Tautomeric Dual‐Site Passivation for Carbon‐Based Printable Mesoscopic Perovskite Solar Cells

Abstract

Although ionic conjugated passivation systems, such as ionic liquids (ILs), have been used to passivate perovskite in carbon‐based printable mesoscopic perovskite solar cells (FP‐PSCs), their tautomerism process and synergistic effect of multifunctional groups have not yet caused enough attention. In this work, a series of novel ILs including 1‐allyl‐3‐methylimidazole tetrafluoroborate ([AMIm]BF4) and 1‐benzyl‐3‐methylimidazole tetrafluoroborate ([BzMIm]BF4) used as passivants for FP‐PSCs are reported. Combining Fourier transform infrared spectroscopy, X‐ray photoelectron spectroscopy (XPS), and density functional theory (DFT) calculation, it is found that one of its tautomers (positive ion at the near end N atom of conjugated side chain) plays a key role on dual‐site simultaneous passivation. As the conjugation degree of side chain increases from allyl to benzyl, it not only effectively inhibits the non‐radiative charge recombination, but also reduces the passivation adsorption energy and increases the charge transfer rate. A high efficiency of 16.87% has been achieved with a high FF (>0.7), a Jsc of 23.88 mA cm–2 value and Voc value up to 1.0 V, by using the “tautomeric dual‐site passivation” strategy.

Machine learning-assisted screening of effective passivation materials for P–I–N type perovskite solar cells

“…After ITIC treatment, the characteristic Pb 4f 5/2, Pb 4f 7/2, N 1s and O 1s peaks all shift to higher binding energies. 48 This reveals that the CO groups and N atoms in ITIC interact with the uncoordinated Pb 2+ ions in the perovskite film, leading to the effective suppression of defects on the surface of the perovskite film. 49,50 Moreover, it is found that a new peak appeared in the ITIC-treated perovskite film, which comes from the S atoms in ITIC, indicating that ITIC is present on the surface of the perovskite film.…”

Chiral Molecular Environment Determining Selective Coordination of Cysteine to Perovskite Halogen Vacancies

“…In addition, no diffraction peaks appear at less than 10°, indicating that the L-or D-cysteine-treated MAPbI 3 perovskite crystals entirely consist of 3D phases. [35,37] As typical crystal planes of perovskite, (110), ( 220), (310), and (413) ones are located at 14.2°, 28.7°, 32.0°, and 43.3°, respectively. [33,36,37] Moreover, as shown in Figure S5, Supporting Information, the intensity of the diffraction peaks of (110), ( 220), (310), and (413) for L-cysteine-treated sample is higher than that of control and D-cysteine-treated one.…”

“…[35,37] As typical crystal planes of perovskite, (110), ( 220), (310), and (413) ones are located at 14.2°, 28.7°, 32.0°, and 43.3°, respectively. [33,36,37] Moreover, as shown in Figure S5, Supporting Information, the intensity of the diffraction peaks of (110), ( 220), (310), and (413) for L-cysteine-treated sample is higher than that of control and D-cysteine-treated one. Among them, that of control is the lowest.…”

EtOH/H2O ratio modulation on carbon for high-Voc (1.03 V) printable mesoscopic perovskite solar cells without any passivation

“…5 To further enhance their photovoltaic performances, extensive research studies have been conducted on the conductivity, energy level matching, hydrophobicity and specific surface area of carbon electrode materials. 6,7 For example, Prof. H. Han et al 8 have systematically optimized the flaky graphite component in the carbon electrode consisting of graphite and carbon black and obtained PCE exceeding 11% due to the low square resistance and large pore size of graphite-based electrodes, facilitating electron/hole separation in the photoelectric conversion process. Then, Y. Yang et al 9 made the first attempt to chlorinate the graphite component for carbon electrode materials to obtain chlorinated graphite (C-Cl x , x = 0.2, 0.4 and 0.6).…”