Successively Regioselective Electrosynthesis and Electron Transport Property of Stable Multiply Functionalized [60]Fullerene Derivatives

Successively Regioselective Electrosynthesis and Electron Transport Property of Stable Multiply Functionalized [60]Fullerene Derivatives

PDF

Xing-Xing Yan¹, Bairu Li², Hao-Sheng Lin¹, Fei Jin², Chuang Niu¹, Kai-Qing Liu¹, Guan-Wu Wang¹^,³, Shangfeng Yang²

Research. Vol 2020 Article ID 2059190

Less

Research. Vol 2020 Article ID 2059190

• Research Article •

Successively Regioselective Electrosynthesis and Electron Transport Property of Stable Multiply Functionalized [60]Fullerene Derivatives

Full

Xing-Xing Yan¹, Bairu Li², Hao-Sheng Lin¹, Fei Jin², Chuang Niu¹, Kai-Qing Liu¹, Guan-Wu Wang¹^,³, Shangfeng Yang²

Affiliations

¹Hefei National Laboratory for Physical Sciences at Microscale, CAS Key Laboratory of Soft Matter Chemistry, Center for Excellence in Molecular Synthesis of CAS, and Department of Chemistry, University of Science and Technology of China, Hefei, Anhui 230026, China

²Hefei National Laboratory for Physical Sciences at Microscale, CAS Key Laboratory of Materials for Energy Conversion, and Department of Materials Science and Engineering, University of Science and Technology of China, Hefei, Anhui 230026, China

³State Key Laboratory of Applied Organic Chemistry, Lanzhou University, Lanzhou, Gansu 730000, China

About Author:

Authors’ Contributions

G.-W. Wang supervised the project. G.-W. Wang and H.-S. Lin conceived the study. X.-X. Yan, B. Li, C. Niu, and K.-Q. Liu performed the experiments and analyzed the data. B. Li fabricated the PSC devices and measured their PCE. F. Jin characterized X-ray structures of two compounds. G.-W. Wang, S. Yang, and X.-X. Yan wrote the paper. All authors discussed the results and commented on the paper. Xing-Xing Yan and Bairu Li contributed equally to this work.

Published: 2020-02-20 doi: 10.34133/2020/2059190

Outline

Abstract

Less

With the recent advance in chemical modification of fullerenes, electrosynthesis has demonstrated increasing importance in regioselective synthesis of novel fullerene derivatives. Herein, we report successively regioselective synthesis of stable tetra- and hexafunctionalized [60]fullerene derivatives. The cycloaddition reaction of the electrochemically generated dianions from [60]fulleroindolines with phthaloyl chloride regioselectively affords 1,2,4,17-functionalized [60]fullerene derivatives with two attached ketone groups and a unique addition pattern, where the heterocycle is rearranged to a [5,6]-junction and the carbocycle is fused to an adjacent [6,6]-junction. This addition pattern is in sharp contrast with that of the previously reported biscycloadducts, where both cycles are appended to [6,6]-junctions. The obtained tetrafunctionalized compounds can be successively manipulated to 1,2,3,4,9,10-functionalized [60]fullerene derivatives with an intriguing “S”-shaped configuration via a novel electrochemical protonation. Importantly, the stability of tetrafunctionalized [60]fullerene products allows them to be applied in planar perovskite solar cells as efficient electron transport layers.

Cite this Article

Xing-Xing Yan, Bairu Li, Hao-Sheng Lin, Fei Jin, Chuang Niu, Kai-Qing Liu, Guan-Wu Wang, Shangfeng Yang. Successively Regioselective Electrosynthesis and Electron Transport Property of Stable Multiply Functionalized [60]Fullerene Derivatives[J]. Research, 2020 , 2020 (2) : 2059190 - . DOI: 10.34133/2020/2059190

Full Text

Less

1. 　Introduction

Less

Over the past two decades, functionalized [60]fullerene (C₆₀) derivatives have attracted wide attention because of their promising applications in materials, nanotechnology, and biological sciences [1–4]. Particularly, some C₆₀ derivatives, represented by [6,6]-phenyl-C₆₁-butyric acid methyl ester (PCBM), have exhibited excellent superiors in perovskite solar cells (PSCs) as electron transport layers (ETLs) [5–7]. However, the number of regioisomers increases dramatically with the number of addends and thus causes the problem of tedious chromatographic separation for individual regioisomer. Only one isomeric monocycloadduct is usually formed, up to 8 regioisomeric biscycloadducts have been isolated from cycloaddition reactions of C₆₀ [8]. On the other hand, the regioisomers of tetrafunctionalized C₆₀ derivatives reported most commonly are 1,2,3,4-isomers (A) [9–14], 1,4,11,15-isomers (B) [15–18], 1,2,4,15-isomers (C) [19–23], and 1,2,3,16-isomers (D) [24–29], while for the hexafunctionalized C₆₀ derivatives, the most frequently encountered regioisomers are 1,2,3,4,5,6-isomers (E) [30–32] and 1,2,4,11,15,30-isomers (F) [15–18, 33–35] (Figure 1). Although the elegant templated multifunctionalizations of fullerenes have been devised to realize high regioselectivity [8, 36], the regiocontrol on the formation of a specific isomer of biscycloadducts and multicycloadducts is still a daunting task.

