Synthesis and properties of 3,4‐dioxythiophene and 1,4‐dialkoxybenzene based copolymers via direct CH arylation: Dopant‐free hole transport material for perovskite solar cells

Abstract

Direct C H arylation coupling reaction has gained significant importance in synthesis of conjugated polymers for organic electronic applications. We report here a facile and straightforward method called "direct C H arylation" reaction to synthesize conjugated 3,4-dioxythiophene and 1,4-dialkoxybenzene based copolymers as hole transport material (HTM) for perovskite solar cells. Two electron-rich conjugated polymers P1-2 were synthesized, in which 1,4-dibromo-2,5-bis(dodecyloxy)benzene and 3,4-dialkoxy-thiophene units were used for polymerization. The resulting polymers were characterized and exhibited high solubility in organic solvents. Electrochemical and optical characterizations were carried out by cyclic voltammetry and UV-Vis-NIR absorption spectroscopy and found that these polymers show higher-lying HOMO energy levels with wide band gap. Density functional theory calculation was performed on these polymers (P1-2) and correlated with our experimental results. Finally, perovskite solar cells were fabricated by solution-processable deposition of P1-2 as dopant-free HTM with device geometry ITO/SnO 2 /Perovskite/HTM(P1/P2)/Ag and achieved a maximum power conversion efficiency of 5.28%. This study provides information on designing and simple preparation by direct C H arylation reaction of higher-lying HOMO energy level polymer as HTM for perovskite solar cells.

Underlying Interface Defect Passivation and Charge Transfer Enhancement via Sulfonated Hole-Transporting Materials for Efficient Inverted Perovskite Solar Cells

“…Most of the reported polymeric HTMs struggle to be truly cost-effective due to the usage of noble metal catalysts during a synthetic process. − Remarkably, the newly developed polymeric HTMs can be obtained by a cheap synthetic route via the Wittig–Hornor reaction (Scheme ) without any precious metal catalysts, which only cost 4–5$ g –1 in laboratory synthesis (Table S1). The 1 H NMR and 13 C NMR spectra are shown in Figures S1–S10.…”

Oxidation of Spiro-OMeTAD in High-Efficiency Perovskite Solar Cells

“…Therefore, seeking to address this issue, the development of new HTMs restricting the use of dopants is highly needed. Hence, dopant-free HTMs − that are able to transport holes without any doping are currently under investigation. The following properties are generally required to obtain high-performance dopant-free HTM devices: (i) appropriate HOMO and LUMO energy levels to guarantee good hole extraction and electron blocking; (ii) excellent hole mobility and conductivity to suppress the need of dopants; (iii) good chemical and thermal stability; (iv) excellent film-processing ability and morphological stability.…”

Electrochemical copolymerization of 3,4-ethylenedioxythiophene and dithienothiophene: influence of feed ratio on electrical, optical and electrochromic properties

“…In continuation of our work on the conjugated copolymers, 39–44 three copolymers based on PEDOT and PDTT were synthesized by using different feed ratios of monomers EDOT and DTT as 2 : 1, 1 : 1 and 1 : 2, respectively. Copolymer films were electrodeposited on the ITO-coated glass surface by electrochemical oxidation of monomers EDOT and DTT, via electro-copolymerization method in 0.1 M TBAClO 4 /MeCN solution.…”