Browsing by Author "Chang, Shao-Ling"

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2-Dimensional cross-shaped tetrathienonaphthalene-based ladder-type acceptor for high-efficiency organic solar cells
(2020-06-28)
Chang, Shao-Ling
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Cao, Fong-Yi
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Huang, Kuo-Hsiu
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Lee, Wei-Liang
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Lee, Meng-Hsun
AnNC-FICnonfullerene acceptor, using a didodecylnaphthodithiophene (NDT) embedded octacyclic ladder-type donorNC, had been described previously. In this work, a new cross-shapedTC-FICnonfullerene acceptor is designed by substitution of the NDT unit in theNCskeleton with a 2-dimensional didodecyltetrathienonaphthalene (TTN) unit. The 2-dimensionalTC pi-system with two vertically fused thiophenes strengthens the electron-donating ability, promotes pi-electron delocalization and enhances intramolecular donor-acceptor charge transfer and intermolecular pi-pi interactions. As a result,TC-FICshows more red-shifted and widened absorption compared to theNC-FICcounterpart. The PBDB-T:TC-FICdevice exhibits a higher efficiency of 11.6% which greatly outperformed the corresponding PBDB-T:NC-FICdevice with an efficiency of 7.52%. The dramatic 54% enhancement in efficiency is ascribed to the improved light-harvesting ability and enhanced charge mobilities which are benefited from the central 2-dimensionalTTNmoiety. By incorporatingPC(71)BMto improve absorption and electron transport, the ternary-blend PBDB-T : TC-FIC : PC(71)BMdevice (1 : 1 : 1 in wt%) achieves a highest PCE of 13.49% with an enhancedJ(sc)of 23.80 mA cm(-2), an FF of 64.4%, and aV(oc)of 0.88 V.
Angular-Shaped 4,9-Dialkylnaphthodithiophene-Based Octacyclic Ladder-Type Non-Fullerene Acceptors for High Efficiency Ternary-Blend Organic Photovoltaics
(2018-08-14)
Cao, Fong-Yi
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Huang, Wen-Chia
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Chang, Shao-Ling
;
Cheng, Yen-Ju
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應用化學系
An angular-shaped 4,9-didodecylnaphthodithiophene-based octacyclic ladder-type structure was developed. This new ladder-type donor (LD) was coupled with electron withdrawing IC and FIC units to form two A-LD-A type non-fullerene acceptor materials, NCIC and NCFIC. NCIC and NCFIC as the n-type acceptors are blended with a p-type donor PBDB-T to form the complementary absorption and suitable energy level alignments. The binary-blend PBDB-T:NCIC and PBDB-T:NCFIC devices achieved an efficiency of 7.3% and 7.5%, respectively. PC71BM was incorporated to form D-1:A(1):A(2) ternary blends which further strengthen the absorption at shorter wavelengths. Introduction of PC71BM not only efficiently improves the absorption but also provides multiple channels for exciton dissociation and electron transport to dramatically improve J(sc). It is interesting to find that the V-oc of the ternary-blend devices is reversely in proportional to the added amount of PC71BM. The device using the PBDB-T:NCIC:PC71BM (1:1:1 in wt %) showed an improved PCE of 8.32%. Moreover, the optimized device using the PBDB-T:NCFIC:PC71BM (1:1:1.5 in wt %) blend achieved the highest efficiency of 9.18%.