The electrophilic-to-nucleophilic reactivity reversal of fullerenes and their derivatives caused by electrochemical reduction opens a new territory in fullerene chemistry and has demonstrated increasing importance in the efficient synthesis of novel fullerene derivatives [37], including the abovementioned types A, C, and D [11, 19, 25–29]. It was interestingly found that the same dianionic [60]fulleroindoline (1a^2–, vide infra) behaved differently toward alkylating and acylating reagents. For example, the reaction of 1a^2– with benzyl bromide gave both mono- and dibenzylated 1,2,3,16-adducts [25], while its reaction with benzoyl chloride could afford only monoacylated 1,2,3,16-adducts [28]. The attempted synthesis of diacylated 1,2,3,16-adducts failed and remains challenging. In our recent work [38], we disclosed the synthesis of tetra- and hexafunctionalized [60]fullerene derivatives with unprecedented addition patterns from the reaction of 1a^2– with 1,2-bis(bromomethyl)benzene. Even though we could capture the intermediate leading to the cyclized 1,2,4,17-adduct, the instability of this unique cyclized product precluded its characterization by ¹³C NMR and single-crystal X-ray analysis. Bearing the aforementioned different reactivity of the same dianionic species toward alkylating and acylating reagents and instability of the previously obtained tetrafunctionalized product in mind, our continuous efforts in electrochemical functionalization of fullerene derivatives [25, 28, 29, 38–41] stimulated us to investigate the reaction of the dianionic [60]fulleroindolines 1a–c^2– with phthaloyl chloride in order to contrast their reactivity behavior and to see if the unprecedented tetrafunctionalized cis-3

′

isomers (type G) and “S”-shaped hexafunctionalized products (type H) bearing two acyl groups can be generated in the present case [42]. It turns out that these two unique types of tetra- and hexafunctionalized products can be successfully synthesized and are stable up to 107−275°C. Intriguingly, the reactivity behaviors of 1a^2– toward 1,2-bis(bromomethyl)benzene and phthaloyl chloride are quite different, and chemical properties of their anionic tetrafunctionalized products also behave divergently. Importantly, the stability of the current tetrafunctionalized products allows them to be utilized in planar perovskite solar cells so as to investigate their electron transport properties.

2. 　Results and Discussion

Less

2.1. 　Electrosynthesis of Tetra- and Hexafunctionalzied Fullerene Derivatives

The dianionic species of [60]fulleroindolines 1 can be obtained by controlled potential electrolysis (CPE) and have ring-opened structures after acceptance of two electrons [25, 28]. For these ring-opened structures, the most negatively charged carbon atom among the fullerene skeleton is located at the para position of the aryl substituents. The reaction of 1^2– with acyl chlorides proceeded via a S_N2 rather than a SET process [28]. Therefore, we surmise that if phthaloyl chloride is chosen to react with 1^2–, a similar S_N2 pathway would afford the anionic intermediate I, followed by the intramolecular S_N2 ring-closure process via C–N bond formation [25, 28] to generate 2 with the heterocycle rearranged to a [5,6]-junction and the carbocycle anchored to a [6,6]-junction (Figure 2). It is noteworthy that our thus designed 1,2,4,17-functionalized C₆₀ derivatives 2 have a unique cis-3

′

addition pattern (Figure 1), which is in sharp contrast with that for the reported typical cis-3 adducts where both cycloadditions occur at [6,6]-junctions [8].

[60]Fulleroindolines 1a–c were synthesized according to our reported procedure [43]. The cyclic voltammograms (CVs) of 1a–c were very similar and showed an irreversible second redox process (Figures S1–S3), hinting that the C–N bond cleavage occurred after receiving two electrons [25–29, 38]. It turned out that the reaction of the dianionic species of 1a–c with phthaloyl chloride indeed afforded the desired cis-3

′

regioisomers 2a–c. The cyclization of 1a^2–, which was obtained by CPE at –1.24 V vs. SCE, with phthaloyl chloride was chosen to screen the optimal reaction conditions (for details, see the text and Table S1 in the Supplementary Materials). It was found that the reaction of 1a^2– with 20 equiv. of phthaloyl chloride in ortho-dichlorobenzene (ODCB) at 0°C for 2 h generated 2a in 40% yield. Similarly, the employment of substrate 1b bearing one methoxy group on the phenyl ring and substrate 1c containing two methoxy groups on the phenyl ring afforded 2b and 2c in 41% and 48% yields, respectively (Figure 3).

Both the first and second redox processes in the CVs of 2a–c were irreversible (Figures S4–S6), suggesting that they could be further electrochemically derivatized. In an attempt to obtain the hexafunctionalized fullerene derivative by protonation of 2a^2– generated from 2a by CPE at –1.20 V with trifluoroacetic acid (TFA), only the protonated 1,2,3,4-adduct IIa [44] of 1a^2– was isolated due to the facile deacylation of the dianionic species and fast concomitant protonation under our conditions. Fortunately, we discovered that with the addition of 1 equiv. of TFA before electroreduction of 2a, the hexafunctionalized fullerene derivative 3a was isolated in 40% yield along with a trace amount of IIa. Further increasing the amount of TFA was detrimental to the product yield. Similarly, products 3b and 3c could be obtained by the electrochemical protonation of 2b and 2c in 33% and 32% yields, respectively (Figure 4). It is believed that product 3 is generated by a highly efficient process of stepwise one-electron reduction and protonation of 2 to give intermediates III and IV, followed by another one-electron reduction to afford V and final protonation (Figure 4). Alternatively, 3 might be generated by a reversal of the sequence as shown in Figure 4 with the first protonation at the carbon atom next to the ketone group. The success for the formation of 3 is probably ascribed to that the presence of TFA facilitates the sequential one-electron reduction and concomitant protonation and thus prohibits the deacylation.

