Hole-Transporting Layer in Perovskite Solar Cells: History
View Latest Version
Please note this is an old version of this entry, which may differ significantly from the current revision.
Contributor:
Dingyan Huang
,
Huimin Xiang
,
Ran Ran
,
Wei Wang
,
Wei Zhou
,
Zongping Shao

Organic-inorganic halide perovskite solar cells (PSCs) have received particular attention because of the high-power conversion efficiencies (PCEs), facile fabrication route and low cost. The hole-transporting layer (HTL) play an important role in PSCs to effectively extract holes from the perovskite film and to transport holes to the metal electrode in normal PSCs. 

  • perovskite solar cells
  • nanostructure
  • inorganic hole-transporting materials

1. The Crucial Roles of HTLs in PSCs

The hole-transporting layer (HTL) play an important role in perovskite solar cells (PSCs) to effectively extract holes from the perovskite film and to transport holes to the metal electrode in normal PSCs [1][2]. In addition, HTLs also function as a barrier to prevent the direct contact of the perovskite film and metal electrode, reducing the potential recombination of electrons and holes in normal PSCs [3][4]. Particularly, the HTL also can significantly affect the grain sizes and grain boundary amount of the perovskite layer in inverted PSCs, which strongly influences the power conversion efficiencies (PCEs) and long-term stability of PSCs [5][6]. Therefore, an ideal HTL should have the following prerequisites [7][8][9][10]. First, HTLs should have high hole mobility to transfer photogenerated holes to the electrode, which is beneficial for the achievement of a high fill factor (FF). It has been reported that when the hole mobility of HTLs was enhanced from 10−6 to 10−4 cm2 V−1 s−1, FF values of corresponding PSCs can be boosted from 0.22 to 0.80 [11]. Second, HTLs should display superior hydrophobicity, (photo)chemical and thermal stability to enhance the durability of PSCs. Third, the low cost of HTLs is also required to promote large-scale production. Forth, a suitable energy level alignment between HTLs and perovskite film is required to reduce the carrier recombination and the hole accumulation at the perovskite film/HTL interface. Fifth, the high film quality of HTLs is also required to improve the coverage of the perovskite film and to promote the deposition of high-quality perovskite film in the normal and inverted PSCs, respectively. The ideal HTL for PSCs should have no interfacial reaction with other functional layers, such as the perovskite film and the metal electrode [12][13]. The chemical corrosion of metal electrodes on the organic HTLs can be inhibited in inorganic HTL-based PSCs due to the more stable interface between inorganic HTL and the metal electrode [14][15]. Until now, the PCEs of inorganic HTL-based PSCs are still lower than those of organic HTL-based PSCs mainly due to the detrimental interfacial reaction between inorganic HTLs and perovskite film, which reduced the hole extraction capability and increased the carrier recombination rate at interfaces, leading to serious open circuit voltages (VOC) loss and accelerated decomposition of perovskite film [16][17]. For example, Ni3+ cations in NiOx HTL can react with the A-site cationic salts in the perovskite precursors, which reduces the amount of Ni3+ cations in NiOx, leading to lower conductivity of NiOx HTL and reduced PCEs of PSCs [18]. In order to reduce the interfacial reaction between the HTL and the perovskite film, Zhang et al. introduced a 2-methyl-1-aziridinepropionate (SaC-100) layer between NiOx and perovskite film to achieve a physical separation [19]. The introduction of the SaC-100 layer not only effectively inhibited the redox reactions at the HTL/perovskite film interface but also increased the amount of Ni3+ cations in NiOx HTL, which efficiently reduced the interfacial defect amount and improved the conductivity of NiOx HTL. Consequently, SaC-100 modified cells exhibited a much higher PCE of 20.21% than that of the unmodified PSC (17.54%). In addition, self-assembled monolayers (SAMs) are also widely employed to reduce interfacial reactions in PSCs due to the ultra-thin, uniform and high-quality film of SAMs, which can effectively passivate interfacial defects, improve interface contact and reduce the VOC loss in PSCs [20]. For instance, Mangalam et al. modified the interface between NiOx HTL and perovskite film by using 4-bromophenylphosphonic acid-based SAMs, which increased the VOC from 0.978 V to 1.029 V, effectively improving the PCEs of PSCs [21]. Up to now, organic HTLs based on polymer small molecules, including polystyrene sulfonate (PEDOT:PSS), Spiro-OMeTAD, etc., have been widely used in PSCs, while inorganic HTLs such as NiOx, CoO, ZnCo2O4 and Fe3O4 have received increasing attention during the past 5 years [8][22][23][24][25].

