Applied Chemistry for Engineering (공업화학)

The Korean Society of Industrial and Engineering Chemistry (한국공업화학회)
권호 표지
DOI QR코드

DOI QR Code

Non-Conjugated Polymer Electrolytes for Polymer Solar Cells

고분자 태양전지를 위한 비공액형 고분자 전해질

  • Received : 2020.08.03
  • Accepted : 2020.08.27
  • Published : 2020.10.12
Download PDF
⟨ Previous Next ⟩

Abstract

Polymer solar cells have attracted extensive attention over the past decade due to their benefits, such as good solution-process-ability, light weight, low-cost, mechanically flexibility, and high efficiency. Conjugated (CPE) and non-conjugated (NPE) polyelectrolyte materials have been employed to avoid the typical weaknesses associated with conventional metal oxide interlayers. However, the application of CPEs is more complicated than that of NPEs because the synthesis procedures are complicated. NPEs containing charged ion groups can provide numerous benefits for renewable energy applications. Especially when implemented in polymer solar cells.

고분자태양전지는 용액공정에 의한 생산이 가능하여, 경량, 저비용, 기계적 유연성 및 고효율과 같은 많은 이점이 있다. 이들은 지난 수십 년 동안 많은 관심을 끌어왔다. 공액 고분자 전해질(conjugated polymer electrolyte, CPE) 및 비공액 고분자 전해질(non-conjugated polymer electrolyte, NPE) 재료는 기존의 금속 산화물 중간층과 관련된 일반적인 약점(전하 수집능력 저하 및 금속/고분자 계면에서의상용성 저하 등)을 극복하기 위해 사용되었다. 그러나 CPE의 합성은 매우 복잡한 합성과정이 필요하며, 대량합성이 어려운 단점이 있다. 따라서 상대적으로 합성이 용이한 NPE를 개발 혹은 기존에 개발되어 있는 NPE를 이용하면 보다 쉽게 단점을 극복할 수 있다. 이온 그룹이 포함되어 있는 경우 NPE는 특히 고분자 태양전지를 구현함에 있어 많은 이점을 제공할 수 있으며, 이에 본 총설에서는 그 동안 개발 혹은 응용되었던 NPE에 대한 내용을 다루었다.

