Ultraviolet-ozone surface modification for non-wetting hole transport materials based inverted planar perovskite solar cells with efficiency exceeding 18%

Xu, Xiuwen; Ma, Chunqing; Cheng, Yuanhang; Xie, Yue‐Min; Yi, Xinjian; Gautam, Bhoj; Chen, Shengmei; Li, Ho-Wa; Lee, Chun‐Sing; So, Franky; Tsang, Sai‐Wing

doi:10.1016/j.jpowsour.2017.06.013

Cited by 106 publications

(84 citation statements)

References 53 publications

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“…The same condition for doped spiro‐OMeTAD based devices led to a performance of 13.38%. In a very recent study, using ultraviolet surface modification method to fabricate hole transporting layers with MEH‐PPV and Poly‐TPD (poly [N,N′‐bis(4‐butylphenyl)‐N,N′‐bis(phenyl)benzidine]) has led to PSC with high PCEs of 10% for MEH‐PPV based devices and PCEs exceeding 18% for Poly‐TPD based PSCs, together with enhanced long‐term stability . By improving the quality of perovskite layer, an air‐processed PSC with remarkable PCE of 18.11% has been reported by Cheng et al In their study, Poly‐TPD has been used as dopant free HTM in an inverted PSC.…”

Section: Dopant‐free Hole Transporting Materials For Pscsmentioning

confidence: 99%

Dopant‐Free Hole Transporting Materials for Perovskite Solar Cells

Rezaee

Liu

et al. 2018

Solar RRL

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This article reviews various dopant-free hole transporting materials (HTMs) used in perovskite solar cells (PSCs) in three main categories including inorganic, polymeric, and small molecule HTMs. PSCs have undergone rapid progress, achieving power conversion efficiencies (PCEs) above 22%. With their low production cost and high efficiencies, PSCs are considered promising next-generation solar cell technology. In all developed architectures for PSCs, including planar and mesoscopic with conventional and inverted structures, HTMs play a significant role in determining the photovoltaic performance of PSCs. Using p-type dopants, however, is considered a common strategy to increase the hole conductivity of HTM, which is usually compensated by a more complicated fabrication procedure, higher production costs, and lower stability of PSC. Although several reviews on HTMs have been published, progress on dopant free HTMs needs to be reviewed and analyzed. Here, a review covering most of the published reports on dopantfree HTMs is presented, and the device structure and fabrication method, HTM layer deposition techniques, and the efficiency and the stability of PSCs are addressed during discussions in each main category. Finally, an outlook on stability and PCE growth in PSCs based on dopant-free HTMs is presented.

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Section: Dopant‐free Hole Transporting Materials For Pscsmentioning

confidence: 99%

Dopant‐Free Hole Transporting Materials for Perovskite Solar Cells

Rezaee

Liu

et al. 2018

Solar RRL

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“…It has been shown that the nonwetting property of hydrophobic conjugated polymers has represented, for a long time, a major hurdle prohibiting their application for the fabrication of inverted PSCs via solution processing . Although surface modification via oxygen plasma or ultraviolet–ozone (UVO) treatment is capable of reducing the surface energy of hydrophobic polymers, these plasma‐based modifications can unfortunately alter the chemical structure of the surface and, thus, change the optoelectronic properties of the HTLs such as work function, transparency, and mobility of the films . To suppress this problem, a gentle physical modification by depositing a layer of insulating mesoporous aluminum oxide (Al 2 O 3 ) on top of the three HTMs (PFO, TFB, and PFB) was performed, which allows to regulate their surface wettabilities without sacrificing optoelectronic properties .…”

Section: Resultsmentioning

confidence: 99%

“…Inorganic hole‐transport materials (HTMs) usually require a high‐temperature sintering process to ensure efficient charge transport . Few p‐type polymeric HTLs based on poly(bis(4‐phenyl)(2,4,6‐trimethylphenyl)amine) (PTAA) and poly[ N,N′ ‐bis(4‐butylphenyl)‐ N,N′ ‐bis(phenyl)benzidine] (poly‐TPD) have demonstrated efficient hole‐extraction capability in inverted PSCs . Nevertheless, it is still highly desired to explore alternative HTMs to broaden the material selection for the manufacture of high‐performance inverted PSCs …”