It is worthwhile and illustrative to compare the different reactivity behaviors of the dianionic [60]fulleroindoline 1a^2– toward the present phthaloyl chloride and the previously investigated 1,2-bis(bromomethyl)benzene and to contrast the physical and chemical properties of the formed multiply functionalized fullerene derivatives [38]. A monoalkylated 1,2,3,16-adduct, which verified the assumed addition preference at the para position of the aryl substituent, could be isolated if the reaction of 1a^2– with 1,2-bis(bromomethyl)benzene proceeded for a short time (10 min, 0°C) and then quenched with TFA. In contrast, the attempts to intercept the anionic intermediate Ia with TFA failed, reflecting that the ring-closure process of Ia was highly rapid to generate 1,2,4,17-adduct 2a. Unlike 1,2-bis(bromomethyl)benzene, phthaloyl chloride reacted with 1a^2– at higher temperature afforded only stable 2a, while the isomeric 1,2,3,4-adduct could not be identified. Product 2a was thermally stable up to 168°C (Figure S11), yet the tetrafunctionalized product from 1,2-bis(bromomethyl)benzene was unstable, tended to decompose, and was partially rearranged to the more stable isomeric 1,2,3,4-adduct. Another difference between these two counterparts was that the acid TFA must be added before the electroreduction of the tetrafunctionalized 2a to successfully form the hexafunctionalized 3a due to the fast deacylation of 2a^2–, while TFA could be added as the proton source after the generation of the dianonic tetrafunctionalized product from 1,2-bis(bromomethyl)benzene.

2.2. 　Characterizations

All new products 1b, 1c, 2a–c, and 3a–c were fully characterized by MALDI-TOF HRMS, ¹H NMR, ¹³C NMR, FT-IR, and UV-Vis spectroscopies. Particularly, the two doublets around 6 ppm with a coupling constant of 2.3 Hz in the ¹H NMR spectra of products 3a–c indicated that they contained two fullerenyl protons in 1,4-arrangement [44]. The HMBC spectrum of 3a clearly showed that the proton (6.09 ppm) at C2 (57.04 ppm) correlated with C1 (61.02 ppm) and C3 (68.32 ppm) and that the proton (6.02 ppm) at C10 (56.03 ppm) correlated with C9 (80.56 ppm) (Figures S7–S8), indicating that these protons and carbons were adjacent. Furthermore, the assigned structures of 2b and 3b were established by the single-crystal X-ray diffraction analyses (Figure 5). This is the first time that the assignment of 1,2,4,17-adducts was confirmed by single-crystal structure.

The single crystal of 2b was obtained through slow diffusion of methanol into a chloroform solution of 2b at 4°C. Figure 5(a) displays the X-ray single-crystal diagram for one of the two enantiomers (0.5 : 0.5) of 2b, where a heterocycle is bonded to C₆₀ through a C_aryl atom and a N atom at C4 and C17 sites, respectively, and two ketone groups are attached to C1 and C2 sites, respectively. The four functionalized fullerene carbon atoms are uplifted from the spherical surface notably because of their sp³ characters with the bond lengths of 1.560(16) Å and 1.594(10) Å for the C1–C2 and C4–C17 bonds, respectively. The bond lengths for C2–C3, C3–C4, and C1–C6 are 1.559(14) Å, 1.444(12) Å, and 1.509(15) Å, respectively, which are within the range of typical C–C single bond lengths, whereas the C5–C6 bond has a bond length of 1.380(15) Å, thus possessing double bond character. The resolved single-crystal structure unambiguously demonstrates that the molecular structure of the obtained 1,2,4,17-adduct has the cis-3

′

addition pattern. The single crystal of 3b was obtained through slow evaporation of a chloroform solution of 3b at 4°C. The X-ray single-crystal diagram for one of the two enantiomers (0.5 : 0.5) of 3b are illustrated in Figure 5(b) and resembles that of 2b except that two additional hydrogen atoms are attached to C2 and C10 atoms. These two carbon atoms bearing hydrogen atoms are also uplifted from the spherical surface notably because of their sp³ characters with the bond lengths of 1.613(7) Å and 1.556(10) Å for the C1–C2 and C9–C10 bonds, respectively. The bond lengths of 1.646(7) Å, 1.601(13) Å, and 1.579(10) Å for C1–C9, C2–C3, and C3–C4, respectively, indicate that they are C–C single bonds; meanwhile, bond lengths for C5–C6 and C11–C12 are 1.358(10) Å and 1.363(11) Å, thus showing double bond character. Intriguingly, the resolved single-crystal structure unequivocally reveals that the molecular structure of the obtained 1,2,3,4,9,10-adduct [45] has a unique “S”-shaped configuration.

2.3. 　Applications in Perovskite Solar Cells

Although products 2a–c and 3a–c bear a heterocycle fused to a [5,6]-junction of C₆₀, they are thermally stable up to 107−275°C, as determined by thermogravimetric analyses (TGA) (Figures S11–S16). Given that fullerene derivatives such as PCBM have strong electron-accepting ability and thus have been popularly applied as ETLs of planar PSCs [46, 47], we next applied two representative highly soluble fullerene products 2a and 2b as novel ETLs of regular-structure (n-i-p) PSC devices with configurations of ITO/ETL/Cs_0.05FA_0.83MA_0.12PbI_2.55Br_0.45 perovskite/Spiro-OMeTAD/Au, in which 2,2

′

,7,7

′

-tetrakis(N,N-di-p-methoxyphenylamine)-9,9

′

-spirobifluorene (Spiro-OMeTAD) was used as the hole transport material (Figure 6(a)). For comparison, devices without ETL and with commonly used PCBM ETL were also fabricated [46, 47]. The current density-voltage (

