Design and Synthesis of Perovskite Materials for Photocatalytic and Photovoltaic Applications

In recent decades, organic-inorganic hybrid perovskite materials have drawn much more attention for their excellent optoelectronic properties and successful applications in photovoltaics, photodetector, light-emitting diodes (LED) and photocatalysis. The traditional perovskite possesses a three-dimensional (3D) structure and is defined as ABX₃ in which the cation A is located at the voids of BX₆ octahedral structure to develop in all three directions_. And the A represents the organic or inorganic cations such as methylammonium (MA⁺) or Cs⁺, the B are the metal cations such as Pb²⁺ or Sn²⁺, and the X is related to the halide anions such as I⁻, Br⁻ and Cl⁻. This kind of traditional 3D perovskite materials have been widely applied in the photovoltaic applications. The traditional small cation at A position can be replaced by some large organic cations. Since the large organic cations are too big to be located into the voids, this kind of perovskite has the orientation preference to grow into two-dimensional (2D) perovskite. The big organic cations show an essential property of moisture resistance which is beneficial for improving the stability of perovskite.

On the other hand, the thin films made from those 3D and 2D materials contain huge amount of tiny crystals with large grain boundaries as well as defects which are harmful for the charge transportation and device performance. Therefore, the research of the single crystal perovskite, which contains no grain boundary inside, have been investigated for solar cells, photodetectors, LEDs, etc.

In this thesis my research not only focus on the perovskite material itself, but also its further application such as photocatalysis, photovoltaic and optoelectronic applications. In general, nano-scale particles and cm-scale single crystals have been synthesised and the related characterizations have confirmed that they are in quite high quality. What should also be mentioned is that the single crystals I have synthesised have achieved the largest size compared with current report. Later the photocatalysis experiments based on the nano-scale particles has been confirmed that the perovskite with mixed-dimensional has excellent photocatalysis ability. Later attempts have been done to modify the electron transport layer to improve the perovskite solar cell performance. Sn doping and KCl modification have been confirmed to have clear enhancement for the solar cell device. Finally, the large size single crystals have been applied for the optoelectronic applications such as LED and photodetectors. With current research progress the LED shows good conduction and the detector shows good response ability. In one word, not only the materials synthesis methods have been improved but also the related applications in photocatalysis, photovoltaic and optoelectronic areas have been tried and shown good results. The details are mentioned below.

Chapter 1 summarizes the development history of perovskite materials for photovoltaics and photocatalysis applications.       

In Chapter 2, 2D, 3D perovskite nanoparticles and (MA) and mixed-dimensional perovskite (MDP) nanoparticles with different ratio of octadecylamine (OA)/methylamine (MA) were prepared and their morphology, optoelectronic performance, electrochemical performance as well as photocatalytic performance were investigated. Impressively, the MDP materials show high charge mobility than those pure 2D and 3D perovskite nanomaterials. In addition, the MDP materials combine the advantages of 2D and 3D perovskite materials characteristic of efficient electron-hole separation and a broad UV-visible light absorption. In the photocatalytic hydrogen evolution reactions, the 3D perovskite shows a rate of 323 μmol g⁻¹ h⁻¹ and 2D shows 192.1 μmol g⁻¹ h⁻¹ within 5 hours under the same conditions. And the MDP perovskites with the OA content of 5%, 10%, 15% and 25% show the hydrogen generation rate of 219.3, 430.2, 960.2 and 274.5 μmol g⁻¹ h⁻¹, respectively. It should be noted that that the photocatalytic H₂ evolution reaction maintains a constant PHE rate within 24-hours. Also, the photocurrent response and EIS studies further support that the MDP of OA_0.15MA_0.85PbI₃ shows the best performance among all those perovskite samples.

Chapter 3 described a low-temperature solution processing method to prepare Sn-doped TiO₂ nanocrystals functioned as an electron transport layer (ETL) in PSCs. Pristine and Sn doped anatase TiO₂ nanocrystals are synthesized successfully with the size of around 4-10 nm. Using the optimal 1.5 atom% (at. %) Sn-doped TiO₂ nanocrystals as ETL in PSC, a power conversion efficiency (PCE) of 17.7% has been achieved, which is higher than the pristine TiO₂ with an PCE of 13.1%. Moreover, the PSC based on the 1.5 at. % Sn-doped TiO₂ shows a best long-time stability and the smallest hysteresis among all samples after 20 days storage. It is believed that the low temperature processed solution processing strategy for the ETL is very powerful for PSC applications.   

In Chapter 4, a new and simple method for processing ETL has been developed for optimizing PSCs performance. The addition of inorganic KCl salt into TiCl₃ solution can work simply with quick response for the preparation TiO₂ nanoparticles as ETL. The PSC with 0.5 M KCl addition show a higher PCE of 19.38% than that the control one with PCE of 17.68%, which is ascribed to the enhanced open circuit voltage (Voc) from 1.10 V for the former to 1.04 V for the latter. Also, the characterizations such as UV/Visible absorption, SCLC, UPS have confirmed that the ETL upon 0.5 M KCl addition shows the highest charge mobility and the least defect which are all beneficial to for PSC performance. Additionally, no other extra treatment except for annealing is necessary for the ETL prepared through this method. Conclusively, an efficient and simple strategy for ETL preparation was developed for the performance improvement of PSCs.

Chapter 5 extended to the study of perovskite single crystals for PSCs application. Typically, a modified method for single crystal growth was developed to prepare the perovskite single crystals effectively, including PEA series ((PEA)₂PbCl₄, (PEA)₂PbBr₄ and (PEA)₂PbI₄) and BA series ((BA)₂(MA)₂Pb₃I₁₀, (BA)₂MAPb₂I₇ and (BA)₂PbI₄)). Subsequently, the LED devices were fabricated based on those PEA series perovskite single crystals with strong photoluminescence. And those BA series with good optoelectronic property and high stability were applied for the photodetectors. It was found that the LED based on the six-layer structure worked very well with good conductivity performance. On the other hand, the photodetector based on the (BA)₂PbI₄ shows a response times of 270 ms for rise time and 334 ms for fall time under the 405 nm irradiation, which are much shorter than that of 580 ms for rise and 670 ms for fall in the device based on the (BA)₂MAPb₂I₇. This work shed light of the commercial applications of the perovskite single crystals in LED and photodetector devices.

In the end, a summary and highlights of the research work involved in this thesis are provided in Chapter 6. 

