Carbon Nanomaterials for Efficient Perovskite Solar Cells


Carbon Nanomaterials for Efficient Perovskite Solar Cells

T. Swetha, Surya Prakash Singh

Metal halide perovskite solar cells (PSCs) have become the future candidates for the replacement of silicon solar cells with an efficiency exceeding 25%. PSCs have significant features like high absorption coefficient, better carrier mobility, and tunable bandgap. Despite these advantages, there are various challenges to reaching better efficiency, durability, and cost-effectiveness. To address these challenges, there is a necessity to develop new materials and modification of the conventional device architecture. In this scenario, Carbon nanotubes (CNTs) have emerged as the promising component for fabricating the PSCs. CNTs have attractive features that can offer unique advantages to enhance stability and device performance. In this chapter, we have discussed the utilization of CNTs in PSCs.

Perovskite Solar Cells, Photovoltaic Applications, Electrodes, Hole-transporting Materials, Carbon Nanotubes

Published online 11/15/2022, 22 pages

Citation: T. Swetha, Surya Prakash Singh, Carbon Nanomaterials for Efficient Perovskite Solar Cells, Materials Research Foundations, Vol. 135, pp 178-199, 2023


Part of the book on Emerging Nanomaterials and Their Impact on Society in the 21st Century

[1] M. Grätzel, Dye-sensitized solar cells J. Photochem. and Photobiol. C: Photochem. Rev. 4 (2003) 145-153.
[2] S. Gunes, H. Neugebauer, N. S. Sariciftci, conjugated polymer-based organic solar cells, Chem. Rev. 107 (2007) 1324-1338.
[3] I. J. Kramer, E. H. Sargent, Colloidal Quantum Dot Photovoltaics: A Path Forward, ACS Nano. 5 (2011) 8506-8514.
[4] S. D. Stranks, G. E. Eperon, G. Grancini, C. Menelaou, M. J. P. Alcocer, T. Leijtens, L. M. Herz, A. Petrozza, H. J. Snaith, Electron-hole diffusion lengths exceeding 1 micrometer in an organometal trihalide perovskite absorber, Science. 342 (2013) 341-344.
[5] G. C. Xing, N. Mathews, S. Y. Sun, S. S. Lim, Y. M. Lam, M. Grätzel, S. Mhaisalkar, T. C. Sum, Long-range balanced electron- and hole-transport lengths in organic-inorganic CH3NH3PbI3, Science. 342 (2013) 344-347.
[6] H. S. Kim, C. R. Lee, J. H. Im, K. B. Lee, T. Moehl, A. Marchioro, S. J. Moon, R. Humphry-Baker, J. H. Yum, J. E. Moser, M. Grätzel, N-G, Park, Lead iodide perovskite sensitized all-solid-state submicron thin film mesoscopic solar cell with efficiency exceeding 9%, Sci. Rep. 2 (2012) 591.
[7] S. D. Stranks, Nonradiative losses in metal halide perovskites, ACS Energy Lett. 2 (2017) 1515-1525.
[8] M. Liu, M. B. Johnston, H. J. Snaith, Efficient planar heterojunction perovskite solar cells by vapour deposition, Nature 501 (2013) 395-398.
[9] N. Aristidou, C. Eames, I. Sanchez-Molina, X. Bu, J. Kosco, M. S. Islam, S. A. Haque, Fast oxygen diffusion and iodide defects mediate oxygen-induced degradation of perovskite solar cells, Nat. Commun. 8 (2017), 15218.
[10] Q. Dong, Y. Fang, Y. Shao, P. Mulligan, J. Qiu, L. Cao, J. Huang, Electron-hole diffusion lengths > 175 μm in solution-grown CH3NH3PbI3 single crystals, Science. 347 (2015) 967-970.
[11] A. Kojima, K. Teshima, Y. Shirai, T. Miyasaka, Organometal halide perovskites as visible-light sensitizers for photovoltaic cells. J. Am. Chem. Soc. 131 (2009) 6050-6051.
[12] J.-H. Im, C. R. Lee, J. W. Lee, S. W. Park, N. G. Park, 6.5% efficient perovskite quantum-dot-sensitized solar cell, Nanoscale, 3 (2011) 4088-4093.