2. Advantages and Disadvantages of Organic HTLs

At present, the most commonly used HTL in PSCs is organic Spiro-OMeTAD, exhibiting relatively high PCEs. Nevertheless, Spiro-OMeTAD suffered from several drawbacks such as high cost, complex synthesis process, poor stability, etc. Furthermore, the PSC with pristine Spiro-OMeTAD delivered a low PCE of 9.7% because of the inferior hole mobility and conductivity induced by the disordered molecule structure of pristine Spiro-OMeTAD [26]. The hole mobility of Spiro-OMeTAD was remarkably enhanced by adding lithium bis(trifluoromethanesulfonyl)imide, 4-tert-butylpyridine and cobalt(III) tris(bis(trifluoromethyl-sulfonyl)imide) to achieve a high PCE of 19.7% [27]. However, the introduction of these additives also brings some unstable factors, which reduce the stability of PSCs [26][28]. For instance, the addition of lithium salts led to inferior moisture stability of PSCs due to the hygroscopic nature, while a detrimental reaction between 4-tert-butylpyridine and halide perovskite accelerated the decomposition of perovskite film during operation [29]. Very recently, Li et al. employed polymethyl methacrylate (PMMA) to modify Spiro-OMeTAD to boost the PCE and moisture stability of PSCs by reducing the interaction between Spiro-OMeTAD/perovskite layers and water [30]. As a result, the cell with PMMA-modified Spiro-OMeTAD produced an attractive PCE of 21.08%, which was much better than the unmodified counterparts. Furthermore, the PCE of the cell with PMMA-modified Spiro-OMeTAD maintained 77% of the initial value after storing in the air with relative humidity (RH) of 40% for 80 days, while the pristine cell deteriorated to 47% of the initial PCE under the same conditions. Besides additive engineering, some researchers have also modified Spiro-OMeTAD by regulating the functional groups in the molecule structure [31][32]. For instance, Jeon et al. tailored the position of methoxy group (para, ortho and meta) in the benzene ring connected with N atom in Spiro-OMeTAD, which significantly affected the electrical and optical properties [31]. It was found that the methoxy group located in the ortho position in Spiro-OMeTAD increased the lowest occupied molecular orbital (LUMO) value of pristine Spiro-OMeTAD while the methoxy group at meta and para positions reduced the LUMO value of pristine Spiro-OMeTAD. Consequently, the cell with ortho-Spiro-OMeTAD exhibited a higher PCE of 16.7% than those of pristine Spiro-OMeTAD (15.2%), meta-Spiro-OMeTAD (13.9%) and para-Spiro-OMeTAD (14.9%) due to the promoted electron blocking and enhanced hole transfer. PEDOT:PSS is a commonly used organic HTL in inverted PSCs due to its superior optical transparency and high conductivity [33][34]. It has been reported that a superb PCE of 20.1% was obtained by using such PEDOT:PSS HTL in inverted PSCs [35]. Nevertheless, the hydrophilic and acidic nature of PEDOT:PSS led to inferior durability of PSCs [36]. Moreover, the VOC of corresponding cells are always less than 0.95 V, which was caused by the energy level mismatch between perovskite film and PEDOT:PSS layer [37]. In summary, although organic HTLs displayed superior hole mobility, the inherent instability under high-temperature and humid conditions remarkably limited further applications in PSCs. Consequently, it is essential to seek intrinsic durable alternative HTLs (e.g., inorganic materials) to achieve high-efficiency and durable PSCs [38][39][40].