Bispentafluorophenyl-Containing Additive: Enhancing Efficiency and Morphological Stability of Polymer Solar Cells via Hand-Grabbing-Like Supramolecular Pentafluorophenyl-Fullerene Interactions
(2017-12-20)
Hung, Kai-En
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Tsai, Che-En
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Chang, Shao-Ling
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Lai, Yu-Ying
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Jeng, U-Ser
A new class of additive materials bis(pentafluorophenyl) diesters (BFEs) where the two pentafluorophenyl (C6F5) moieties are attached at the both ends of a linear aliphatic chain with tunable tether lengths (BFS, BF7, and BF13) were designed and synthesized. In the presence of BF7 to restrict the migration of fullerehe by hand-grabbing-like supramolecular interactions induced between the C6F5 groups and the surface of fullerene, the P3HT:PC61BM:BF7 device showed stable device characteristiCs after thermal heating at 150 degrees C for 25, 'IL The morphologies Of the active layers were systematically investigated by optical microscopy, grazing-incidence small-angle X-ray scattering (GISAXS), and atomic force microscopy. The tether length between the two C6F5 groups plays a pivotal role in controlling the intermolecular attractions. BF13 with a long and flexible tether might form a BF13-fullerene sandwich complex that fails to prevent fullerene's movement and aggregation, while BF5 with too short tether length decreases the possibility of interactions between the C6F5 groups and the fullerenes. BF7 with the optimal tether length has the best ability to stabilize the morphology. In sharp contrast, the nonfluorinated BP7 analogue without C6F5-C-60 physical interactions does not have the capability of morphological stabilization, unambiguously revealing the necessity of the C6F5 group. Most importantly, the function of BF7 can be also applied to the high-performance PffBT4BT-20D:PC71BM system, which exhibited an original PCE of 8.80%. After thermal heating at 85 degrees C for 200 h, the efficiency of the Pffi3T4BT-20D:PC71BM:BF7 device only decreased slightly to 7.73%, maintaining 88% of its original efficiency. To the best of our knowledge, this is the first time that the thermabdriven morphological evolution of the high-performance PffBT4BT-20D polymer has been investigated, and its morphological stability in the inverted device can be successfully preserved by the incorporation of BF7. This research also demonstrates that BF7 is not only effective with PC61BM but also to PC71BM.
Forced coplanarity of dithienofluorene-based non-fullerene acceptors to achieve high-efficiency organic solar cells
(2019-08-14)
Cao, Fong-Yi
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Huang, Po-Kai
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Su, Yen-Chen
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Huang, Wen-Chia
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Chang, Shao-Ling
Ladder-type structures have been the key element for high performance non-fullerene acceptors (NFAs). In this work, two dithieno[3,2-b:6,7-b ']fluorine (DTF)-based nonfullerene acceptors, non-bridged DTFT5-FIC and carbon-bridged DTFT9-FIC, with an identical conjugated backbone were designed and synthesized for investigation of the planarization effect. The chemical rigidification with forced coplanarity indeed plays a pivotal role in determining the molecular properties. Compared to the non-bridged open-chain DTFT5-FIC counterpart, the nonacyclic ladder-type DTFT9-FIC with a fully planarized backbone exhibits higher thermal stability, bathochromic absorption and higher electron mobility. The devices using PBDB-T as the p-type polymer and fully planar DTFT9-FIC as the acceptor showed a high efficiency of 9.58%, which is superior to that of the device using the partially planar DTFT5-FIC material (5.45%). By incorporating PC71BM as the second acceptor to enhance the absorption at shorter wavelengths, optimize the morphology and facilitate electron transport, the ternary-blend device using PBDB-T:DTFT9-FIC:PC71BM achieved the highest PCE of 11.82% with a V-oc of 0.88 V, a higher J(sc) of 20.59 mA cm(-2), and an FF of 65.27%.