近几十年来，有机-无机杂化钙钛矿材料因其优异的光电性能以及在光伏、光电探测器、发光二极管（LED）和光催化领域的成功应用而备受关注。传统的钙钛矿具有三维（3D）结构，定义为 ABX₃，其中阳离子 A 位于 BX₆ 八面体结构的空隙处，向三个方向发展。其中A代表有机或无机阳离子如甲基铵（MA+）或Cs+，B代表金属阳离子如Pb²⁺或Sn²⁺，X与卤化物阴离子如I^-、Br^-和Cl^-有关。这种传统的3D钙钛矿材料已广泛应用于光伏应用中。 A位传统的小阳离子可以被一些大的有机阳离子代替。由于大的有机阳离子太大而无法定位到空隙中，这种钙钛矿具有生长成二维（2D）钙钛矿的取向偏好。大的有机阳离子表现出重要的抗湿性，有利于提高钙钛矿的稳定性。

另一方面，由这些 3D 和 2D 材料制成的薄膜含有大量具有大晶界的微小晶体以及对电荷传输和器件性能有害的缺陷。因此，对内部不含晶界的单晶钙钛矿进行了研究，用于太阳能电池、光电探测器、LED等。

在本论文中，我的研究不仅关注钙钛矿材料本身，还关注其进一步的应用，如光催化、光伏和光电应用。一般来说，已经合成了纳米级颗粒和厘米级单晶，相关表征已经证实它们具有相当高的质量。还应该提到的是，与目前的报道相比，合成的单晶达到了最大的尺寸。后来基于纳米级粒子的光催化实验证实了具有混合维数的钙钛矿具有优异的光催化能力。后来尝试修改电子传输层以改善钙钛矿太阳能电池的性能。Sn掺杂和 KCl 改性已被证实对太阳能电池器件具有明显的增强作用。最后，大尺寸单晶已应用于光电应用，如 LED 和光电探测器。随着目前的研究进展，LED表现出良好的传导性，探测器表现出良好的响应能力。总之，不仅材料合成方法得到了改进，而且在光催化、光伏和光电领域的相关应用也得到了尝试，并取得了良好的效果。详情如下所述。

第一章总结了用于光伏和光催化应用的钙钛矿材料的发展历史。

在第二章中，制备了具有不同十八胺（OA）/甲胺（MA）比例的2D、3D钙钛矿纳米颗粒和（MA）和混合维钙钛矿（MDP）纳米颗粒及其形貌、光电性能、电化学性能以及光催化性能。令人印象深刻的是，MDP 材料显示出比纯 2D 和 3D 钙钛矿纳米材料高的电荷迁移率。此外，MDP 材料结合了 2D 和 3D 钙钛矿材料的优点，即有效的电子-空穴分离和广泛的紫外-可见光吸收。在光催化析氢反应中，在相同条件下3D钙钛矿在5小时内表现出 323μmolg^-1h^-1 的速率，2D 表现出 192.1μmolg^-1h^-1 的速率。 OA 含量为5%、10%、15% 和25% 的 MDP 钙钛矿的产氢率分别为 219.3、430.2、960.2 和 274.5μmolg^-1h^-1。应该注意的是，光催化析氢反应在 24 小时内保持恒定的 PHE 速率。此外，光电流响应和EIS研究进一步支持 OA_0.15MA_0.85PbI₃的MDP 在所有钙钛矿样品中表现出最佳性能。

第 3 章描述了一种低温溶液处理方法来制备Sn掺杂的TiO₂纳米晶体，作为PSC中的电子传输层(ETL)。成功合成了原始和 Sn 掺杂的锐钛矿TiO₂纳米晶体，尺寸约为4-10nm。使用最佳的1.5 atom% (at.%) Sn 掺杂的 TiO₂纳米晶体作为PSC中的ETL，已实现17.7%的转换效率(PCE)，高于PCE为13.1%的原始TiO₂。而且PSC基于 1.5at.%Sn掺杂的TiO₂在储存20天后在所有样品中显示出最好的长期稳定性和最小的滞后。相信ETL的低温处理溶液处理策略对于PSC应用来说是非常强大的。

在第 4 章中，开发了一种新的、简单的 ETL 处理方法，用于优化 PSC 的性能。在TiCl₃溶液中加入无机KCl盐可以简单、快速地制备作为ETL的TiO₂纳米颗粒。添加0.5M KCl的PSC的PCE比PCE为17.68%的对照组高，达到19.38%，这归因于开路电压 (Voc) 从1.04V提高到1.10V。此外，紫外/可见光吸收、SCLC、UPS 等表征已经证实，添加0.5M KCl后的 ETL 显示出最高的电荷迁移率和最少的缺陷，这些都有利于PSC性能。此外，通过这种方法制备的ETL除了退火之外不需要其他额外的处理。总之，本实验为提高PSC的性能开发了一种有效且简单的 ETL 准备策略。

第 5 章扩展到了用于光电应用的钙钛矿单晶的研究。开发了一种改进的单晶生长方法以有效地制备钙钛矿单晶，包括 PEA 系列 ((PEA)₂PbCl₄、(PEA)₂PbBr₄ 和 (PEA)₂PbI₄) 和 BA 系列 ((BA)₂(MA)₂Pb₃I₁₀ , (BA)₂MAPb₂I₇ 和 (BA)₂PbI₄))。随后，基于那些具有强光致发光的PEA系列钙钛矿单晶制造了LED器件。光电探测器采用光电性能好、稳定性高的BA系列。结果发现，基于六层结构的LED工作得非常好，具有良好的导电性能。另一方面，基于(BA)₂PbI₄的光电探测器在405nm辐照下的上升时间响应时间为270ms，下降时间为334ms，远低于基于(BA)₂MAPb₂I₇的器件580ms和670ms。这项工作揭示了钙钛矿单晶在 LED 和光电探测器设备中的商业应用。