J

−

V

) curves of the PSC devices based on different ETLs with optimized thicknesses measured under one sun illumination are shown in Figure 6(b), and the measured photovoltaic parameters, including open-circuit voltage (

V oc

), short-circuit current (

J sc

), fill factor (FF), power conversion efficiency (PCE), series resistance (

R s

), and shunt resistance (

R sh

) of the best performance devices, are summarized in Table 1. The control device without ETL showed a

V oc

of 1.10 V, a

J sc

of 17.92 mA cm^-2, an FF of 54.71%, and a PCE of 10.77%. When 2a and 2b were incorporated as ETLs, the device performance enhanced obviously. The 2a-based device exhibited an increased PCE of 13.81%, calculated from a

V oc

of 1.09 V, a

J sc

of 20.82 mA cm^-2, and an FF of 60.65%. Upon using 2b as ETL, PCE of the device increased further to 14.04%, which approached that of the PCBM-based device (14.49%). These results showed the considerably good electron transport properties of 2a and 2b.

It is known that n-i-p PSC devices based on the conventional TiO₂ ETL usually suffer from severe current-voltage hysteresis [7]. To examine the hysteresis of

J

−

V

curves of our devices based on 2a or 2b ETL, we measured the

J

−

V

curves in different scan directions (Figure 7), and the corresponding device parameters are given in Table 2. The control device without ETL showed severe hysteresis with a hysteresis index, defined as

PCE reverse − PCE forward / PCE reverse

[48], of 20.6%. Upon incorporating 2a or 2b ETL, the device exhibited negligible hysteresis with a small hysteresis index of 1.80% or 1.51%, respectively. This is similar to the case of PCBM ETL. Such a dramatic suppression of the hysteresis may come from the improved electron transport due to the strong electron-accepting ability of 2a and 2b, resulting in suppressed charge accumulation at the perovskite/ITO interface [49, 50]. Therefore, these results along with the comparable PCE to PCBM reveal the promising applications of 2a and 2b in PSCs.

3. 　Conclusion

Less

In summary, we have achieved an efficient and regioselective synthesis of the diacylated products of fulleroindolines 1a–c by the reaction of the electrochemically generated dianionic 1a–c^2– with phthaloyl chloride. The obtained tetrafunctionalized fullerene products are 1,2,4,17-adducts 2a–c and have a unique cis-3

′

addition pattern where the heterocycle is rearranged to a [5,6]-junction and the carbocycle is appended to a [6,6]-junction. Intriguingly, 1,2,4,17-adducts can be successively protonated to provide hexafunctionalized fullerene products 3a–c by a stepwise one-electron reduction and protonation of 2a–c, which are 1,2,3,4,9,10-adducts and possess an intriguing “S”-shaped addition pattern. The tetra- and hexafunctionalized fullerene derivatives have been fully characterized by spectroscopic data and single-crystal X-ray diffraction analyses. Both 2a–c and 3a–c are stable up to 107−275°C, and representative fullerene products show considerably good electron transport performance in planar perovskite solar cells. This study paves the way to regiocontrolled synthesis of novel multifunctionalized fullerene derivatives toward applications in energy conversion.

4. 　Materials and Methods

Less

4.1. 　General Procedure for Synthesis of 2a–c

The dianionic 1^2– was obtained by electroreduction from [60]fulleroindoline 1 (0.02 mmol) at –1.24 V by CPE and then reacted with phthaloyl chloride (0.40 mmol or 0.20 mmol). After being stirred at 0°C for 2 h, the resulting mixture was directly filtered through a silica gel (200–300 mesh) plug with CS₂/CH₂Cl₂ (1 : 1

v / v

) to remove the supporting electrolyte and insoluble materials and then evaporated in vacuo to remove the solvent. Next, the residue was further separated on a silica gel column (300–400 mesh) with CS₂/CH₂Cl₂ as the eluent to afford 2 as an amorphous brown solid along with unreacted 1.

4.2. 　General Procedure for Synthesis of 3a–c

The mixture of 2 (0.01 mmol) and TFA (0.74 μL, 0.01 mmol) was dissolved in ODCB containing 0.1 M TBAP and then electroreduced by CPE at –1.20 V or –1.13 V. The potentiostat was turned off after the theoretical coulomb was reached. The resulting mixture was directly filtered through a silica gel (200–300 mesh) plug with CS₂/CH₂Cl₂ (1 : 1

v / v

) to remove the supporting electrolyte and insoluble materials and then evaporated in vacuo to remove the solvent. Next, the residue was further separated on a silica gel column (300–400 mesh) with CS₂/CH₂Cl₂ as the eluent to afford 3 as an amorphous red-brown solid along with a minor byproduct II.