Keywords

References

  1. H. Y. Chen, J. Hou, S. Zhang, Y. Liang, G. Yang, Y. Yang, L. Yu, Y. Wu, and G. Li, Polymer solar cells with enhanced open-circuit voltage and efficiency, Nat. Photonics, 3, 649-653 (2009). https://doi.org/10.1038/nphoton.2009.192
  2. G. Zhang, Y. Fu, L. Qiu, and Z. Xie, Synthesis and characterization of thieno[3,4-c]pyrrole-4,6-dione and pyrrolo[3,4-c]pyrrole-1,4-dione-based random polymers for photovoltaic applications, Polymer, 53, 4407-4412 (2012). https://doi.org/10.1016/j.polymer.2012.08.011
  3. C. A. Junwu and C. Yong, Development of novel conjugated donor polymers for high-efficiency bulk-heterojunction photovoltaic devices, Acc. Chem. Res., 42, 1709-1718 (2009). https://doi.org/10.1021/ar900061z
  4. C. H. Woo, B. C. Thompson, B. J. Kim, M. F. Toney, and J. M. J. Frechet, The influence of poly(3-hexylthiophene) regioregularity on fullerene-composite solar cell performance, J. Am. Chem. Soc., 130, 16324-16329 (2008). https://doi.org/10.1021/ja806493n
  5. G. Dennler, M. C. Scharber, and C. J. Brabec, Polymer-fullerene bulk-heterojunction solar cells, Adv. Mater., 21, 1323-1338 (2009). https://doi.org/10.1002/adma.200801283
  6. H. Zhou, L. Yang, and W. You, Rational design of high performance conjugated polymers for organic solar cells, Macromolecules, 45, 607-632 (2012). https://doi.org/10.1021/ma201648t
  7. P. M. Beaujuge and J. M. J. Frechet, Molecular design and ordering effects in ${\pi}$-functional materials for transistor and solar cell applications, J. Am. Chem. Soc., 133, 20009-20029 (2011). https://doi.org/10.1021/ja2073643
  8. C.-Y. Lee, B. S. Kim, K. H. Kim, Y. Yoon, M. W. Lee, D. H. Choi, M. J. Ko, H. Kim, D. K. Lee, and K. Kim, Synthesis and characterization of wide range light absorbing poly(dithieno[3,2-b:2',3'-d]thiophene-alt-3,6-bis(thiophen-2-yl)-2,5-di-n-octyl-pyrrolo[3,4-c]pyrrole-1,4-dione) for polymer solar cells, Synth. Met., 164, 64-68 (2013). https://doi.org/10.1016/j.synthmet.2012.12.028
  9. N. Blouin, A. Michaud, D. Gendron, S. Wakim, E. Blair, R. Neagu-Plesu, M. Belletête, G. Durocher, Y. Tao, and M. Leclerc, Toward a rational design of poly(2,7-carbazole) derivatives for solar cells, J. Am. Chem. Soc., 130, 732-742 (2008). https://doi.org/10.1021/ja0771989
  10. G. Zhang, Y. Fu, Z. Xie, and Q. Zhang, Synthesis and photovoltaic properties of new low bandgap isoindigo-based conjugated polymers, Macromolecules, 44, 1414-1420 (2011). https://doi.org/10.1021/ma102357b
  11. J. L. Bredas, D. Beljonne, V. Coropceanu, and J. Cornil, Charge-transfer and energy-transfer processes in ${\pi}$-conjugated oligomers and polymers: A molecular picture, Chem. Rev., 104, 4971-5003 (2004). https://doi.org/10.1021/cr040084k
  12. X. Bulliard, S. G. Ihn, S. Yun, Y. Kim, D. Choi, J. Y. Choi, M. Kim, M. Sim, J. H. Park, W. Choi, and K. Cho, Enhanced performance in polymer solar cells by surface energy control, Adv. Funct. Mater., 20, 4381-4387 (2010). https://doi.org/10.1002/adfm.201000960
  13. Y. Sun, J. H. Seo, C. J. Takacs, J. Seifter, and A. J. Heeger, Inverted polymer solar cells integrated with a low-temperature-annealed sol-gel-derived ZnO film as an electron transport layer, Adv. Mater., 23, 1679-1683 (2011). https://doi.org/10.1002/adma.201004301
  14. F. C. Krebs, T. Tromholt, and M. Jorgensen, Upscaling of polymer solar cell fabrication using full roll-to-roll processing, Nanoscale, 2, 873-886 (2010). https://doi.org/10.1039/b9nr00430k
  15. H. Schmidt, K. Zilberberg, S. Schmale, H. Flügge, T. Riedl, and W. Kowalsky, Transient characteristics of inverted polymer solar cells using titaniumoxide interlayers, Appl. Phys. Lett., 96, 2008-2011 (2010).
  16. C. S. Kim, S. S. Lee, E. D. Gomez, J. B. Kim, and Y. L. Loo, Transient photovoltaic behavior of air-stable, inverted organic solar cells with solution-processed electron transport layer, Appl. Phys. Lett., 94, 10-13 (2009).
