Gradual Fluorination on the Phenyl Side Chains for Benzodithiophene-Based Linear Polymers to Improve the Photovoltaic Performance
Gradual Fluorination on the Phenyl Side Chains for Benzodithiophene-Based Linear Polymers to Improve the Photovoltaic Performance
复制标题
苯并二噻吩基线性聚合物的苯基侧链逐渐氟化以提高光伏性能
DOI：
10.1021/acsami.0c07720
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发表时间：
2020
影响因子：
9.5
通讯作者：
Erjun Zhou
中科院分区：
文献类型：
--
作者：
Peng Lei;Bao Zhang;You Chen;Yanfang Geng;Qingdao Zeng;Ailing Tang;Erjun Zhou
为了研究在苯并[1,2-b:4,5-b ']二噻吩（BDT）基共聚物的共轭苯基侧链上引入氟原子的影响，设计并合成了三种新的给π -受体（D - π-A）替代聚合物spe40、PE42和pe44。苯基取代的bdt、噻吩[3,2-b]噻吩和苯并[d][1,2,3]三唑（BTA）分别作为给体、π桥和受体单元，形成线性聚合物骨架。当在pe40的苯基侧单元中引入两个或四个氟原子时，聚合物spe42和pe44在原始和混合薄膜中表现出能级逐渐降低和结晶度增加。氟原子的增加逐渐改善了以Y6为受体的聚合物太阳能电池的性能参数。pe40:Y6器件的功率转换效率（PCE）高达7.07%，短路（JSC）为21.36 mA cm-2，开路VOC为0.65 V，填充因子（FF）为0.51，pe42:Y6的PCE较好，为10.11% (JSC= 23.25 mA cm-2，VOC= 0.74 V, FF = 0.59)， pe44:Y6的PCE最好，为13.62% （JSC= 25.29 mA cm-2，VOC= 0.82 V, FF = 0.66）。合适的供体和受体之间的能量偏移，高且平衡的载流子迁移率，以及最佳的共混膜形态是pe44:Y6组合的高性能的原因。我们的研究结果表明，在BDT的苯基单元上引入更多的氟原子是打破voc、JSC和FF之间权衡的一种有前景的方法，最终提高PSCs的性能。
To study the impact of introducing fluorine atoms onto the conjugated phenyl side chains of benzo[1,2-b:4,5-b′]dithiophene (BDT)-based copolymers, three novel donor−π–acceptor (D−π–A) alternative polymersPE40,PE42, andPE44were designed and synthesized. The phenyl-substituted-BDT, thieno[3,2-b]thiophene, and benzo[d][1,2,3]triazole (BTA) served as the donor, π-bridge, and acceptor units, respectively, to enable linear polymer backbones. When introducing two or four fluorine atoms into the phenyl side units ofPE40, the polymersPE42andPE44demonstrate a gradual decrease of energy levels and an increase of crystallinity in the pristine and blend films. It was noted that the increase in fluorine atoms gradually improved the performance parameters of polymer solar cells (PSCs) with Y6 as the acceptor. ThePE40:Y6 device yielded a power conversion efficiency (PCE) of up to 7.07% with a short-circuit (JSC) of 21.36 mA cm–2, an open-circuVOC) of 0.65 V, and a fill factor (FF) of 0.51, andPE42:Y6 exhibited a better PCE of 10.11% (JSC= 23.25 mA cm–2,VOC= 0.74 V, and FF = 0.59), whilePE44:Y6 exhibited the best PCE of 13.62% (JSC= 25.29 mA cm–2,VOC= 0.82 V, and FF = 0.66). The suitable energy offsets between the donor and the acceptor, high and balanced charge-carrier mobility, and the optimal morphology of the blend film contributed to the high performance ofPE44:Y6 combination. Our results demonstrate that introducing more fluorine atoms onto the phenyl side units of BDT is a prospective approach to break the trade-offs betweenVOC,JSC, and FF, and finally improve the performance of PSCs.