High-Performance Organic Solar Cells with Efficient Semiconducting Small Molecules Containing an Electron-Rich Benzodithiophene Derivative

Lim, Namwoo; Cho, Nara; Paek, Sanghyun; Kim, Chulwoo; Lee, Jae Kwan; Ko, Jaejung

doi:10.1021/cm5004092

Cited by 62 publications

(44 citation statements)

References 24 publications

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“…However, a couple of differences exist between these small molecules. [36] The electrochemical property of DR3TBDTT-S-E was measured by the cyclic voltammetry (CV) method using Ag/Ag + as the reference electrode ( Figure S2, Supporting Information). [29] Therefore, the absorption profile of DR3TBDTT-S-E is slightly different from that of DR3TBDTT, but exhibits obvious red-shifted absorption at about 60 nm compared with DCAO3TBDTT.…”

Section: Design Synthesis Optical and Electrochemical Propertiesmentioning

confidence: 99%

Constructing High‐Performance All‐Small‐Molecule Ternary Solar Cells with the Same Third Component but Different Mechanisms for Fullerene and Non‐fullerene Systems

Chang

Zhu

et al. 2019

Advanced Energy Materials

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donors used, OSCs fall into two categories: polymer solar cells and small-molecule solar cells. While according to the acceptor used, they can be divided into fullerene solar cells and non-fullerene solar cells. Polymer solar cells have always been the focus of attention, and a breakthrough, that is., a power conversion efficiency (PCE) of over 15% has been achieved for this type of device. [9] In contrast, a noticeable gap exists between small-molecule solar cells and polymer solar cells whether in terms of performances or the research scale. However, small molecule donors still have some unique advantages over polymer donors, such as definite chemical structure, extremely high purity and excellent reproducibility, which could be better suited for future large-scale applications of OSCs. [10][11][12][13] Particularly, there has been a new upsurge for developing all-small-molecule solar cells owing to the widespread use of non-fullerene acceptors. [14,15] Although currently both fullerene-and non-fullerene-based allsmall-molecule solar cells present high PCEs of over 11%, [16,17] the defects in each system should be clearly addressed. For instance, due to the weak absorption ability of fullerene acceptors, such as [6,6]-phenyl-C 61 -butyric acid methyl ester (PC 61 BM) and [6,6]-phenyl-C 71 -butyric acid methyl ester (PC 71 BM), in the short-wavelength and near-infrared regions, it is difficult to obtain much higher photocurrent. [18] On the other hand, when selecting a non-fullerene acceptor, like IDIC, [19] which possesses superior crystallization capability, [20] it is hard to achieve ideal film morphology with nanoscale phase separation. Therefore, overcoming these issues for binary devices is of great importance for continued evolution of all-small-molecule solar cells.Here, utilizing the individual advantages of both fullerene and non-fullerene acceptors has been demonstrated as an attractive strategy to resolve the above-mentioned problems. [21] Recently, several cases of all-small-molecule ternary solar cells with significant increase in the PCE, which employed one small molecule donor material, one fullerene acceptor (PC 71 BM) and one non-fullerene acceptor, have been reported. [21,22] In these cases, PC 71 BM has played an important role in modulating the film morphology of the ternary system, which could significantly facilitate charge generation and transportation and suppress charge recombination. As a result, the short-circuit current Two types of all-small-molecule ternary solar cells consisting of two smallmolecule donors and one acceptor (fullerene/non-fullerene) are developed. Interestingly, both these devices have a common component: a carefully designed medium bandgap small molecule, which possesses appropriate energy levels and displays good compatibility with the host donor. In the fullerene system, the charge-relaying role of the additive donor is confirmed by the improved charge transportation and suppressed charge recombination. While in the non-fullerene system, the mixed face-on and ed...

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Section: Design Synthesis Optical and Electrochemical Propertiesmentioning

confidence: 99%

Constructing High‐Performance All‐Small‐Molecule Ternary Solar Cells with the Same Third Component but Different Mechanisms for Fullerene and Non‐fullerene Systems

Chang

Zhu

et al. 2019

Advanced Energy Materials

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“…24 In order to improve the performance of PSCs, the synthetic versatility of organic chemistry is used for the development of novel materials. [32][33][34][35][36] Therefore, in this study, 4,8-bis(2-alkoxy)benzo[1,2-b:4,5-b 0 ]dithiophene (BDT) was incorporated in a benzotriazole (BTZ) and thiophene bearing polymer backbone due to its aforementioned properties. Since the first introduction of the BDT unit, it has been coupled with thieno- [3,4-b]thiophene (TT), 25,26 dithiophene-2-yl-2,1,3-benzothiadiazole (DTBT), 27 thieno [3,4-c]pyrrole-4,6-dione (TPD) 28- 30 and diketopyrrolopyrrole (DPP) to form copolymers.…”