Haptacyclic Carbazole-Based Ladder-Type Nonfullerene Acceptor with Side-Chain Optimization for Efficient Organic Photovoltaics
(2017-12-06)
Hsiao, Yu-Tang
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Li, Chia-Hua
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Chang, Shao-Ling
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Heo, Soowon
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Tajima, Keisuke
In this research, a haptacyclic carbazole-based dithienocyclopentacarbazole (DTCC) ladder-type structure was formylated to couple with two 1,1-dicyanomethylene-3-indanone (IC) moieties, forming a new nonfullerene acceptor DTCCIC-C17 using a bulky branched 1-octylnonayl side chain at the nitrogen of the embedded carbazole and four 4-octylphenyl groups at the sp(3)-carbon bridges. The rigid and coplanar main-chain backbone of the DTCC core provides a broad light-absorbing window and a higher-lying LUMO energy level, whereas the bulky flanked side chains reduce intermolecular interactions, making DTCCIC-C17 amorphous with excellent solution processability. The DTCCIC-C17 as an acceptor is combined with a medium band gap polymer poly[(2,6-(4,8-bis(5-(2-ethylhexyl)thiophen-2-y1)-benzo[1,2-b:4,5-bldithiophene))-alt-(5,5-(1',3'-di-2-thieny1-5',7'-bis(2-ethylhexyl)benzo[1',2'-c:4',5'-c']dithiophene-4,8-dione))] (PBDB-T) as the donor in the active layer to obtain suitable highest occupied molecular orbital/lowest unoccupied molecular orbital energy alignments and complimentary absorption. The devices with an inverted configuration (ITO/ZnO/active layer/MoO3/Ag) without using an aqueous poly(3,4-ethylenedioxythiophene) polystyrene sulfonate layer were fabricated for better device stability. When the diiodooctane-treated PBDB-T:DTCCIC-C17 active layer was thermally annealed at 50 degrees C for 10 min, the device achieved the highest efficiency of 9.48% with a high V-oc of 0.98 V, a J(sc) of 14.27 mA cm(-2), and an FF of 0.68.
Highly Efficient Inverted D:A(1):A(2) Ternary Blend Organic Photovoltaics Combining a Ladder-type Non-Fullerene Acceptor and a Fullerene Acceptor
(2017-07-26)
Chang, Shao-Ling
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Cao, Fong-Yi
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Huang, Wen-Chia
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Huang, Po-Kai
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Hsu, Chain-Shu
A formylated benzodi(cyclopentadithiophene) (BD CPDT) ladder-type structure with forced coplanarity is coupled with two 1,1-dicyanomethylene-3-indanone (IC) moieties via olefination to form a non-fullerene acceptor, BDCPDT-IC. The BDCPDT-IC, as an acceptor (A(1)) with broad light-absorbing ability and excellent solution processability, is combined with a second PC71BM acceptor (A(2)) and a medium band gap polymer, PBDB-T, as the donor (D) to form a ternary blend with gradient HOMO/LUMO energy alignments and panchromatic absorption. The device with the inverted architecture using the D:A(1):A(2) ternary blend has achieved a highest efficiency of 9.79% with a superior J(sc) of 16.84 mA cm(-2).
Isomerically Pure Benzothiophene-Incorporated Acceptor: Achieving Improved V-oc and J(sc) of Nonfullerene Organic Solar Cells via End Group Manipulation
(2019-09-11)
Chang, Shao-Ling
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Hung, Kai-En
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Cao, Fong-Yi
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Huang, Kuo-Hsiu
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Hsu, Chain-Shu
Benzene-based 1,1-dicyanomethylene-3-indanone (IC) derivatives have been widely utilized as the end-group to construct acceptor-donor-acceptor type nonfullerene acceptors (A-D-A type NFAs). The extension of the end-group conjugation of nonfullerene acceptors (NFAs) is a rational strategy to facilitate intermolecular stacking of the end-groups which are responsible for efficient electron transportation. A bicyclic benzothiophene-based end-group acceptor, 2-(3-oxo-2,3-dihydro-1H-benzo[b]cyclopenta[d]thiophen-1-ylidene)malononitrile, denoted as alpha-BC was designed and synthesized. The Knoevenagel condensation of the unsymmetrical 1,3-diketo-precursor with one equivalent of malononitrile selectively reacts with the keto group attached at the alpha-position of the thiophene unit, leading to the isomerically pure benzothiophene-fused alpha-BC. The well-defined alpha-BC with extended conjugation was condensed with three different ladder-type diformylated donors to form three new A-D-A NFAs named BDCPDT-BC, DTCC-BC, and ITBC, respectively. The corresponding IC-based BDCPDT-IC, DTCC-IC, and ITIC model compounds were also synthesized for comparison. The incorporation of the electron-rich benzothiophene unit in the end-group upshifts the lowest unoccupied molecular orbital energy levels of the NFAs, which beneficially enlarges the V-oc values. On the other hand, the benzothiophene unit in alpha-BC not also imparts an optical transition in the shorter wavelengths around 340-400 nm for a better light harvesting ability but also promotes the antiparallel pi-pi stacking of the end-groups for efficient electron transport. The organic photovoltaic cell devices using a PBDB-T polymer and BC-based NFAs all showed the improved V-oc and J(sc) values. The BDCPDT-BC- and DTCC-BC-based devices exhibited a power conversion efficiency (PCE) of 10.82 and 10.74%, respectively, which outperformed the corresponding BDCPDT-IC-, and DTCC-IC-based devices (9.33 and 9.25%). More importantly, the ITBC-based device delivered the highest PCE of 12.07% with a J(sc) of 19.90 mA/cm(2), a V-oc of 0.94 V, and an fill factor of 64.51%, representing a 14% improvement relative to the traditional ITIC-based device (10.05%).
