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Perovskite solar modules hit new efficiency record
Accepted Manuscript Research Highlight Perovskite solar modules hit new efficiency record Yang Bai, Lianzhou Wang PII: DOI: Reference:
S2095-9273(17)30502-9 https://doi.org/10.1016/j.scib.2017.09.021 SCIB 233
To appear in:
Science Bulletin
Please cite this article as: Y. Bai, L. Wang, Perovskite solar modules hit new efficiency record, Science Bulletin (2017), doi: https://doi.org/10.1016/j.scib.2017.09.021
This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
Research Highlight Perovskite solar modules hit new efficiency record Yang Bai, Lianzhou Wang* Nanomaterials Centre, Australian Institute for Bioengineering and Nanotechnology and School of Chemical Engineering, The University of Queensland, Brisbane 4072, Australia *Corresponding Author, Email: [email protected] The last few years witnessed exceptional advancement of organohalide perovskite photovoltaics owing to their intriguing optoelectronic properties. The power conversion efficiency (PCE) of the state-of-art lab-scale perovskite solar cells (PSCs) has skyrocketed from 3.8% to a certified value of 22.1% (aperture area of 0.046 cm2) [1], approaching the stage where up-scaling to commercial dimensions is an imperative. Recently, some promising results have been demonstrated for perovskite device with larger active area of ca. 1 cm2. By using a vacuum-flash assisted solution process, Grätzel and co-workers [2] reported a certified PCE of 19.6% for mesoscopic PSCs with an aperture area exceeding 1 cm2. The PCE record of 1 cm2 mesoscopic PSCs was further improved to 19.7% by suppressing the formation of deep-level defects [1]. In the meantime, rapid progress is also seen in planar PSCs and a certified PCE of 19.5% was achieved for an active area of 1.1 cm2 [3]. However, two major challenges still hamper the commercial manufacturing of efficient perovskite solar modules when the device area becomes much larger than 1 cm2. The first key issue is the dramatic reduction in the quality and uniformity of perovskite film with active areas scaled up to several dozens of cm2 using the current technology. The other major barrier to industrial scale deployment lies in the solvent handling and toxicology concerns associated with a large-scale operating with highly hazardous solvents such as N, N-dimethylformamide (DMF) [4, 5]. Very excitingly, a research team of from Shanghai Jiao Tong University (China) and National Institute for Materials Science (Japan) reported a new scalable deposition route for methyl ammonium lead halide perovskite films free of solvent or vacuum tackling the above challenges [6]. With rapid conversion of amine complex precursors to perovskite
films followed by a pressure application step in air at low temperatures, they have successfully fabricated high-quality, large-area perovskite films that were free of pinholes and highly uniform, and achieved a certified record PCE of 12.1% for a mesoscopic perovskite solar module with an aperture area of as large as 36.1 cm2. Thanks to the molecular interactions between the –NH3+ from CH3NH3X or Pb2+ from PbX2 (X is I, Br, or Cl) and –NH2 from CH3NH2 gas [6, 7], Han and co-workers [6] succeeded in producing liquid-state amine complex perovskite precursors by direct reaction between CH3NH3I and PbI2 powder and pre-dried CH3NH2 gas for perovskite film deposition. As CH3NH2 gas would be easily released from the complex at low temperatures (<50 ℃), the molecular interactions within the amine complex precursor were very weak, which enabled a solvent- and vacuum-free processing route to the formation of high-quality perovskite films under mild conditions. Fig. 1a shows the diagram of the pressure processing method for the deposition of perovskite films. The liquid amine complex precursor was first loaded on the substrate with an area of 8 cm × 8 cm, followed by applying an ultra-smooth and flat polyimide (PI) film onto the precursor (Fig. 1a, (I)) Subsequently, a pneumatically driven squeezing board was used to apply pressure and spread the liquid precursor evenly under the PI film (Fig. 1a, (II)). The pressure was controllable and maintained for 60 s before moving the assembly on a hotplate at 50 ℃ for 2 min. The PI film was eventually peeled off at a speed of 50 mm/s, yielding a highly compact and uniform perovskite film in ambient air when CH 3NH2 gas was released (Fig. 1a, (III)). The top-view scanning electron microscopy (SEM) image as shown in Fig. 1b verified that the perovskite film fabricated by the present method was dense and pin-hole-free. In contrast, the pressure-processed perovskite film comprised of grains with size of 0.8-1.0 µm that were 3-4 times larger than those (200-300 nm) of perovskite film prepared by spin-coating followed with a post-treatment in CH3NH2 gas. In addition, the observed much sharper and more intense peaks in the X-ray diffraction (XRD) pattern (Fig. 1c) indicated the higher crystallinity and larger grain size with less scattering at grain boundaries in pressure-processed perovskite film, which was consistent with SEM results and may lead to reduced trap states and enhanced photovoltaic performance. The fabricated perovskite solar module as exhibited in Fig. 1d
was composed of 10 inter-connected sub-cells each with an area of about 3.6 cm2. The diagram of the module structure was illustrated in Fig. 1e. The I-V curves of a mesoscopic solar module (36.1 cm2) with different sweeping directions were given in Fig. 1f and a slight hysteresis was observed. To confirm the efficiency, the module of >36 cm2 size fully covered by a black mask received an impressive certified PCE of 12.1%, which is so far the largest efficient perovskite solar cells reported.
