Highly efficient ITO-free organic solar cells with a column-patterned microcavity

Huang, Jiang; Zhao, Dan; Dou, Zifan; Fan, Qingshan; Li, Na; Peng, Shuihai; Liu, Haoran; Jiang, Yadong; Yu, Junsheng; Li, Chang‐Zhi

doi:10.1039/d0ee03387a

Cited by 32 publications

(27 citation statements)

References 59 publications

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“…Organic solar cells (OSCs) can directly convert sunlight into electricity and possess some specific advantages, such as light weight, flexibility, [1][2][3] semitransparency, [4] and large-area manufacture [5] through simple solution-processing technique. During the past two decades, OSCs have gained tremendous progress, benefitted mainly from the fast development of active layer materials, [6][7][8][9] device structure, [10,11] and interface engineering, [12][13][14][15][16] highlighting the great potential for largescale commercial applications. Photovoltaic performance, stability, and cost are the three most crucial issues that should be addressed seriously for the future commercial application of OSCs.…”

Section: Introductionmentioning

confidence: 99%

15.71% Efficiency All‐Small‐Molecule Organic Solar Cells Based on Low‐Cost Synthesized Donor Molecules

Guo

Qiu

Yang

et al. 2021

Adv Funct Materials

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Low cost, high efficiency, and high stability are the three key issues of organic solar cells (OSCs) that should be carefully considered to meet the requirement of future commercial applications. Therefore, the development of high-performance organic photovoltaic materials with low synthetic cost has been becoming a crucial challenge in the field of OSCs. Herein, two new low-cost small-molecule donors (SM-BF1 and SM-BF2) are designed and synthesized with a facile synthetic route by replacing 4-bromo-2-fluorobenzenethiol and 4-bromo-3-fluorobenzenethiol with lowcost 4-bromo-2-fluoro-1-iodobenzene and 4-bromo-3-fluoro-1-iodobenzene as key raw materials. Besides, the influence of the chemical steric effect of the phenyl conjugated side chains of the benzodithiophene (BDT) unit on photophysical properties, charge transfer, and photovoltaic properties are deeply investigated by the modulation of fluorine atom substituted position. As a result, SM-BF1 with ortho-fluorinated substituent has outstanding crystallization properties and better miscibility with acceptor Y6 and exhibits more desirable morphology and more balanced chargecarrier transport properties, leading to a superior power conversion efficiency (PCE) to 15.71%. More encouragingly, according to the figure of merit (FOM) and the industrial figure of merit (i-FOM) to evaluate the small-molecule donors, the SM-BF1-based device has excellent potential for future commercial applications.

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Section: Introductionmentioning

confidence: 99%

15.71% Efficiency All‐Small‐Molecule Organic Solar Cells Based on Low‐Cost Synthesized Donor Molecules

Guo

Qiu

Yang

et al. 2021

Adv Funct Materials

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“…Up to now, the highest power conversion efficiency (PCE) of OSCs based on FREAs has reached 18%, demonstrating the bright future for practical application. [2][3][4][5][6][7][8][9] Although FREAs can achieve high efficiency, they are expensive and their syntheses are complicated, which usually includes low-yield ring-closure reactions. For the commercialization of OSCs, it is highly desired to develop highperformance and low-cost nonfullerene acceptors.…”

mentioning

confidence: 99%

Simple Nonfused Ring Electron Acceptors with 3D Network Packing Structure Boosting the Efficiency of Organic Solar Cells to 15.44%

