Tetra-alkyl-substituted copper (II) phthalocyanines as dopant-free hole-transport layers for planar perovskite solar cells with enhanced open circuit voltage and stability

Wang, Yulong; Liu, Xiaoyuan; Shan, Haiquan; Chen, Qian; Liu, Tuo; Sun, Xize; Ma, Dongying; Zhang, Zihao; Xu, Jie; Xu, Zong‐Xiang

doi:10.1016/j.dyepig.2016.12.067

Cited by 48 publications

(35 citation statements)

References 38 publications

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“…[151] In 2015, Ke et al demonstrated efficient room-temperature fully vacuum-processed perovskite solar cells using using CuPc (Figure 15) as the HTM and achieved a PCE of 15.42%. Besides, CuPc derivatives have been reported by many groups, like tetramethyl copper(II)phthalocyanine (CuMePc), [137] tetra-ethyl copper(II)phthalocyanine (CuEtPc), [137] and copper(II) phthalocyanine (CuPc-TIPS) ( Figure 15). In the same year, Zhang and co-workers reported highly stable CuPc as HTM material in combination with the low temperature and doctor-blade technique processed carbon as cathode material for the development of the MAPbI 3 -based perovskite solar cell.…”

Section: Wwwadvancedsciencenewscommentioning

confidence: 99%

Less is More: Dopant‐Free Hole Transporting Materials for High‐Efficiency Perovskite Solar Cells

Zhou

Wen

Gao

2018

Advanced Energy Materials

252

217

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years, the demands for reducing the fabrication costs and the energy payback time of photovoltaic devices led to the invention of emerging third-generation PV technologies, such as dye-sensitized solar cells (DSSCs), organic photovoltaic (OPV), quantum dots solar cells, and the latest perovskite solar cells (PSCs). Among them, PSC is the only technology that combines both merits of low processing energy cost and high power conversion efficiency (PCE), which makes it possible to replace the silicon-based PV technology.Since the first reports by Bach and Grätzel et al. about the use of 2,2′,7,7′tetrakis(N,N-di-p-methoxyphenylamine)-9,9′-spirobifluorene (spiro-OMeTAD) as the hole-transporting material (HTM) in solid-state DSSCs (ssDSSC), spiro-OMeTAD becomes the benchmark of all the new HTMs developed for ssDSSC and PSCs. Contrary to the popular myth, spiro-OMeTAD is not completely amorphous but a semi-crystalline organic p-type semiconductor with a glass transition temperature of 121 °C and a melting point of 246 °C. [1] Its chemical structure is shown in Figure 1a and Grätzel's lab first revealed the crystal structure in 2014 [2] ( Figure 1b). It has a large bandgap of 2.98 eV and yields almost colorless thin films when deposited from solution in organic solvents such as toluene or chlorobenzene. The first oxidation potential of spiro-OMeTAD is found to be approximately −5.1 eV as derived from electrochemical and photoelectron spectroscopy measurements. [3] In the case of the solid-state PSCs reported since 2012, [4,5] the PCE of lab-made devices has increased from 9.7% [6] to above 21% [7] in 2017, owing to the improvement in the perovskite composition and device engineering. However, on account of several desirable properties, (i) favorable glass transition temperature; (ii) reasonable solubility; (iii) proper ionization potential; (iii) low visible light absorption; and (iv) appropriate solid-state morphology, spiro-OMeTAD has remained as the material of choice when high PCEs are demanded. Due to the fact that spiro-OMeTAD suffers from a relatively low conductivity in its pristine form, all the eyecatching PCEs were achieved by adding additives and/or dopants-a standard technique used to tune the electrical properties of both organic and inorganic semiconductors. Typical additives including 4-tert-butylpyridine (TBP) and lithium bis(trifluoromethyl sulfonyl)imide (LiTFSI) were added to the spin-coating formulation of spiro-MeOTAD and Perovskite solar cells have delivered power conversion efficiency beyond 22% in less than seven years, implying the potential for the paradigm shift of lowcost photovoltaics with high efficiency and low embedded energy. Besides the "perovskite fever," the development of new hole transport materials (HTM), especially dopant-free HTMs, is another research hotspot. This is because the currently used HTMs, such as spiro-OMeTAD derivatives, require additional chemical doping process to ensure sufficient conductivity and proper ionic potential level for efficient hole transport and colle...

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Section: Wwwadvancedsciencenewscommentioning

confidence: 99%

Less is More: Dopant‐Free Hole Transporting Materials for High‐Efficiency Perovskite Solar Cells

Zhou

Wen

Gao

2018

Advanced Energy Materials

252

217

View full text Add to dashboard Cite

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“…The hole mobility of CuPrPc was measured using the space‐charge‐limited current (SCLC) method, as extracted from the current density–voltage ( J–V ) characteristics of SCLC (Figure b). The hole mobility of dopant‐free CuPrPc was found to be 2.16 × 10 −3 cm 2 Vs −1 , which is higher than that of CuMePc and CuEtPc with edge‐on orientation …”

Section: Summary Of Photovoltaic Parameters Of Pscs Employing Htm Of mentioning

confidence: 86%

“…The CuPrPc ‐based device shows enhanced IPCE over the whole visible wavelength range from 300 to 800 nm. This device has higher IPCE than CuPc‐, CuMePc‐, CuEtPc‐, and Spiro‐OMeTAD‐based devices. The integrated short circuit current density is 23 mA cm −2 , which is consistent with the J – V measurements.…”