3. The Superiority of Inorganic HTLs and the Importance of Nanostructure Construction

Recently, inorganic materials have emerged as new-generation HTLs to replace organic counterparts due to several distinct advantages such as superior hole collection/migration capability, high conductivity, stability and light transmittance, easy adjustment of energy levels, low cost, simple fabrication, etc. [8][41][42][43]. Until now, several inorganic materials have been utilized as HTLs for PSCs, including NiOx, CuOx, CuS, MoS2, VOx, WO3, CuSCN, etc. [7][8][41][42][44][45]. Since the first investigation of inorganic HTLs for PSCs, numerous efforts have been devoted to boosting the PCEs of inorganic HTL-based PSCs [41][46][47][48]. Fortunately, the obtained PCEs of inorganic HTL-based PSCs are now comparable to those of their organic counterparts. In 2014, Wang et al. firstly employed the spin coating method to fabricate NiOx HTL in mesoporous PSCs to obtain a PCE of 9.51% [49]. In addition to the development of fabrication methods, interface engineering and functional doping have also been employed to boost the PCEs of inorganic HTL-based PSCs [50][51]. For instance, Yip et al. modified NiOx/MAPbI3 interface with diethanolamine (DEA) to improve the charge extraction capability and to reduce the charge recombination rate, and a high PCE of 18.1% was obtained [50]. As for the functional doping, Xiang et al. co-doped NiOx by lithium (Li+) and magnesium (Mg2+) as HTLs for PSCs [51]. The cell with such co-doped NiOx exhibited a superior PCE of >20%, which was assigned to the improved conductivity and more proper energy level alignment induced by Li+ and Mg2+ doping, respectively. Until now, the solution-based routes are the most widely used methods to fabricate inorganic HTLs for PSCs because of their excellent universality and cost-effectiveness.
Nevertheless, the bulk inorganic HTLs suffered from large particle sizes, which were very difficult to be well dispersed in the solution. As a result, many pinholes and cracks were formed in the solution-processed bulk inorganic HTLs, leading to increased carrier recombination and an inferior coverage on the perovskite layer, which strongly affected the PCEs and stability of corresponding PSCs. On this basis, nanostructure construction is introduced to develop inorganic HTLs with nanoparticles and special morphologies to enhance the PCEs of PSCs. Several promising nanostructured inorganic HTLs such as NiOx nanoparticles (NPs), CoO NPs, Fe3O4 NPs, Cr/CuGaO2-CC/NiOx nanocomposites, NiCo2O4 NWs, etc., have been designed and developed to boost the PCEs of PSCs due to smaller grain sizes and better dispersion in solution than the bulk counterparts, leading to more compact and flatter hole-transporting films [8][24][25][52][53][54]. In addition, nanostructured inorganic HTLs not only effectively reduced the reflection loss caused by light scattering and improved the light capturing efficiency but also increased the interfacial contact area between HTL and perovskite film, which significantly improved the carrier extraction rate and suppressed the charge recombination.

This entry is adapted from the peer-reviewed paper 10.3390/nano12152592

References

  1. Igbari, F.; Li, M.; Hu, Y.; Wang, Z.-K.; Liao, L.-S. A room-temperature CuAlO2 hole interfacial layer for efficient and stable planar perovskite solar cells. J. Mater. Chem. A 2016, 4, 1326–1335.
  2. Motta, C.; El-Mellouhi, F.; Sanvito, S. Charge carrier mobility in hybrid halide perovskites. Sci. Rep. 2015, 5, 12746.
