Stable and efficient hole transporting materials with a dimethylfluorenylamino moiety for perovskite solar cells

Choi, Hyeju; Cho, Jin Woo; Kang, Moon‐Sung; Ko, Jaejung

doi:10.1039/c5cc01471a

Cited by 64 publications

(34 citation statements)

References 28 publications

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“…In this study,t he hole-transporting performance of 1 and 2 thin films was evaluated to apply HTM layers to PSCs by means of the space-charge limited current (SCLC) method (Figure 7a). [56,57] The hole-mobility of 1 and 2 was determined to be 2.4 10 À6 and 1.1 10 À5 cm V À1 s À1 ,r espectively.A lthough 2 exhibits ab etter hole mobility relative to 1,t he value of 2 is lower by one order of magnitude compared with that of Spiro-OMeTAD (2.9 10 À4 cm V À1 s À1 ).…”

Section: Resultsmentioning

confidence: 98%

“…Furthermore, the cross‐shaped 1 and 2 showed an excellent solubility in organic solvents and can form uniformly thin layers through their slow crystallization. In this study, the hole‐transporting performance of 1 and 2 thin films was evaluated to apply HTM layers to PSCs by means of the space‐charge limited current (SCLC) method (Figure a) . The hole‐mobility of 1 and 2 was determined to be 2.4×10 −6 and 1.1×10 −5 cm V −1 s −1 , respectively.…”

Section: Resultsmentioning

confidence: 99%

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Regioregular Phthalocyanines Substituted with Bulky Donors at Non‐Peripheral Positions

Yamamoto

Kuribayashi

Murakami

et al. 2017

Chemistry A European J

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Three regioregular phthalocyanines (1-3) were synthesized selectively by the cyclic tetramerization of phthalonitriles bearing a bulky diarylamine substituent at the next position of nitrile. The steric repulsion at the tetramerization of bulky phthalonitriles allowed for the selective formation of regioregular phthalocyanines as confirmed by NMR and single crystal X-ray structural analyses. The absorption spectrum of 1 substituted with di(4-tert-butylphenyl)amine groups at the non-peripheral positions showed a non-split Q-band at 764 nm, which was redshifted by 83 nm compared with that of metal free phthalocyanine (H Pc). The TD-DFT calculation and electrochemical studies prove that the substitution of diarylamine groups at the α-positions effectively destabilizes the HOMO energy level, which causes a large redshift of the Q-band. Moreover, 1 can generate a one-electron oxidation species through chemical oxidation. The Q-band position of 2 bearing 4,4'-dimetoxyphenylamine units was further shifted by 10 nm compared with that of 1. In addition, 3 having carbazole units showed a small redshift of the Q-band relative to H Pc. The hole-mobility of 2 in thin film was determined to be 1.1×10 cm V s by using a space charge limited current method. A perovskite solar cell employing 2 as a hole-transporting layer gave an efficiency of 5.1 % under standard global 100 Wcm AM 1.5 G illumination.

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Section: Resultsmentioning

confidence: 98%

Section: Resultsmentioning

confidence: 99%

Regioregular Phthalocyanines Substituted with Bulky Donors at Non‐Peripheral Positions

Yamamoto

Kuribayashi

Murakami

et al. 2017

Chemistry A European J

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“…Although, Spiro‐OMeTAD can be pre‐oxidized to avoid addition of the Li‐TFSI dopant, it still remains a relatively expensive material and thus far all record devices have incorporated Li‐TFSI . To find a suitable alternative to Spiro‐OMeTAD, various HTMs such as poly(3‐hexylthiophene‐2,5‐diyl) (P3HT), poly(3,4‐ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS), carbon nanotubes, copper iodide (CuI) and copper(I) thiocyanate (CuSCN) have been investigated . CuSCN is a solution processable, thermally robust, p‐type semiconductor with a high hole mobility, and even at the research scale is very low cost (£0.5/g) .…”

Section: Introductionmentioning

confidence: 99%

Identification and Mitigation of a Critical Interfacial Instability in Perovskite Solar Cells Employing Copper Thiocyanate Hole‐Transporter