最后，第六章对本论文所涉及的研究工作亮点进行了总结。

[1] Arthouros Zervos, R.A., Marit Brommer, 2020 Global Status Report. 2021, REN21.2. STYLOS, et al., Carbon footprint of polycrystalline photovoltaic systems. Journal of Cleaner Production, 2014. 64(2): p. 639-645.3. Lanz, A., J. Heffel, and C. Messer, Hydrogen Fuel Cell Engines and Related Technologies. Nasa Sti/recon Technical Report N, 2001. 3.4. Pawar, S.A., et al., Hydrothermal growth of photoelectrochemically active titanium dioxide cauliflower-like nanostructures. Electrochimica Acta, 2014. 117(4): p. 470-479.5. Al-Ali, K., S. Kodama, and H. Sekiguchi, Modeling and simulation of methane dry reforming in direct-contact bubble reactor. Solar Energy, 2014. 102(4): p. 45-55.6. Catlow, C.R.A., et al., Computational Approaches to the Determination of Active Site Structures and Reaction Mechanisms in Heterogeneous Catalysts. Philosophical Transactions, 2005. 363(1829): p. 913-936.7. Wang, X.W., et al., Enhanced photocatalytic hydrogen evolution by prolonging the lifetime of carriers in ZnO/CdS heterostructures. Chemical Communications, 2009. 23(23): p. 3452-3454.8. Hagfeldt, A. and M. Graetzel, Light-Induced Redox Reactions in Nanocrystalline Systems. Chemical Reviews, 1995. 95:1(1): p. 49-68.9. Müller, H.D. and F. Steinbach, Decomposition of isopropyl alcohol photosensitized by zinc oxide. Nature, 1970. 225(5234): p. 728.10. Steinbach, F., Influence of metal support and ultraviolet irradiation on the catalytic activity of nickel oxide. Nature, 1969. 221(5181): p. 657.11. Fujishima, A. and K. Honda, Electrochemical photolysis of water at a semiconductor electrode. Nature, 1972. 238(5358): p. 37-38.12. Hashimoto, K., H. Irie, and A. Fujishima, TiO2 photocatalysis: a historical overview and future prospects. Japanese journal of applied physics, 2005. 44(12R): p. 8269.13. Roy, S.C., et al., Toward solar fuels: photocatalytic conversion of carbon dioxide to hydrocarbons. Acs Nano, 2010. 4(3): p. 1259-1278.14. Asahi, R., et al., Visible-light photocatalysis in nitrogen-doped titanium oxides. science, 2001. 293(5528): p. 269-271.15. Hu, C.-C. and H. Teng, Structural features of p-type semiconducting NiO as a co-catalyst for photocatalytic water splitting. Journal of Catalysis, 2010. 272(1): p. 1-8.16. Feng, J., J. Han, and X. Zhao, Synthesis of CuInS2 quantum dots on TiO2 porous films by solvothermal method for absorption layer of solar cells. Progress in Organic Coatings, 2009. 64(2-3): p. 268-273.17. Ouyang, S., et al., Effective decolorizations and mineralizations of organic dyes over a silver germanium oxide photocatalyst under indoor-illumination irradiation. Applied Catalysis A: General, 2009. 366(2): p. 309-314.18. Frame, F.A., et al., First demonstration of CdSe as a photocatalyst for hydrogen evolution from water under UV and visible light. Chemical Communications, 2008(19): p. 2206-2208.19. Wang, X., et al., A metal-free polymeric photocatalyst for hydrogen production from water under visible light. Nature materials, 2009. 8(1): p. 76.20. Zeng, H., et al., ACS Nano 2, 1661 (2008). CrossRef| PubMed| CAS| Web of Science® Times Cited. 95.21. Zhang, X.-F., et al., Facile phthalocyanine doping into PEDOT leads to highly efficient and stable inverted metal halide perovskite solar cells. Journal of Materials Chemistry A, 2018. 6(26): p. 12515-12522.22. Scaife, D., Oxide semiconductors in photoelectrochemical conversion of solar energy. Solar Energy, 1980. 25(1): p. 41-54.23. Thompson, T.L. and J.T. Yates, Surface science studies of the photoactivation of TiO2 new photochemical processes. Chemical Reviews, 2006. 106(10): p. 4428-4453.24. Tong, H., et al., Nano‐photocatalytic materials: possibilities and challenges. Advanced materials, 2012. 24(2): p. 229-251.25. Norman, J., et al. Studies of the sulfur-iodine thermochemical water-splitting cycle. in Hydrogen Energy Progress. 1981.26. Cerri, G., et al., Sulfur–Iodine plant for large scale hydrogen production by nuclear power. International Journal of Hydrogen Energy, 2010. 35(9): p. 4002-4014.27. Esswein, A.J. and D.G. Nocera, Hydrogen production by molecular photocatalysis. Chemical reviews, 2007. 107(10): p. 4022-4047.28. Levy‐Clement, C., et al., Spontaneous photoelectrolysis of HBr and HI. Journal of The Electrochemical Society, 1982. 129(8): p. 1701-1705.29. Huskinson, B., et al., A high power density, high efficiency hydrogen–chlorine regenerative fuel cell with a low precious metal content catalyst. Energy & Environmental Science, 2012. 5(9): p. 8690-8698.30. Im, J.-H., et al., 6.5% efficient perovskite quantum-dot-sensitized solar cell. Nanoscale, 2011. 3(10): p. 4088-4093.31. (NREL), T.N.R.E.L. Best Research-Cell Efficiencies. 2018 [cited 2018 20180716]; Available from: https://www.nrel.gov/pv/assets/images/efficiency-chart-20180716.jpg.32. Xing, G., et al., Low-temperature solution-processed wavelength-tunable perovskites for lasing. Nature materials, 2014. 13(5): p. 476.33. Tan, Z.-K., et al., Bright light-emitting diodes based on organometal halide perovskite. Nature nanotechnology, 2014. 9(9): p. 687.34. Westbrook, R.J.E., et al., Effect of Interfacial Energetics on Charge Transfer from Lead Halide Perovskite to Organic Hole Conductors. The Journal of Physical Chemistry C, 2018. 122(2): p. 1326-1332.35. Zhao, B., et al., High-efficiency perovskite–polymer bulk heterostructure light-emitting diodes. Nature Photonics, 2018.36. Vassilakopoulou, A., D. Papadatos, and I. Koutselas, Light emitting diodes based on blends of quasi-2D lead halide perovskites stabilized within mesoporous silica matrix. Microporous and Mesoporous Materials, 2017. 249: p. 165-175.37. Cao, D.H., et al., 2D Homologous Perovskites as Light-Absorbing Materials for Solar Cell Applications. J Am Chem Soc, 2015. 