High-Light-Tolerance PbI₂ Boosting the Stability and Efficiency of Perovskite Solar Cells

Abstract

Excess lead iodide (PbI2) plays a crucial role in passivating the defects of perovskite films and boosting the power conversion efficiency (PCE) of perovskite solar cells (PSCs). However, the photolysis of PbI2 is easily triggered by light illumination, which accelerates the decomposition of perovskite materials and weakens the long-term stability of PSCs. Herein, the high light tolerance of lead iodide (PbI2) is reported by introducing an electron-donor molecule, namely, 2-thiophenecarboxamide (2-TCAm), to strengthen the [PbX6]4– frame. Characterization reveals that the retarded decomposition of PbI2 is attributed to the interactions between Pb2+ and the organic functional groups in 2-TCAm as well as the optimized distribution of PbI2. The crystallization and morphology of 2-TCAm-doped perovskite films are improved simultaneously. The 2-TCAm-based PSCs achieve a 16.8% increase in PCE and nearly 12 times increase in the lifetime as compared to the reference device. The demonstrated method provides insight into the stability of PbI2 and its influence on PSCs.

From Structural Design to Functional Construction: Amine Molecules in High‐Performance Formamidinium‐Based Perovskite Solar Cells

“…One pair is conjugated with the two double bonds to form a delocalized π bond, and the other pair can form coordination bonds with Pb 2+ ions in perovskites. Thus, thiophenamine additives have been used in PSCs with the expectation of defect passivation and conductivity improvement [117–120] …”

From Structural Design to Functional Construction: Amine Molecules in High‐Performance Formamidinium‐Based Perovskite Solar Cells

“…However, there are still many heterocyclic molecules worth exploring, such as furan, pyrrole, piperidine, and their derivatives, since they may provide unimaginable possibilities for the development of highly stable and efficient PSCs. [117] Copyright 2021, American Chemical Society. c) Schematic representation of the TTMAI structure and illustration of the solar cell architecture.…”

“…One pair is conjugated with the two double bonds to form a delocalized π bond, and the other pair can form coordination bonds with Pb 2+ ions in perovskites. Thus, thiophenamine additives have been used in PSCs with the expectation of defect passivation and conductivity improvement [117–120] …”

“…[124] Copyright 2020, The Royal Society of Chemistry. bending cycles 2020 [114] 2-thiophenecarboxamide no in precursor (7.5 mg ml À 2021 [117] 2018 [125] 1-adamantylamine no post-treatment (1.5 mg ml À x 20.16 ambient, dark, ca. 87 % after 1000 h 2021 [120] 2-thiophenemeth- after 1000 h 2020 [124] cyclohexylammonium no post-treatment (5 mM IPA, additional 100 °C annealing for 3 min) FAPbI 3 24.98 ambient, dark, ca.…”

“…Thus, thiophenamine additives have been used in PSCs with the expectation of defect passivation and conductivity improvement. [117][118][119][120] Beside defect passivation, the interactions between S or N in thiophenamine molecules and Pb 2 + ions can strengthen the [PbX 6 ] 4À frame and hinder the ion migration and aggregation of PbI 2 , thereby leading to improved phase stability. For example, Chen et al introduced 2-thiophenecarboxamide (2-TCAm) to enhance the light tolerance of lead iodide (PbI 2 ) prepared in the first step.…”