4.3. 　Device Fabrication of Perovskite Solar Cells

The patterned ITO-coated glass was cleaned by sequential ultrasonic treatment in detergent, deionized water, acetone, and isopropanol for 15 min and then treated with ultraviolet-ozone for 20 min. The PCBM (20 mg mL^-1 in ODCB) or representative fullerene derivative (2a and 2b, saturated solution in ODCB) was deposited on the ITO substrates by spin coating at 2000 rpm for 60 s. The as-spun films were annealed at 100°C for 10 min. Next, Cs_0.05FA_0.83MA_0.12PbI_2.55Br_0.45 perovskite precursor solution (1.3 M dissolved in dimethyl sulfoxide and N,N-dimethylformamide with a volume ratio of 2 : 8, with molar ratios of PbI₂/PbBr₂, 1.1 : 0.2; FAI : MABr, 1 : 0.2; CsI/(FAI+MABr), 0.05 : 0.95; PbI₂/FAI, 1.1 : 1; and PbBr₂ : MABr, 1 : 0.2) was spin-coated onto the substrates with a two-step procedure. The first step was 2000 rpm for 10 s with an acceleration of 200 rpm. The second step was 6000 rpm for 30 s with an acceleration of 2000 rpm. At 15 s before the end of the second procedure, 100 μL chlorobenzene (CB) was dropped on the spinning substrate. The substrate was then immediately transferred on a hotplate and heated at 100°C for 60 min. After the perovskite films were cooled down to room temperature, the hole transport layer was deposited on top of the perovskite film by spin coating at 3000 rpm for 30 s using a CB solution which contained 73.2 mg mL^-1 of Spiro-OMeTAD and 28.8 μL mL^-1 of tert-butylpyridine, as well as 18.8 μL mL^-1 of bis(trifluoromethane)sulfonimide lithium salt (Li-TFSI, 520 mg mL^-1 in acetonitrile). Finally, the device was transferred into a vacuum chamber (10^-6 torr), and an Au electrode (ca. 55 nm thick) was thermally deposited through a shadow mask to define the effective active area of the device (0.10 cm²).

Funding

Less

National Key Research and Development Program of China Stem Cell and Translational Research(2017YFA0402800)
Chinese Academy of Sciences(XDB20000000)
National Natural Science Foundation of China(51572254; 21572211)

References

Less

Hirsch

, and Brettreich

, “Fullerenes: chemistry and reactions,” Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim, 2005

Diederich

, and Gómez-López

, “Supramolecular fullerene chemistry,” Chemical Society Reviews, vol. 28, no. 5, pp. 263–277, 1999

Nakamura

, and Isobe

, “Functionalized fullerenes in water. The first 10 years of their chemistry, biology, and nanoscience,” Accounts of Chemical Research, vol. 36, no. 11, pp. 807–815, 2003

C.-Z.

, Yip

H.-L.

, and Jen

A. K.-Y.

, “Functional fullerenes for organic photovoltaics,” Journal of Materials Chemistry, vol. 22, no. 10, pp. 4161–4177, 2012

Cui

, Li

, and Li

, “Fullerene derivatives for the applications as acceptor and cathode buffer layer materials for organic and perovskite solar cells,” Advanced Energy Materials, vol. 7, no. 10, pp. 1601251–1601271, 2017

, Zhen

, Wan

, Lei

, Liu

, Jia

, Wu

, Zeng

, Zhang

, Wang

G. W.

, Chen

, and Yang

, “Anchoring fullerene onto perovskite film via grafting pyridine toward enhanced electron transport in high-efficiency solar cells,” ACS Applied Materials & Interfaces, vol. 10, no. 38, pp. 32471–32482, 2018

Deng

L.-L.

, Xie

S.-Y.

, and Gao

, “Fullerene-based materials for photovoltaic applications: toward efficient, hysteresis-free, and stable perovskite solar cells,” Advanced Electronic Materials, vol. 4, no. 10, pp. 1700435–1700452, 2018

Nakamura

, O-kawa

, and Nishimura

, “Biscycloaddition to [60]fullerene: regioselectivity and its control with templates,” Bulletin of the Chemical Society of Japan, vol. 76, no. 5, pp. 865–882, 2003

Jensen

A. W.

, Khong

, Saunders

, Wilson

S. R.

, and Schuster

D. I.

, “Photocycloaddition of cyclic 1,3-diones to C₆₀,” Journal of the American Chemical Society, vol. 119, no. 31, pp. 7303–7307, 1997

Yamada

, Schweizer

W. B.

, Schoenebeck

, and Diederich

, “Unprecedented thermal rearrangement of push–pull-chromophore–[60]fullerene conjugates: formation of chiral 1,2,9,12-tetrakis-adducts,” Chemical Communications, vol. 46, no. 29, pp. 5334–5336, 2010

Yang

W.-W.

, Li

Z.-J.

, Li

F.-F.

, and Gao

, “Electrochemical and H/D-labeling study of oxazolino[60]fullerene rearrangement,” The Journal of Organic Chemistry, vol. 76, no. 5, pp. 1384–1389, 2011

C.-L.

, Liu

, Li

D.-D.

, Zhu

S.-E.

, and Wang

G.-W.

, “Synthesis and functionalization of [60]fullerene-fused imidazolines,” Organic Letters, vol. 15, no. 7, pp. 1532–1535, 2013

Chen

, Bao

, Peng

, Zheng

, Xie

, and Lu

, “Rigid tether directed regioselective synthesis and crystallographic characterization of labile 1,2,3,4-bis(triazolino)[60]fullerene and its thermolized derivatives,” Angewandte Chemie, International Edition, vol. 55, no. 39, pp. 11887–11891, 2016

Jiang

S.-P.

, Zhang

, Wang

C.-Y.

, Yang

, and Wang

G.-W.

, “Cascade radical reaction of N-sulfonyl-2-allylanilines with [60]fullerene: synthesis and functionalization of (2-Indolinyl)methylated hydrofullerenes,” Organic Letters, vol. 19, no. 19, pp. 5110–5113, 2017

Schick

, Kampe

K.-D.

, and Hirsch

, “Reaction of [60]fullerene with morpholine and piperidine: preferred 1,4-additions and fullerene dimer formation,” Journal of the Chemical Society, Chemical Communications, no. 19, pp. 2023–2024, 1995

Murata

, Shiro

, and Komatsu

, “Synthesis, X-ray structure, and properties of the first tetrakisadduct of fullerene C₆₀ Having a fulvene-type π-system on the spherical surface,” Journal of the American Chemical Society, vol. 119, no. 34, pp. 8117–8118, 1997

Deng

L.-L.

