Merocyanine with Hole-Transporting Ability and Efficient Defect Passivation Effect for Perovskite Solar Cells

Abstract

Development of charge-transporting molecules that can simultaneously passivate multiple surface defects of perovskites is highly desirable for further performance increase of perovskite solar cells (PVSCs). Herein, we describe a simple strategy for designing a passivation molecule with good hole mobility based on conjugated merocyanine dye. Remarkably, we reveal that merocyanine with zwitterionic resonance structure character in the ground state can efficiently passivate the deep-level defects such as lead/iodide vacancies and eliminate the negative effects of neutral iodine defects, leading to an effective reduction of charge recombination and a preferred band bending at the surface of the perovskite film for hole extraction. Therefore, a significant increase in power conversion efficiency (PCE) from 19.78% to 22.04% is achieved for the dye-treated conventional n-i-p PVSCs. Our work shows a new molecular platform for designing efficient defect passivation molecules for perovskites.

Efficient and Stable Carbon‐Based CsPbIBr2 Perovskite Solar Cells by 4‐Aminomethyltetrahydropyran Acetate Modification

“…At last, transient photovoltage (TPV; Figure 6c) and transient photocurrent (TPC; Figure 6d) measurements were also performed. [ 49–50 ] TPV measurement is performed under open‐circuit conditions, so its decay kinetics is mainly related the carrier lifetime produced by recombination. After 4‐AMTHP‐Ac modification, the charge recombination lifetime increases significantly from 0.182 to 0.621 ms.…”

Methylthiophene terminated D–π–D molecular semiconductors as multifunctional interfacial materials for high performance perovskite solar cells

“…The slower photovoltage decay rate of the SIM-containing devices indicates that charge carrier recombination is effectively suppressed, which has a positive effect on enhancing V OC . 62,63 The photocurrent decay shows a reverse trend relative to that of the photovoltage. The faster photocurrent decay of the SIMcontaining devices can be ascribed to the higher charge extraction efficiency.…”

Wide Bandgap Interface Layer Induced Stabilized Perovskite/Silicon Tandem Solar Cells with Stability over Ten Thousand Hours

“…In contrast to the pristine perovskite, the Fermi level ( E f = hν − E cutoff ) of the perovskite film with CsBr interface layer improved from −5.05 to −4.99 eV, which is conducive to boosting the built‐in electric field of the device and further enhancing the V OC . According to the formula: VBM = −(21.22 − E cutoff + E i ), [ 52,53 ] the calculated VBM of the film with CsBr interface layer raised from −5.758 to −5.611 eV, whereas the VBM of the intrinsic Spiro‐TTB is −5.046 eV based on Figure 3d,e, more moderate energy level gradient between perovskite and HTL can promote carrier extraction tends to be faster, and the recombination at the interface will also be alleviated.…”