13.34 % Efficiency Non‐Fullerene All‐Small‐Molecule Organic Solar Cells Enabled by Modulating the Crystallinity of Donors via a Fluorination Strategy

Ge, Jinfeng; Xie, Lingchao; Peng, Ruixiang; Fanady, Billy; Huang, Jiaming; Song, Wei; Yan, Tingting; Zhang, Wenxia; Ge, Ziyi

doi:10.1002/anie.201910297

Cited by 171 publications

(141 citation statements)

References 43 publications

Supporting

Mentioning

139

Contrasting

Order By: Relevance

“…[ 20 ] However, the small molecule SM1‐F was just reported by Ge et al and named as BTEC‐1F during the preparation of this manuscript. [ 50 ] It was found that the highest occupied molecular orbital (HOMO) energy levels were down‐shifted and the hole mobility of blend films with Y6 acceptor was increased from SM1 to SM1‐S to SM1‐F. In addition, crystallinity and aggregation behavior of the SM donors are influenced by the substituents.…”

Section: Figurementioning

confidence: 99%

Highly Efficient All‐Small‐Molecule Organic Solar Cells with Appropriate Active Layer Morphology by Side Chain Engineering of Donor Molecules and Thermal Annealing

et al. 2020

View full text Add to dashboard Cite

Organic semiconductor (OS) materials have drawn extensive attention during the past several decades, due to their superiorities in fabricating low-cost, lightweight, and flexible devices. [1][2][3][4] The photovoltaic performance of organic solar cells (OSCs) has achieved tremendous improvement during the past two decades, benefitted from the innovation of novel OS materials and device technologies. [5][6][7][8][9][10][11][12] Smallmolecule OS materials, compared with polymer OS material, possess the distinct advantages of well-defined chemical structure, easy purification, and better repeatability. [13][14][15][16][17] However, the power conversion efficiency (PCE) of the all small-molecule SM-OSCs (SM-OSCs) with small molecule donor and small molecule acceptor always lags behind that of polymer solar cells (PSCs) with conjugated polymer donor and small molecule It is very important to fine-tune the nanoscale morphology of donor:acceptor blend active layers for improving the photovoltaic performance of all-small-molecule organic solar cells (SM-OSCs). In this work, two new small molecule donor materials are synthesized with different substituents on their thiophene conjugated side chains, including SM1-S with alkylthio and SM1-F with fluorine and alkyl substituents, and the previously reported donor molecule SM1 with an alkyl substituent, for investigating the effect of different conjugated side chains on the molecular aggregation and the photophysical, and photovoltaic properties of the donor molecules. As a result, an SM1-F-based SM-OSC with Y6 as the acceptor, and with thermal annealing (TA) at 120 °C for 10 min, demonstrates the highest power conversion efficiency value of 14.07%, which is one of the best values for SM-OSCs reported so far. Besides, these results also reveal that different side chains of the small molecules can distinctly influence the crystallinity characteristics and aggregation features, and TA treatment can effectively fine-tune the phase separation to form suitable donor-acceptor interpenetrating networks, which is beneficial for exciton dissociation and charge transportation, leading to highly efficient photovoltaic performance.

show abstract

Section: Figurementioning

confidence: 99%

Highly Efficient All‐Small‐Molecule Organic Solar Cells with Appropriate Active Layer Morphology by Side Chain Engineering of Donor Molecules and Thermal Annealing

et al. 2020

View full text Add to dashboard Cite

show abstract

“…The other is halogenation, which means to introduce fluorine, chlorine or bromine atoms to the specific positions of some representative units to adjust the energy levels and crystalline properties of the small molecule donor. On the basis of this strategy, several small molecular donors, such as benzodithiophene-Cl (BTR-Cl), BSFTR and BTEC-2F have been developed (see Table 1) and the corresponding OSCs achieve PCEs over 13% when blended with the small molecule acceptor Y6 [28][29][30]. It is well known that variations in morphology induced by the changes in crystallinity and molecular orientation have a significant impact on the performance of OSCs [31][32][33][34].…”