, Xie

S.-L.

, Yuan

, Liu

R. F.

, Feng

, Sun

L. C.

, Lu

, Xie

S. Y.

, Huang

R. B.

, and Zheng

L. S.

, “High LUMO energy level C₆₀(OCH₃)₄ derivatives: Electronic acceptors for photovoltaic cells with higher open-circuit voltage,” Solor Energy Materials and Solar Cells, vol. 111, pp. 193–199, 2013

Clikeman

T. T.

, Deng

S. H. M.

, Avdoshenko

, Wang

X.-B.

, Popov

A. A.

, Strauss

S. H.

, and Boltalina

O. V.

, “Fullerene “superhalogen” radicals: the substituent effect on electronic properties of 1,7,11,24,27-C₆₀X₅,” Chemistry – A European Journal, vol. 19, no. 45, pp. 15404–15409, 2013

Kadish

K. M.

, Gao

, Caemelbecke

E. V.

, Suenobu

, and Fukuzumi

, “Electrosynthesis and structural characterization of two (C₆H₅CH₂)₄C₆₀ Isomers,” Journal of the American Chemical Society, vol. 122, no. 4, pp. 563–570, 2000

Matsuo

, Iwashita

, Abe

, Li

C. Z.

, Matsuo

, Hashiguchi

, and Nakamura

, “Regioselective synthesis of 1,4-di(organo)[60]fullerenes through DMF-assisted monoaddition of silylmethyl grignard reagents and subsequent alkylation reaction,” Journal of the American Chemical Society, vol. 130, no. 46, pp. 15429–15436, 2008

Nambo

, Wakamiya

, Yamaguchi

, and Itami

, “Regioselective unsymmetrical tetraallylation of C₆₀ through palladium catalysis,” Journal of the American Chemical Society, vol. 131, no. 42, pp. 15112–15113, 2009

Kuvychko

I. V.

, Streletskii

A. V.

, Shustova

N. B.

, Seppelt

, Drewello

, Popov

A. A.

, Strauss

S. H.

, and Boltalina

O. V.

, “Soluble chlorofullerenes C₆₀Cl_2,4,6,8,10. Synthesis, purification, compositional analysis, stability, and experimental/theoretical structure elucidation, including the X-ray structure of C₁-C₆₀Cl₁₀,” Journal of the American Chemical Society, vol. 132, no. 18, pp. 6443–6462, 2010

Chang

W.-W.

, Li

Z.-J.

, Yang

W.-W.

, and Gao

, “Reactions of anionic oxygen nucleophiles with C₆₀ revisited,” Organic Letters, vol. 14, no. 9, pp. 2386–2389, 2012

Rubin

, Ganapathi

P. S.

, Franz

, An

Y.-Z.

, Qian

, and Neier

, “Tandem nucleophilic addition/Diels–Alder reaction of N-butadienyl N,O-ketene silyl acetals with C₆₀: stereoselective formation of bicyclic octahydroquinolino-1,2,3,4-tetrahydrobuckminsterfullerenes and combined NMR spectroscopic and computational evaluation of the functionalization reactions,” Chemistry – A European Journal, vol. 5, no. 11, pp. 3162–3184, 1999

Xiao

, Zhu

S.-E.

, Liu

D.-J.

, Suzuki

, Lu

, and Wang

G. W.

, “Regioselective electrosynthesis of rare 1,2,3,16-functionalized [60]fullerene derivatives,” Angewandte Chemie, International Edition, vol. 53, no. 11, pp. 3006–3010, 2014

Hou

H.-L.

, Li

Z.-J.

, and Gao

, “Reductive benzylation of C₆₀ imidazoline with a bulky addend,” Organic Letters, vol. 16, no. 3, pp. 712–715, 2014

Z.-J.

, Li

S.-H.

, Sun

, Hou

H.-L.

, and Gao

, “Reductive benzylation of singly bonded 1,2,4,15-C₆₀ dimers with an oxazoline or imidazoline heterocycle: unexpected formation of 1,2,3,16-C₆₀ adducts and insights into the reactivity of singly bonded C₆₀ dimers,” The Journal of Organic Chemistry, vol. 80, no. 7, pp. 3566–3571, 2015

Lin

H.-S.

, Matsuo

, Wang

J.-J.

, and Wang

G.-W.

, “Regioselective acylation and carboxylation of [60]fulleroindoline via electrochemical synthesis,” Organic Chemistry Frontiers, vol. 4, no. 4, pp. 603–607, 2017

, Wang

J.-J.

, and Wang

G.-W.

, “Palladium-catalyzed synthesis of [60]fullerene-fused benzofurans via heteroannulation of phenols,” Chemical Communication, vol. 53, no. 11, pp. 1852–1855, 2017

Hsu

H.-F.

, and Shapley

J. R.

, “Ru₃(CO)₉(μ3-η²,η²,η²-C₆₀): A Cluster Face-Capping, Arene-Like Complex of C₆₀,” Journal of the American Chemical Society, vol. 118, no. 38, pp. 9192–9193, 1996

Tajima

, and Takeuchi

, “Discovery of C₆₀O₃ isomer having C_3ν symmetry,” The Journal of Organic Chemistry, vol. 67, no. 5, pp. 1696–1698, 2002

Chuang

S.-C.