  17. H. Kang, S. Hong, J. Lee, and K. Lee, Electrostatically self-assembled nonconjugated polyelectrolytes as an ideal interfacial layer for inverted polymer solar cells, Adv. Mater., 24, 3005-3009 (2012). https://doi.org/10.1002/adma.201200594
  18. C. He, C. Zhong, H. Wu, R. Yang, W. Yang, F. Huang, G. C. Bazan, and Y. Cao, Origin of the enhanced open-circuit voltage in polymer solar cells via interfacial modification using conjugated polyelectrolytes, J. Mater. Chem., 20, 2617-2622 (2010). https://doi.org/10.1039/b921775d
  19. H. S. Jung and T. Q. Nguyen, Electronic properties of conjugated polyelectrolyte thin films, J. Am. Chem. Soc., 130, 10042-10043 (2008). https://doi.org/10.1021/ja801451e
  20. S. I. Na, T. S. Kim, S. H. Oh, J. Kim, S. S. Kim, and D. Y. Kim, Enhanced performance of inverted polymer solar cells with cathode interfacial tuning via water-soluble polyfluorenes, Appl. Phys. Lett., 97, 4-7 (2010).
  21. Y. Zhou, F. Li, S. Barrau, W. Tian, O. Inganas, and F. Zhang, Inverted and transparent polymer solar cells prepared with vacuum-free processing, Sol. Energy Mater. Sol. Cells, 93, 497-500 (2009). https://doi.org/10.1016/j.solmat.2008.11.002
  22. T. T. Do, H. S. Hong, Y. E. Ha, G. E. Lim, Y. S. Won, and J. H. Kim, Investigation of the effect of conjugated oligoelectrolyte as a cathode buffer layer on the photovoltaic properties, Synth. Met., 198, 122-130 (2014). https://doi.org/10.1016/j.synthmet.2014.10.006
  23. A. R. Vancha, S. Govindaraju, K. V. L. Parsa, M. Jasti, M. González-García, and R. P. Ballestero, Use of polyethyleneimine polymer in cell culture as attachment factor and lipofection enhancer, BMC Biotechnol., 4, 1-12 (2004). https://doi.org/10.1186/1472-6750-4-1
  24. S. Jaffar, K. T. Nam, A. Khademhosseini, J. Xing, R. S. Langer, and A. M. Belcher, Layer-by-layer surface modification and patterned electrostatic deposition of quantum dots, Nano Lett., 4, 1421-1425 (2004). https://doi.org/10.1021/nl0493287
  25. F. Yamauchi, K. Kato, and H. Iwata, Layer-by-layer assembly of poly(ethyleneimine) and plasmid DNA onto transparent indium-tin oxide electrodes for temporally and spatially specific gene transfer, Langmuir, 21, 8360-8367 (2005). https://doi.org/10.1021/la0505059
  26. S. Lee, S. Park, N. Sylvianti, H. K. Choi, and J. H. Kim, Cathode modification of polymer solar cells by electrostatically self-assembled zwitterionic non-conjugated polyelectrolyte, Synth. Met., 209, 441-446 (2015). https://doi.org/10.1016/j.synthmet.2015.08.030
  27. N. Sylvianti, T. T. Do, M. A. Marsya, J. Park, Y. C. Kang, and J. H. Kim, Self-assembled poly(4-vinylpyridine) as an interfacial layer for polymer solar cells, Bull. Korean Chem. Soc., 37, 13-18 (2016). https://doi.org/10.1002/bkcs.10613
  28. W. Lee, S. Jeong, C. Lee, G. Han, C. Cho, J. Y. Lee, and B. J. Kim, Self-organization of polymer additive, poly(2-vinylpyridine) via one-step solution processing to enhance the efficiency and stability of polymer solar cells, Adv. Energy Mater., 7, 1-9 (2017).
  29. G. E. Lim, Y. E. Ha, M. Y. Jo, J. Park, Y. C. Kang, and J. H. Kim, Nonconjugated anionic polyelectrolyte as an interfacial layer for the organic optoelectronic devices, ACS Appl. Mater. Interfaces, 5, 6508-6513 (2013). https://doi.org/10.1021/am400478b
  30. H. Wang, W. Zhang, C. Xu, X. Bi, B. Chen, and S. Yang, Efficiency enhancement of polymer solar cells by applying poly(vinylpyrrolidone) as a cathode buffer layer via spin coating or self-assembly, ACS Appl. Mater. Interfaces, 5, 26-34 (2013). https://doi.org/10.1021/am302317v
  31. Y. E. Ha, G. E. Lim, M. Y. Jo, J. Park, Y.-C. Kang, S.-J. Moon, and J. H. Kim, Enhancing the efficiency of opto-electronic devices by the cathode modification, J. Mater. Chem. C, 2, 3820-3825 (2014). https://doi.org/10.1039/C3TC32430C