Fig. 1 (a) Diagram of the pressure processing method for the deposition of perovskite films. The steps of the pressure processing method: (I) add amine complex precursors and cover with PI film; (II) apply pressure; and (III) heat and peel off the PI film. SEM images (b) and XRD patterns (c) of the perovskite film converted from amine complex precursors via the pressure processing method (the present technique), in comparison with images and patterns from a reference sample that was deposited by the spin-coating method with a post-treatment by CH3NH2 gas. (d) Photograph of a module. (e) Diagram of the module structure. (f) I-V curves of a solar module measured in backward (from VOC to ISC) and forward (from ISC to VOC) modes under simulated solar light, AM 1.5G, 100 mW/cm2. Reprinted with permission from ref. [6]. Copyright © 2017 Nature Publishing Group.
Such solvent- and vacuum-free approach represents an important milestone of lowcost, green fabrication of high-quality perovskite films for commercial optoelectronic devices on a large scale. We can foresee its great potential for use in developing largearea perovskite/silicon tandem devices. It may also be easily adopted for the up-scaling of
flexible device manufacturing. However, it is of great interest to have more insightful understanding on the molecular interactions within the amine complex as well as the perovskite crystallization processes, which may be beneficial for extending this route to a variety of material systems such as mixed cation perovskites. In addition to the fundamental progress, we also do expect to see more advancements of practical application in the near future, such as series resistance reduction in solar modules, suitable additive [8] in amine complex precursors for defect passivation, modified device architectures with reduced hysteresis, further improved efficiency and better stability.
References [1] W. S. Yang, B. W. Park, E. H. Jung, et al. Iodide management in formamidinium-leadhalide–based perovskite layers for efficient solar cells. Science, 2017, 356: 1376-1379 [2] X. Li, D. Bi, C. Yi, et al. A vacuum flash–assisted solution process for high-efficiency large-area perovskite solar cells. Science, 2016, 353: 58-62 [3] H. Tan, A. Jain, O. Voznyy, et al. Efficient and stable solution-processed planar perovskite solar cells via contact passivation. Science, 2017, 355:722-726 [4] K. L. Gardner, J. G. Tait, T. Merckx, et al. Nonhazardous solvent systems for processing perovskite photovoltaics. Adv Energy Mater, 2016, 6: 1600386 [5] N. K. Noel, S. N. Habisreutinger, B. Wenger, et al. A low viscosity, low boiling point, clean solvent system for the rapid crystallisation of highly specular perovskite films. Energy Environ Sci, 2017, 10:145-152 [6] H. Chen, F. Ye, W. Tang, et al. A solvent- and vacuum-free route to large-area perovskite films for efficient solar modules. Nature, 2017, DOI:10.1038/nature23877 [7] Z. Zhou, Z. Wang, Y. Zhou, et al. Methylamine-gas-induced defect-healing behavior of CH3NH3PbI3 thin films for perovskite solar cells. Angew Chem Int Ed, 2015, 54: 9705-9709 [8] L. Zuo, H. Guo, D. W. deQuilettes, et al. Polymer-modified halide perovskite films for efficient and stable planar heterojunction solar cells. Sci Adv, 2017, 3: e1700106
S2095-9273(17)30502-9 https://doi.org/10.1016/j.scib.2017.09.021 SCIB 233
To appear in:
Science Bulletin
Please cite this article as: Y. Bai, L. Wang, Perovskite solar modules hit new efficiency record, Science Bulletin (2017), doi: https://doi.org/10.1016/j.scib.2017.09.021
This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
Research Highlight Perovskite solar modules hit new efficiency record Yang Bai, Lianzhou Wang* Nanomaterials Centre, Australian Institute for Bioengineering and Nanotechnology and School of Chemical Engineering, The University of Queensland, Brisbane 4072, Australia *Corresponding Author, Email: [email protected] The last few years witnessed exceptional advancement of organohalide perovskite photovoltaics owing to their intriguing optoelectronic properties. The power conversion efficiency (PCE) of the state-of-art lab-scale perovskite solar cells (PSCs) has skyrocketed from 3.8% to a certified value of 22.1% (aperture area of 0.046 cm2) [1], approaching the stage where up-scaling to commercial dimensions is an imperative. Recently, some promising results have been demonstrated for perovskite