Theoretical Investigation of the Open Circuit Voltage: P3HT/9,9′-Bisfluorenylidene Derivative Devices

Carlotto, Silvia

doi:10.1021/jp503040n

Cited by 9 publications

(3 citation statements)

References 60 publications

(123 reference statements)

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“…A4: θ 1 = 21˚ θ 2 = 1˚ A2: θ 1 = 23˚ θ 2 = -1˚A5: θ 1 = 30˚ θ 2 = -28Å 3: θ 1 = 26˚ θ 2 = -5˚ A6: θ 1 = 30˚ θ 2 = 81 [31] . 从分子尺度考虑, D-A 界面载流子的复合速率可以用 HOMO D 与 LUMO A 之间的电子耦合 V if 来度量 [19] . V if 越小, 复合速率越低, 越有利于提高太阳能电池的能量转换效率.…”

Section: D-a 界面模型构建unclassified

Molecular design of the NDI derivatives electron acceptors and theoretical adjustment of the open-circuit voltage

Yin¹,

Shao²,

Wang³

et al. 2016

Sci. Sin.-Chim

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Based on naphthalene diimide (NDI) unit, 6 electron acceptor molecules An (n=1−6) have been designed, and their geometric configurations, the characteristics of frontier molecular orbital and optical properties have been investigated by density functional theory. Furthermore, the donor-acceptor (D-A) interfaces are respectively simulated by combining the 6 acceptors with the selected three donors Dm (m=1−3). Then the degree of interface recombination is evaluated from the single molecule scale. The results provide an efficient way to adjust the recombination that is through strong H-bond interaction to change the distance and displacements of D-A interface by introducing N, O, S heteroatoms. The fine-tuning of D-A interfacial stacking, reducing interface recombination, can enhance the open-circuit voltage (V oc). In addition, the proper calculated results of electronic coupling between HOMO of donors and LUMO of acceptors showing the donor and acceptor materials both with good planar combined can lead to serious recombination against high open-circuit voltage. While in organic solar cell, acceptor with good planar combined with non-planar donor materials, to form optical active layer, is an effective approach to obtain high V oc. Considering ΔE L , V if , the planarity of donor and acceptor molecules and light absorption efficiency, D3-A5 combination is the most promising candidate of optical active layer materials in organic solar cell.

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Section: D-a 界面模型构建unclassified

Molecular design of the NDI derivatives electron acceptors and theoretical adjustment of the open-circuit voltage

Yin¹,

Shao²,

Wang³

et al. 2016

Sci. Sin.-Chim

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“…Overcrowded ethylenes are a class of compounds that show thermochromic − and photochromic behaviors − and have been extensively studied as prototype models of molecular motors and electro- or photoswitchable units. − Recently, some overcrowded ethylenes based on the 9,9′-bisfluorenylidene (BF) backbone have been reported as effective electron-accepting components in bulk heterojunction solar cells. − In 1997, bis{4 H ,8 H -4-(dicyanomethylene)benzo[1,2- c :4,5- c ′]bis[1,2,5]thiadiazol-8-ylidene} (denoted as OCE1, Figure ) was reported to be a strong electron acceptor, comparable to tetracyanoquinodimethane (TCNQ), and displays a conformational behavior analogous to existing overcrowded ethylenes . This molecule has a unique design featuring electron-deficient thiadiazole rings and electron-withdrawing CN groups.…”

Section: Introductionmentioning

confidence: 99%

Quantum Chemical Studies on Electron-Accepting Overcrowded Ethylene with a Polarizable Skeleton