[13] J. H.; Jang, I. H.; Pellet, N.; Grätzel, M.; Park, N. G. Growth of CH3NH3PbI3 cuboids with controlled size for high-efficiency perovskite solar cells Nat. Nanotechnol. 9 (2014) 927-932.
[14] H. Zhou, Q. Chen, G. Li, S. Luo, T. B. Song, H. Duan, Z. Hong, J. You, Y. Liu, Y. Yang, Interface engineering of highly efficient perovskite solar cells Science 345 (2014) 542-546.
[15] J. Burschka, N. Pellet, S. J. Moon, R. Humphry-Baker, P. Gao, M. K. Nazeeruddin, M. Grätzel, Sequential deposition as a route to high-performance perovskite-sensitized solar cells, Nature, 499 (2013) 316-319.
[16] Y. Rong, Y. Hu, A. Mei, H. Tan, M. I. Saidaminov, S. I. Seok, M. D. McGehee, E. H. Sargent, H. Han, Challenges for commercializing perovskite solar cells Science, 361 (2018) 1214-1220.
[17] J. Correa-Baena, M. Saliba, T. Buonassisi, M. Grätzel, A. Abate, W. Tress, A. Hagfeldt, Promises and challenges of perovskite solar cells, Science. 358 (2017) 739-744.
[18] R. Wang, M. Mujahid, Y. Duan, Z. Wang, J. Xue, Y. Yang, A Review of Perovskites Solar Cell Stability, A Review of Perovskites Solar Cell Stability, Adv. Funct. Mater. 29 (2019) 1808843.
[19] C. C. Boyd, R. Cheacharoen, T. Leijtens, M. D. Understanding degradation mechanisms and improving stability of perovskite photovoltaics, Chem. Rev. 119 (2019) 3418-3451.
[20] M. Cai, Y. Wu, H. Chen, X. Yang, Y. Qiang, L. Han, Cost-Performance Analysis of Perovskite Solar Modules, Cost-Performance Analysis of Perovskite Solar Modules, Adv. Sci. 4 (2017) 1600269.
[21] H. Tsai, W. Nie, J. Blancon, C. C. Stoumpos, R. Asadpour, B. Harutyunyan, A. J. Neukirch, R. Verduzco, J. J. Crochet, S. Tretiak, L. Pedesseau, J. Even, M. A. Alam, G. Gupta, J. Lou, P. M. Ajayan, M. J. Bedzyk, M. G. Kanatzidis, A. D. Mohite, High-efficiency two-dimensional Ruddlesden-Popper perovskite solar cells, Nature. 536 (2016) 312-316.
[22] H. Chen, F. Ye, W. Tang, J. He, M. Yin, Y. Wang, F. Xie, E. Bi, X. Yang, M. Grätzel, L. Han, A solvent- and vacuum-free route to large-area perovskite films for efficient solar modules, Nature. 550 (2017) 92-95.
[23] S. Turren-Cruz, A. Hagfeldt, M. Saliba, Methylammonium-free, high-performance, and stable perovskite solar cells on a planar architecture, Science. 362 (2018) 449-453.
[24] H. Min, M. Kim, S. Lee, H. Kim, G. Kim, K. Choi, J. H. Lee, S. I. Seok, Efficient, stable solar cells by using inherent bandgap of α-phase formamidinium lead iodide, Science. 366 (2019) 749-753.
[25] Y. Wang, M. I. Dar, L. K. Ono, T. Zhang, M. Kan, Y. Li, L. Zhang, X. Wang, Y. Yang, X. Gao, Y. Qi, M. Grätzel, Y. Zhao, Thermodynamically stabilized β-CsPbI 3-based perovskite solar cells with efficiencies >18, Science. 2019, 365, 591-595.
[26] Q. Jiang, L. Wang, C. Yan, C. Liu, Z. Guo, N. Wang, Nano-mesoporous TiO2 Vacancies Modification for Halide Perovskite Solar Cells, Eng Sci. 1 (2018) 64-68.
[27] E. H. Jung, N. J. Jeon, E. Y. Park, C. S. Moon, T. J. Shin, T. Yang, J. H. Noh, J. Seo, Efficient, stable and scalable perovskite solar cells using poly(3-hexylthiophene), Nature. 567 (2019) 511-515.