Wang

Lü

Liu

et al. 2021

Advanced Energy Materials

150

122

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Zhan et al. reported a fused ring electron acceptor (FREA) ITIC with an acceptordonor-acceptor (A-D-A) type structure. [1] Subsequently, numerous FREAs are developed by researchers, which largely promoted the photovoltaic performance of OSCs. Recently, Zou et al. developed a series of A-DA′D-A type FREAs (Y6 series). Up to now, the highest power conversion efficiency (PCE) of OSCs based on FREAs has reached 18%, demonstrating the bright future for practical application. [2][3][4][5][6][7][8][9] Although FREAs can achieve high efficiency, they are expensive and their syntheses are complicated, which usually includes low-yield ring-closure reactions. For the commercialization of OSCs, it is highly desired to develop highperformance and low-cost nonfullerene acceptors. Therefore, we want to develop simple nonfused ring electron acceptors (NFREAs) to replace the high-cost FREAs. In 2017, we first postulated and proved that intramolecular noncovalent interactions could be used to partially replace chemical bonds to synthesize NFREAs. [10] Since then, small fused ring building blocks such as indacenodithiophene (IDT), [11][12][13][14] cyclopentadithiophene (CPDT), [15][16][17][18][19][20][21][22][23][24] etc., were often used for the construction of NFREAs. Later, researchers also developed fully nonfused ring electron acceptors. [25][26][27] However, the photovoltaic performance of the solar cells based on NFREAs is still far behind the FREAs.Typical FREAs consist of a fused ring core, side chains, and two electron-withdrawing terminal groups. [28][29][30][31] The planar fused ring core is beneficial for the electron delocalization. The side chain can increase the solubility and affect the molecular stacking of acceptors. The electron-withdrawing terminal group such as 3-(1,1-dicyanomethylene)-5,6-difluoro-1-indanone can induce a strong intramolecular charge transfer (ICT) effect in the acceptor molecule, which can remarkably broaden the absorption, lower the energy levels (especially the lowest unoccupied molecular orbital (LUMO)), and enhance the molecular stacking. [32][33][34] Besides these basic characteristics, recent reports begin to focus on molecular stacking model. There is growing evidence that high-performance FREAs possess a 3D network packing structure, being in favor of facilitating multiple charge transport, achieving small exciton binding energy, and reducing energy loss in OSCs. [5,[35][36][37][38][39] Unlike rigid FREAs, the molecular Three nonfused ring electron acceptors (NFREAs; 2Th-2F, BTh-Th-2F, and 2BTh-2F) with thieno[3,2-b]thiophene bearing two bis(4-butylphenyl)amino substituents as the core, 3-octylthiophene or 3-octylthieno[3,2-b]thiophene as the spacer, and 3-(1,1-dicyanomethylene)-5,6-difluoro-1-indanone as the terminal group are designed and synthesized. The molar extinction coefficient of acceptors and the electron mobility of blend films gradually increase with increasing π-conjugation length. Moreover, 2BTh-2F displays a planar molecular conformation assisted by S•••N and S•••O intr...

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“…The TUA structure features low-cost and ITO-free merits, and has great potential for practical applications of OPVs. [47,53,54] The strong reflectance of the Ag layers and complicated optical interference produces a strong optical microcavity effect within the device chamber and makes the light-trapping properties very sensitive to the device structure. [53,54] Therefore, before implanting the active layer into the TUA structure, we carried out thorough optical simulations to optimize the device configuration.…”

Section: Tua Device Structurementioning

confidence: 99%

“…[47,53,54] The strong reflectance of the Ag layers and complicated optical interference produces a strong optical microcavity effect within the device chamber and makes the light-trapping properties very sensitive to the device structure. [53,54] Therefore, before implanting the active layer into the TUA structure, we carried out thorough optical simulations to optimize the device configuration. Figure 1c shows the active layer and TeO 2 thicknessdependent J SC of TUA-based OPV, with ultrathin Ag thickness fixed at 11 nm.…”

Section: Tua Device Structurementioning

confidence: 99%

High‐Efficiency ITO‐Free Organic Photovoltaics with Superior Flexibility and Upscalability

et al. 2022

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Developing indium‐tin‐oxide (ITO)‐free flexible organic photovoltaics (OPVs) with upscaling capacity is of great significance for practical applications of OPVs. Unfortunately, the efficiencies of the corresponding devices lag far behind those of ITO‐based rigid small‐area counterparts. To address this issue, an advanced device configuration is designed and fabricated featuring a top‐illuminated structure with ultrathin Ag as the transparent electrode. First, a conjugated polyelectrolyte layer, i.e., PCP‐Li, is inserted to effectively connect the bottom Ag anode and the hole transport layer, achieving good photon to electron conversion. Second, charge collecting grids are deposited to suppress the increased resistance loss with the upscaling of the device area, realizing almost full retention of device efficiency from 0.06 to 1 cm2. Third, the designed device delivers the best efficiency of 15.56% with the area of 1 cm2 on polyimide substrate, representing as the record among the ITO‐free, large‐area, flexible OPVs. Interestingly, the device exhibits no degradation after 100 000 bending cycles with a radius of 4 mm, which is the best result for flexible OPVs. This work provides insight into device structure design and optimization for OPVs with high efficiency, low cost, superior flexibility, and upscaling capacity, indicating the potential for the future commercialization of OPVs.

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Highly efficient ITO-free organic solar cells with a column-patterned microcavity

Abstract: To achieve high-efficiency organic solar cells (OSCs) requires well balancing the trade-off between the voltage loss and photocurrent generation of bulk heterojunction (BHJ) blends. In this work, we develop high-performance...

Cited by 32 publications

References 59 publications

15.71% Efficiency All‐Small‐Molecule Organic Solar Cells Based on Low‐Cost Synthesized Donor Molecules

15.71% Efficiency All‐Small‐Molecule Organic Solar Cells Based on Low‐Cost Synthesized Donor Molecules

Simple Nonfused Ring Electron Acceptors with 3D Network Packing Structure Boosting the Efficiency of Organic Solar Cells to 15.44%

High‐Efficiency ITO‐Free Organic Photovoltaics with Superior Flexibility and Upscalability

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