Novel Push-Pull Benzodithiophene-Containing Polymers as Hole-Transport Materials for Efficient Perovskite Solar Cells

Abstract

Donor-acceptor conjugated polymers are considered advanced semiconductor materials for the development of thin-film electronics. One of the most attractive families of polymeric semiconductors in terms of photovoltaic applications are benzodithiophene-based polymers owing to their highly tunable electronic and physicochemical properties, and readily scalable production. In this work, we report the synthesis of three novel push–pull benzodithiophene-based polymers with different side chains and their investigation as hole transport materials (HTM) in perovskite solar cells (PSCs). It is shown that polymer P3 that contains triisopropylsilyl side groups exhibits better film-forming ability that, along with high hole mobilities, results in increased characteristics of PSCs. Encouraging a power conversion efficiency (PCE) of 17.4% was achieved for P3-based PSCs that outperformed the efficiency of devices based on P1, P2, and benchmark PTAA polymer. These findings feature the great potential of benzodithiophene-based conjugated polymers as dopant-free HTMs for the fabrication of efficient perovskite solar cells.

Remarkable Enhancement of Hole Mobility of Novel DA‐D’‐AD Small Molecules by Thermal Annealing: Effect of the D’‐Bridge Block.

“…Synthesis of benzodithiophene-based compounds 10-13 was described in details in our previous work. [21] Small molecules were purified by standard column chromatography using silica and a mixture of hexane and toluene as eluent. Finally, all compounds were precipitated from toluene with cold ethanol.…”

“…Synthesis of benzodithiophene‐based compounds 10 – 13 was described in details in our previous work [21] …”

“…Therefore, easy processing along with modulation of properties of OSMs by molecular design allows to fabricate various electronic devices such as organic solar cells, [4] organic photodetectors, [5,6] and organic field‐effect transistors [7] with desired functions. In the last decade, organic semiconductors with conjugated backbone structure have also found application in perovskite solar cells as dopant‐free hole‐ or electron‐transport materials [8,9] …”

Hole-transporting interlayers based on pyrazine-containing conjugated polymers for perovskite solar cells

“…Monomer BDT was obtained by the method reported previously. 22 The detailed synthetic procedures and characterization are described in the Experimental section (NMR spectra are presented in Fig. S1-S12, ESI †).…”

“…In our previous work, three (X-ADA) n benzodithiophene-containing ( BDT ) polymers have been designed and investigated as HTMs in n–i–p PSCs. 22 We showed that the introduction of triisopropylsilyl side chains into the benzodithiophene X block provides better film-forming properties and increased charge carrier mobility of the resulting polymer compared to the polymeric HTMs consisting of alkyl- or alkoxy-substituted BDT blocks. The best cells with the BDT -based HTM yielded a PCE of ca.…”