[28] R. G. Chaudhary, A. K. Potbhare, P. B. Chouke, A. R. Rai, R.P. Mishra, M. Desimone, A. Abdala, Graphene-Based Nanomaterials and their Nanocomposites with Metal Oxides: Biosynthesis, Electrochemical, Photocatalytic and Antimicrobial Applications, Magnetic Oxides and Composites II, Materials Research Forum, 83 (2020) 79-116.
[29] A. U. Chaudhry, A. Abdala, S. P. Lonkar, R. G. Chudhary, A. Mabrouk, Thermal, electrical, and mechanical properties of highly filled HDPE/graphite nanoplatelets composites, Mater. Today: Proc, 29 (2020) 704-708.
[30] S. N. Habisreutinger, T. Leijtens, G. E. Eperon, S. D. Stranks, R. J. Nicholas, H. J. Snaith, Enhanced Hole Extraction in Perovskite Solar Cells Through Carbon Nanotubes J. Phys. Chem. Lett. 5 (2014) 4207-4212.
[31] S. Iijima, Helical microtubules of graphitic carbon, Nature. 354 (1991) 56-58.
[32] S. Iijima, T. Ichihashi, Single-shell carbon nanotubes of 1-nm diameter, Nature. 363 (1993) 603-605.
[33] Z. Ku, Y. Rong, M. Xu, T. Liu, H. Han, Full printable processed mesoscopic CH₃NH₃PbI₃/TiO₂ heterojunction solar cells with carbon counter electrode, Sci. Rep. 3 (2013) 3132.
[34] R. K. Mishra, K. Verma, R. G. Chaudhary, T. Lambat, K. Joseph, An efficient fabrication of polypropylene hybrid nanocomposites using carbon nanotubes and PET fibrils, Mater. Today: Proc, 29 (2020) 794-800.
[35] H. Chen, S. Yang, Carbon-Based Perovskite Solar Cells without Hole Transport Materials: The Front Runner to the Market? Adv. Mater. 29 (2017) 1603994.
[36] L. Fagiolari, F. Bella, Carbon-based materials for stable, cheaper and large-scale processable perovskite solar cells, Energy Environ. Sci. 12 (2019) 3437-3472.
[37] P. M. Ajayan, Nanotubes from Carbon, Chem. Rev. 99 (1999) 1787-1800.
[38] T. Belin, F. Epron, Characterization methods of carbon nanotubes: a review. J. Mater. Sci. Eng. B 119 (2005) 105-118.
[39] M. S. Dresselhaus, G. Dresselhaus, A. Jorio, Unusual properties and structure of carbon nanotubes Annu. Rev. Mater. Res. 34 (2004) 247-278.
[40] Y. Maeda, S. Kimura, M. Kanda, Y. Hirashima, T. Hasegawa, T. Wakahara, Y. Lian, T. Nakahodo, T. Tsuchiya, T. Akasaka, J. Lu, X. Zhang, Y. Yu, S. Nagase, S. Kazaoui, N. Minami, T. Shimizu, H. Tokumoto, R. Saito, Large-scale separation of metallic and semiconducting single-walled carbon nanotubes, J. Am. Chem. Soc. 127 (2005) 10287-10290.
[41] Liu, Y. Cheng, Z. Ge, Understanding of perovskite crystal growth and film formation in scalable deposition processes, Chem. Soc. Rev. 49 (2020) 1653-1687.
[42] J. Jiang, J. Xu, H. Walter, A. Kazi, D. Wang, G. Wangila, M. Mortazavi, C. Yan, Q. Jiang, The doping of alkali metal for halide perovskites, ES Mater. Manuf. 7 (2020) 25-33.
[43] E. Aydin, M. De Bastiani, S. De Wolf, Defect and Contact Passivation for Perovskite Solar Cells, Adv. Mater. 31 (2019) 1900428.
[44] H. D. Kim, H. Ohkita, H. Benten, S. Ito, Photovoltaic performance of perovskite solar cells with different grain sizes, Adv. Mater. 28 (2016) 917-922.
[45] W. Nie, H. Tsai, R. Asadpour, J. Blancon, A. J. Neukirch, G. Gupta, J. J. Crochet, M. Chhowalla, S. Tretiak, M. A. Alam, H. Wang, A. D. Mohite, High-efficiency solution-processed perovskite solar cells with millimeter-scale grains, Science. 347 (2015) 522-525.