  3. Kim, H.-S.; Lee, C.-R.; Im, J.-H.; Lee, K.-B.; Moehl, T.; Marchioro, A.; Moon, S.-J.; Humphry-Baker, R.; Yum, J.-H.; Moser, J.E. Lead iodide perovskite sensitized all-solid-state submicron thin film mesoscopic solar cell with efficiency exceeding 9%. Sci. Rep. 2012, 2, 591.
  4. Miyata, A.; Mitioglu, A.; Plochocka, P.; Portugall, O.; Wang, J.T.-W.; Stranks, S.D.; Snaith, H.J.; Nicholas, R.J. Direct measurement of the exciton binding energy and effective masses for charge carriers in organic-inorganic tri-halide perovskites. Nat. Phys. 2015, 11, 582–587.
  5. Zhao, D.; Sexton, M.; Park, H.Y.; Baure, G.; Nino, J.C.; So, F. High-efficiency solution-processed planar perovskite solar cells with a polymer hole transport layer. Adv. Energy Mater. 2015, 5, 1401855.
  6. Bag, A.; Radhakrishnan, R.; Nekovei, R.; Jeyakumar, R. Effect of absorber layer, hole transport layer thicknesses, and its doping density on the performance of perovskite solar cells by device simulation. Sol. Energy 2020, 196, 177–182.
  7. Singh, R.; Singh, P.K.; Bhattacharya, B.; Rhee, H.-W. Review of current progress in inorganic hole-transport materials for perovskite solar cells. Appl. Mater. Today 2019, 14, 175–200.
  8. Kung, P.K.; Li, M.H.; Lin, P.Y.; Chiang, Y.H.; Chan, C.R.; Guo, T.F.; Chen, P. A Review of inorganic hole transport materials for perovskite solar cells. Adv. Mater. Interfaces 2018, 5, 1800882.
  9. Yu, Z.; Sun, L. Inorganic hole-transporting materials for perovskite solar cells. Small Methods 2018, 2, 1700280.
  10. Yin, X.; Guo, Y.; Xie, H.; Que, W.; Kong, L.B. Nickel oxide as efficient hole transport materials for perovskite solar cells. Sol. RRL 2019, 3, 1900001.
  11. Cavinato, L.M.; Fresta, E.; Ferrara, S.; Costa, R.D. Merging biology and photovoltaics: How nature helps sun-catching. Adv. Energy Mater. 2021, 11, 2100520.
  12. Zhao, P.; Kim, B.J.; Jung, H.S. Passivation in perovskite solar cells: A review. Mater. Today Energy 2018, 7, 267–286.
  13. Tumen-Ulzii, G.; Matsushima, T.; Adachi, C. Mini-review on efficiency and stability of perovskite solar cells with Spiro-OMeTAD hole transport layer: Recent progress and perspectives. Energy Fuels 2021, 35, 18915–18927.
  14. Saianand, G.; Sonar, P.; Wilson, G.J.; Gopalan, A.I.; Roy, V.A.; Unni, G.E.; Qiao, Q. Current advancements on charge selective contact interfacial layers and electrodes in flexible hybrid perovskite photovoltaics. J. Energy Chem. 2021, 54, 151–173.
  15. Nazari, P.; Ansari, F.; Abdollahi, B.; Ahmadi, V.; Payandeh, M.; Salavati-Niasari, M. Physicochemical interface engineering of CuI/Cu as advanced potential hole-transporting materials/metal contact couples in hysteresis-free ultralow-cost and large-area perovskite solar cells. J. Phys. Chem. C. 2017, 121, 21935–21944.
  16. Zhang, L.; Zhou, X.; Xie, J.; Hu, B.; Liu, P.; Chen, S.; Bae, S.-H.; Kim, J.; Dai, S.; Xu, B. Learning from hole-transporting polymers in regular perovskite solar cells to construct efficient conjugated polyelectrolytes for inverted devices. Chem. Eng. J. 2021, 420, 129735.