137(24): p. 7843-50.38. Younts, R., et al., Efficient Generation of Long-Lived Triplet Excitons in 2D Hybrid Perovskite. Adv Mater, 2017. 29(9).39. Wang, Z., et al., Efficient ambient-air-stable solar cells with 2D–3D heterostructured butylammonium-caesium-formamidinium lead halide perovskites. Nature Energy, 2017. 2(9).40. Ma, C., et al., 2D/3D perovskite hybrids as moisture-tolerant and efficient light absorbers for solar cells. Nanoscale, 2016. 8(43): p. 18309-18314.41. Ohl, R., Light sensitive device. 1946: U.S.42. Smith, D.D., et al. Generation III high efficiency lower cost technology: Transition to full scale manufacturing. in 2012 38th IEEE Photovoltaic Specialists Conference. 2012. IEEE.43. Polman, A., et al., Photovoltaic materials: Present efficiencies and future challenges. Science, 2016. 352(6283).44. O'regan, B. and M. Grätzel, A low-cost, high-efficiency solar cell based on dye-sensitized colloidal TiO 2 films. nature, 1991. 353(6346): p. 737-740.45. Kojima, A., et al., Organometal halide perovskites as visible-light sensitizers for photovoltaic cells. Journal of the American Chemical Society, 2009. 131(17): p. 6050-6051.46. NREL. Best Research-Cell Efficiency Chart. 2021; Available from: https://www.nrel.gov/pv/cell-efficiency.html.47. LU, L., et al., Pollution problems in the production process of solar cells. Scientia Sinica Chimica, 2013. 43(6): p. 687-703.48. Green, M.A., et al., Solar cell efficiency tables (Version 55). Progress in Photovoltaics: Research and Applications, 2020. 28(1): p. 3-15.49. Keavney, C., V. Haven, and S. Vernon. Emitter structures in MOCVD InP solar cells. in IEEE Conference on Photovoltaic Specialists. 1990. IEEE.50. Dharmadasa, I., et al., Improvement of composition of CdTe thin films during heat treatment in the presence of CdCl 2. Journal of Materials Science: Materials in Electronics, 2017. 28(3): p. 2343-2352.51. Hirai, Y., Y. Kurokawa, and A. Yamada, Numerical study of Cu (In, Ga) Se2 solar cell performance toward 23% conversion efficiency. Japanese Journal of Applied Physics, 2013. 53(1): p. 012301.52. Niki, S., et al., CIGS absorbers and processes. Progress in Photovoltaics: Research and Applications, 2010. 18(6): p. 453-466.53. Katagiri, H., et al., Development of CZTS-based thin film solar cells. Thin Solid Films, 2009. 517(7): p. 2455-2460.54. Wang, W., et al., Device characteristics of CZTSSe thin‐film solar cells with 12.6% efficiency. Advanced Energy Materials, 2014. 4(7): p. 1301465.55. Mathew, S., et al., Dye-sensitized solar cells with 13% efficiency achieved through the molecular engineering of porphyrin sensitizers. Nature chemistry, 2014. 6(3): p. 242-247.56. Cui, Y., et al., Single‐junction organic photovoltaic cells with approaching 18% efficiency. Advanced Materials, 2020. 32(19): p. 1908205.57. Yu, R., H. Yao, and J. Hou, Recent progress in ternary organic solar cells based on nonfullerene acceptors. Advanced Energy Materials, 2018. 8(28): p. 1702814.58. Kim, J.-Y., et al., Highly efficient copper–indium–selenide quantum dot solar cells: suppression of carrier recombination by controlled ZnS overlayers. ACS nano, 2015. 9(11): p. 11286-11295.59. Nozik, A.J., Quantum dot solar cells. Physica E: Low-dimensional Systemsand Nanostructures, 2002. 14(1-2): p. 115-120.60. Lund, H.J.E., Renewable energy strategies for sustainable development. 2007. 32(6): p. 912-919.61. Fujishima, A. and K.J.N. Honda, Electrochemical photolysis of water at a semiconductor electrode. 1972. 238(5358): p. 37-38.62. Mills, A., S.L.J.J.o.P. Hunte, and P.A. Chemistry, An overview of semiconductor photocatalysis. 1997. 108(1): p. 1-35.63. Choi, W., A. Termin, and M.R.J.J.o.P.C. Hoffmann, The Role of Metal Ion Dopants in Quantum-Sized TiO2: Correlation between Photoreactivity and Charge Carrier Recombination Dynamics. 1994. 98(51): p. 13669-13679.64. X, W., et al., A metal-free polymeric photocatalyst for hydrogen production from water under visible|[nbsp]|light. 2009. 8(1): p. 76-80.65. Park, S., et al., Photocatalytic hydrogen generation from hydriodic acid using methylammonium lead iodide in dynamic equilibrium with aqueous solution. Nature Energy, 2016. 2(1).66. Park, J.W., Z.S. Khan, and H.J.K.Y.J.M.P. Kim, A Surface Modification of Hastelloy X by a SiC Coating and an Ion Beam Irradiation for a Potential use for Iodine-Sulfur Cycle in Nuclear Hydrogen Production System. 2008. 1125: p. 1125-R06-08.67. Wu, Y., et al., Composite of CH3 NH3 PbI3 with Reduced Graphene Oxide as a Highly Efficient and Stable Visible-Light Photocatalyst for Hydrogen Evolution in Aqueous HI Solution. Adv Mater, 2018. 30(7).68. Xu, Y.F., et al., A CsPbBr3 Perovskite Quantum Dot/Graphene Oxide Composite for Photocatalytic CO2 Reduction. J Am Chem Soc, 2017. 139(16): p. 5660-5663.69. Petrov, A.A., et al., A new formation strategy of hybrid perovskites via room temperature reactive polyiodide melts. Materials Horizons, 2017. 4(4): p. 625-632.70. Mateen, M., et al., High-performance mixed-cation mixed-halide perovskitesolar cells enabled by a facile intermediate engineering technique. Journal of Power Sources, 2020. 448: p. 227386.71. Gonzalez-Carrero, S., et al., Blue-luminescent organic lead bromide perovskites: highly dispersible and photostable materials. Journal of Materials Chemistry A, 2015. 3(26): p. 14039-14045.72. Chen, B.-X., et al., Large-grained perovskite films via FA x MA 1−x Pb(I x Br 1−x ) 3 single crystal precursor for efficient solar cells. Nano Energy, 2017. 34: p. 264-270.73. Liu, T., et al., Inverted Perovskite Solar Cells: Progresses and Perspectives. Advanced Energy Materials, 2016. 6(17).74. Koh, T.M., et al., Nanostructuring Mixed-Dimensional Perovskites: A Route Toward Tunable, Efficient Photovoltaics. Adv Mater, 2016. 