[46] D. W. de Quilettes, S. M. Vorpahl, S. D. Stranks, H. Nagaoka, G. E. Eperon, M. E. Ziffer, H. J. Snaith, D. S. Ginger, Impact of microstructure on local carrier lifetime in perovskite solar cells, Science 348 (2015) 683-686.
[47] F. Zhang, K. Zhu, Additive engineering for efficient and stable perovskite solar cells, Adv. Energy Mater. 10 (2020) 1902579.
[48] S. Liu, Y. Guan, Y. Sheng, Y. Hu, Y. Rong, A. Mei, H. Han, A review on additives for halide perovskite solar cells, Adv. Energy Mater. 10 (2020) 1902492.
[49] R. Liu, K. Xu, Micro, Solvent engineering for perovskite solar cells: a review, Nano Lett. 2020, 15, 349-353.
[50] A. Dubey, N. Adhikari, S. Mabrouk, F. Wu, K. Chen, S. Yang, Q. Qiao, A strategic review on processing routes towards highly efficient perovskite solar cells, J. Mater. Chem. A 6 (2018) 2406-2431.
[51] Y. Chen, M. He, J. Peng, Y. Sun, Z. Liang, structure and growth control of organic-inorganic halide perovskites for optoelectronics: from polycrystalline films to single crystals, Adv. Sci. 3 (2016) 1500392.
[52] Li, H. Wang, D. Kufer, L. Liang, W. Yu, E. Alarousu, C. Ma, Y. Li, Z. Liu, C. Liu, N. Wei, F. Wang, L. Chen, O. F. Mohammed, A. Fratalocchi, X. Liu, G. Konstantatos, T. Wu, Ultrahigh carrier mobility achieved in photoresponsive hybrid perovskite films via coupling with single-walled carbon nanotubes, Adv. Mater. 29 (2017) 1602432.
[53] Y. Zhang, L. Tan, Q. Fu, L. Chen, T. Ji, X. Hua, Y. Chen, Enhancing the grain size of organic halide perovskites by sulfonate-carbon nanotube incorporation in high performance perovskite solar cells, Chem. Commun., 52 (2016) 5674-5677.
[54] M. Bag, L. A.Renna, S. P. Jeong, X. Han ,C. L.Cutting, D.Maroudas, D.Venkataraman, Evidence for reduced charge recombination in carbon nanotube/perovskite-based active layers, Chem. Phys. Lett. 662 (2016) 35-41.
[55] S. Seo, Il Jeon, R. Xiang, C. Lee, H. Zhang, T. Tanaka, J-W Lee, D. Suh, T. Ogamoto, R. Nishikubo,e A. Saeki, S. Chiashi, J. Shiomi, H. Kataura, H. M. Lee, Y. Yang, Y. Matsuo, S. Maruyama , Semiconducting carbon nanotubes as crystal growth templates and grain bridges in perovskite solar cells, J. Mater. Chem. A, 7 (2019) 12987-12992
[56] H. Lin, S. Okawa, Y. Ma, S. Yotsumoto, C. Lee, S. Tan, S. Manzhos, M. Yoshizawa, S. Chiashi, H. M. Lee, T. Tanaka, H. Kataura, I. Jeon, Y. Matsuo, S. Maruyama, Polyaromatic nanotweezers on semiconducting carbon nanotubes for the growth and interfacing of lead halide perovskite crystal grains in solar cells, Chem. Mater. 32 (2020) 5125.
[57] Y. Wang, W. Li, T. Zhang, D. Li, M. Kan, X. Wang, X. Liu, T. Wang,Y. Zhao, Highly Efficient (110) Orientated FA-MA mixed cation perovskite solar cells via functionalized carbon nanotube and methylammonium chloride additive, Small Methods, 4 (2020) 1900511.
[58] N. Cheng, P. Liu, F. Qi, Y. Xiao, W. Yu, Z. Yu, W. Liu, S. Guo, X. Zhao, Effect of oxygen plasma treatment on the electrochemical performance of the rayon and polyacrylonitrile based carbon felt for the vanadium redox flow battery application, J. Power Sources 332 (2016) 24-29.
[59] S. S. Hosseini, M. Adelifard. The effect of multi-walled carbon nanotubes and reduced graphene oxide doping on the optical and photovoltaic performance of Ag2B1I5-based solar cells, J. Electron. Mater. 49 (2020) 5790-5800.
