研究目的

The research objective stands with the synthesis of novel and highly soluble D-A random copolymer, RCP-BTT, which could be used as HTM for PSCs. The RCP-BTT comprising, 2-ethylhexylalkyl side chain-substituted benzo[1,2-b:4,5-b’]dithiophene (BDT) as donor units and phenyl end-group functionalized 5-octyl-thieno[3,4-c]-pyrrole-4,6-diones (PhC8TPD) derivative and 2-ethylhexylalkyl-3-fluorinated thieno[3,4-b]thiophene-2-carboxylate (FTT) derivative as two different acceptor units.

研究成果

We report the design and synthesis of novel HTM based on RCP-BTT random copolymer, which demonstrated high efficiency in the PSC as compared to PTB7. The D-A random copolymer approach of RCP-BTT is derived from backbone structure of PTB7 to bring out deeper HOMO energy level and beneficial for hole extraction. RCP-BTT is highly soluble and exhibits excellent film formability with a very thin layer, which affords effective interfacial surface contact with perovskite. The RCP-BTT with deeper HOMO energy level has proven the enhancement in Voc by comparing the device performance with PTB7. Upon addition of dopants, the hole mobility of RCP-BTT is enhanced from ~10?5 cm2 V?1 s?1 to ~10?3 cm2 V?1 s?1 resulting from efficient charge carrier transport. The photovoltaic performances of RCP-BTT with dopant have established in the Voc of 1.09V, Jsc of 19.51 mAcm-2, FF of 69 % and delivered the efficiency of 14.57% with respect to dopant-free as well as PTB7 with dopant. Moreover, dopant-free RCP-BTT reveals good durability for compatible PSCs.

研究不足

The research limitations include the need for further tuning of physical and optoelectronics properties by choosing appropriate donor and acceptor in the PSC as well as other semiconducting applications.