  17. Wang, C.; Hu, J.; Li, C.; Qiu, S.; Liu, X.; Zeng, L.; Liu, C.; Mai, Y.; Guo, F. Spiro-linked molecular hole-transport materials for highly efficient inverted perovskite solar cells. Sol. RRL 2020, 4, 1900389.
  18. Boyd, C.C.; Shallcross, R.C.; Moot, T.; Kerner, R.; Bertoluzzi, L.; Onno, A.; Kavadiya, S.; Chosy, C.; Wolf, E.J.; Werner, J.; et al. Overcoming redox reactions at perovskite-nickel oxide interfaces to boost voltages in perovskite solar cells. Joule 2020, 4, 1759–1775.
  19. Zhang, J.; Long, J.; Huang, Z.; Yang, J.; Li, X.; Dai, R.; Chen, Y. Obstructing interfacial reaction between NiOx and perovskite to enable efficient and stable inverted perovskite solar cells. Chem. Eng. J. 2021, 426, 131357.
  20. Lin, C.H.; Hu, L.; Guan, X.; Kim, J.; Huang, C.Y.; Huang, J.K.; Wu, T. Electrode engineering in halide perovskite electronics: Plenty of room at the interfaces. Adv. Mater. 2022, 34, 2108616.
  21. Mangalam, J.; Rath, T.; Weber, S.; Kunert, B.; Dimopoulos, T.; Fian, A.; Trimmel, G. Modification of NiOx hole transport layers with 4-bromobenzylphosphonic acid and its influence on the performance of lead halide perovskite solar cells. J. Mater. Sci. Mater. Electron. 2019, 30, 9602–9611.
  22. Jheng, B.R.; Chiu, P.T.; Yang, S.H.; Tong, Y.L. Using ZnCo2O4 nanoparticles as the hole transport layer to improve long term stability of perovskite solar cells. Sci. Rep. 2022, 12, 2921.
  23. Omrani, M.; Keshavarzi, R.; Abdi-Jalebi, M.; Gao, P. Impacts of plasmonic nanoparticles incorporation and interface energy alignment for highly efficient carbon-based perovskite solar cells. Sci. Rep. 2022, 12, 5367.
  24. Li, B.; Rui, Y.; Xu, J.; Wang, Y.; Yang, J.; Zhang, Q.; Müller-Buschbaum, P. Solution-processed p-type nanocrystalline CoO films for inverted mixed perovskite solar cells. J. Colloid. Interf. Sci. 2020, 573, 78–86.
  25. Ansari, F.; Salavati-Niasari, M.; Amiri, O.; Mir, N.; Abdollahi Nejand, B.; Ahmadi, V. Magnetite as inorganic hole transport material for lead halide perovskite-based solar cells with enhanced stability. Ind. Eng. Chem. Res. 2020, 59, 743–750.
  26. Franckevičius, M.; Mishra, A.; Kreuzer, F.; Luo, J.; Zakeeruddin, S.M.; Grätzel, M. A dopant-free spirobi dithiophene] based hole-transport material for efficient perovskite solar cells. Mater. Horiz. 2015, 2, 613–618.
  27. Ahn, N.; Son, D.-Y.; Jang, I.-H.; Kang, S.M.; Choi, M.; Park, N.-G. Highly reproducible perovskite solar cells with average efficiency of 18.3% and best efficiency of 19.7% fabricated via Lewis base adduct of lead (II) iodide. J. Am. Chem. Soc. 2015, 137, 8696–8699.
  28. Chen, Y.; Yang, X.; Wang, W.; Ran, R.; Zhou, W.; Shao, Z. Tuning the A-site cation deficiency of La0.8Sr0.2FeO3−δ perovskite oxides for high-efficiency triiodide reduction reaction in dye-sensitized solar cells. Energy Fuels 2020, 34, 11322–11329.
  29. Ren, G.; Han, W.; Deng, Y.; Wu, W.; Li, Z.; Guo, J.; Bao, H.; Liu, C.; Guo, W. Strategies of modifying spiro-OMeTAD materials for perovskite solar cells: A review. J. Mater. Chem. A 2021, 9, 4589–4625.