28(19): p. 3653-61.75. Yu, D., et al., Dimensionality and Interface Engineering of 2D Homologous Perovskites for Boosted Charge-Carrier Transport and Photodetection Performances. J Phys Chem Lett, 2017. 8(12): p. 2565-2572.76. Cohen, B.-E., M. Wierzbowska, and L. Etgar, High Efficiency and High Open Circuit Voltage in Quasi 2D Perovskite Based Solar Cells. Advanced Functional Materials, 2017. 27(5).77. Hamaguchi, R., et al., Formamidine and cesium-based quasi-two-dimensional perovskites as photovoltaic absorbers. Chem Commun (Camb), 2017. 53(31): p. 4366-4369.78. Liu, J., et al., Observation of Internal Photoinduced Electron and Hole Separation in Hybrid Two-Dimentional Perovskite Films. J Am Chem Soc, 2017. 139(4): p. 1432-1435.79. Chen, S. and G. Shi, Two-Dimensional Materials for Halide Perovskite-Based Optoelectronic Devices. Advanced Materials, 2017. 29(24).80. Gan, X., et al., 2D homologous organic-inorganic hybrids as light-absorbers for planer and nanorod-based perovskite solar cells. Solar Energy Materials and Solar Cells, 2017. 162: p. 93-102.81. Wu, C., et al., Cost-effective sustainable-engineering of CH3NH3PbI3 perovskite solar cells through slicing and restacking of 2D layers. Nano Energy, 2017. 36: p. 295-302.82. Grätzel, M.J.A.o.C.R., The Rise of Highly Efficient and Stable Perovskite Solar Cells. 2017. 50(3): p. 487.83. Abate, A., et al., Perovskite solar cells from the lab to the assembly line. 2017. 24(13).84. Christians, J.A., et al., Tailored interfaces of unencapsulated perovskite solar cells for >1,000 hour operational stability. 2017.85. Arora, N., et al., Perovskite solar cells with CuSCN hole extraction layers yield stabilized efficiencies greater than 20. 2017. 358(6364): p. 768-771.86. Correabaena, J.P., et al., Promises and challenges of perovskite solar cells. 2017. 358(6364): p. 739-744.87. Kim, M., et al., A High Temperature-Short Time Annealing Process for High Performance Large-Area Perovskite Solar Cells. 2017. 11(6): p. acsnano.7b02015.88. Eggenhuisen, T.M., et al., Digital fabrication of organic solar cells by Inkjet printing using non-halogenated solvents. 2015. 134: p. 364-372.89. Li, D., et al., Low-temperature processed amorphous Bi2S3 film as an inorganic electron transport layer for perovskite solar cells. 2016. 3(11): p. acsphotonics.6b00582.90. CE, A., et al., Cell-Specific Delivery of Diverse Cargos by Bacteriophage MS2 Virus-like Particles. 2011. 5(7): p. 5729-5745.91. Ke, W., et al., Low-Temperature Solution-Processed Tin Oxide as an Alternative Electron Transporting Layer for Efficient Perovskite Solar Cells. 2015. 137(21): p. 6730-6733.92. Yu, H., et al., Superfast Room‐Temperature Activation of SnO2 Thin Films via Atmospheric Plasma Oxidation and their Application in Planar Perovskite Photovoltaics. 2018. 30(10).93. Psc, S., et al., Novel Low-Temperature Process for Perovskite Solar Cells with a Mesoporous TiO2 Scaffold. 2017. 9(36): p. 30567-30574.94. Dong, X., et al., High crystallization of a multiple cation perovskite absorber for low-temperature stable ZnO solar cells with high-efficiency of over 20%. 2018. 10(15): p. 7218-7227.95. Liu, Z., et al., 15% efficient carbon based planar-heterojunction perovskite solar cells using a TiO 2/SnO 2 bilayer as the electron transport layer. 2018. 6(17): p. 7409-7419.96. Mahmud, M.A., et al., Adsorbed carbon nanomaterials for surface and interface-engineered stable rubidium multi-cation perovskite solar cells. 2018. 10(2): p. 773-790.97. Deng, X., et al., Room-temperature processing of TiO x electron transporting layer for perovskite solar cells. 2017. 8(14): p. 3206-3210.98. Cui, Q., et al., Improved efficient perovskite solar cells based on Ta-doped TiO 2 nanorod arrays. 2017. 9(47): p. 18897-18907.99. Numata, Y., et al., Nb-doped amorphous titanium oxide compact layer for formamidinium-based high efficiency perovskite solar cells by low-temperature fabrication. 2018. 6(20): p. 9583-9591.100. Mali, S.S., et al., Synthesis of SnO 2 nanofibers and nanobelts electron transporting layer for efficient perovskite solar cells. 2018. 10(17): p. 8275-8284.101. Liu, S., E. Guo, and L.J.J.o.M.C. Yin, Tailored visible-light driven anatase TiO 2 photocatalysts based on controllable metal ion doping and ordered mesoporous structure. 2012. 22(11): p. 5031-5041.102. Liu, H., et al., Nano-structured electron transporting materials for perovskite solar cells. 2016. 8(12): p. 6209-6221.103. Anaya, M., et al., ABX3 perovskites for tandem solar cells. 2017. 1(4): p. 769-793.104. Li, Z., et al., Scalable fabrication of perovskite solar cells. 2018. 3(4): p. 18017.105. Ekimov, A.I., A.L. Efros, and A.A.J.S.S.C. Onushchenko, Quantum size effect in semiconductor microcrystals. 1985. 56(11): p. 921-924.106. Ye, P., et al., Wide bandgap small molecular acceptors for low energy loss organic solar cells. 2017. 5(47): p. 12591-12596.107. Gong, X., et al., Bulk Heterojunction Solar Cells with Large Open‐Circuit Voltage: Electron Transfer with Small Donor‐Acceptor Energy Offset. 2011. 23(20): p. 2272-2277.108. Li, J., et al., Sn doped TiO2 nanotube with oxygen vacancy for highly efficient visible light photocatalysis. 2016. 679: p. 454-462.109. Duan, Y., et al., Sn-doped TiO2 photoanode for dye-sensitized solar cells. 2012. 116(16): p. 8888-8893.110. Harunsani, M.H., et al., Electronic and Structural Properties of Sn x Ti1− x O2 (0.0≤ x≤ 0.1) Solid Solutions. 2010. 22(4): p. 1551-1558.111. Rao, A.R., V.J.S.e.m. Dutta, and s. cells, Low-temperature synthesis of TiO2 nanoparticles and preparation of TiO2 thin films by spray deposition. 2007. 91(12): p. 1075-1080.112. Shaislamov, U. and B.L.J.i.j.o.h.e. Yang, Single crystalline TiO2 nanorods with enhanced visible light activity for solar hydrogen generation. 