[60] V. T. Tiong, N. D. Pham, T. Wang, T. Zhu, X. Zhao, Y. Zhang, Q. Shen, J. Bell, L. Hu, S. Dai, H. Wang, Octadecylamine-functionalized single-walled carbon nanotubes for facilitating the formation of a monolithic perovskite layer and stable solar cells, Adv. Funct. Mater. 28 (2018) 1705545.
[61] M. M. Lee, J. Teuscher, T. Miyasaka, T. N. Murakami, H. J. Snaith, Efficient hybrid solar cells based on meso-superstructured organometal halide perovskites., Science. 338 (2012) 643-647.
[62] T. Leijtens, J. Lim, J. Teuscher, T. Park and H. J. Snaith, Charge Density Dependent mobility of organic hole-transporters and mesoporous tio2 determined by transient mobility spectroscopy: implications to dye-sensitized and organic solar cells, Adv. Mater., 25 (2013) 3227-3233.
[63] Z. Li, S. a Kulkarni, P. P. Boix, E. Shi, A. Cao, K. Fu, S. K. Batabyal, J. Zhang, Q. Xiong, L.H. Wong, N. Mathews and S. G. Mhaisalkar, Laminated carbon nanotube networks for metal electrode-free efficient perovskite solar cells, ACS Nano. 8 (2014) 6797-6804.
[64] A. Mei, X. Li, L. Liu, Z. Ku, T. Liu, Y. Rong, M. Xu, M. Hu, J. Chen, Y. Yang, M. Grätzel and H. Han, S, A hole-conductor-free, fully printable mesoscopic perovskite solar cell with high stability, Science. 345 (2014) 295-298.
[65] H. Zhou, Y. Shi, Q. Dong, H. Zhang, Y. Xing, K. Wang, Y. Du and T. Ma, Hole-conductor-free, metal-electrode-free TiO2/ CH3NH3PbI3 heterojunction solar cells based on a low-temperature carbon electrode, J. Phys. Chem. Lett. 5 (2014) 3241-3246.
[66] X. Xu, Z. Liu, Z. Zuo, M. Zhang, Z. Zhao, Y. Shen, H. Zhou, Q. Chen, Y. Yang and M. Wang, Hole selective NiO contact for efficient perovskite solar cells with carbon electrode, Nano Lett. 15 (2015) 2402-2408.
[67] S. N. Habisreutinger, 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. 14 (2014) 5561-5568.
[68] S. N. Habisreutinger, T. Leijtens, G. E. Eperon, S. D. Stranks, R. J. Nicholas and H. J. Snaith, Enhanced hole extraction in perovskite solar cells through carbon nanotubes, J. Phys. Chem. Lett. 5 (2014) 4207-4212.
[69] A. Du Pasquier, H. E. Unalan, A. Kanwal, S. Miller, and M. Chhowalla, Conducting and transparent single-wall carbon nanotube electrodes for polymer-fullerene solar cells, Appl. Phys. Lett. 87 (2005) 1-3.
[70] K. Aitola, A. Kaskela, J. Halme, V. Ruiz, A. G. Nasibulin, E. I. Kauppinen and P. D. Lund, Single-walled carbon nanotube thin-film counter electrodes for indium tin oxide-free plastic dye solar cells, J. Electrochem. Soc. 157 (2010) B1831-B1837.
[71] K. Aitola, J. Halme, S. Feldt, P. Lohse, M. Borghei, A. Kaskela, A. G. Nasibulin, E. I. Kauppinen, P. D. Lund, G. Boschloo and A. Hagfeldt, Highly catalytic carbon nanotube counter electrode on plastic for dye solar cells utilizing cobalt-based redox mediator, Electrochim. Acta, 111 (2013) 206-209.
[72] Kalita, G.; Adhikari, S.; Aryal, H.R.; Afre, R.; Soga, T.; Sharon, M.; Umeno, M. Functionalization of multi-walled carbon nanotubes (MWCNTs) with nitrogen plasma for photovoltaic device application. Curr. Appl. Phys. 9 (2009) 346-351.
[73] J. B. Raoof, R. Ojani, M. Baghayeri, M. Amiri-Aref, Application of a glassy carbon electrode modified with functionalized multi-walled carbon nanotubes as a sensor device for simultaneous determination of acetaminophen and tyramine, Anal. Methods. 4 (2012) 1579-1587.
[74] E. Frackowiak, Carbon materials for supercapacitor application. Phys. Chem. Chem. Phys. 9 (2007) 1774-1785.
