TIPS修饰的二噻并苯并二噻吩基太阳能电池材料研究

Study of Solar CellMaterials based on TIPS-modified Dithieno[2,3-d∶2′,3′-d′]benzo[1,2-b∶4,5-b′]dithiophene Unit

以5,10-双[三异丙基硅乙炔基]二噻并[2,3-d∶2′,3′-d′]苯并[1,2-b∶4,5-b′]二噻吩作给电子单元、苯并三氮唑(BTz)/异靛蓝(ID)作缺电子单元,合成两个D-A型交替共聚物:PDTBDT-TIPS-BTz和PDTBDT-TIPS-ID,并对其热稳定性、吸收特性、能级、分子构型和光伏性能进行了研究.一方面,TIPS侧基的引入大幅度降低了材料的HOMO能级,提高太阳能电池的开路电压;另一方面,强缺电子单元ID引入到D-A交替共聚物主链,明显降低带隙、拓宽了吸光范围.太阳能电池器件测试结果显示:PDTBDT-TIPS-ID表现出相对较高的能量转化效率2.92%,是PDTBDT-TIPS-BTz的1.77倍,这些提高主要得益于窄带隙材料能够更好地吸收太阳光.

Two donor-acceptor type alternatingcopolymers,namely,PDTBDT-TIPS-BTzandPDTBDT-TIPS-ID,were designed and synthesized,respectively,utilizing dithieno[2,3-d∶2′,3′-d′]benzo[1,-b∶4,5-b′]dithiophene（DTBDT）modified by triisopropylsilylethynyl（TIPS）as donor unit,benzotriazole（BTz）and/orisoindigo（ID）as acceptor moiety.The thermostability,absorption,energy level,molecular configuration and photovoltaic performance of these two materials were further investigated.On the one hand,the introduction of TIPS side chain into backbone of polymer main chain decreased greatly the highest occupied molecular orbital（HOMO）energy level and further enhance the open circuit voltage（VOC）.On the other hand,the ID unit with much stronger withdrawing-electron ability than that of BTz was selected as acceptor part in D-A structure,which could reduce the optical bandgap and broaden the absorption range.The solar cell device based on PDTBDT-TIPS-ID exhibited the higher power conversion efficiency（PCE）of 2.92%,which was 1.77 times higher than that of PDTBDT-TIPS-BTz.The enhanced PCE was as-cribed to the increase of the short circuit density（JSC）which was benefited from the capturing more sunlight of low bandgap material PDTBDT-TIPS-ID.