  30. Li, Y.; Li, Z.; Liu, F.; Wei, J. Defects and passivation in perovskite solar cells. Surf. Innov. 2022, 10, 3–20.
  31. Jeon, N.J.; Lee, H.G.; Kim, Y.C.; Seo, J.; Noh, J.H.; Lee, J.; Seok, S.I. O-Methoxy substituents in Spiro-OMeTAD for efficient inorganic-organic hybrid perovskite solar cells. J. Am. Chem. Soc. 2014, 136, 7837–7840.
  32. Hu, Z.; Fu, W.; Yan, L.; Miao, J.; Yu, H.; He, Y.; Huang, W. Effects of heteroatom substitution in spiro-bifluorene hole transport materials. Chem. Sci. 2016, 7, 5007–5012.
  33. Wu, F.; Yan, K.; Wu, H.; Niu, B.; Liu, Z.; Li, Y.; Zuo, L.; Chen, H. Tuning interfacial chemical interaction for high-performance perovskite solar cell with PEDOT:PSS as hole transporting layer. J. Mater. Chem. A 2021, 9, 14920–14927.
  34. Shi, H.; Liu, C.; Jiang, Q.; Xu, J. Effective approaches to improve the electrical conductivity of PEDOT: PSS: A review. Adv. Electron. Mater. 2015, 1, 1500017.
  35. Cheng, N.; Liu, Z.; Yu, Z.; Li, W.; Zhao, Z.; Xiao, Z.; Lei, B.; Sun, S.; Zi, W. High performance inverted perovskite solar cells using PEDOT:PSS/KCl hybrid hole transporting layer. Org. Electron. 2021, 98, 106298.
  36. Li, P.; Mohamed, M.I.O.; Xu, C.; Wang, X.; Tang, X. Electrical property modified hole transport layer (PEDOT:PSS) enhance the efficiency of perovskite solar cells: Hybrid co-solvent post-treatment. Org. Electron. 2020, 78, 105582.
  37. Hu, W.; Xu, C.Y.; Niu, L.B.; Elseman, A.M.; Wang, G.; Liu, D.B.; Yao, Y.Q.; Liao, L.P.; Zhou, G.D.; Song, Q.L. High open-circuit voltage of 1.134 V for inverted planar perovskite solar cells with sodium citrate-doped PEDOT:PSS as a hole transport layer. ACS Appl. Mater. Interfaces 2019, 11, 22021–22027.
  38. Neophytou, M.; Griffiths, J.; Fraser, J.; Kirkus, M.; Chen, H.; Nielsen, C.B.; McCulloch, I. High mobility, hole transport materials for highly efficient PEDOT:PSS replacement in inverted perovskite solar cells. J. Mater. Chem. C 2017, 5, 4940–4945.
  39. Anrango-Camacho, C.; Pavón-Ipiales, K.; Frontana-Uribe, B.A.; Palma-Cando, A. Recent advances in hole-transporting layers for organic solar cells. Nanomaterials 2022, 12, 443.
  40. Patel, V.D.; Gupta, D. Solution-processed metal-oxide based hole transport layers for organic and perovskite solar cell: A review. Mater. Today Commun. 2022, 31, 103664.
  41. Islam, M.A.; Sarkar, D.K.; Shahinuzzaman, M.; Wahab, Y.A.; Khandaker, M.U.; Tamam, N.; Sulieman, A.; Amin, N.; Akhtaruzzaman, M. Green synthesis of lead sulphide nanoparticles for high-efficiency perovskite solar cell applications. Nanomaterials 2022, 12, 1933.
  42. Mashreghi, A.; Maleki, K.; Moradzadeh, M. Two-phase synthesized Cu2ZnSnS4 nanoparticles as inorganic hole-transporting material of paintable carbon-based perovskite solar cells. Sol. Energy 2020, 201, 547–554.
