Downwards tuning the HOMO level of polythiophene by carboxylate substitution for high open-circuit-voltage polymer solar cells
Downwards tuning the HOMO level of polythiophene by carboxylate substitution for high open-circuit-voltage polymer solar cells
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DOI：
10.1039/c1py00327e
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发表时间：
2011-11
影响因子：
4.6
通讯作者：
Maojie Zhang;Xia Guo;Yang Yang-Yang;Jing Zhang;Zhiguo Zhang;Yongfang Li
中科院分区：
文献类型：
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作者：
Maojie Zhang;Xia Guo;Yang Yang-Yang;Jing Zhang;Zhiguo Zhang;Yongfang Li
采用钯催化的Stille偶联方法，对聚噻吩的最高占据轨道（HOMO）进行了下调，合成了三种含羧酸酯取代基的聚噻吩衍生物PT-C1、PT-C2和PT-C3。该聚合物显示出与区域规整的聚（3-己基噻吩）（P3 HT）相似的可见吸收光谱。通过连接羧酸酯取代基，与（ca. -4.8 eV）。以这三种聚合物为给体、PC 70 BM为受体的聚合物太阳能电池（PSC）均表现出较高的开路电压（Voc），约为1.5V。0.8基于PT-C3：PC 70 BM = 1：1.5（w/w）的PSC的功率转换效率（PCE）达到3.87%，其中Voc = 0.78 V，短路电流（Jsc）为9.68 mA cm-2，并且在AM 1.5，100 mW cm-2的照明下填充因子（FF）为51.2%。这些结果表明，连接羧酸酯取代基是一种简单而有效的方法来调节聚噻吩衍生物的能级，PT-C3是一种有前途的PSC供体材料。
Three polythiophene derivatives with carboxylate substituents, PT–C1, PT–C2 and PT–C3 were synthesized by the Pd-catalyzed Stille-coupling method, for downwards tuning of the highest occupied molecular orbital (HOMO) of polythiophene. The polymers show similar visible absorption spectra to that of regioregular poly(3-hexylthiophene) (P3HT). By attaching the carboxylate substituent, the HOMO energy level downwards shifted to −5.15, −5.11 and −5.10 eV for PT–C1, PT–C2 and PT–C3, respectively, in comparison with that (ca. −4.8 eV) for P3HT. The polymer solar cells (PSCs) based on the three polymers as donor and PC70BM as acceptor all exhibit relatively high open circuit voltage (Voc) of ca. 0.8 V. The power conversion efficiency (PCE) of the PSCs based on PT–C3: PC70BM = 1 : 1.5 (w/w) reached 3.87% with Voc = 0.78 V, short circuit current (Jsc) of 9.68 mA cm−2 and fill factor (FF) of 51.2% under the illumination of AM1.5, 100 mW cm−2. These results indicate that attaching the carboxylate substituent is a simple and effective way to modulate energy levels of polythiophene derivatives and PT–C3 is a promising donor material for PSCs.