Tada

Fukushima²,

Hada

et al. 2017

J. Phys. Chem. A

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We report the quantum chemical studies on the neutral and radical anion forms of an electron-accepting overcrowded ethylene (OCE1) featuring a highly polarizable skeleton based on the density functional theory (DFT) approach using the M06-2X hybrid functional. Calculated results indicate that OCE1 (bis{4H,8H-4-(dicyanomethylene)benzo[1,2-c:4,5-c']bis[1,2,5]thiadiazol-8-ylidene}) shows conformational behaviors and energetics similar to those of bianthrone (OCE2), a typical thermochromic overcrowded ethylene. Neutral OCE1 and its radical anion have antifolded (afOCE1) and twisted (tOCE1) isomers on their potential energy surfaces. The calculated isomerization barrier heights of OCE1 and its radical anion are considerably low, indicating that its conformation is susceptible to interactions with surrounding molecules. While two afOCE1 molecules can form a simple π-stacked dimer, tOCE1 tends to be converted to afOCE1 when the two tOCE1 molecules come close together, indicating the instability of tOCE1 in the homogeneous OCE1 solid state. The thermochromic behavior difference between OCE1 and OCE2 in solution is closely associated with the considerably small energy difference between the afOCE1 and the tOCE1 as compared with OCE2. The properties of OCE1 are also compared with other typical electron-accepting overcrowded ethylenes in terms of electronic structure, energetics, and conformational behaviors.

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“…载流子收集效率 η CC 主要受载流子迁移率和各种复合的影响, 其中 D-A 界面的载流子复合会造成光电压损失, 不利于获得高的开路电压 V oc . D-A 界面载流子的复合程度可以用给体的 HOMO(HOMO D )与受体的 LUMO(LUMO A )之间的电子耦合 V if 来度量 [4] . 这四步所对应的效率共同决定了 OPV 器件能量转换效率 η 的大小 [5～8] .…”

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Molecular Design of Benzothiadiazole Derivatives Electron Acceptors and Matching of Donor-Acceptor Materials

Shao¹,

Yang²,

Yin³

et al. 2016

Acta Chim. Sinica

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To better understand the relationships between the microstructure and the optoelectronic characteristics of the electron acceptor and to meet the needs of donor-acceptor materials with excellent optical properties for solar cell, a series of acceptor molecules with A′-π-A-π-A′ type are designed. In these molecules, the core framework of benzothiadiazole is used as an acceptor (A), three kinds of conjugated heterocyclics (A′) with different abilities of electron-withdrawing and steric effects are applied as the terminals, and various conjugated structures, such as the double bond, thiophene, benzothiophene and vinyl thiophene, are utilized as π-bridge, respectively. Their geometric configurations, the characteristics of frontier molecular orbital, optical properties, as well as the electronic reorganization energy are predicted by DFT-B3LYP and TD-DFT-CAM-B3LYP. Solvent effects from acetone and chlorobenzene on molecular properties are studied. Furthermore, the Donor-Acceptor (D-A) interfaces are respectively constructed by combining the excellent acceptors with the selected two donors. The DFT-D3 method is used to scan the binding energy of D-A complex, in order to determine the stacked displacement of the interface. The degree of interface recombination is evaluated by calculating electronic coupling (V if) between HOMO of donors and LUMO of acceptors. The results show that modifying benzothiadiazole with a reasonable substituent is an effective way to adjust LUMO energy levels and lead to the noticeable variation of the energy gap. Combining planar electron acceptor materials (A′-π-A-π-A′ type) with non-planar electron donor materials (D), to form the optical active layer is a practical approach for preventing interface recombination and achieving high open-circuit voltage (V oc). Considering ΔE L , V if , light absorption efficiency, and solvation effect, D1-1aγ and D1-2aγ combinations are the most promising candidates of optical active layer materials in organic solar cell.

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Theoretical Investigation of the Open Circuit Voltage: P3HT/9,9′-Bisfluorenylidene Derivative Devices

Cited by 9 publications

References 60 publications

Molecular design of the NDI derivatives electron acceptors and theoretical adjustment of the open-circuit voltage

Molecular design of the NDI derivatives electron acceptors and theoretical adjustment of the open-circuit voltage

Quantum Chemical Studies on Electron-Accepting Overcrowded Ethylene with a Polarizable Skeleton

Molecular Design of Benzothiadiazole Derivatives Electron Acceptors and Matching of Donor-Acceptor Materials

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