  43. Xi, Q.; Gao, G.; Zhou, H.; Zhao, Y.; Wu, C.; Wang, L.; Guo, P.; Xu, J. Highly efficient inverted solar cells based on perovskite grown nanostructures mediated by CuSCN. Nanoscale 2017, 9, 6136–6144.
  44. Chen, W.; Wu, Y.; Yue, Y.; Liu, J.; Zhang, W.; Yang, X.; Chen, H.; Bi, E.; Ashraful, I.; Grätzel, M. Efficient and stable large-area perovskite solar cells with inorganic charge extraction layers. Science 2015, 350, 944–948.
  45. Ye, X.; Wen, Z.; Zhang, R.; Ling, H.; Xia, J.; Lu, X. High-performance and stable inverted perovskite solar cells using low-temperature solution-processed CuNbOx hole transport layer. J. Power Sources 2021, 483, 229194.
  46. Zhang, H.; Wang, H.; Zhu, H.; Chueh, C.C.; Chen, W.; Yang, S.; Jen, A.K.Y. Low-temperature solution-processed CuCrO2 hole-transporting layer for efficient and photostable perovskite solar cells. Adv. Energy Mater. 2018, 8, 1702762.
  47. Islam, M.B.; Yanagida, M.; Shirai, Y.; Nabetani, Y.; Miyano, K. NiOx hole transport layer for perovskite solar cells with improved stability and reproducibility. ACS Omega 2017, 2, 2291–2299.
  48. Pandey, J.; Hua, B.; Ng, W.; Yang, Y.; van der Veen, K.; Chen, J.; Geels, N.J.; Luo, J.-L.; Rothenberg, G.; Yan, N. Developing hierarchically porous MnOx/NC hybrid nanorods for oxygen reduction and evolution catalysis. Green Chem. 2017, 19, 2793–2797.
  49. Wang, K.-C.; Jeng, J.-Y.; Shen, P.-S.; Chang, Y.-C.; Diau, E.W.-G.; Tsai, C.-H.; Chao, T.-Y.; Hsu, H.-C.; Lin, P.-Y.; Chen, P. P-type mesoscopic nickel oxide/organometallic perovskite heterojunction solar cells. Sci. Rep. 2014, 4, 4756.
  50. Wang, K.-C.; Shen, P.-S.; Li, M.-H.; Chen, S.; Lin, M.-W.; Chen, P.; Guo, T.-F. Low-temperature sputtered nickel oxide compact thin film as effective electron blocking layer for mesoscopic NiO/CH3NH3PbI3 perovskite heterojunction solar cells. ACS Appl. Mater. Interfaces 2014, 6, 11851–11858.
  51. Xiang, W.; Pan, J.; Chen, Q. In situ formation of NiOx interlayer for efficient n-i-p inorganic perovskite solar cells. ACS Appl. Energy Mater. 2020, 3, 5977–5983.
  52. Papadas, I.T.; Ioakeimidis, A.; Armatas, G.S.; Choulis, S.A. Low-temperature combustion synthesis of a spinel NiCo2O4 hole transport layer for perovskite photovoltaics. Adv. Sci. 2018, 5, 1701029.
  53. Ouyang, D.; Chen, C.; Huang, Z.; Zhu, L.; Yan, Y.; Choy, W.C.H. Hybrid 3D nanostructure-based hole transport layer for highly efficient inverted perovskite solar cells. ACS Appl. Mater. Interfaces 2021, 13, 16611–16619.
  54. Li, Z. Stable perovskite solar cells based on WO3 nanocrystals as hole transport layer. Chem. Lett. 2015, 44, 1140–1141.
More
© Text is available under the terms and conditions of the Creative Commons Attribution (CC BY) license; additional terms may apply. By using this site, you agree to the Terms and Conditions and Privacy Policy.
This entry is offline, you can click here to edit this entry!
Video Production Service
Feedback