Section: Introductionmentioning

confidence: 99%

Polyfluorene Copolymers as High‐Performance Hole‐Transport Materials for Inverted Perovskite Solar Cells

You

Peng

et al. 2019

Solar RRL

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Inverted perovskite solar cells (PSCs) that can be entirely processed at low temperatures have attracted growing attention due to their cost‐effective production. Hole‐transport materials (HTMs) play an essential role in achieving efficient inverted PSCs, as they determine the effectiveness of charge extraction and recombination at interfaces. Herein, three polyfluorene copolymers (TFB, PFB, and PFO) are investigated as HTMs for construction of inverted PSCs. It is found that the photovoltaic performance of the solar cells is closely correlated with the electronic properties of the HTMs. Due to its high mobility along with the favored energy‐level alignment with perovskite, TFB shows superior charge extraction and suppressed interfacial recombination than PFB‐ and PFO‐based devices, which delivers a high efficiency of 18.48% with an open‐circuit voltage (VOC) of up to 1.1 V. In contrast, the presence of a large energy barrier in the PFO‐based devices results in substantial losses in both VOC and photocurrent. These results demonstrate that TFB can serve as a superior HTM for inverted PSCs. Moreover, it is anticipated that the performance of the three HTMs identified here might guide the molecular design of novel HTMs for the manufacture of highly efficient inverted PSCs.

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“…A couple of recent works have demonstrated that SAM based dopant‐free organic hole‐extracting layers (HEL) can be used to construct efficient p–i–n structured PSCs . Although the self‐assembly route can lead to uniform and ultrathin organic HELs, the subsequent deposition of perovskite becomes difficult due to the nonwetting issue, which hampers the fabrication of large‐area uniform perovskite thin films. Most critically, large‐area perovskite cells or modules have not been achieved via this SAM route.…”

Section: Introductionmentioning

confidence: 99%

Synergistic Coassembly of Highly Wettable and Uniform Hole‐Extraction Monolayers for Scaling‐up Perovskite Solar Cells

et al. 2019

Adv Funct Materials

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All organic charge‐transporting layer (CTL)‐featured perovskite solar cells (PSCs) exhibit distinct advantages, but their scaling‐up remains a great challenge because the organic CTLs underneath the perovskite are too thin to achieve large‐area homogeneous layers by spin‐coating, and their hydrophobic nature further hinders the solution‐based fabrication of perovskite layer. Here, an unprecedented anchoring‐based coassembly (ACA) strategy is reported that involves a synergistic coadsorption of a hydrophilic ammonium salt CA‐Br with hole‐transporting triphenylamine derivatives to acquire scalable and wettable organic hole‐extraction monolayers for p–i–n structured PSCs. The ACA route not only enables ultrathin organic CTLs with high uniformity but also eliminates the nonwetting problem to facilitate large‐area perovskite films with 100% coverage. Moreover, incorporation of CA‐Br in the ACA strategy can distinctly guarantee a high quality of electronic connection via the cations' vacancy passivation. Consequently, a high power‐conversion‐efficiency (PCE) of 17.49% is achieved for p–i–n structured PSCs (1.02 cm2), and a module with an aperture area of 36 cm2 shows PCE of 12.67%, one of the best scaling‐up results among all‐organic CTL‐based PSCs. This work demonstrates that the ACA strategy can be a promising route to large‐area uniform interfacial layers as well as scaling‐up of perovskite solar cells.

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Ultraviolet-ozone surface modification for non-wetting hole transport materials based inverted planar perovskite solar cells with efficiency exceeding 18%

Cited by 106 publications

References 53 publications

Dopant‐Free Hole Transporting Materials for Perovskite Solar Cells

Dopant‐Free Hole Transporting Materials for Perovskite Solar Cells

Polyfluorene Copolymers as High‐Performance Hole‐Transport Materials for Inverted Perovskite Solar Cells

Synergistic Coassembly of Highly Wettable and Uniform Hole‐Extraction Monolayers for Scaling‐up Perovskite Solar Cells

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