  32. F. Zhang, M. Ceder, and O. Inganas, Enhancing the photovoltage of polymer solar cells by using a modified cathode, Adv. Mater., 19, 1835-1838 (2007). https://doi.org/10.1002/adma.200602597
  33. Y. Yang, C. Zhou, S. Xu, H. Hu, B. Chen, J. Zhang, S. Wu, W. Liu, and X. Zhao, Improved stability of quasi-solid-state dye-sensitized solar cell based on poly (ethylene oxide)-poly (vinylidene fluoride) polymer-blend electrolytes, J. Power Sources, 185, 1492-1498 (2008). https://doi.org/10.1016/j.jpowsour.2008.09.034
  34. M. A. K. L. Dissanayake, C. A. Thotawatthage, G. K. R. Senadeera, T. M. W. J. Bandara, W. J. M. J. S. R. Jayasundera, and B. E. Mellander, Efficiency enhancement by mixed cation effect in dye-sensitized solar cells with PAN based gel polymer electrolyte, J. Photochem. Photobiol. A Chem., 246, 29-35 (2012). https://doi.org/10.1016/j.jphotochem.2012.06.023
  35. Z. Lan, J. Wu, D. Wang, S. Hao, J. Lin, and Y. Huang, Quasi-solid state dye-sensitized solar cells based on gel polymer electrolyte with poly(acrylonitrile-co-styrene)/NaI +$I_2$, Sol. Energy, 80, 1483-1488 (2006). https://doi.org/10.1016/j.solener.2005.11.007
  36. K. Tennakone, G. K. R. Senadeera, V. P. S. Perera, I. R. M. Kottegoda, and L. A. A. De Silva, Dye-sensitized photoelectrochemical cells based on porous $SnO_2/ZnO$ composite and $TiO_2$ films with a polymer electrolyte., Chem. Mater., 11, 2474-2477 (1999). https://doi.org/10.1021/cm990165a
  37. T. M. W. J. Bandara, M. A. K. L. Dissanayake, and B. E. Mellander, Dye sensitized solar cells with poly(acrylonitrile) based plasticized electrolyte containing $MgI_2$, Electrochim. Acta, 55, 2044-2047 (2010). https://doi.org/10.1016/j.electacta.2009.11.031
  38. O. A. Ileperuma, M. A. K. L. Dissanayake, S. Somasunderam, and L. R. A. K. Bandara, Photoelectrochemical solar cells with polyacrylonitrile-based and polyethylene oxide-based polymer electrolytes, Sol. Energy Mater. Sol. Cells, 84, 117-124 (2004). https://doi.org/10.1016/j.solmat.2004.02.040
  39. O. A. Ileperuma, G. R. A. Kumara, H. S. Yang, and K. Murakami, Quasi-solid electrolyte based on polyacrylonitrile for dye-sensitized solar cells, J. Photochem. Photobiol. A Chem., 217, 308-312 (2011). https://doi.org/10.1016/j.jphotochem.2010.10.024
  40. K. Yuan, L. Chen, and Y. Chen, Versatile electron-collecting interfacial layer by in situ growth of silver nanoparticles in nonconjugated polyelectrolyte aqueous solution for polymer solar cells, J. Phys. Chem. B, 118, 11563-11572 (2014). https://doi.org/10.1021/jp506869q
  41. Y. J. Park , M. J. Cha, Y. J. Yoon, S. Cho, J. Y. Kim, J. H. Seo, and B. Walker, Improved performance in n-type organic field-effect transistors via polyelectrolyte-mediated interfacial doping, Adv. Electron. Mater., 3, 1-7 (2017).
  42. H. Zhang, H. Azimi, Y. Hou, T. Ameri, T. Przybilla, E. Spiecker, M. Kraft, U. Scherf, and C. J. Brabec, Improved high-efficiency perovskite planar heterojunction solar cells via incorporation of a polyelectrolyte interlayer, Chem. Mater., 26, 5190-5193 (2014). https://doi.org/10.1021/cm502864s
  43. J. H. Kang, Y. J. Park, M. J. Cha, Y. Yi, A. Song, K.-B. Chung, J. H. Seo, and B. Walker, Effect of counter-ions on the properties and performance of non-conjugated polyelectrolyte interlayers in solar cell and transistor devices, RSC Adv., 9, 20670-20676 (2019). https://doi.org/10.1039/C9RA04299G
  44. J. H. Lee, Y. J. Park, J. H. Seo, and B. Walker, Hybrid lead-halide polyelectrolytes as interfacial electron extraction layers in inverted organic solar cells, Polymers, 12, 743 (2020). https://doi.org/10.3390/polym12040743