Section: Summary Of Photovoltaic Parameters Of Pscs Employing Htm Of mentioning

confidence: 91%

“…This stability of the perovskite layer could be induced by the protecting effect of the dense and smooth in the CuPrPc film with high hydrophobicity. The water droplet contact angle of 106.6° is obtained for CuPrPc (Figure S8), which is much larger than that of Spiro‐OMeTAD (65.5°) . Thus, the perovskite layer in the solar cell can be more efficiently protected using propyl‐substituted copper phthalocyanine complex as the HTM and prevent the penetration of atmospheric moisture into the perovskite layer.…”

Section: Summary Of Photovoltaic Parameters Of Pscs Employing Htm Of mentioning

confidence: 99%

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Tetra‐Propyl‐Substituted Copper (II) Phthalocyanine as Dopant‐Free Hole Transporting Material for Planar Perovskite Solar Cells

et al. 2018

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Solution‐processed hole transporting materials (HTMs) that are dopant‐free show promise for use in low‐cost, high‐performance perovskite solar cells (PSCs). In this study, a new HTM of copper (II) phthalocyanine with tetra‐propyl‐substituted function groups (CuPrPc) is reported. It is found that CuPrPc could form face‐on molecular orientation when spin‐coated on perovskite, resulting in high hole mobility and hydrophobic surface. These properties are more favorable for hole transport and moisture resistance applications in PSCs. Solution‐processed planar PSCs utilizing CuPrPc as HTM are fabricated and tested. PSC with CuPrPc exhibited highest power conversion efficiency of 17.8%. Furthermore, beneficial from the hydrophobic nature of CuPrPc, the devices with CuPrPc as HTM show improved stability and retain over 94% of their initial efficiency even after storage in humidity about 75% for 800 h without encapsulation, which is much better than the performance of PSCs based on Spiro‐OMeTAD HTM.

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“…[22] Precursor dispersions (2.5 mg mL À1 )w ere prepared by dispersing SnO 2 nanoparticles in ethanol, and then spin-coated on the FTO substrates with as peed of 1000 rpm for 40 s. The perovskite layer was then fabricated on SnO 2 film. The patterned FTO glass was precleaned in an ultrasonic bath of acetone and isopropyl alcohol and then treated in an ultraviolet ozone chamber (Novascan Company, USA) for 20 min, SnO 2 ETL and perovskite layer were prepared by reported procedure.…”

Section: Fabrication and Measurement Of Pscsmentioning

confidence: 99%

Ultrasonic‐Assisted Wet Chemistry Synthesis of Ultrafine SnO₂ Nanoparticles for the Electron‐Transport Layer in Perovskite Solar Cells

et al. 2018

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SnO was recently employed as an efficient electron-transport layer (ETL) in perovskite solar cells (PSCs) and high power conversion efficiencies (PCEs) have been reported. However, it is still challenging to fabricate SnO thin films through facile solution-based synthesis at low temperature (<150 °C) to be compatible with the large scale module fabrication, especially for flexible devices. Here, we report a low temperature solution-based method for preparation of SnO nanoparticles. Ultrasonic-assisted wet chemistry synthesis of ultrafine SnO nanocrystals with particle size ranging from 2 to 5 nm was achieved by employing a SnCl ⋅5 H O solution in a mixed ethanol-water solution and with no annealing step. The crystallinity and microstructure of the SnO nanoparticles were investigated by X-ray diffraction (XRD) and transmission electron microscopy (TEM), as well as selected area electron diffraction (SAED) analysis. The added water in ethanol and increased pH values were demonstrated as two key factors to successful fabrication of highly crystallized samples with high reproducability. An efficiency of 16.56 % was achieved for PSCs based on SnO nanoparticles synthesized by ultrasonic-assisted wet chemistry.

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Tetra-alkyl-substituted copper (II) phthalocyanines as dopant-free hole-transport layers for planar perovskite solar cells with enhanced open circuit voltage and stability

Cited by 48 publications

References 38 publications

Less is More: Dopant‐Free Hole Transporting Materials for High‐Efficiency Perovskite Solar Cells

Less is More: Dopant‐Free Hole Transporting Materials for High‐Efficiency Perovskite Solar Cells

Tetra‐Propyl‐Substituted Copper (II) Phthalocyanine as Dopant‐Free Hole Transporting Material for Planar Perovskite Solar Cells

Ultrasonic‐Assisted Wet Chemistry Synthesis of Ultrafine SnO₂ Nanoparticles for the Electron‐Transport Layer in Perovskite Solar Cells

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Tetra-alkyl-substituted copper (II) phthalocyanines as dopant-free hole-transport layers for planar perovskite solar cells with enhanced open circuit voltage and stability

Cited by 48 publications

References 38 publications

Less is More: Dopant‐Free Hole Transporting Materials for High‐Efficiency Perovskite Solar Cells

Less is More: Dopant‐Free Hole Transporting Materials for High‐Efficiency Perovskite Solar Cells

Tetra‐Propyl‐Substituted Copper (II) Phthalocyanine as Dopant‐Free Hole Transporting Material for Planar Perovskite Solar Cells

Ultrasonic‐Assisted Wet Chemistry Synthesis of Ultrafine SnO2 Nanoparticles for the Electron‐Transport Layer in Perovskite Solar Cells

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Ultrasonic‐Assisted Wet Chemistry Synthesis of Ultrafine SnO₂ Nanoparticles for the Electron‐Transport Layer in Perovskite Solar Cells