Modulation of Perovskite Grain Boundaries by Electron Donor–Acceptor Zwitterions R,R-Diphenylamino-phenyl-pyridinium-(CH₂)_n-sulfonates: All-Round Improvement on the Solar Cell Performance

Abstract

Inverted perovskite solar cells (PSCs) have attracted intense attention because of their insignificant hysteresis and low-temperature fabrication process. However, the efficiencies of inverted PSCs are still inferior to those of commercialized silicon solar cells. Also, the poor stability of PSCs is one of the major impedances to commercialization. Herein, we rationally designed and synthesized a new series of electron donor ( R , R -diphenylamino) and acceptor (pyridimium-(CH 2 ) n -sulfonates) zwitterions as a boundary modulator and systematically investigated their associated interface properties. Comprehensive physical and optoelectronic studies verify that these zwitterions provide a four-in-one functionality: balancing charge carrier transport, suppressing less-coordinated Pb 2+ defects, enhancing moisture resistance, and reducing ion migration. Although each functionality may have been reported by specific passivating molecules, a strategy that simultaneously regulates the charge-transfer balance and three other functionalities has not yet been developed. The results are to make an omnidirectional improvement of PSCs. Among all zwitterions, 4-(4-(4-(di-(4-methoxylphenyl)amino)phenyl)propane-1-ium-1-yl)butane-1-sulfonate (OMeZC3) optimizes the balance hole/electron mobility ratio of perovskite to 0.91, and the corresponding PSCs demonstrate a high power conversion efficiency (PCE) of up to 23.15% free from hysteresis, standing out as one of the champion PSCs with an inverted structure. Importantly, the OMeZC3-modified PSC exhibits excellent long-term stability, maintaining almost its initial PCE after being stored at 80% relative humidity for 35 days.

Effect of an Aromatic Sulfonate Ligand on the Photovoltaic Performance of Molybdenum Cluster-Sensitized Solar Cells

“…The sulfonate acceptors on NS in MINS possibly accelerate the recombination rate of the excited electrons, causing a slight decrease in the emission lifetime with different amounts of NS. The sulfonate functional group has already been investigated as an acceptor to balance the charge carrier transport, enhance the moisture resistance, and reduce the migration of photosensitizers for enhancing the performances of perovskite solar cells. , …”

“…The sulfonate functional group has already been investigated as an acceptor to balance the charge carrier transport, enhance the moisture resistance, and reduce the migration of photosensitizers for enhancing the performances of perovskite solar cells. 50,51 In order to deeply understand how the charge recombination on the Mo 6 cluster occurs on the interface of the photoelectrode, the luminescence lifetimes of the MI and nonisolated MINS clusters homogeneously deposited on the mesoporous TiO 2 photoelectrode were investigated (Figure 4c). As demonstrated in Table 1, the LUMO energies of MI and MINS are −3.48 eV, which are compatible with the injection into the CB at −4.0 eV of TiO 2 .…”

Multifunctional chemical anchors achieve a boosted fill factor and mitigate ion migration of high-stability perovskite solar cells

“…On the one hand, the functional bond in passivators can only effectively interact with a single type of charge defect in perovskites. Consequently, several passivation agents with zwitterions, namely both negatively and positively charged chemical anchors, such as OMeZC3 16 with both Pb-O bond and CH-anion interactions, dapsone 4,4′-diaminodiphenyl sulfone 10 with both the OvSvO group and the -NH 2 group, and 1-amino pyridine iodine (AmPyI) 17 with an amino functional group and N-point, have been proved to inactivate the ionic defects in the surface or GBs of perovskite layers. On the other hand, some passivators, such as polymers, are insulants, which may have a detrimental influence on carrier transport in PSCs.…”

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

“…Although perovskite exhibits excellent optoelectronic properties, its further development is hindered by various ionic defects generated during the crystallization process, such as positive vacancy defects caused by I – loss and negative vacancy defects generated by the escape of organic cations . These defects easily beget diverse trap states that trap normal electrons, hindering the transport of charge carriers, which results in nonradiative charge recombination and energy loss. , Moreover, the defects would also allow air and water in the external environment to infiltrate the perovskite lattice and induce the degradation of the perovskite inorganic octahedral lattice, thereby resulting in deterioration of the optoelectronic properties of perovskites, especially the NLO properties . Thus, addressing perovskite defects to improve the structural stability of perovskites has become a pressing problem to be solved for developing such NLO materials and constructing high-performance perovskite-based photonic devices.…”