Liu

Pathak

Sakai

et al. 2016

Adv Materials Inter

112

101

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Metal halide perovskites have emerged as one of the most promising materials for photovoltaics (PVs), with power conversion efficiency of over 22% already demonstrated. In order to compete with traditional crystalline silicon PV, cost and stability are equally important issues that need to be considered besides efficiency. Copper thiocyanate (CuSCN) is an interesting candidate to be used as an inexpensive, thermally stable p‐type charge conducting material in perovskite solar cells. Here, we report 13% efficient perovskite solar cells employing CuSCN as the hole‐transport material. We compare the stability of cells employing CuSCN with those employing the archetypical organic hole‐transporter 2,2′,7,7′‐Tetrakis (N,N‐di‐p‐methoxyphenyl‐amine) 9,9′‐Spirobifluorene (Spiro‐OMeTAD), under elevated temperature in ambient atmosphere. Surprisingly, we find that the devices employing CuSCN degrade faster under elevated temperatures than the devices employing Spiro‐OMeTAD. We discover that an interfacial degradation mechanism occurs at the heterojunction between the perovskite absorber and the CuSCN, even in a dry nitrogen atmosphere, identifying the presence of a critical instability. Interestingly, with the additional coating of the completed cells with a thin film of insulating poly(methyl methacrylate) (PMMA), functioning as a rudimentary “on‐cell” encapsulation, we significantly alleviate this issue and deliver efficient perovskite solar cells which survive for more than 1000 hours at 85 °C in air with only 25% degradation in performance. Beyond identifying a critical area to address in order to enable CuSCN to be useful for long term operation in perovskite solar cells, our findings indicate that the role of the “encapsulant” is to both keep the environment out, and keep degradation products within the cell.

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“…[5] Normally, spiro-OMeTAD was used as HTM in the high-performance perovskite solar cells. [8][9] As unique two-dimensional (2D) carbon materials, graphene and their derivatives have attracted great attention due to their excellent electrical conductivity and mechanical property, which have already shown great potential in PSCs. Therefore, it would be of high importance to develop more convenient HTM for further cost reduction and large-scale implementation of PSCs.…”

Section: Introductionmentioning

confidence: 99%

“…Therefore, it would be of high importance to develop more convenient HTM for further cost reduction and large-scale implementation of PSCs. [8][9] As unique two-dimensional (2D) carbon materials, graphene and their derivatives have attracted great attention due to their excellent electrical conductivity and mechanical property, which have already shown great potential in PSCs. [10][11][12] Moreover, reduced graphene oxide (RGO) has recently been demonstrated to act as an effective alternative for spiro-OMeTAD in PSCs, which has achieved a PCE of~10 % due to its higher conductivity (~300 S m À 1 ).…”

Section: Introductionmentioning

confidence: 99%

Reduced Graphene Oxide/CZTS_xSe_1‐x Composites as a Novel Hole‐Transport Functional Layer in Perovskite Solar Cells

Han

Yin

et al. 2019

ChemElectroChem

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Exploiting lower cost and more stable hole-transport materials to replace spiro-OMeTAD is a hot topic in the research field of perovskite solar cells (PSCs). This work exploits a novel holetransport composite containing reduced graphene oxides (RGO) and Cu 2 ZnSn(SSe) 4 (CZTS x Se 1-x ) by a green sol-gel method for efficient perovskite solar cells. The composition and crystalline structure of CZTS x Se 1-x were examined by Raman and X-ray photoelectron spectroscopy as well as by X-ray diffraction measurements. Compared with a pristine RGO hole-transport layer (HTL), the PSC with RGO/CZTS x Se 1-x composite shows an improved photovoltaic performance and enhanced stability. A maximum power conversion efficiency (PCE) of 10.08 % and an enhanced stability were obtained for the cell with the RGO/ CZTS 0.5 Se 0.5 composite. Moreover, only 14 % efficiency reduction ratio was observed for the device stored in air at room temperature after 500 hours without encapsulation. In addition, the different S/Se ratios of CZTS x Se 1-x showed distinct photovoltaic properties of the PSCs, which is attributed to the change of energetic structures, confirmed by electrochemical characterizations.

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Stable and efficient hole transporting materials with a dimethylfluorenylamino moiety for perovskite solar cells

Cited by 64 publications

References 28 publications

Regioregular Phthalocyanines Substituted with Bulky Donors at Non‐Peripheral Positions

Regioregular Phthalocyanines Substituted with Bulky Donors at Non‐Peripheral Positions

Identification and Mitigation of a Critical Interfacial Instability in Perovskite Solar Cells Employing Copper Thiocyanate Hole‐Transporter

Reduced Graphene Oxide/CZTS_xSe_1‐x Composites as a Novel Hole‐Transport Functional Layer in Perovskite Solar Cells

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Stable and efficient hole transporting materials with a dimethylfluorenylamino moiety for perovskite solar cells

Cited by 64 publications

References 28 publications

Regioregular Phthalocyanines Substituted with Bulky Donors at Non‐Peripheral Positions

Regioregular Phthalocyanines Substituted with Bulky Donors at Non‐Peripheral Positions

Identification and Mitigation of a Critical Interfacial Instability in Perovskite Solar Cells Employing Copper Thiocyanate Hole‐Transporter

Reduced Graphene Oxide/CZTSxSe1‐x Composites as a Novel Hole‐Transport Functional Layer in Perovskite Solar Cells

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Product

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About

Reduced Graphene Oxide/CZTS_xSe_1‐x Composites as a Novel Hole‐Transport Functional Layer in Perovskite Solar Cells