, Clemente

F. R.

, Khan

S. I.

, Houk

K. N.

, and Rubin

, “Approaches to open fullerenes: a 1,2,3,4,5,6-hexaadduct of C₆₀,” Organic Letters, vol. 8, no. 20, pp. 4525–4528, 2006

Birkett

P. R.

, Hitchcock

P. B.

, Kroto

H. W.

, Taylor

, and Walton

D. R. M.

, “Preparation and characterization of C₆₀Br₆ and C₆₀Br₈,” Nature, vol. 357, no. 6378, pp. 479–481, 1992

Gan

, Huang

, Zhang

, Cheng

, Li

, and Shang

, “Fullerenes as a tert-butylperoxy radical trap, metal catalyzed reaction of tert-butyl hydroperoxide with fullerenes, and formation of the first fullerene mixed peroxides C₆₀(O)(OO^tBu)₄ and C₇₀(OO^tBu)₁₀,” Journal of the American Chemical Society, vol. 124, no. 45, pp. 13384–13385, 2002

Matsuo

, and Nakamura

, “Selective multiaddition of organocopper reagents to fullerenes,” Chemical Reviews, vol. 108, no. 8, pp. 3016–3028, 2008

Diederich

, and Kessinger

, “Templated regioselective and stereoselective synthesis in fullerene chemistry,” Account of Chemical Research, vol. 32, no. 6, pp. 537–545, 1999

Echegoyen

, and Echegoyen

L. E.

, “Electrochemistry of fullerenes and their derivatives,” Account of Chemical Research, vol. 31, no. 9, pp. 593–601, 1998

Liu

K.-Q.

, Wang

J.-J.

, Yan

X.-X.

, Niu

, and Wang

G.-W.

, “Regioselective electrosynthesis of tetra- and hexa-functionalized [60]fullerene derivatives with unprecedented addition patterns,” Chemical Science, vol. 11, no. 2, pp. 384–388, 2020

Niu

, Zhou

D.-B.

, Yang

, Yin

Z.-C.

, and Wang

G.-W.

, “A retro Baeyer–Villiger reaction: electrochemical reduction of [60]fullerene-fused lactones to [60]fullerene-fused ketones,” Chemical Science, vol. 10, no. 10, pp. 3012–3017, 2019

Niu

, Li

, Yin

Z.-C.

, Yang

, and Wang

G.-W.

, “Electrochemical benzylation of [60]fullerene-fused lactones: unexpected formation of ring-opened adducts and their photovoltaic performance,” Organic Letters, vol. 21, no. 18, pp. 7346–7350, 2019

Huissain

, Chen

, Yang

, and Wang

G.-W.

, “Palladium-catalyzed heteroannulation of indole-1-carboxamides with [60]fullerene and subsequent electrochemical transformations,” Organic Letters, vol. 21, no. 21, pp. 8568–8571, 2019

The isomers of biscycloadducts fused to a [6,6]-junction and a [5,6]-junction are named as cis

′

isomers in order to differentiate them from those (cis isomers) fixed to two [6,6]-junctions. The order of precedence for the cis

′

isomers is decided by the priority in locant numbers. The nomenclature of ^fC or ^fA for an enantiomer is dependent on the clockwise or anticlockwise numbering of the fullerene carbon atoms (see Ref. [1])

, “The isomers of biscycloadducts fused to a [6,6]-junction and a [5,6]-junction are named as cis′ isomers in order to differentiate them from those (cis isomers) fixed to two [6,6]-junctions. The order of precedence for the cis′ isomers is decided by the priority in locant numbers. The nomenclature of ^fC or ^fA for an enantiomer is dependent on the clockwise or anticlockwise numbering of the fullerene carbon atoms (see Ref. [1]),”

Zhu

, and Wang

G.-W.

, “Palladium-catalyzed heteroannulation of [60]fullerene with anilides via C-H bond activation,” Organic Letters, vol. 11, no. 19, pp. 4334–4337, 2009

Xiao

, and Wang

, “A 1,2,3,4-tetrahydrofullerene derivative generated from a [60]fulleroindoline: regioselective electrosynthesis and computational study,” Chinese Journal of Chemistry, vol. 32, no. 8, pp. 699–702, 2014

, “The nomenclatures for the pair of enantiomers can be ^fA- and ^fC-1,2,3,4,9,10-adducts or ^fC- and ^fA-1,2,3,4,16,17-adducts, depending on clockwise or anticlockwise numbering of the fullerene carbon atoms (see Ref. [1]),”

Ryu

, Seo

, Shin

S. S.

, Kim

Y. C.

, Jeon

N. J.

, Noh

J. H.

, and Seok

S. I.

, “Fabrication of metal-oxide-free CH₃NH₃PbI₃ perovskite solar cells processed at low temperature,” Journal of Materials Chemistry A, vol. 3, no. 7, pp. 3271–3275, 2015

Wang

Y.-C.

, Li

, Zhu

, Liu

, Zhang

, and Fang

, “Efficient and hysteresis-free perovskite solar cells based on a solution processable polar fullerene electron transport layer,” Advanced Energy Materials, vol. 7, no. 21, pp. 1701144–1701153, 2017

Jiang

, Wang

, Jin

, Zhang

, Lei

, Bin

, Zhang

Z. G.

, Li

, and Liu

S. F.

, “Polymer doping for high-efficiency perovskite solar cells with improved moisture stability,” Advanced Energy Materials, vol. 8, no. 3, pp. 1701757–1701765, 2018

Cho

A.-N.

, Jang

I.-H.

, Seo

J.-Y.

, and Park

N.-G.

