28 Aug 16:49
by Sung Yong Byeon,
Dong Ryun Lee,
Kyoung Soo Yook,
Jun Yeob Lee
Recent progress regarding thermally activated delayed fluorescence (TADF) sensitized fluorescent organic light‐emitting diodes (OLEDs) is discussed, based on both external quantum efficiency, reported by material, and device engineering.
Abstract
The external quantum efficiency (EQE) of organic light‐emitting diodes (OLEDs) has been dramatically improved by developing highly efficient organic emitters such as phosphorescent emitters and thermally activated delayed fluorescent (TADF) emitters. However, high‐EQE OLED technologies suffer from relatively poor device lifetimes in spite of their high EQEs. In particular, the short lifetimes of blue phosphorescent and TADF OLEDs remain a big hurdle to overcome. Therefore, the high‐EQE approach harvesting singlet excitons of fluorescent emitters by energy transfer processes from the host or sensitizer has been explored as an alternative for high‐EQE OLED strategies. Recently, there has been a big jump in the EQE and device lifetime of singlet‐exciton‐harvesting fluorescent OLEDs. Recent progress on the materials and device structure is discussed herein.
27 Aug 16:56
by Minwoo Nam,
Joo‐han Kang,
Jisu Shin,
Jihye Na,
Yunjae Park,
Junhee Cho,
Byunghoon Kim,
Hyun Hwi Lee,
Rakwoo Chang,
Doo‐Hyun Ko
This study provides important guidelines for the third component in ternary organic photovoltaics (OPVs), involving high molecular compatibility with main components and favorable ternary junction formation with cascade band alignment. With a high efficiency in any irradiation conditions (≈26.4% under light‐emitting diodes) and superior thermal durability, ternary OPVs incorporating nonfullerene acceptors open new opportunities in broad practical applications.
Abstract
Ternary blend approaches are demonstrated as a universal means to improve overall performance of organic photovoltaics (OPVs) in both indoor and outdoor conditions. A comparative study on two donors:one acceptor (2D:1A) and one donor:two acceptors (1D:2A) ternary blends shows that both approaches are universally effective for indoor and outdoor operation; the 1D:2A devices incorporating a nonfullerene acceptor (NFA) benefit from less charge recombination and higher power conversion efficiencies (PCEs) for various irradiation conditions, while the performance of the 2D:1A blends depends on the emission spectrum of the incident light source. The synergistic merits of NFAs and ternary structure in the 1D:2A ternary OPVs secure better performance and generality regardless of the incident lighting. A combination of experimental and theoretical analyses unveils that NFAs optimize packing and arrangement of molecules to build efficient cascade ternary junctions in the 1D:2A blends, which can be important design guidelines for the third component in ternary OPVs. The optimized 1D:2A ternary OPV exhibits a new record PCE of 25.6% under a 200 lux light‐emitting diode (LED) and 26.4% under a 1000 lux LED, and superior durability under industrial relevant thermal stress, suggesting new opportunities in diverse practical applications challenging the currently dominant PV technologies.
27 Aug 06:09
by Herim Han and Eung-Gun Kim*
Chemistry of Materials
DOI: 10.1021/acs.chemmater.9b01364
25 Aug 13:03
by Sung Jae Jeon,
Yong Woon Han,
Doo Kyung Moon
This study presents a reasonable strategy for designing 2DBDT‐chlorinated thiophene‐based donor polymers with balanced molecular weight and solubility by modifying the structure of previously reported low cost P(Cl) to achieve high‐efficiency polymer solar cells (PSCs). As a result, the new P(Cl–Cl)(BDD = 0.2) reaches a high power conversion efficiency of 13.9% using eco‐friendly solvents for commercialization of PSCs.