Section: Introductionmentioning

confidence: 99%

15.3% efficiency all-small-molecule organic solar cells enabled by symmetric phenyl substitution

et al. 2020

View full text Add to dashboard Cite

Synergistic optimization of donor-acceptor blend morphologyis a hurdle in the path of realizing efficient non-fullerene small-molecule organic solar cells (NFSM-OSCs) due to the anisotropic conjugated backbones of both donor and acceptor. Therefore, developing a facile molecular design strategy to effectively regulate the crystalline properties of photoactive materials, and thus, enable the optimization of blend morphology is of vital importance. In this study, a new donor molecule B1, comprising phenyl-substituted benzodithiophene (BDT) central unit, exhibits strong interaction with the non-fullerene acceptor BO-4Cl in comparison with its corresponding thiophene-substituted BDT-based material, BTR. As a result, the B1 is affected and induced from an edgeon to a face-on orientation by the acceptor, while the BTR and the acceptor behave individually for the similar molecular orientation in pristine and blend films according to grazing incidence wide angle X-ray scattering results. It means the donor-acceptor blend morphology is synergistically optimized in the B1 system, and the B1:BO-4Cl-based devices achieve an outstanding power conversion efficiency (PCE) of 15.3%, further certified to be 15.1% by the National Institute of Metrology, China. Our results demonstrate a simple and effective strategy to improve the crystalline properties of the donor molecule as well as synergistically optimize the morphology of the all-small-molecule system, leading to the high-performance NFSM-OSCs.

show abstract

“…Compared to the PM6:L11 blend with a µ e,SCLC of 4.3 × 10 −4 cm 2 V −1 s −1 , the PM6:L14 blend shows a higher µ e,SCLC of 6.6 × 10 −4 cm 2 V −1 s −1 , resulting in more balanced mobilities with a µ h,SCLC /µ e,SCLC value of 1.23 and contributing to higher J sc and FF. [39][40] Morphological characterizations of the blend films are performed by atomic force microscopy (AFM), transmission electron microscopy (TEM), and GIWAXS. As shown in Figure S9 (Supporting Information), the height images of two films feature smooth surfaces.…”

mentioning

confidence: 99%

A Narrow‐Bandgap n‐Type Polymer with an Acceptor–Acceptor Backbone Enabling Efficient All‐Polymer Solar Cells

et al. 2020

View full text Add to dashboard Cite

of these FREAs can be fine-tuned by optimizing the intramolecular charge transfer character while maintaining their key characteristics as efficient electron acceptor materials. [4-6] The FREAs with fine-tailored properties enable the state-of-the-art power conversion efficiencies (PCEs) surpassing 16% in OSCs. [7-12] Among various OSCs, all-polymer solar cells (all-PSCs) employing conjugated polymers as both the electron donors and acceptors, have recently attracted great attention because of some unique advantages including superior stability and mechanical robustness. [13-20] However, only a few polymer acceptors can yield PCEs over 8% till now (see Figure S1 and Table S1, Supporting Information) due to the scarcity of highly electron-deficient building blocks. For instance, classical naphthalene diimide and perylene diimidebased donor-acceptor (D-A)-type polymer acceptors (see Figure S2a, Supporting Information) suffer from poor absorption coefficient in the long-wavelength region and (or) the localized lowest unoccupied molecular orbital (LUMO), which limits the short-circuit currents density (J sc) and V oc , together with Narrow-bandgap polymer semiconductors are essential for advancing the development of organic solar cells. Here, a new narrow-bandgap polymer acceptor L14, featuring an acceptor-acceptor (A-A) type backbone, is synthesized by copolymerizing a dibrominated fused-ring electron acceptor (FREA) with distannylated bithiophene imide. Combining the advantages of both the FREA and the A-A polymer, L14 not only shows a narrow bandgap and high absorption coefficient, but also low-lying frontier molecular orbital (FMO) levels. Such FMO levels yield improved electron transfer character, but unexpectedly, without sacrificing open-circuit voltage (V oc), which is attributed to a small nonradiative recombination loss (E loss,nr) of 0.22 eV. Benefiting from the improved photocurrent along with the high fill factor and V oc , an excellent efficiency of 14.3% is achieved, which is among the highest values for all-polymer solar cells (all-PSCs). The results demonstrate the superiority of narrow-bandgap A-A type polymers for improving all-PSC performance and pave a way toward developing high-performance polymer acceptors for all-PSCs.

show abstract

13.34 % Efficiency Non‐Fullerene All‐Small‐Molecule Organic Solar Cells Enabled by Modulating the Crystallinity of Donors via a Fluorination Strategy

Cited by 171 publications

References 43 publications

Highly Efficient All‐Small‐Molecule Organic Solar Cells with Appropriate Active Layer Morphology by Side Chain Engineering of Donor Molecules and Thermal Annealing

Highly Efficient All‐Small‐Molecule Organic Solar Cells with Appropriate Active Layer Morphology by Side Chain Engineering of Donor Molecules and Thermal Annealing

15.3% efficiency all-small-molecule organic solar cells enabled by symmetric phenyl substitution

A Narrow‐Bandgap n‐Type Polymer with an Acceptor–Acceptor Backbone Enabling Efficient All‐Polymer Solar Cells

Contact Info

Product

Resources

About