device with larger active area of ca. 1 cm2. By using a vacuum-flash assisted solution process, Grätzel and co-workers [2] reported a certified PCE of 19.6% for mesoscopic PSCs with an aperture area exceeding 1 cm2. The PCE record of 1 cm2 mesoscopic PSCs was further improved to 19.7% by suppressing the formation of deep-level defects [1]. In the meantime, rapid progress is also seen in planar PSCs and a certified PCE of 19.5% was achieved for an active area of 1.1 cm2 [3]. However, two major challenges still hamper the commercial manufacturing of efficient perovskite solar modules when the device area becomes much larger than 1 cm2. The first key issue is the dramatic reduction in the quality and uniformity of perovskite film with active areas scaled up to several dozens of cm2 using the current technology. The other major barrier to industrial scale deployment lies in the solvent handling and toxicology concerns associated with a large-scale operating with highly hazardous solvents such as N, N-dimethylformamide (DMF) [4, 5]. Very excitingly, a research team of from Shanghai Jiao Tong University (China) and National Institute for Materials Science (Japan) reported a new scalable deposition route for methyl ammonium lead halide perovskite films free of solvent or vacuum tackling the above challenges [6]. With rapid conversion of amine complex precursors to perovskite
films followed by a pressure application step in air at low temperatures, they have successfully fabricated high-quality, large-area perovskite films that were free of pinholes and highly uniform, and achieved a certified record PCE of 12.1% for a mesoscopic perovskite solar module with an aperture area of as large as 36.1 cm2. Thanks to the molecular interactions between the –NH3+ from CH3NH3X or Pb2+ from PbX2 (X is I, Br, or Cl) and –NH2 from CH3NH2 gas [6, 7], Han and co-workers [6] succeeded in producing liquid-state amine complex perovskite precursors by direct reaction between CH3NH3I and PbI2 powder and pre-dried CH3NH2 gas for perovskite film deposition. As CH3NH2 gas would be easily released from the complex at low temperatures (<50 ℃), the molecular interactions within the amine complex precursor were very weak, which enabled a solvent- and vacuum-free processing route to the formation of high-quality perovskite films under mild conditions. Fig. 1a shows the diagram of the pressure processing method for the deposition of perovskite films. The liquid amine complex precursor was first loaded on the substrate with an area of 8 cm × 8 cm, followed by applying an ultra-smooth and flat polyimide (PI) film onto the precursor (Fig. 1a, (I)) Subsequently, a pneumatically driven squeezing board was used to apply pressure and spread the liquid precursor evenly under the PI film (Fig. 1a, (II)). The pressure was controllable and maintained for 60 s before moving the assembly on a hotplate at 50 ℃ for 2 min. The PI film was eventually peeled off at a speed of 50 mm/s, yielding a highly compact and uniform perovskite film in ambient air when CH 3NH2 gas was released (Fig. 1a, (III)). The top-view scanning electron microscopy (SEM) image as shown in Fig. 1b verified that the perovskite film fabricated by the present method was dense and pin-hole-free. In contrast, the pressure-processed perovskite film comprised of grains with size of 0.8-1.0 µm that were 3-4 times larger than those (200-300 nm) of perovskite film prepared by spin-coating followed with a post-treatment in CH3NH2 gas. In addition, the observed much sharper and more intense peaks in the X-ray diffraction (XRD) pattern (Fig. 1c) indicated the higher crystallinity and larger grain size with less scattering at grain boundaries in pressure-processed perovskite film, which was consistent with SEM results and may lead to reduced trap states and enhanced photovoltaic performance. The fabricated perovskite solar module as exhibited in Fig. 1d
was composed of 10 inter-connected sub-cells each with an area of about 3.6 cm2. The diagram of the module structure was illustrated in Fig. 1e. The I-V curves of a mesoscopic solar module (36.1 cm2) with different sweeping directions were given in Fig. 1f and a slight hysteresis was observed. To confirm the efficiency, the module of >36 cm2 size fully covered by a black mask received an impressive certified PCE of 12.1%, which is so far the largest efficient perovskite solar cells reported.