2013. 38(33): p. 14180-14188.113. Yang, D., et al., Surface optimization to eliminate hysteresis for record efficiency planar perovskite solar cells. 2016. 9(10): p. 3071-3078.114. Shao, S., et al., N-type polymers as electron extraction layers in hybrid perovskite solar cells with improved ambient stability. 2016. 4(7): p. 2419-2426.115. Peng, W., et al., Influence of growth temperature on bulk and surface defects in hybrid lead halide perovskite films. 2016. 8(3): p. 1627-1634.116. Jones, M. and G.D.J.J.o.M.C. Scholes, On the use of time-resolved photoluminescence as a probe of nanocrystal photoexcitation dynamics. 2010. 20(18): p. 3533-3538.117. Shalan, A.E., et al., Optimization of a compact layer of TiO 2 via atomic-layer deposition for high-performance perovskite solar cells. 2017. 1(7): p. 1533-1540.118. Saliba, M., et al., Incorporation of rubidium cations into perovskite solar cells improves photovoltaic performance. Science, 2016. 354(6309): p. 206-209.119. Chen, W., et al., Efficient and stable large-area perovskite solar cells with inorganic charge extraction layers. Science, 2015. 350(6263): p. 944-948.120. Tsai, H., et al., High-efficiency two-dimensional Ruddlesden–Popper perovskite solar cells. Nature, 2016. 536(7616): p. 312-316.121. Xiao, Z., et al., Solvent annealing of perovskite‐induced crystal growth for photovoltaic‐device efficiency enhancement. Advanced Materials, 2014. 26(37): p. 6503-6509.122. (NREL), N.R.E.L. Best Research-Cell Efficiencies Chart. 2021; Available from: https://www.nrel.gov/pv/cell-efficiency.html.123. Kang, D.H. and N.G. Park, On the current–voltage hysteresis in perovskite solar cells: dependence on perovskite composition and methods to remove hysteresis. Advanced Materials, 2019. 31(34): p. 1805214.124. Boyd, C.C., et al., Overcoming Redox Reactions at Perovskite-Nickel Oxide Interfaces to Boost Voltages in Perovskite Solar Cells. Joule, 2020. 4(8): p. 1759-1775.125. Tan, H., et al., Efficient and stable solution-processed planar perovskite solar cells via contact passivation. Science, 2017. 355(6326): p. 722-726.126. Zheng, X., et al., Defect passivation in hybrid perovskite solar cells using quaternary ammonium halide anions and cations. Nature Energy, 2017. 2(7): p. 1-9.127. Peng, J., et al., Interface passivation using ultrathin polymer–fullerene films for high-efficiency perovskite solar cells with negligible hysteresis. Energy & Environmental Science, 2017. 10(8): p. 1792-1800.128. Gao, F., et al., Recent progresses on defect passivation toward efficient perovskite solar cells. Advanced Energy Materials, 2020. 10(13): p. 1902650.129. Tress, W., et al., Inverted current–voltage hysteresis in mixed perovskite solar cells: polarization, energy barriers, and defect recombination. Advanced Energy Materials, 2016. 6(19): p. 1600396.130. Zhang, S., et al., Evaporated potassium chloride for double-sided interfacial passivation in inverted planar perovskite solar cells. Journal of Energy Chemistry, 2020. 54: p. 493-500.131. Chen, L., et al., Compact layer influence on hysteresis effect in organic–inorganic hybrid perovskite solar cells. Electrochemistry Communications, 2016. 68: p. 40-44.132. Shao, Y., Y. Yuan, and J. Huang, Correlation of energy disorder and open-circuit voltage in hybrid perovskite solar cells. Nature Energy, 2016. 1(1): p. 1-6.133. Li, X., et al., Improved performance and stability of perovskite solar cells by crystal crosslinking with alkylphosphonic acid ω-ammonium chlorides. Nature chemistry, 2015. 7(9): p. 703-711.134. Azpiroz, J.M., et al., Defect migration in methylammonium lead iodide and its role in perovskite solar cell operation. Energy & Environmental Science, 2015. 8(7): p. 2118-2127.135. Yang, W.S., et al., High-performance photovoltaic perovskite layers fabricated through intramolecular exchange. Science, 2015. 348(6240): p. 1234-1237.136. Rashad, M., et al., Enhancement of TiO 2 nanoparticle properties and efficiency of dye-sensitized solar cells using modifiers. Applied Nanoscience, 2013. 3(2): p. 167-174.137. Zhang, F., et al., Over 20% PCE perovskite solar cells with superior stability achieved by novel and low-cost hole-transporting materials. Nano Energy, 2017. 41: p. 469-475.138. Wang, Q., et al., Scaling behavior of moisture-induced grain degradation in polycrystalline hybrid perovskite thin films. Energy & Environmental Science, 2017. 10(2): p. 516-522.139. Ke, W., et al., Low-temperature solution-processed tin oxide as an alternative electron transporting layer for efficient perovskite solar cells. Journal of the American Chemical Society, 2015. 137(21): p. 6730-6733.140. Ke, W., et al., Effects of annealing temperature of tin oxide electron selective layers on the performance of perovskite solar cells. Journal of Materials Chemistry A, 2015. 3(47): p. 24163-24168.141. Jiang, Q., et al., Enhanced electron extraction using SnO 2 for high-efficiency planar-structure HC (NH 2) 2 PbI 3-based perovskite solar cells. Nature Energy, 2016. 2(1): p. 1-7.142. Shao, Y., et al., Origin and elimination of photocurrent hysteresis by fullerene passivation in CH 3 NH 3 PbI 3 planar heterojunction solar cells. Nature communications, 2014. 5(1): p. 1-7.143. Bi, C., et al., Spontaneous passivation of hybrid perovskite by sodium ions from glass substrates: mysterious enhancement of device efficiency revealed. ACS Energy Letters, 2017. 2(6): p. 1400-1406.144. Wojciechowski, K., et al., C60 as an efficient n-type compact layer in perovskite solar cells. The journal of physical chemistry letters, 2015. 6(12): p. 2399-2405.145. Wang, C., et al., Low-temperature plasma-enhanced atomic layer deposition of tin oxide electron selective layers for highly efficient planar perovskite solar cells. Journal of Materials Chemistry A, 2016. 