Energy transfer within small molecule/conjugated polymer blends enhances photovoltaic efficiency

Lin, Yu Che; Su, Yu Wei; Li, Jia Xing; Lin, Bo Hsien; Chen, Chung Hao; Chen, Hsiu Cheng; Wu, Kaung‐Hsiung; Yang, Yang; Wei, Kung‐Hwa

doi:10.1039/c7ta04144f

Cited by 51 publications

(24 citation statements)

References 78 publications

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“…Due to the limitation of the energy transfer radius, the energy donor and acceptor need have close contact with each other, between which the distance should be maintained <10 nm and in order to occur efficient energy transfer. The third components, as an energy donor, can harvest solar photons and transfer the photogenerated excited states to the energy acceptor, from which the excited states can dissociate and generate more free charge carriers, resulting in higher current density . Benten et al improved the photovoltaic performance of PTB7‐Th:N2200‐based all‐polymer devices by introducing a wide‐bandgap polymer (PCDTBT) as the third component .…”

Section: Versatile Functions Of the Third Components And Fundamental mentioning

confidence: 99%

Recent Progress in Ternary Organic Solar Cells Based on Nonfullerene Acceptors

Yao

Hou

2018

Advanced Energy Materials

178

118

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facilitate the practical application of photovoltaic technology. [11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26] In ternary OSCs, the third components not only can provide a broadened light harvesting, but also have other important roles, such as facilitating exciton dissociation and charge transport and optimizing the film morphology. As a result, the main parameters of OSCs, i.e., the open-circuit voltage (V oc ), short-circuit current density (J sc ), and fill factor (FF), can be individually or simultaneously enhanced by incorporating different third components into different binary systems, such as conjugated polymers, [11][12][13][14][15][16][17][18] small molecules, [19][20][21][22] and quantum dots. [23] The PCEs of ternary OSCs have recently exceeded 11%. [24][25][26] In previous works, fullerene derivatives such as PC 61 BM or PC 71 BM have been utilized as the dominate electron acceptors in OSCs, and the most of studies on ternary OSCs were based on these fullerene acceptors. [17][18][19] However, fullerenes derivatives have several shortcomings, such as weak absorption in the visible region, limited tunability of energy levels, and poor stability. [27][28][29] Meanwhile, successful ternary OSCs have mostly focused on the combination of two donors and one fullerene derivative, rather than the ternary systems with two acceptors due to a lack of suitable materials. Most recently, considerable efforts have been paid to the nonfullerene OSCs, and many highly efficient nonfullerene acceptors, such as arylene imide-based, [30][31][32][33][34][35][36][37][38][39][40] indacenodithiophene (IDT)-based, [41][42][43][44][45][46][47][48][49][50][51][52] and diketopyrrolopyrrole-based small molecules, have been developed. [53][54][55][56] To date, the PCEs of both single-junction [57] and tandem [58] nonfullerene-acceptor-based OSCs have reached over 13% efficiencies. The new emerging highly efficient acceptors show various absorption spectra and energy levels, suggesting their great potential in constructing ternary OSCs.In this research news article, we first summarize the versatile functions of the third components in ternary OSCs and then present the recent progress in nonfullerene-based ternary OSCs, especially on those reported in the last two years. Finally, we discuss the upcoming challenges and the promising outlook for ternary OSCs.

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Section: Versatile Functions Of the Third Components And Fundamental mentioning

confidence: 99%

Recent Progress in Ternary Organic Solar Cells Based on Nonfullerene Acceptors

Yao

Hou

2018

Advanced Energy Materials

178

118

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“…Moreover, small conjugated molecules are often used as dopants in organic electronics . Additionally, the blending of polymers and small molecules having similar chemical structure is a promising approach to enhance the energy transfer from a high‐band‐gap small molecule to a low‐band‐gap polymer and to optimize in‐plane packing, arising from the presence of shorter conjugated fragments …”