New Thieno[3,2-b]thiophene-Based Acceptor: Tuning Acceptor Strength of Ladder-Type N-Type Materials to Simultaneously Achieve Enhanced V-OC and J(SC) of Nonfullerene Solar Cells
(2018-07-01)
Chang, Shao-Ling
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Cao, Fong-Yi
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Huang, Wen-Chia
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Huang, Po-Kai
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Huang, Kuo-Hsiu
A new thieno[3,2-b]thiophene-incorporated acceptor TTC has been developed. The TTC acceptor was installed in a haptacyclic ladder-type core (BDCPDT) to furnish an n-type BDCPDT-TTC. The standard PBDB-T:BDCPDT-IC device showed a PCE of 9.33% with a V-OC of 0.86 V and a J(SC) of 16.56 mA/cm(2). By molecular engineering of the acceptor unit, the BDCPDT:PBDB-T-based device delivered an enhanced efficiency of 10.29% with a simultaneously enhanced V-OC of 0.94 V and J(SC) of 17.72 mA/cm(2). Incorporation of the electron-donating thieno[3,2-b]thiophene unit into the acceptor moiety decreases the electron accepting strength, thereby upshifting the HOMO/LUMO energy levels to decrease the Delta E-HOMO and E-LOSS achieving a larger Voc. Second, the extended conjugated bicyclic thieno[3,2-b]thiophene ring beneficially induces an additional optical transition at short wavelengths, leading to improvement of J. Alternatively, BDCPDT-FIC installed with the fluorinated acceptor shows more red-shifted absorption to achieve a high J of 19.12 mA/cm(2).
Synthesis and Molecular Properties of Two Isomeric Dialkylated Tetrathienonaphthalenes
(2016-02-05)
Chang, Shao-Ling
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Lu, Chih-Wen
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Lai, Yu-Ying
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Hsu, Jhih-Yang
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Cheng, Yen-Ju
Isomeric 2,8-distannyl 5,11-didodecyl alpha/beta-TTN (1, tetrathienonaphthalene = TTN) and 2,8-didodecyl 5,11-distannyl alpha beta-TTN (2) have been designed and successfully synthesized. The naphthalene core structures in alpha beta-TTNs were constructed by a systematic protocol using PtCl2-catalyzed cyclization followed by oxidative Scholl annulation in good yields. Compared to the one-dimensional naphthodithiophene derivatives, the two-dimensional alpha beta-TTN molecules showed good solubility, extended conjugation, strong absorptivity, and highly coplanar structures. Compounds 1 and 2 were polymerized with a 5,5\'-dibromo-2,2\'-bithiophene-based monomer to afford 2,8-alpha beta-PTTNTT and 5,11-alpha beta-PTTNTT copolymers. 2,8-alpha beta-PTTNTT with the alpha-aNDT moiety in the main chain exhibited a higher hole mobility of 1.26 X 10(-2) cm(2) V-1 s(-1).