4(31): p. 12080-12087.146. Jiang, J., et al., ITIC surface modification to achieve synergistic electron transport layer enhancement for planar-type perovskite solar cells with efficiency exceeding 20%. Journal of Materials Chemistry A, 2017. 5(20): p. 9514-9522.147. Liu, X., et al., Exploring Inorganic Binary Alkaline Halide to Passivate Defects in Low‐Temperature‐Processed Planar‐Structure Hybrid Perovskite Solar Cells. Advanced Energy Materials, 2018. 8(20): p. 1800138.148. Abdi-Jalebi, M., et al., Maximizing and stabilizing luminescence from halide perovskites with potassium passivation. Nature, 2018. 555(7697): p. 497-501.149. Saidaminov, M.I., et al., High-quality bulk hybrid perovskite single crystals within minutes by inverse temperature crystallization. Nature communications, 2015. 6(1): p. 1-6.150. Li, D., et al., Bifunctional Ultrathin PCBM Enables Passivated Trap States and Cascaded Energy Level toward Efficient Inverted Perovskite Solar Cells. ACS Applied Materials & Interfaces, 2020. 12(17): p. 20103-20109.151. Yang, S., et al., Tailoring passivation molecular structures for extremely small open-circuit voltage loss in perovskite solar cells. Journal of the American Chemical Society, 2019. 141(14): p. 5781-5787.152. Maiberg, M., et al., Theoretical study of time-resolved luminescence in semiconductors. III. Trap states in the band gap. Journal of Applied Physics, 2015. 118(10): p. 105701.153. Duan, J., et al., Lanthanide Ions Doped CsPbBr3 Halides for HTM‐Free 10.14%‐Efficiency Inorganic Perovskite Solar Cell with an Ultrahigh Open‐Circuit Voltage of 1.594 V. Advanced Energy Materials, 2018. 8(31): p. 1802346.154. Xie, F., et al., Vertical recrystallization for highly efficient and stable formamidinium-based inverted-structure perovskite solar cells. Energy & Environmental Science, 2017. 10(9): p. 1942-1949.155. Chen, S., et al., Understanding the Interplay of Binary Organic Spacer in Ruddlesden–Popper Perovskites toward Efficient and Stable Solar Cells. Advanced Functional Materials, 2020. 30(10): p. 1907759.156. Yue, S., et al., Efficacious engineering on charge extraction for realizing highly efficient perovskite solar cells. Energy & Environmental Science, 2017. 10(12): p. 2570-2578.157. Tavakoli, M.M., et al., Mesoscopic Oxide Double Layer as Electron Specific Contact for Highly Efficient and UV Stable Perovskite Photovoltaics. Nano Letters, 2018. 18(4): p. 2428-2434.158. Snaith, H.J., Perovskites: the emergence of a new era for low-cost, high-efficiency solar cells. The journal of physical chemistry letters, 2013. 4(21): p. 3623-3630.159. Burschka, J., et al., Sequential deposition as a route to high-performance perovskite-sensitized solar cells. Nature, 2013. 499(7458): p. 316-319.160. Prathapani, S., P. Bhargava, and S. Mallick, Electronic band structure and carrier concentration of formamidinium–cesium mixed cation lead mixed halide hybrid perovskites. Applied Physics Letters, 2018. 112(9): p. 092104.161. Cheng, X., et al., Single crystal perovskite solar cells: development and perspectives. Advanced Functional Materials, 2020. 30(4): p. 1905021.162. Jiang, Q., et al., Surface passivation of perovskite film for efficient solar cells. Nature Photonics, 2019. 13(7): p. 460-466.163. de Quilettes, D.W., et al., Impact of microstructure on local carrier lifetime in perovskite solar cells. Science, 2015. 348(6235): p. 683-686.164. Bai, Y., et al., Oligomeric silica-wrapped perovskites enable synchronous defect passivation and grain stabilization for efficient and stable perovskite photovoltaics. ACS Energy Letters, 2019. 4(6): p. 1231-1240.165. Bi, D., et al., High‐performance perovskite solar cells with enhanced environmental stability based on amphiphile‐modified CH3NH3PbI3. Advanced Materials, 2016. 28(15): p. 2910-2915.166. Luo, D., et al., Enhanced photovoltage for inverted planar heterojunction perovskite solar cells. Science, 2018. 360(6396): p. 1442-1446.167. Ding, J., et al., Cesium Decreases Defect Density and Enhances Optoelectronic Properties of Mixed MA1–x Cs x PbBr3 Single Crystal. The Journal of Physical Chemistry C, 2019. 123(24): p. 14969-14975.168. Dang, Y., et al., Formation of hybrid perovskite tin iodide single crystals by top‐seeded solution growth. Angewandte Chemie International Edition, 2016. 55(10): p. 3447-3450.169. Liu, Y., et al., A 1300 mm2 ultrahigh‐performance digital imaging assembly using high‐quality perovskite single crystals. Advanced Materials, 2018. 30(29): p. 1707314.170. Dong, Q., et al., Electron-hole diffusion lengths> 175 μm in solution-grown CH3NH3PbI3 single crystals. Science, 2015. 347(6225): p. 967-970.171. Wang, X.D., et al., Recent Advances in Halide Perovskite Single‐Crystal Thin Films: Fabrication Methods and Optoelectronic Applications. Solar RRL, 2019. 3(4): p. 1800294.172. Chen, Z., et al., Single-crystal MAPbI3 perovskite solar cells exceeding 21% power conversion efficiency. ACS Energy Letters, 2019. 4(6): p. 1258-1259.173. Wang, K., et al., Mono-crystalline perovskite photovoltaics toward ultrahigh efficiency? Joule, 2019. 3(2): p. 311-316.174. Liu, Y., et al., Surface-tension-controlled crystallization for high-quality 2D perovskite single crystals for ultrahigh photodetection. Matter, 2019. 1(2): p. 465-480.175. Pan, W., et al., Cs 2 AgBiBr 6 single-crystal X-ray detectors with a low detection limit. Nature photonics, 2017. 11(11): p. 726-732.176. Li, W.-G., et al., A formamidinium–methylammonium lead iodide perovskite single crystal exhibiting exceptional optoelectronic properties and long-term stability. Journal of Materials Chemistry A, 2017. 