, “Dependence of hysteresis on the perovskite film thickness: inverse behavior between TiO₂ and PCBM in a normal planar structure,” Journal of Materials Chemistry A, vol. 6, no. 37, pp. 18206–18215, 2018

Aygüler

M. F.

, Hufnagel

A. G.

, Rieder

, Wussler

, Jaegermann

, Bein

, Dyakonov

, Petrus

M. L.

, Baumann

, and Docampo

, “Influence of fermi level alignment with tin oxide on the hysteresis of perovskite solar cells,” ACS Applied Materials & Interfaces, vol. 10, no. 14, pp. 11414–11419, 2018

Appendix

Less

Year 2020 volume 2020 Issue 2

PDF

Cite this Article

BibTeX

Article Info

doi: 10.34133/2020/2059190

Receive Date：2019-12-08
Online Date：2026-10-27
Published：2020-02-20

Article Data

Affiliations

History

Received：2019-12-08
Accepted：2020-01-04

Funding

National Key Research and Development Program of China Stem Cell and Translational Research(2017YFA0402800)

Chinese Academy of Sciences(XDB20000000)

National Natural Science Foundation of China(51572254; 21572211)

Affiliations

³State Key Laboratory of Applied Organic Chemistry, Lanzhou University, Lanzhou, Gansu 730000, China

References

Share

https://castjournals.cast.org.cn/joweb/research/EN/10.34133/2020/2059190

Share to

Scan QR to access full text

Cite this article

BibTeX

Citations

表12种不同金属材料的力学参数

科 Family	属数 Number of genus	种数 Number of species	占总种数比例 Percentage of total species (%)	属 Genus	种数 Number of species	占总种数比例 Percentage of total species (%)
鹅膏菌科Amanitaceae	2	11	5.26	鹅膏菌属 Amanita	10	4.78
小菇科 Mycenaceae	2	12	5.74	丝盖伞属 Inocybe	5	2.39
多孔菌科 Polyporaceae	8	14	6.70	蜡蘑属 Laccaria	5	2.39
红菇科 Russulaceae	3	23	11.00	小皮伞属 Marasmius	6	2.87
				小菇属 Mycena	11	5.26
				光柄菇属 Pluteus	5	2.39
				红菇属 Russula	17	8.13
				栓菌属 Trametes	5	2.39

关闭全屏

BibTeX
EndNote
RefWorks
TxT

Table 1: Device parameters of PSCs without ETL and with 2a, 2b, and PCBM as ETLs.

ETL	$V oc$ (V)	$J sc$ (mA cm^-2)	FF	PCE (%)	$R s$ (Ω cm²)	$R sh$ (Ω cm²)
—	1.10	17.92	54.71	10.77	7.7	297.6
2a	1.09	20.82	60.65	13.81	6.4	515.4
2b	1.08	20.56	63.12	14.04	5.0	487.1
PCBM	1.11	22.45	58.37	14.49	6.0	304.2

Table 2: Photovoltaic parameters of the best performance devices without ETL and with 2a, 2b, and PCBM as ETL in different scan directions.

ETL	Direction	$V o c$ (V)	$J s c$ (mA cm^-2)	FF (%)	PCE (%)	Hysteresis index (%)
—	Reverse	1.11	16.58	56.49	10.36	20.60%
—	Forward	1.07	15.81	48.53	8.23	20.60%

2a	Reverse	1.09	20.20	57.90	12.78	1.80%
2a	Forward	1.09	20.22	56.89	12.55	1.80%

2b	Reverse	1.12	19.05	61.94	13.26	1.51%
2b	Forward	1.12	19.30	60.17	13.06	1.51%

PCBM	Reverse	1.11	22.45	58.37	14.49	2.40%
PCBM	Forward	1.10	21.86	58.90	14.14	2.40%

Figure 1: Addition patterns of tetra- and hexafunctionalized [60]fullerene derivatives.

Figure 2: Synthetic design for the unprecedented cis-3 $′$ regioisomer.

Figure 3: Reaction of the electrochemically generated 1^2– with phthaloyl chloride. Unless otherwise specified, all the reactions were performed with 0.02 mmol of 1^2– and 0.4 mmol of phthaloyl chloride in 25 mL of ODCB at 0°C for 2 h under an argon atmosphere. ^aIsolated yield. ^b10 equiv. of phthaloyl chloride.

Figure 4: Syntheses of 3a, 3b, and 3c. Unless otherwise specified, all the reactions were performed with 0.01 mmol of 2, 0.01 mmol of TFA, and CPE at –1.20 V, at 25°C under an argon atmosphere. ^aIsolated yield. ^bCPE at –1.13 V.

Figure 5: (a) ORTEP diagram of one enantiomer of 2b with thermal ellipsoids shown at 50% probability. (b) ORTEP diagram of one enantiomer of 3b with thermal ellipsoids shown at 50% probability. The chloroform molecules are omitted for clarity.

Figure 6: (a) Schematic structure of the n-i-p PSC device with or without (w/o) fullerene derivative as the ETL. (b) $J$ − $V$ curves of the n-i-p PSC devices without ETL and with PCBM, 2a, and 2b as the ETL measured under illumination of an AM 1.5 solar simulator (100 mW cm^-2) in air. The scanning direction was from open-circuit voltage to short-circuit (reverse), and the scan speed was 100 mV s^-1.

Figure 7: The $J$ - $V$ curves of the PSCs using different fullerene derivatives, (a) without ETL, (b) PCBM, (c) 2a, and (d) 2b as the ETL in different scan directions.

Articles: Latest Articles; Most Read; Collections

Updates: Events; News; Multimedia

About: About Us

Contact

No. 86 Xueyuan South Road, Haidian District, Beijing

100081

010-62662699(Operation and Technical Support)

qkjq@cast.org.cn

Copyright © 2025 China Association for Science and Technology. All rights reserved. For all open access content, the relevant licensing terms apply.
Sponsored by the Office of the Leading Group for Cybersecurity and Informatization of CAST, and supported by Science and Technology Review Publishing House