  45. S. Woo, W. Hyun Kim, H. Kim, Y. Yi, H. K. Lyu, and Y. Kim, 8.9% single-stack inverted polymer solar cells with electron-rich polymer nanolayer-modified inorganic electron-collecting buffer layers, Adv. Energy Mater., 4, 1-7 (2014). https://doi.org/10.1142/9789814513289_0001
  46. A. K. K. Kyaw, D. H. Wang, V. Gupta, J. Zhang, S. Chand, G. C. Bazan, and A. J. Heeger, Efficient solution-processed small-molecule solar cells with inverted structure, Adv. Mater., 25, 2397-2402 (2013). https://doi.org/10.1002/adma.201300295
  47. C. Duan, K. Zhang, C. Zhong, F. Huang, and Y. Cao, Recent advances in water/alcohol-soluble ${\pi}$-conjugated materials: New materials and growing applications in solar cells, Chem. Soc. Rev., 42, 9071-9104 (2013). https://doi.org/10.1039/c3cs60200a
  48. W. Lee, J. H. Seo, and H. Y. Woo, Conjugated polyelectrolytes: A new class of semiconducting material for organic electronic devices, Polymer, 54, 5104-5121 (2013). https://doi.org/10.1016/j.polymer.2013.07.015
  49. C. H. Wu, C. Y. Chin, T. Y. Chen, S. N. Hsieh, C. H. Lee, T. F. Guo, A. K. Y. Jenf, and T. C. Wen, Enhanced performance of polymer solar cells using solution-processed tetra-n-alkyl ammonium bromides as electron extraction layers, J. Mater. Chem. A, 1, 2582-2587 (2013). https://doi.org/10.1039/c2ta00975g
  50. M. Matsumoto, H. Miyazaki, K. Matsuhiro, Y. Kumashiro, and Y. Takaoka, A dye sensitized $TiO_2$ photoelectrochemical cell constructed with polymer solid electrolyte, Solid State Ionics, 89, 263-267 (1996). https://doi.org/10.1016/0167-2738(96)00347-5
  51. J. Xia, F. Li, C. Huang, J. Zhai, and L. Jiang, Improved stability quasi-solid-state dye-sensitized solar cell based on polyether framework gel electrolytes, Sol. Energy Mater. Sol. Cells, 90, 944-952 (2006). https://doi.org/10.1016/j.solmat.2005.05.021
  52. J. Wu, Z. Lan, D. Wang, S. Hao, J. Lin, Y. Wei, S. Yin, and T. Sato, Quasi-solid state dye-sensitized solar cells-based gel polymer electrolytes with poly(acrylamide)-poly(ethylene glycol) composite, J. Photochem. Photobiol. A Chem., 181, 333-337 (2006). https://doi.org/10.1016/j.jphotochem.2005.12.015
  53. H. Yang, M. Huang, J. Wu, Z. Lan, S. Hao, and J. Lin, The polymer gel electrolyte based on poly(methyl methacrylate) and its application in quasi-solid-state dye-sensitized solar cells, Mater. Chem. Phys., 110, 38-42 (2008). https://doi.org/10.1016/j.matchemphys.2008.01.010
  54. R. Shanti, F. Bella, Y. S. Salim, S. Y. Chee, S. Ramesh, and K. Ramesh, Poly(methyl methacrylate-co-butyl acrylate-co-acrylic acid): Physico-chemical characterization and targeted dye sensitized solar cell application, Mater. Des., 108, 560-569 (2016). https://doi.org/10.1016/j.matdes.2016.07.021
  55. W. Li, J. Kang, X. Li, S. Fang, Y. Lin, G. Wang, and X. Xiao, A novel polymer quaternary ammonium iodide and application in quasi-solid-state dye-sensitized solar cells, J. Photochem. Photobiol. A Chem., 170, 1-6 (2005). https://doi.org/10.1016/j.jphotochem.2004.07.016
  56. P. Zhou, Z. Fang, W. Zhou, Q. Qiao, M. Wang, T. Chen, and S. Yang, Nonconjugated polymer poly(vinylpyrrolidone) as an efficient interlayer promoting electron transport for perovskite solar cells, ACS Appl. Mater. Interfaces, 9, 32957-32964 (2017). https://doi.org/10.1021/acsami.7b12135
  57. B. Walker, A. Tamayo, J. Yang, J. Z. Brzezinski, and T. Q. Nguyen, Solution-processed small molecule-based blue light-emitting diodes using conjugated polyelectrolytes as electron injection layers, Appl. Phys. Lett., 93, 91-94 (2008).
  58. Y. Zhou, C. Fuentes-Hernandez, J. Shim, J. Meyer, A. J. Giordano, H. Li, P. Winget, T. Papadopoulos, H. Cheun, J. Kim, M. Fenoll, A. Dindar, W. Haske, E. Najafabadi, T. M. Khan, H. Sojoudi, S. Barlow, S. Graham, J. L. Bredas, S. R. Marder, A. Kahn, B. Kippelen, A universal method to produce low-work function electrodes for organic electronics, Science, 336, 327-332 (2012). https://doi.org/10.1126/science.1218829
