Synergistic Effect of 2-(Trifluoromethyl) Benzimidazole on the Stability and Performance of Perovskite Solar Cells

Abstract

The quality of the perovskite active layer directly impacts the photovoltaic performance of perovskite solar cells (PSCs). Unfortunately, perovskite films produced through solution methods often have a significant number of defects on their surface, which lead to a substantial degradation in the performance of devices. For this reason, a multifunctional additive 2-(trifluoromethyl) benzimidazole (TFMBI) is introduced into perovskite films. Based on the Lewis acid/base coordination principle, the TFMBI double site cooperatively passivates surface defects, inhibiting carrier non-radiative recombination. Simultaneously, the hydrophobic solid group (−CF 3 ) of TFMBI covers the surface, establishing a moisture-oxygen barrier and improving the environmental stability of the devices. In consequence, the power conversion efficiency (PCE) of TFMBI-modified PSCs reached 23.16%, significantly higher than the pristine one with a PCE of 20.62%. Additionally, the unencapsulated target device retained 90.32% of its initial PCE even after being reserved in the air with a relative humidity of 20−30% for 60 days.

Surface-anchoring fluorinated sulfonate enables efficient and stable perovskite photovoltaics

“…4c and d, which was conducive to achieving an appropriate energy level match, facilitating the extraction/transportation of holes and gaining a higher V OC . 50,55–57 This was in agreement with the KPFM results. The Urbach energy ( E U ) measurement was used to probe the structural quantity and energy loss of perovskite films.…”

“…5h, upon TFS-TFMS modification, the PSCs delivered an elevated V bi from 0.93 to 1.05 V, indicating the robust driving force to separate and transfer photo-generated carriers, which was beneficial to improve the V OC of devices. 57,79 Furthermore, the interfacial carrier dynamic behaviors of PSCs were elucidated via electrochemical impedance spectroscopy (EIS). An equivalent circuit model was empirically fitted to the process of carrier transportation and recombination, corresponding to the charge transport capacitance ( C ct ) and transfer resistance ( R ct ) in high frequency arcs, and the carrier recombination capacitance ( C rec ) and recombination resistance ( R rec ) in low frequency arcs, respectively.…”

Donor–π–Acceptor Porphyrin-Assisted Bifunctional Defect Passivation for Enhanced Temporal Domain-/Wavelength-Dependent Nonlinear Absorption Properties in Perovskite Films

“…XPS technique was performed to characterize the surface chemical state of perovskite films and examine the interaction between the perovskite surface and porphyrin. As depicted in Figure a, the porphyrin-passivated films showcased two dominating peaks at 143.2 and 138.3 eV for MAPbI 3 /Por1 , 143.1 and 138.1 eV for MAPbI 3 /Por2 , and 142.7 and 137.9 eV for MAPbI 3 /Por3 , which correspond to the Pb 4f 5/2 and Pb 4f 7/2 , respectively, while the pristine film exhibits the binding energies for Pb 4f 5/2 at 143.4 eV and Pb 4f 7/2 at 138.5 eV . These shifts toward lower binding energies are observed in the films with porphyrin modification, suggesting a strong interaction between porphyrin and perovskite.…”

“…As depicted in Figure 3a, the porphyrin-passivated films showcased two dominating peaks at 143.2 and 138.3 eV for MAPbI 3 /Por1, 143.1 and 138.1 eV for MAPbI 3 /Por2, and 142.7 and 137.9 eV for MAPbI 3 /Por3, which correspond to the Pb 4f 5/2 and Pb 4f 7/2 , respectively, while the pristine film exhibits the binding energies for Pb 4f 5/2 at 143.4 eV and Pb 4f 7/2 at 138.5 eV. 39 These shifts toward lower binding energies are observed in the films with porphyrin modification, suggesting a strong interaction between porphyrin and perovskite. For the MAPbI 3 /Por1 film, the amino group of Por1 is protonated by MA + to form NH 3 + , which can accept electrons from 41 providing intuitive evidence for this coordination interaction between undercoordinated Pb 2+ within perovskite and the carboxyl group within porphyrin.…”

Preparation and performance testing of novel bendable optically transparent fluorinated hyperbranched linear long chain segment poly(amide-imide) films

“…5d). 58 The good hydrophobicity also provides favorable support for the stable dielectric constants of the PAI films.…”