodology for 30% Efficient Perovskite Solar Cells," Chem, 2020.
[20] R. Wang, M. Mujahid, Y. Duan, Z. K. Wang, J. Xue, and Y. Yang, "A review of perovskites solar cell stability," Advanced Functional Materials, vol. 29, no. 47, p. 1808843, 2019.
[21] D. Liu, J. Yang, and T. L. Kelly, "Compact layer free perovskite solar cells with 13.5% efficiency," Journal of the American Chemical Society, vol. 136, no. 49, pp. 17116-17122, 2014.
[22] W. Ke et al., "Efficient hole-blocking layer-free planar halide perovskite thin-film solar cells," Nature communications, vol. 6, no. 1, pp. 1-7, 2015.
[23] L. Etgar et al., "Mesoscopic CH3NH3PbI3/TiO2 heterojunction solar cells," Journal of the American Chemical Society, vol. 134, no. 42, pp. 17396-17399, 2012.
[24] N. Marinova, S. Valero, and J. L. Delgado, "Organic and perovskite solar cells: Working principles, materials and interfaces," Journal of colloid and interface science, vol. 488, pp. 373-389, 2017.
[25] M. Xiao et al., "A fast deposition‐crystallization procedure for highly efficient lead iodide perovskite thin‐film solar cells," Angewandte Chemie International Edition, vol. 53, no. 37, pp. 9898-9903, 2014.
[26] Y. Zhou, 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," Journal of Materials Chemistry A, vol. 3, no. 15, pp. 8178-8184, 2015.
[27] N. Ahn, 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," Journal of the American Chemical Society, vol. 137, no. 27, pp. 8696-8699, 2015.
[28] J.-H. Im, I.-H. Jang, N. Pellet, M. Grätzel, and N.-G. Park, "Growth of CH3NH3PbI3 cuboids with controlled size for high-efficiency perovskite solar cells," Nature nanotechnology, vol. 9, no. 11, pp. 927-932, 2014.
[29] Y. Wu et al., "Retarding the crystallization of PbI2 for highly reproducible planar-structured perovskite solar cells via sequential deposition," Energy & Environmental Science, vol. 7, no. 9, pp. 2934-2938, 2014.
[30] T. Zhang, M. Yang, Y. Zhao, and K. Zhu, "Controllable sequential deposition of planar CH3NH3PbI3 perovskite films via adjustable volume expansion," Nano letters, vol. 15, no. 6, pp. 3959-3963, 2015.
[31] J. Mo et al., "Enhanced efficiency of planar perovskite solar cells via a two-step deposition using DMF as an additive to optimize the crystal growth behavior," Journal of Materials Chemistry A, vol. 5, no. 25, pp. 13032-13038, 2017.
[32] T.-Y. Hsieh, C.-K. Huang, T.-S. Su, C.-Y. Hong, and T.-C. Wei, "Crystal growth and dissolution of methylammonium lead iodide perovskite in sequential deposition: correlation between morphology evolution and photovoltaic performance," ACS applied materials & interfaces, vol. 9, no. 10, pp. 8623-8633, 2017.
[33] G. Zhou et al., "Application of cesium on the restriction of precursor crystallization for highly reproducible perovskite solar cells exceeding 20% efficiency," ACS applied materials & interfaces, vol. 10, no. 11, pp. 9503-9513, 2018.
[34] G. Balaji et al., "CH3NH3PbI3 from non-iodide lead salts for perovskite solar cells via the formation of PbI2," Physical Chemistry Chemical Physics, vol. 17, no. 16, pp. 10369-10372, 2015.
[35] Q. Chen et al., "Planar heterojunction perovskite solar cells via vapor-assisted solution process," Journal of the American Chemical Society, vol. 136, no. 2, pp. 622-625, 2014.
[36] A. K. Jena, A. Kulkarni, and T. Miyasaka, "Halide perovskite photovoltaics: background, status, and future prospects," Chemical reviews, vol. 119, no. 5, pp. 3036-3103, 2019.
[37] J. W. Lee, D. J. Seol, A. N. Cho, and N. G. Park, "High‐efficiency perovskite solar cells based on the black polymorph of HC(NH2)2PbI3," Advanced Materials, vol. 26, no. 29, pp. 4991-4998, 2014.
[38] W. S. Yang et al., "High-performance photovoltaic perovskite layers fabricated through intramolecular exchange," Science, vol. 348, no. 6240, pp. 1234-1237, 2015.
[39] T. Leijtens, K. Bush, R. Cheacharoen, R. Beal, A. Bowring, and M. D. McGehee, "Towards enabling stable lead halide perovskite solar cells; interplay between structural, environmental, and thermal stability," Journal of Materials Chemistry A, vol. 5, no. 23, pp. 11483-11500, 2017.
[40] W. Li, J. Fan, J. Li, G. Niu, Y. Mai, and L. Wang, "High performance of perovskite solar cells via catalytic treatment in two-step process: the case of solvent engineering," ACS Applied Materials & Interfaces, vol. 8, no. 44, pp. 30107-30115, 2016.
[41] G. Niu, W. Li, J. Li, X. Liang, and L. Wang, "Enhancement of thermal stability for perovskite solar cells through cesium doping," RSC advances, vol. 7, no. 28, pp. 17473-17479, 2017.
[42] M. Saliba et al., "Incorporation of rubidium cations into perovskite solar cells improves photovoltaic performance," Science, vol. 354, no. 6309, pp. 206-209, 2016.