Abstract
To industrialize nonfullerene polymer solar cells (NFPSCs), the molecular design of the donor polymers must feature low‐cost materials and a high overall yield. Two chlorinated thiophene‐based polymers, P(F–Cl) and P(Cl–Cl), are synthesized by introducing halogen effects like fluorine (F) and chlorine (Cl) to the previously reported P(Cl), which exhibits low complexity. However, the molecular weights of these polymers are insufficient owing to their low solubility, which in turn is caused by introducing rigid halogen atoms during the polymerization. Thus, they show relatively low power conversion efficiencies (PCEs) of 11.8% and 10.3%, respectively. To overcome these shortcomings, two new terpolymers are designed and synthesized by introducing a small amount of 1,3‐bis(5‐bromothiophen‐2‐yl)‐5,7‐bis(2‐ethylhexyl)benzo[1,2‐c:4,5‐c′]dithiophene‐4,8‐dione (BDD) unit into each backbone, namely, P(F–Cl)(BDD = 0.2) and P(Cl–Cl)(BDD = 0.2). As a result, both polymers remain inexpensive and show a better molecular weight–solubility balance, achieving high PCEs of 12.7% and 13.9%, respectively, in NFPSCs processed using eco‐friendly solvents.
25 Aug 13:01
by Youdi Zhang†‡, Ying Wang†, Tao Yang?, Tao Liu*?, Yiqun Xiao#, Xinhui Lu#, He Yan*?, Zhongyi Yuan*†‡, Yiwang Chen*†‡§, and Yongfang Li?
ACS Applied Materials & Interfaces
DOI: 10.1021/acsami.9b11700
25 Aug 07:59
Energy Environ. Sci., 2019, 12,3118-3132
DOI: 10.1039/C9EE02295C, Paper
Rui Sun, Jie Guo, Qiang Wu, Zhuohan Zhang, Wenyan Yang, Jing Guo, Mumin Shi, Yaohong Zhang, Simon Kahmann, Long Ye, Xuechen Jiao, Maria A. Loi, Qing Shen, Harald Ade, Weihua Tang, Christoph J. Brabec, Jie Min
This article analyzes and discusses a multi-objective optimization-based layer-by-layer blade-coating approach, which provides a new technology choice for large-scale manufacturing of organic solar cells.
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24 Aug 07:31
by Christopher M. Tonge and Zachary M. Hudson*
Journal of the American Chemical Society
DOI: 10.1021/jacs.9b07156
20 Aug 03:15
by Jae Won Lee,
Sungwoo Jung,
Tae Won Lee,
Jinhyeong Jo,
Hee Young Chae,
Keunsu Choi,
Jae Joon Kim,
Jun Hee Lee,
Changduk Yang,
Jeong Min Baik
A polyimide‐based polymer based on 6FDA‐APS is synthesized for the effective dielectric of triboelectric nanogenerator (TENG). A maximum charge density of about 860 µC m−2 is obtained from the TENG, possessing the most negative electrostatic potential and the low‐lying lowest unoccupied molecular orbital level, which leads to excellent charge retention characteristics and enhanced charge transfer capability. A 6FDA‐APS‐driven gas sensor network system is demonstrated.
Abstract
High‐output triboelectric nanogenerators (TENGs) are demonstrated based on polyimide (PI)‐based polymers by introducing functionalities (e.g., electron‐withdrawing and electron‐donating groups) into the backbone. The TENG based on 6FDA‐APS PI, possessing the most negative electrostatic potential and the low‐lying lowest unoccupied molecular orbital level, produces the highest effective charge density of about 860 µC m−2 in practical working conditions with the ion injection process. This may be ascribed to the excellent charge‐retention characteristics as well as the enhanced charge transfer capability, which increases the output power by 7 times compared to the commercially available Kapton film‐based TENG. Finally, a 6FDA‐APS‐driven sensor network system is demonstrated, providing the identity of three gases (H2, CO, and NO2) by illuminating the light‐emitting diodes within several seconds.
19 Aug 08:21
by Dongling Zhou,
Wai‐Pong To,
Yoonhyun Kwak,
Yongsuk Cho,
Gang Cheng,
Glenna So Ming Tong,
Chi‐Ming Che
Donor–acceptor type cyclometalated Au(III) alkynyl complexes display highly efficient thermally activated delayed fluorescence (TADF) with Φ up to 88% in thin films and emission lifetimes of ≈1–2 µs at room temperature. Vacuum‐deposited organic light‐emitting diodes (OLEDs) with these emissive dopants achieve external quantum efficiencies (EQEs) and luminance of up to 23.4% and 70 300 cd m−2, respectively.