5(36): p. 19431-19438.177. Hutter, E.M., et al., Direct–indirect character of the bandgap in methylammonium lead iodide perovskite. Nature materials, 2017. 16(1): p. 115-120.178. Liu, Y., et al., Thinness‐and shape‐controlled growth for ultrathin single‐crystalline perovskite wafers for mass production of superior photoelectronic devices. Advanced materials, 2016. 28(41): p. 9204-9209.179. Chen, Z., et al., Thin single crystal perovskite solar cells to harvest below-bandgap light absorption. Nature communications, 2017. 8(1): p. 1-7.180. Brenner, T.M., D. a. Egger, L. Kronik, G. Hodes, D. Cahen. Nat. Rev. Mater, 2016. 1: p. 15007.181. Zhu, H., et al., Lead halide perovskite nanowire lasers with low lasing thresholds and high quality factors. Nature materials, 2015. 14(6): p. 636-642.182. Chen, Z., et al., Efficient inorganic solar cells from aqueous nanocrystals: the impact of composition on carrier dynamics. RSC advances, 2015. 5(91): p. 74263-74269.183. Huang, J., Y. Shao, and Q. Dong, Organometal trihalide perovskite single crystals: a next wave of materials for 25% efficiency photovoltaics and applications beyond? The Journal of Physical Chemistry Letters, 2015. 6(16): p. 3218-3227.184. Luan, M., et al., Controllable growth of bulk cubic-phase CH 3 NH 3 PbI 3 single crystal with exciting room-temperature stability. CrystEngComm, 2016. 18(28): p. 5257-5261.185. Eames, C., et al., Ionic transport in hybrid lead iodide perovskite solar cells. Nature communications, 2015. 6(1): p. 1-8.186. Shao, Y., et al., Grain boundary dominated ion migration in polycrystalline organic–inorganic halide perovskite films. Energy & Environmental Science, 2016. 9(5): p. 1752-1759.187. Dang, Y., et al., Bulk crystal growth of hybrid perovskite material CH 3 NH 3 PbI 3. CrystEngComm, 2015. 17(3): p. 665-670.188. Zhumekenov, A.A., et al., The role of surface tension in the crystallization of metal halide perovskites. ACS Energy Letters, 2017. 2(8): p. 1782-1788.189. Liu, Y., et al., 20‐mm‐Large single‐crystalline formamidinium‐perovskite wafer for mass production of integrated photodetectors. Advanced Optical Materials, 2016. 4(11): p. 1829-1837.190. Wang, Y., et al., High‐Temperature Ionic Epitaxy of Halide Perovskite Thin Film and the Hidden Carrier Dynamics. Advanced Materials, 2017. 29(35): p. 1702643.191. Yin, J., G. Zhang, and X. Tao, A fractional crystallization technique towards pure mega-size CsPb 2 Br 5 single crystal films. CrystEngComm, 2019. 21(9): p. 1352-1357.192. Liu, Y., et al., Multi-inch single-crystalline perovskite membrane for high-detectivity flexible photosensors. Nature communications, 2018. 9(1): p. 1-11.193. Saidaminov, M.I., et al., Retrograde solubility of formamidinium and methylammonium lead halide perovskites enabling rapid single crystal growth. Chemical communications, 2015. 51(100): p. 17658-17661.194. Su, J., D. Chen, and C. Lin, Growth of large CH3NH3PbX3 (X= I, Br) single crystals in solution. Journal of Crystal Growth, 2015. 422: p. 75-79.195. Chen, P., et al., Progress and Perspective in Low‐Dimensional Metal Halide Perovskites for Optoelectronic Applications. Solar Rrl, 2018. 2(3): p. 1700186.196. Cao, D.H., et al., 2D homologous perovskites as light-absorbing materials for solar cell applications. Journal of the American Chemical Society, 2015. 137(24): p. 7843-7850.197. Rao, H.-S., et al., A micron-scale laminar MAPbBr 3 single crystal for an efficient and stable perovskite solar cell. Chemical communications, 2017. 53(37): p. 5163-5166.198. Li, W.-G., et al., A laminar MAPbBr 3/MAPbBr 3− x I x graded heterojunction single crystal for enhancing charge extraction and optoelectronic performance. Journal of Materials Chemistry C, 2019. 7(19): p. 5670-5676.199. Gu, Z., et al., A general printing approach for scalable growth of perovskite single-crystal films. Science advances, 2018. 4(6): p. eaat2390.200. Schlipf, J., et al., Top-Down approaches towards single crystal perovskite solar cells. Scientific reports, 2018. 8(1): p. 1-8.201. Lv, Q., et al., A universal top-down approach toward thickness-controllable perovskite single-crystalline thin films. Journal of Materials Chemistry C, 2018. 6(16): p. 4464-4470.202. Detchprohm, T., K. Hiramatsu, H. Amano, and I. Akasaki. Appl. Phys. Lett, 1992. 61: p. 2668.203. Chen, J., et al., Single-crystal thin films of cesium lead bromide perovskite epitaxially grown on metal oxide perovskite (SrTiO3). Journal of the American Chemical Society, 2017. 139(38): p. 13525-13532.204. Liu, Y., et al., Fast growth of thin MAPbI3 crystal wafers on aqueous solution surface for efficient lateral‐structure perovskite solar cells. Advanced Functional Materials, 2019. 29(47): p. 1807707.205. Yang, S., et al., Ultrathin two‐dimensional organic–inorganic hybrid perovskite nanosheets with bright, tunable photoluminescence and high stability. Angewandte Chemie International Edition, 2017. 56(15): p. 4252-4255.206. Stoumpos, C.C., et al., Ruddlesden–Popper hybrid lead iodide perovskite 2D homologous semiconductors. Chemistry of Materials, 2016. 28(8): p. 2852-2867.207. Wang, J., et al., Investigation of Electrode Electrochemical Reactions in CH3NH3PbBr3 Perovskite Single‐Crystal Field‐Effect Transistors. Advanced Materials, 2019. 31(35): p. 1902618.208. Yao, F., et al., Room-temperature liquid diffused separation induced crystallization for high-quality perovskite single crystals. Nature communications, 2020. 11(1): p. 1-9.209. Li, R., et al., Zn doped MAPbBr 3 single crystal with advanced structural and optical stability achieved by strain compensation. Nanoscale, 2020. 12(6): p. 3692-3700.210. Nie, W., et al., High-efficiency solution-processed perovskite solar cells with millimeter-scale grains. Science, 2015. 347(6221): p. 522-525.