Fig. 1 (a) Diagram of the pressure processing method for the deposition of perovskite films. The steps of the pressure processing method: (I) add amine complex precursors and cover with PI film; (II) apply pressure; and (III) heat and peel off the PI film. SEM images (b) and XRD patterns (c) of the perovskite film converted from amine complex precursors via the pressure processing method (the present technique), in comparison with images and patterns from a reference sample that was deposited by the spin-coating method with a post-treatment by CH3NH2 gas. (d) Photograph of a module. (e) Diagram of the module structure. (f) I-V curves of a solar module measured in backward (from VOC to ISC) and forward (from ISC to VOC) modes under simulated solar light, AM 1.5G, 100 mW/cm2. Reprinted with permission from ref. [6]. Copyright © 2017 Nature Publishing Group.
Such solvent- and vacuum-free approach represents an important milestone of lowcost, green fabrication of high-quality perovskite films for commercial optoelectronic devices on a large scale. We can foresee its great potential for use in developing largearea perovskite/silicon tandem devices. It may also be easily adopted for the up-scaling of
flexible device manufacturing. However, it is of great interest to have more insightful understanding on the molecular interactions within the amine complex as well as the perovskite crystallization processes, which may be beneficial for extending this route to a variety of material systems such as mixed cation perovskites. In addition to the fundamental progress, we also do expect to see more advancements of practical application in the near future, such as series resistance reduction in solar modules, suitable additive [8] in amine complex precursors for defect passivation, modified device architectures with reduced hysteresis, further improved efficiency and better stability.
References [1] W. S. Yang, B. W. Park, E. H. Jung, et al. Iodide management in formamidinium-leadhalide–based perovskite layers for efficient solar cells. Science, 2017, 356: 1376-1379 [2] X. Li, D. Bi, C. Yi, et al. A vacuum flash–assisted solution process for high-efficiency large-area perovskite solar cells. Science, 2016, 353: 58-62 [3] H. Tan, A. Jain, O. Voznyy, et al. Efficient and stable solution-processed planar perovskite solar cells via contact passivation. Science, 2017, 355:722-726 [4] K. L. Gardner, J. G. Tait, T. Merckx, et al. Nonhazardous solvent systems for processing perovskite photovoltaics. Adv Energy Mater, 2016, 6: 1600386 [5] N. K. Noel, S. N. Habisreutinger, B. Wenger, et al. A low viscosity, low boiling point, clean solvent system for the rapid crystallisation of highly specular perovskite films. Energy Environ Sci, 2017, 10:145-152 [6] H. Chen, F. Ye, W. Tang, et al. A solvent- and vacuum-free route to large-area perovskite films for efficient solar modules. Nature, 2017, DOI:10.1038/nature23877 [7] Z. Zhou, Z. Wang, Y. Zhou, et al. Methylamine-gas-induced defect-healing behavior of CH3NH3PbI3 thin films for perovskite solar cells. Angew Chem Int Ed, 2015, 54: 9705-9709 [8] L. Zuo, H. Guo, D. W. deQuilettes, et al. Polymer-modified halide perovskite films for efficient and stable planar heterojunction solar cells. Sci Adv, 2017, 3: e1700106