Abstract
Thermally stable, strongly luminescent gold‐TADF emitters are the clue to realize practical applications of gold metal in next generation display and lighting technology, a scarce example of which is herein described. A series of donor–acceptor type cyclometalated gold(III) alkynyl complexes with some of them displaying highly efficient thermally activated delayed fluorescence (TADF) with Φ up to 88% in thin films and emission lifetimes of ≈1–2 µs at room temperature are developed. The emission color of these complexes is readily tunable from green to red by varying the donor unit and cyclometalating ligand. Vacuum‐deposited organic light‐emitting diodes (OLEDs) with these complexes as emissive dopants achieve external quantum efficiencies (EQEs) and luminance of up to 23.4% and 70 300 cd m−2, respectively.
19 Aug 05:13
by Janina Diekmann†, Julia Gontcharov‡, Sascha Fro¨bel†§, Christian Torres Ziegenbein†?, Wolfgang Zinth‡, and Peter Gilch*†
Journal of the American Chemical Society
DOI: 10.1021/jacs.9b06521
15 Aug 15:12
by Tingting Yan,
Wei Song,
Jiaming Huang,
Ruixiang Peng,
Like Huang,
Ziyi Ge
High efficiencies of 16.67% (certified as 16.0%) for rigid and 14.06% for flexible organic solar cells (OSCs) are achieved by employing a PM6:Y6:PC71BM ternary system. This is a promising ternary heterojunction strategy for the development of highly efficient rigid and flexible OSCs.
Abstract
Ternary heterojunction strategies appear to be an efficient approach to improve the efficiency of organic solar cells (OSCs) through harvesting more sunlight. Ternary OSCs are fabricated by employing wide bandgap polymer donor (PM6), narrow bandgap nonfullerene acceptor (Y6), and PC71BM as the third component to tune the light absorption and morphologies of the blend films. A record power conversion efficiency (PCE) of 16.67% (certified as 16.0%) on rigid substrate is achieved in an optimized PM6:Y6:PC71BM blend ratio of 1:1:0.2. The introduction of PC71BM endows the blend with enhanced absorption in the range of 300–500 nm and optimises interpenetrating morphologies to promote photogenerated charge dissociation and extraction. More importantly, a PCE of 14.06% for flexible ITO‐free ternary OSCs is obtained based on this ternary heterojunction system, which is the highest PCE reported for flexible state‐of‐the‐art OSCs. A very promising ternary heterojunction strategy to develop highly efficient rigid and flexible OSCs is presented.
15 Aug 15:00
by Lingyun Zhu†, Zeyi Tu‡, Yuanping Yi*‡, and Zhixiang Wei*†
The Journal of Physical Chemistry Letters
DOI: 10.1021/acs.jpclett.9b02161
15 Aug 14:57
by Haoran Wang‡, Hui Bian‡, Zhiwen Jin*†, Hong Zhang†?, Lei Liang‡, Jialun Wen‡, Qian Wang*†, Liming Ding*§, and Shengzhong Frank Liu*‡
Chemistry of Materials
DOI: 10.1021/acs.chemmater.9b02248
15 Aug 14:57
by Pascal S. Engl‡, Andreas P. Ha¨ring‡, Florian Berger, Georg Berger, Alberto Pe´rez-Bitria´n, and Tobias Ritter*
Journal of the American Chemical Society
DOI: 10.1021/jacs.9b07323
14 Aug 00:06
by Haoran Liu,
Zhi‐Xi Liu,
Shuxu Wang,
Jiang Huang,
Huanxin Ju,
Qi Chen,
Junsheng Yu,
Hongzheng Chen,
Chang‐Zhi Li
The introduction of funtional molecular self‐assembled monolayers (SAMs) atop of zinc oxide (ZnO) effectively optimizes the energetic and heterojunction properties of the organic–metal oxide interface to improve the performance and photostability of nonfullerene polymer solar cells.