[43] J. K. Nam et al., "Potassium incorporation for enhanced performance and stability of fully inorganic cesium lead halide perovskite solar cells," Nano letters, vol. 17, no. 3, pp. 2028-2033, 2017.
[44] S. D. Stranks et al., "Electron-hole diffusion lengths exceeding 1 micrometer in an organometal trihalide perovskite absorber," Science, vol. 342, no. 6156, pp. 341-344, 2013.
[45] S. T. Williams, F. Zuo, C.-C. Chueh, C.-Y. Liao, P.-W. Liang, and A. K.-Y. Jen, "Role of chloride in the morphological evolution of organo-lead halide perovskite thin films," ACS nano, vol. 8, no. 10, pp. 10640-10654, 2014.
[46] J. H. Noh, 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 letters, vol. 13, no. 4, pp. 1764-1769, 2013.
[47] Y. Shao, Z. Xiao, C. Bi, Y. Yuan, and J. Huang, "Origin and elimination of photocurrent hysteresis by fullerene passivation in CH3NH3PbI3 planar heterojunction solar cells," Nature communications, vol. 5, no. 1, pp. 1-7, 2014.
[48] H. J. Snaith et al., "Anomalous hysteresis in perovskite solar cells," The journal of physical chemistry letters, vol. 5, no. 9, pp. 1511-1515, 2014.
[49] M. Ye et al., "Recent advances in interfacial engineering of perovskite solar cells," Journal of Physics D: Applied Physics, vol. 50, no. 37, p. 373002, 2017.
[50] F. Li and M. Liu, "Recent efficient strategies for improving the moisture stability of perovskite solar cells," Journal of Materials Chemistry A, vol. 5, no. 30, pp. 15447-15459, 2017.
[51] Q. Chen et al., "Controllable self-induced passivation of hybrid lead iodide perovskites toward high performance solar cells," Nano letters, vol. 14, no. 7, pp. 4158-4163, 2014.
[52] D.-Y. Son et al., "Self-formed grain boundary healing layer for highly efficient CH3NH3PbI3 perovskite solar cells," Nature Energy, vol. 1, no. 7, pp. 1-8, 2016.
[53] Q. Jiang et al., "Planar‐structure perovskite solar cells with efficiency beyond 21%," Advanced materials, vol. 29, no. 46, p. 1703852, 2017.
[54] D. Bi et al., "Efficient luminescent solar cells based on tailored mixed-cation perovskites," Science advances, vol. 2, no. 1, p. e1501170, 2016.
[55] K. T. Cho et al., "Highly efficient perovskite solar cells with a compositionally engineered perovskite/hole transporting material interface," Energy & Environmental Science, vol. 10, no. 2, pp. 621-627, 2017.
[56] J. Cao et al., "Identifying the molecular structures of intermediates for optimizing the fabrication of high-quality perovskite films," Journal of the American Chemical Society, vol. 138, no. 31, pp. 9919-9926, 2016.
[57] J.-H. Im, H.-S. Kim, and N.-G. Park, "Morphology-photovoltaic property correlation in perovskite solar cells: One-step versus two-step deposition of CH3NH3PbI3," Apl Materials, vol. 2, no. 8, p. 081510, 2014.
[58] M. Li et al., "Comparison of processing windows and electronic properties between CH3NH3PbI3 perovskite fabricated by one-step and two-step solution processes," Organic Electronics, vol. 63, pp. 159-165, 2018.
[59] M. R. Ahmadian-Yazdi, F. Zabihi, M. Habibi, and M. Eslamian, "Effects of process parameters on the characteristics of mixed-halide perovskite solar cells fabricated by one-step and two-step sequential coating," Nanoscale research letters, vol. 11, no. 1, pp. 1-11, 2016.
[60] Available: https://www.renishaw.com.tw/tw/photoluminescence-explained--25809
[61] W. Melitz, J. Shen, A. C. Kummel, and S. Lee, "Kelvin probe force microscopy and its application," Surface science reports, vol. 66, no. 1, pp. 1-27, 2011.
[62] S. P. Harvey, Z. Li, J. A. Christians, K. Zhu, J. M. Luther, and J. J. Berry, "Probing perovskite inhomogeneity beyond the surface: TOF-SIMS analysis of halide perovskite photovoltaic devices," ACS applied materials & interfaces, vol. 10, no. 34, pp. 28541-28552, 2018.
[63] J. J. Yoo et al., "An interface stabilized perovskite solar cell with high stabilized efficiency and low voltage loss," Energy & Environmental Science, vol. 12, no. 7, pp. 2192-2199, 2019.
[64] C. Wang et al., "Compositional and morphological engineering of mixed cation perovskite films for highly efficient planar and flexible solar cells with reduced hysteresis," Nano Energy, vol. 35, pp. 223-232, 2017.
[65] Y.-J. Wei, C.-G. Liu, and L.-P. Mo, "Ultraviolet absorption spectra of iodine, iodide ion and triiodide ion," Guang pu xue yu guang pu fen xi= Guang pu, vol. 25, no. 1, p. 86, 2005.
[66] Nanolayer Research: Methodology and Technology for Green Chemistry.
[67] P. Gratia et al., "Intrinsic halide segregation at nanometer scale determines the high efficiency of mixed cation/mixed halide perovskite solar cells," Journal of the American Chemical Society, vol. 138, no. 49, pp. 15821-15824, 2016.