[75] T. Zhang, F. Ran, Design strategies of 3d carbon-based electrodes for charge/ion transport in lithium-ion battery and sodium ion battery, Adv. Funct. Mater. 31 (2021) 2010041.
[76] C. Phillips, A. Al-Ahmadi, S.J. Potts, T. Claypole, D. Deganello, The effect of graphite and carbon black ratios on conductive ink performance. J. Mater. Sci. 52 (2017) 9520-9530.
[77] A. Ji, Y. Chen, X. Wang, C. Xu, Inkjet printed flexible electronics on paper substrate with reduced graphene oxide/carbon black ink, J. Mater. Sci. Mater. Electron. 29 (2018) 13032-13042.
[78] H. Zhang, N. Chen, C. Sun, X. Luo, Investigations on physicochemical properties and electrochemical performance of graphite felt and carbon felt for iron-chromium redox flow battery, Int. J. Energy Res. 44 (2020) 3839-3853.
[79] N. S.bisreutinger, T. Leijtens, G. E. Eperon, S. D. Stranks, R. J. Nicholas, H. J. Snaith, Carbon nanotube/ polymer composites as a highly stable hole collection layer in perovskite solar cells, Nano Lett. 14 (2014) 5561-5568.
[80] S.N. Habisreutinger, T. Leijtens, G. E. Eperon, S. D. Stranks, R. J. Nicholas, H. J. Snaith, Research update: strategies for improving the stability of perovskite solar cells, J. Phys. Chem. Lett. 5 (2014) 4207-4212.
[81] G, Mazzotta, M. Dollmann, S. N. Habisreutinger, M. G. Cristoforo, Z. Wang, H. J Snaith, M. K Riede, R.J Nicholas, Solubilization of carbon nanotubes with ethylene-vinyl acetate for solution-processed conductive films and charge extraction layers in perovskite solar cells, ACS Appl. Mater. Interfaces. 11 (2019) 1185-1191.
[82] S. N. Habisreutinger, N. K. Noel, B. W. Larson, O. G. Reid, J. L. Blackburn, Rapid charge-transfer cascade through SWCNT composites enabling low-voltage losses for perovskite solar cells, ACS Energy Lett. 4 (2019) 1872-1879.
[83] K. Wang, C. Liu, P. Du, J. Zheng, and X. Gong, Bulk heterojunction perovskite hybrid solar cells with large fill factor, Energy Environ. Sci. 8 (2015) 1245-1255.
[84] J. Xu, A. Buin, A. H. Ip, W. Li, O. Voznyy, R. Comin, M. Yuan, S. Jeon, Z. Ning, J. J. McDowell, P. Kanjanaboos, J-P Sun, X. Lan, L. N. Quan, D. Ha Kim, I. G. Hill, P. Maksymovych, E. H. Sargent, Perovskite-fullerene hybrid materials suppress hysteresis in planar diodes, Nature Comm. 8 (2015) 7081.
[85] K. Aitola, K. Sveinbjornsson, J. P. Correa Baena, A. Kaskela, A. Abate, Y. Tian, E. M. J. Johansson, M. Grätzel, E. Kauppinen, A. Hagfeldt, G. Boschloo, Carbon nanotube-based hybrid hole-transporting material and selective contact for high efficiency perovskite solar cells, Energy Environ. Sci. 9 (2016) 461-466.
[86] K. Aitola, K. Domanski, J-P. C-Baena, K. Sveinbjörnsson, M. Saliba, A. Abate, M. Grätzel, E. Kauppinen, E. M. J. Johansson, W. Tress, Hagfeldt, G. Boschloo, High temperature-stable perovskite solar cell based on low-cost carbon nanotube hole contact, Adv. Mater. 29 (2017) 1606398
[87] T. Miletić, E. Pavoni, V. Trifiletti, A. Rizzo, A. Listorti, S. Colella, N. Armaroli, D. Bonifazi, covalently functionalized SWCNTs as tailored p-type dopants for perovskite solar cells, ACS Appl. Mater. Interfaces. 8 (2016) 27966-27973.
[88] J. Lee, M. M. Menamparambath, J. Y. Hwang, S. Hierarchically structured hole transport layers of spiro-OMeTAD nd multiwalled carbon nanotubes for perovskite solar cells, Chem Sus Chem. 8 (2015) 2358.