Abstract
Charge events across organic–metal oxide heterointerfaces routinely occur in organic electronics, yet strongly influence their overall performance and stability. They become even more complicated and challenging for the heterojunction conditions in polymer solar cells (PSCs), especially when nonfullerene acceptors with varied energetics are employed. In this work, an effective interfacial strategy that utilizes novel small molecule self‐assembled monolayers (SAMs) is developed to improve the electronic and electric, as well as chemical properties of organic–zinc oxide (ZnO) interfaces for nonfullerene PSCs. It is revealed that the tailored SAMs with well‐controlled energy levels and molecular dipoles can effectively optimize the energetic barrier and work function (WF) of heterointerface for optimal electron extraction. In addition, the introduction of SAMs atop of ZnO facilitates not only acceptor segregation near the n‐contact interface, but also passivation of the photocatalytic activities for ZnO, to improve overall performance and photo stability of the derived nonfullerene PSCs. Overall, the methodology and structure–property relationship revealed herein would be beneficial for a wide range of hybrid electronics.
14 Aug 00:02
by Emmanuel Odella§‡, Brian L. Wadsworth§‡, S. Jimena Mora§‡, Joshua J. Goings†‡, Mioy T. Huynh†, Devens Gust§, Thomas A. Moore§, Gary F. Moore*§, Sharon Hammes-Schiffer*†, and Ana L. Moore*§
Journal of the American Chemical Society
DOI: 10.1021/jacs.9b06978
14 Aug 00:01
by Jae Won Lee,
Sungwoo Jung,
Tae Won Lee,
Jinhyeong Jo,
Hee Young Chae,
Keunsu Choi,
Jae Joon Kim,
Jun Hee Lee,
Changduk Yang,
Jeong Min Baik
A polyimide‐based polymer based on 6FDA‐APS is synthesized for the effective dielectric of triboelectric nanogenerator (TENG). A maximum charge density of about 860 µC m−2 is obtained from the TENG, possessing the most negative electrostatic potential and the low‐lying lowest unoccupied molecular orbital level, which leads to excellent charge retention characteristics and enhanced charge transfer capability. A 6FDA‐APS‐driven gas sensor network system is demonstrated.
Abstract
High‐output triboelectric nanogenerators (TENGs) are demonstrated based on polyimide (PI)‐based polymers by introducing functionalities (e.g., electron‐withdrawing and electron‐donating groups) into the backbone. The TENG based on 6FDA‐APS PI, possessing the most negative electrostatic potential and the low‐lying lowest unoccupied molecular orbital level, produces the highest effective charge density of about 860 µC m−2 in practical working conditions with the ion injection process. This may be ascribed to the excellent charge‐retention characteristics as well as the enhanced charge transfer capability, which increases the output power by 7 times compared to the commercially available Kapton film‐based TENG. Finally, a 6FDA‐APS‐driven sensor network system is demonstrated, providing the identity of three gases (H2, CO, and NO2) by illuminating the light‐emitting diodes within several seconds.
14 Aug 00:00
by Yatong Chen,
Xiuwen Xu,
Ning Cai,
Sainan Qian,
Ruixi Luo,
Yanping Huo,
Sai‐Wing Tsang
With the synthesis of two novel hole transport materials, the inverted planar perovskite solar cell achieves a high fill factor of 81.7%, with an efficiency exceeding 19%. More importantly, a highly possible correlation between the molecular packing, hole mobility, and device performance is revealed, which provides some insights for the rational design of hole transport materials.
Abstract
In this paper, two novel D‐π‐D hole‐transporting materials (HTM) are reported, abbreviated as BDT‐PTZ and BDT‐POZ, which consist of 4,8‐di(hexylthio)‐benzo[1,2‐b:4,5‐b′]dithiophene (BDT) as π‐conjugated linker, and N‐(6‐bromohexyl) phenothiazine (PTZ)/N‐(6‐bromohexyl) phenoxazine (POZ) as donor units. The above two HTMs are deployed in p‐i‐n perovskite solar cells (PSCs) as dopant‐free HT layers, exhibiting excellent power conversion efficiencies of 18.26% and 19.16%, respectively. Particularly, BDT‐POZ demonstrates a superior fill factor of 81.7%, which is consistent with its more efficient hole extraction and transport verified via steady‐state/transient fluorescence spectra and space‐charge‐limited current technique. Single‐crystal X‐ray diffraction characterization implies these two molecules present diverse packing tendencies, which may account for various interfacial hole‐transport ability in PSCs.
