Effect of carbon hybridization in 9H-fluorene unit on the photovoltaic properties of different fluorene-based conjugated polymers

Lin, Zhiguan; Wang, Gang; Li, Ling; Lu, Zhenhuan; Hai, Jiefeng; Li, Ming; Tang, Weihua

doi:10.1177/0954008317716526

Cited by 4 publications

(2 citation statements)

References 43 publications

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“…The thermogravimetric analysis (TGA) revealed their decomposition temperature ( T d , 5% weight loss) as 350 °C, 326 °C, 337 °C, and 311°C for DDTC‐4F, DTCBT8‐4F, DDTP‐4F, and DTPBT8‐4F, respectively (Figure S20, Supporting Information), indicating good thermal stability for long‐term device operation. [ 47 ]…”

Section: Resultsmentioning

confidence: 99%

“…The thermogravimetric analysis (TGA) revealed their decomposition temperature (T d , 5% weight loss) as 350 °C, 326 °C, 337 °C, and 311°C for DDTC-4F, DTCBT8-4F, DDTP-4F, and DTPBT8-4F, respectively (Figure S20, Supporting Information), indicating good thermal stability for long-term device operation. [47] Optical properties of four UFAs were investigated by UV-vis spectroscopy in both dilute chloroform solutions and thin films, and relevant results are displayed in Figure 2b,c. The detailed photoelectronic data are listed in Table 1.…”

Section: Synthesis and Opto-electronic Properties Of Ufasmentioning

confidence: 99%

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Unfused Acceptors Matching π‐Bridge Blocks with Proper Frameworks Enable Over 12% As‐Cast Organic Solar Cells

Liu

Lin

Cao

et al. 2022

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for electron-rich unit, A and A 1 for electrondeficient unit) to exhibit broad spectral absorption and suitable crystallinity. [12][13][14][15][16][17][18] However, some of their intrinsic factors seriously hinder the commercialization of OSCs, such as complicated synthesis and tedious device post-treatment. For this reason, unfused-ring acceptors (UFAs) have thus been proposed and now become a new hotspot in the field of OSCs. [19][20][21][22][23][24][25][26][27] Compared with rigid FREAs, UFAs adopt intramolecular noncovalent interactions) to ensure their coplanar backbones for high carrier mobility. [28][29][30][31][32][33][34][35] At present, the state-of-theart UFAs have pushed the maximum PCE to 15.44% after careful device optimization. [32] Currently, most high-efficiency OSCs depend on device optimization including additives usage, spin-coating with hot solutions or on hot plates, and thermal annealing. [20][21][22]32,36] However, some additives may cause environmental pollution, while thermal annealing and hot spin-coating may increase energy consumption and process complexity. The exploring high-performance UFAs is highly demanding for as-cast OSCs, thus raising higher requirements for their structure design.For the development of UFAs, many up-and-coming building blocks have emerged. Among them, dithiophene cyclopentadiene (DTC) and dithieno[3,2-b:2",3"-d]pyrrole (DTP) are very promising tricyclic aromatic units and have been widely used in high-performance UFAs (Figure 1 and Table S1, Supporting Information). DTC has stronger electron-donating ability, lower lying π*-orbitals and larger planar structure compared to monocyclic thiophene. [37] Due to the sp 3 carbon atoms of DTC, bulky substituents are introduced to suppress intermolecular aggregation and thus fine-tune phase separation. [19] Liu et al. introduced DTC as the π-bridge blocks of symmetric UFA (BTzO-4F), yielding a high PCE of 13.8% in the optimized OSCs. [27] Zhang et al. developed DTC-bridged UFAs by taking advantage of noncovalent intramolecular interactions with alkoxylbenzene core and fluorinated cyclopenta[b]naphthalen-1-ylidene) malononitriles as accepting end, which achieved a record PCE of 14.53% for OSCs after optimized with thermal annealing and solvent additives. [38] In contrast, DTP unit has an extended delocalized π-electron conjugation system with a sp 2 -hybridized nitrogen atom and a lone electron pair in its vertical p orbital, which enables DTP block to promote intramolecular charge transfer (ICT) and fine-tune energy levels. [39] Therefore, not only Emerging unfused-ring acceptors (UFAs) have been explored in pursuit of low-cost high-efficient organic solar cells (OSCs). Assembling unfused building blocks into proper frameworks are challenging for the molecular design of UFAs. The authors report herein four UFAs adopting either dithiophene cyclopentadiene (DTC) or dithieno[3,2-b:2',3'-d]pyrrole (DTP) as π-bridge units with different molecular frameworks for high-efficient as-cast OSCs. All these acceptors exhibit stron...

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Section: Resultsmentioning

confidence: 99%

Section: Synthesis and Opto-electronic Properties Of Ufasmentioning

confidence: 99%