  59. B. Walker, H. Choi, and J. Y. Kim, Interfacial engineering for highly efficient organic solar cells, Curr. Appl. Phys., 17, 370-391 (2017). https://doi.org/10.1016/j.cap.2016.12.007
  60. J. H. Seo, A. Gutacker, Y. Sun, H. Wu, F. Huang, Y. Cao, U. Scherf, A. J. Heeger, and G. C. Bazan, Improved high-efficiency organic solar cells via incorporation of a conjugated polyelectrolyte interlayer, J. Am. Chem. Soc., 133, 8416-8419 (2011). https://doi.org/10.1021/ja2037673
  61. H. L. Yip and A. K. Y. Jen, Recent advances in solution-processed interfacial materials for efficient and stable polymer solar cells, Energy Environ. Sci., 5, 5994-6011 (2012). https://doi.org/10.1039/c2ee02806a
  62. Z. He, C. Zhong, S. Su, M. Xu, H. Wu, and Y. Cao, Enhanced power-conversion efficiency in polymer solar cells using an inverted device structure, Nat. Photonics, 6, 591-595 (2012). https://doi.org/10.1038/nphoton.2012.190
  63. M. Y. Jo, Y. E. Ha, and J. H. Kim, Polyviologen derivatives as an interfacial layer in polymer solar cells, Sol. Energy Mater. Sol. Cells, 107, 1-8 (2012). https://doi.org/10.1016/j.solmat.2012.08.003
  64. V. Raj and S. Kunnetheeri, Nonconjugated polyelectrolyte as efficient fluorescence quencher and their applications as biosensors: Polymer-polymer interaction, ISRN Anal. Chem., 2014, 1-8 (2014).
  65. E. K. Kim, N. K. Shrestha, W. Lee, G. Cai, and S. H. Han, Influence of water-soluble conjugated/non-conjugated polyelectrolytes on electrodeposition of nanostructured $MnO_2$ film for supercapacitors, Mater. Chem. Phys., 155, 211-216 (2015). https://doi.org/10.1016/j.matchemphys.2015.02.027
  66. W. Shin, N. Sylvianti, M. A. Marsya, D. S. Putri, D. W. Chang, J. Kim, Y. W. Kim, T. D. Kim, S. Yoo, and J. Kim, Cathode modification of polymer solar cells by ultrahydrophobic polyelectrolyte, Mol. Cryst. Liq. Cryst., 635, 6-11 (2016). https://doi.org/10.1080/15421406.2016.1199965
  67. H. B. Kim, Y. J. Yoon, J. Jeong, J. Heo, H. Jang, J. H. Seo, B. Walker, and J. Y. Kim, Peroptronic devices: Perovskite-based light-emitting solar cells, Energy Environ. Sci., 10, 1950-1957 (2017). https://doi.org/10.1039/C7EE01666B
  68. B. H. Hamilton, K. A. Kelly, W. Malasi, and C. J. Ziegler, Tetrakis(imidazolyl)borate-based coordination polymers: Group II network solids, $M[B(Im)_4]_2(H_2O)_2$ (M = Mg, Ca, Sr), Inorg. Chem., 42, 3067-3073 (2003). https://doi.org/10.1021/ic026244x
  69. M. Y. Jo, Y. E. Ha, and J. H. Kim, Interfacial layer material derived from dialkylviologen and sol-gel chemistry for polymer solar cells, Org. Electron., 14, 995-1001 (2013). https://doi.org/10.1016/j.orgel.2013.01.022
  70. T. T. Do, H. S. Hong, Y. E. Ha, J. Park, Y. C. Kang, and J. H. Kim, Effect of polyelectrolyte electron collection layer counteranion on the properties of polymer solar cells, ACS Appl. Mater. Interfaces, 7, 3335-3341 (2015). https://doi.org/10.1021/am5082606
  71. S. Prescher, F. Polzer, Y. Yang, M. Siebenbürger, M. Ballauff, and J. Yuan, Polyelectrolyte as solvent and reaction medium, J. Am. Chem. Soc., 136, 12-15 (2014). https://doi.org/10.1021/ja409395y
  72. F. Kretschmer, U. Mansfeld, S. Hoeppener, M. D. Hager, and U. S. Schubert, Tunable synthesis of poly(ethylene imine)-gold nanoparticle clusters, Chem. Commun., 50, 88-90 (2014). https://doi.org/10.1039/C3CC45090B
  73. T. L. Guo, J. G. Li, D. H. Ping, X. Sun, and Y. Sakka, Controlled photocatalytic growth of Ag nanocrystals on brookite and rutile and their SERS performance, ACS Appl. Mater. Interfaces, 6, 236-243 (2014). https://doi.org/10.1021/am404027m
  74. M. Rycenga, C. M. Cobley, J. Zeng, W. Li, C. H. Moran, Q. Zhang, D. Qin, and Y. Xia, Controlling the synthesis and assembly of silver nanostructures for plasmonic applications, Chem. Rev., 111, 3669-3712 (2011). https://doi.org/10.1021/cr100275d