13 Aug 11:29
by Tonghui Wang, Veaceslav Coropceanu, and Jean-Luc Bre´das*
Chemistry of Materials
DOI: 10.1021/acs.chemmater.9b02284
12 Aug 07:17
by Dongling Zhou,
Wai‐Pong To,
Yoonhyun Kwak,
Yongsuk Cho,
Gang Cheng,
Glenna So Ming Tong,
Chi‐Ming Che
Donor–acceptor type cyclometalated Au(III) alkynyl complexes display highly efficient thermally activated delayed fluorescence (TADF) with Φ up to 88% in thin films and emission lifetimes of ≈1–2 µs at room temperature. Vacuum‐deposited organic light‐emitting diodes (OLEDs) with these emissive dopants achieve external quantum efficiencies (EQEs) and luminance of up to 23.4% and 70 300 cd m−2, respectively.
Abstract
Thermally stable, strongly luminescent gold‐TADF emitters are the clue to realize practical applications of gold metal in next generation display and lighting technology, a scarce example of which is herein described. A series of donor–acceptor type cyclometalated gold(III) alkynyl complexes with some of them displaying highly efficient thermally activated delayed fluorescence (TADF) with Φ up to 88% in thin films and emission lifetimes of ≈1–2 µs at room temperature are developed. The emission color of these complexes is readily tunable from green to red by varying the donor unit and cyclometalating ligand. Vacuum‐deposited organic light‐emitting diodes (OLEDs) with these complexes as emissive dopants achieve external quantum efficiencies (EQEs) and luminance of up to 23.4% and 70 300 cd m−2, respectively.
12 Aug 03:47
by Ling Hong,
Huifeng Yao,
Ziang Wu,
Yong Cui,
Tao Zhang,
Ye Xu,
Runnan Yu,
Qing Liao,
Bowei Gao,
Kaihu Xian,
Han Young Woo,
Ziyi Ge,
Jianhui Hou
Eco‐compatible solvent‐processed organic photovoltaic cells with over 16% power conversion efficiency are achieved via modifying the flexible alkyl chains of BTP‐4F‐8. Combining with the polymer donor T1, over 14% power conversion efficiencies are obtained not only for using several kinds of greener solvents like o‐xylene, 1,2,4‐trimethylbenzene, and tetrahydrofuran but also for 1.07 cm2 cells by the blade‐coating method.
Abstract
Recent advances in nonfullerene acceptors (NFAs) have enabled the rapid increase in power conversion efficiencies (PCEs) of organic photovoltaic (OPV) cells. However, this progress is achieved using highly toxic solvents, which are not suitable for the scalable large‐area processing method, becoming one of the biggest factors hindering the mass production and commercial applications of OPVs. Therefore, it is of great importance to get good eco‐compatible processability when designing efficient OPV materials. Here, to achieve high efficiency and good processability of the NFAs in eco‐compatible solvents, the flexible alkyl chains of the highly efficient NFA BTP‐4F‐8 (also known as Y6) are modified and BTP‐4F‐12 is synthesized. Combining with the polymer donor PBDB‐TF, BTP‐4F‐12 shows the best PCE of 16.4%. Importantly, when the polymer donor PBDB‐TF is replaced by T1 with better solubility, various eco‐compatible solvents can be applied to fabricate OPV cells. Finally, over 14% efficiency is obtained with tetrahydrofuran (THF) as the processing solvent for 1.07 cm2 OPV cells by the blade‐coating method. These results indicate that the simple modification of the side chain can be used to tune the processability of active layer materials and thus make it more applicable for the mass production with environmentally benign solvents.
