Triarylamine-Functionalized Imidazolyl-Capped Bithiophene Hole Transporting Material for Cost-Effective Perovskite Solar Cells

Abstract

Triarylamine end-capped-functionalized arylene-imidazole derivatives were synthesized from readily accessible, inexpensive precursors and employed as hole transporting materials (HTMs) in perovskite solar cells (PSCs). All the HTMs displayed high thermal decomposition temperatures (>410 °C), which is beneficial for realizing stable PSC devices. In addition, the new HTMs show appropriate energy level alignment with the perovskite layer, ensuring efficient hole transfer from perovskites to HTMs. Interestingly, PSCs fabricated with the triarylamine-functionalized imidazolyl-capped bithiophene molecule (DImBT-4D) as the HTM exhibited the best power conversion efficiency of 20.11%, comparable to that of the benchmark HTM spiro-OMeTAD, prompting it be a prospective candidate for large-scale PSC applications.

Triphenylamine (TPA)‐Functionalized Structural Isomeric Polythiophenes as Dopant Free Hole‐Transporting Materials for Tin Perovskite Solar Cells

“…The HOMO energy level of each polymer versus NHE is estimated by adding 4.44 eV to the oxidation potential. [ 52 ] The values of the HOMO levels of 1–5 obtained from the oxidation potentials are thus −5.26, −5.30, −5.30, −5.31, and −5.35 eV, respectively. Note, all the new TPA‐functionalized polythiophenes possess higher HOMO energies than poly‐TPD.…”

Recent studies on small molecular and polymeric hole‐transporting materials for high‐performance perovskite solar cells

“…In addition, the new HTMs show appropriate energy level alignment with the perovskite layer, ensuring efficient hole transfer from perovskites to HTMs. The simple synthesis of the HTM and the relatively low cost of the materials could contribute toward the commercialization of PSCs [100]. Recently, we designed and developed isomeric HTMs by altering the position of the imidazole group over the bithiophene central core.…”

Design and synthesis of multifaceted dicyanomethylene rhodanine linked thiophene: a SnOx–perovskite dual interface modifier facilitating enhanced device performance through improved Fermi level alignment, defect passivation and reduced energy loss

“…SnO x and perovskite energy levels were taken from reported literature. 52,53 The energy levels of the AA6 molecule were obtained by adopting the measurement procedure earlier reported by Abate et al 54 and Nazeeruddin et al 55 These values were then used for constructing PSC energy levels as shown in Fig. 5a.…”