Section: Introductionmentioning

confidence: 99%

A comparative analysis of symmetric diketopyrrolopyrrole‐cored small conjugated molecules with aromatic flanks: From geometry to charge transport

et al. 2018

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Diketopyrrolopyrrole (DPP) derivatives are promising compounds for application in organic electronics. Here, we investigate several symmetrical N‐unsubstituted and N‐methyl substituted DPPs which differ in the heteroatom in the aromatic flanks. The conformational, electronic, and optical properties are characterized for single molecules in vacuum or a solvent. The intermolecular interactions are evaluated for interacting dimers. Here, a number of stacking geometries is tested, and dimers with mutual orientation of the molecules corresponding to the minimal binding energies are determined. The predicted charge carrier mobilities for stacks having minimal binding energies corroborate experimentally measured values. We conclude that DFT prediction of such stacks is a promising and computationally inexpensive approach to a rough estimation of transport properties. Additionally, the super‐cell of the experimentally resolved crystal structure is used to study the dynamics and to compute the charge transport along the hopping pathways. We discuss obtained high mobilities and relate them to the symmetry of DPP core. © 2018 Wiley Periodicals, Inc.

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“…While the EQE curves kept their higher values in long wave range of 600–750 nm, which exhibited different trend with the absorption spectra as discussed above. This enhancement mainly caused by two aspects: the one is efficient energy transfer from photoexcited DIBC to the donor PTB7‐Th and the other one is the fact that the intermolecular hydrogen interaction optimized the film morphology and improved charge dynamics as demonstrated in the following. Besides, internal quantum efficiencies (IQEs) of these devices have been estimated with the equation

IQE (λ) = EQE (λ) {/Abs}_{AL} (λ)

…”

Section: Resultsmentioning

confidence: 88%

Hydrogen Bond Induced Green Solvent Processed High Performance Ternary Organic Solar Cells with Good Tolerance on Film Thickness and Blend Ratios

Zhao

et al. 2019

Adv Funct Materials

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For comprehensive development of organic solar cells (OSCs), some factors such as environmental stability, low cost, insensitive film thickness, component contents tolerance, and green preparation processes are equally crucial to achieve high power conversion efficiencies (PCEs). In this work, a small molecule 3-(diethylamino)-7-imino-7H-benzo[4,5]imidazo[1,2-a]chromeno[3,2-c]pyridine-6-carbonitrile (DIBC), which is commercially available at low cost, is utilized to realize high-performance ternary OSCs. Demonstrated via Fourier transform infrared and 2D-1 HNMR, DIBC can form hydrogen bond interactions with [6,6]-phenyl-C 71 -butyric acid methyl ester (PC 71 BM) in solid films. Further electrostatic potential (ESP) calculations indicate that the hydrogen bond interaction enhances the ESP of PC 71 BM and accelerates charge transport between donor and acceptor. As a result, poly(4,8-bis(5-(2-ethylhexyl)thiophen-2-yl) benzo[1,2-b;4,5-b0]dithiophene-2,6diylalt-(4-(2-ethylhexyl)-3-fluorothieno[3,4-b]thiophene-)-2-carboxylate-2-6-diyl(PTB7-Th):DIBC:PC 71 BM-based ternary OSC achieves a maximum efficiency of 12.17%, which is the best result of green solvent processed fullerene OSCs at present. It is noteworthy that the ternary OSCs also show great tolerance to film thickness and blend ratios. These unique properties are attributed to the hydrogen-bond-linked DIBC and PC 71 BM, which modulates molecule distribution and improves film morphology with an interpenetrating network structure. Furthermore, the DIBC containing device also exhibits good thermal and light radiation stability. These results illustrate that intermolecular hydrogen bond interaction has great potential for realizing high-performance OSCs.

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Energy transfer within small molecule/conjugated polymer blends enhances photovoltaic efficiency

Cited by 51 publications

References 78 publications

Recent Progress in Ternary Organic Solar Cells Based on Nonfullerene Acceptors

Recent Progress in Ternary Organic Solar Cells Based on Nonfullerene Acceptors

A comparative analysis of symmetric diketopyrrolopyrrole‐cored small conjugated molecules with aromatic flanks: From geometry to charge transport

Hydrogen Bond Induced Green Solvent Processed High Performance Ternary Organic Solar Cells with Good Tolerance on Film Thickness and Blend Ratios

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