12 Aug 03:46
by Yunpeng Qin,
Shaoqing Zhang,
Ye Xu,
Long Ye,
Yi Wu,
Jingyi Kong,
Bowei Xu,
Huifeng Yao,
Harald Ade,
Jianhui Hou
A new method of depressing E
loss for nonfullerene organic solar cells (OSCs) is reported, in which a small molecular material (NRM‐1) can be selectively dispersed into the acceptor phase in the PBDB‐T:IT‐4F‐based OSC, resulting in lower Elossrad and Elossnonrad and hence significant improvement in V
OC, and under an optimal feed ratio of NRM‐1, an enhanced efficiency can be gained.
Abstract
Reducing energy loss (E
loss) is of critical importance to improving the photovoltaic performance of organic solar cells (OSCs). Although nonradiative recombination (Elossnonrad) is investigated in quite a few works, the method for modulating Elossnonrad is seldom reported. Here, a new method of depressing E
loss is reported for nonfullerene OSCs. In addition to ternary‐blend bulk heterojunction (BHJ) solar cells, it is proved that a small molecular material (NRM‐1) can be selectively dispersed into the acceptor phase in the PBDB‐T:IT‐4F‐based OSC, resulting in lower Elossrad and Elossnonrad, and hence a significant improvement in the open‐circuit voltage (V
OC); under an optimal feed ratio of NRM‐1, an enhanced power conversion efficiency can also be gained. Moreover, the role of NRM‐1 in the method is illustrated and its applicability for several other representative OSCs is validated. This work paves a new pathway to reduce the E
loss for nonfullerene OSCs.
12 Aug 02:10
by Jongho Ahn†, Sora Oh†§, HyunKyung Lee†, Sangjun Lee†, Chang Eun Song*‡§, Hang Ken Lee‡, Sang Kyu Lee†§, Won-Wook So‡, Sang-Jin Moon‡§, Eunhee Lim?, Won Suk Shin*†§?, and Jong-Cheol Lee*†§
ACS Applied Materials & Interfaces
DOI: 10.1021/acsami.9b09256
09 Aug 08:02
by Hartmut Yersin*, Larisa Mataranga-Popa, Rafal Czerwieniec, and Yan Dovbii
Chemistry of Materials
DOI: 10.1021/acs.chemmater.9b01168
08 Aug 05:52
by Xunchang Wang†‡, Keke Dou§, Bilal Shahid†‡, Zhilin Liu†, Yonghai Li*†, Mingliang Sun§, Nan Zheng*?, Xichang Bao*†, and Renqiang Yang*†
Chemistry of Materials
DOI: 10.1021/acs.chemmater.9b01957
08 Aug 05:50
by Jenna M. Franke†, Benjamin K. Raliski†, Steven C. Boggess†, Divya V. Natesan†, Evan T. Koretsky†, Patrick Zhang†, Rishikesh U. Kulkarni†, Parker E. Deal†, and Evan W. Miller*†‡§
Journal of the American Chemical Society
DOI: 10.1021/jacs.9b05912
08 Aug 02:40
by Ling Hong†§, Huifeng Yao*‡§, Runnan Yu‡§, Ye Xu‡§, Bowei Gao‡§, Ziyi Ge*†§, and Jianhui Hou*‡§
ACS Applied Materials & Interfaces
DOI: 10.1021/acsami.9b10243
08 Aug 02:36
by Dong Li†§, Xiang Wang‡§?, Zuzhang Lin†, Yuanhui Zheng†, Qianqing Jiang†, Naihang Zheng†§, Weifeng Zhang†, Kui-juan Jin*‡§?, and Gui Yu*†§
ACS Applied Materials & Interfaces
DOI: 10.1021/acsami.9b07863
08 Aug 02:35
by Jian Cao, Qi-Ming Liu, Si-Jie Bai, Hua-Chun Wang, Xiancheng Ren, and Yun-Xiang Xu*
ACS Applied Materials & Interfaces
DOI: 10.1021/acsami.9b07677
08 Aug 02:35
by Yuli Yin†, Zhi Zheng†, Yi Lu†, Daoyuan Chen†, Ming Liu†, Fengyun Guo†, Shiyong Gao†, Liancheng Zhao†, and Yong Zhang*†‡
ACS Applied Materials & Interfaces
DOI: 10.1021/acsami.9b07067