Section: Introductionmentioning

confidence: 99%

Synthesis of a benzotriazole bearing alternating copolymer for organic photovoltaic applications

et al. 2015

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A low band gap donor-acceptor (D-A) copolymer PTBTBDT, namely, poly(2-dodecyl-4,7-di(thiophen-2yl)-2H-benzo [d][1,2,3]triazole-alt-4,8-bis(2-ethylhexyloxy)benzo[1,2-b:4,5-b 0 ]dithiophene), was designed and synthesized via a Pd-catalyzed Stille polycondensation reaction. The polymer was characterized using 1 H NMR spectroscopy, UV-vis absorption spectroscopy, cyclic voltammetry, and gel permeation chromatography (GPC). PTBTBDT has good solubility in common organic solvents, good thermal stability, broad absorption, low band gap and exhibits not only high hole mobility but also moderate photovoltaic properties. PTBTBDT displays broad absorption in the wavelength range from 300 nm to 630 nm, and its HOMO and LUMO energy levels were calculated to be À4.98 eV and À3.34 eV, respectively.Bulk heterojunction solar cells were fabricated using PTBTBDT as the electron donor and PC 70 BM as the acceptor. The device exhibits a power conversion efficiency of 2.12% with a current density of 5.45 mA cm À2 , an open-circuit voltage of 0.72 V, and a fill factor of 54% under the illumination of AM 1.5 G, 100 mW cm À2 .Under similar device fabrication conditions, the PTBTBDT based device showed considerably improved efficiency among its previously synthesized counterparts, i.e. PBDTDTBTz and PBDTBTz based devices, which have 1.7% and 1.4% efficiencies, respectively. The hole mobility of the PTBTBDT : PC 70 BM (1 : 2 w/w) blend reached up to 1.47 Â 10 À3 cm 2 V À1 s À1 as calculated by the space-charge-limited current (SCLC) method. By side-chain engineering, this study demonstrates a good example of tuning the absorption range, energy level, charge transport, and photovoltaic properties of polymers.

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“…However, further experiments are still need to fully understand the detailed reasons. Nevertheless, the PCE of 5.62% for the 4 :PC 61 BM cells is among the best performance for cells based on COOP-capped BDT derivatives [21–23 35–37]. …”

Section: Resultsmentioning

confidence: 99%

Effect of the π-conjugation length on the properties and photovoltaic performance of A–π–D–π–A type oligothiophenes with a 4,8-bis(thienyl)benzo[1,2-b:4,5-b′]dithiophene core

Yin

Wang

Lin

et al. 2016

Beilstein J. Org. Chem.

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SummaryBenzo[1,2-b:4,5-b′]dithiophene (BDT) is an excellent building block for constructing π-conjugated molecules for the use in organic solar cells. In this paper, four 4,8-bis(5-alkyl-2-thienyl)benzo[1,2-b:4,5-b′]dithiophene (TBDT)-containing A–π–D–π–A-type small molecules (COOP-nHT-TBDT, n = 1, 2, 3, 4), having 2-cyano-3-octyloxy-3-oxo-1-propenyl (COOP) as terminal group and regioregular oligo(3-hexylthiophene) (nHT) as the π-conjugated bridge unit were synthesized. The optical and electrochemical properties of these compounds were systematically investigated. All these four compounds displayed broad absorption bands over 350–600 nm. The optical band gap becomes narrower (from 1.94 to 1.82 eV) and the HOMO energy levels increased (from −5.68 to −5.34 eV) with the increase of the length of the π-conjugated bridge. Organic solar cells using the synthesized compounds as the electron donor and PC61BM as the electron acceptor were fabricated and tested. Results showed that compounds with longer oligothiophene π-bridges have better power conversion efficiency and higher device stability. The device based on the quaterthiophene-bridged compound 4 gave a highest power conversion efficiency of 5.62% with a V OC of 0.93 V, J SC of 9.60 mA·cm−2, and a FF of 0.63.

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High-Performance Organic Solar Cells with Efficient Semiconducting Small Molecules Containing an Electron-Rich Benzodithiophene Derivative

Cited by 62 publications

References 24 publications

Constructing High‐Performance All‐Small‐Molecule Ternary Solar Cells with the Same Third Component but Different Mechanisms for Fullerene and Non‐fullerene Systems

Constructing High‐Performance All‐Small‐Molecule Ternary Solar Cells with the Same Third Component but Different Mechanisms for Fullerene and Non‐fullerene Systems

Synthesis of a benzotriazole bearing alternating copolymer for organic photovoltaic applications

Effect of the π-conjugation length on the properties and photovoltaic performance of A–π–D–π–A type oligothiophenes with a 4,8-bis(thienyl)benzo[1,2-b:4,5-b′]dithiophene core

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