Zwitterions for Organic/Perovskite Solar Cells, Light‐Emitting Devices, and Lithium Ion Batteries: Recent Progress and Perspectives

Abstract

are covalently bonded and their unique characteristics enable them to demonstrate special performance in applications and distinguish them from other conventional organic salts. [12][13][14] Recently, a significant attention has been paid to the use of zwitterions owing to their solubility in polar solvents for solution processing, [15][16][17] and dipole formation for the transfer of carriers [18][19][20] and ions. [21][22][23] Zwitterions have emerged as alternatives to the widely used building blocks such as conventional ionic groups, for developing new functional materials. The presence of both negative and positive ions in the same molecule enables zwitterions to develop interfacial dipole. The ability of zwitterions to develop interfacial dipole provides a new pathway to utilize them as interfacial layer in optoelectronic devices, including organic solar cells (OSCs), perovskite solar cells (PVSCs), and organic light-emitting devices (OLEDs), as well as electrolyte additives for energy devices such as lithium ion batteries (LIBs).It is well known that the ability to transport the charge carriers between the electrodes and organic layers is very crucial to obtain highly efficient electronic devices. [24] A mismatch between the energy levels of organic layers and inorganic electrodes leads to the generation of an energy barrier that hampers the extraction or injection of charge carriers. [25] To get rid of this obstacle, an interlayer between the electrodes and organic layers is applied to facilitate the transfer of charges in organic devices. In OLEDs, interlayers are used to enhance charge injection and reduce the height of Schottky barrier. While in the case of OSCs and PVSCs, apart from the enhancement in charge injection, they also play an important role to increase the built-in electric field across the active layer, ensuring efficient extraction of photogenerated charge carriers. [26][27][28][29][30] Therefore, the design and development of effective interlayer materials for interfacial modification are crucial for high-performance electronic devices. Recently, some significant advances have been demonstrated by applying an interfacial layer between the electrodes and organic layers, resulting in power conversion efficiencies (PCEs) to exceed 14% for single-junction OSCs by choosing appropriate photoactive layer. [31,32] Among different interlayer materials used so far, zwitterionic materials have been proved Zwitterions, a class of materials that contain covalently bonded cations and anions, have been extensively studied in the past decades owing to their special features, such as excellent solubility in polar solvents, for solution processing and dipole formation for the transfer of carriers and ions. Recently, zwitterions have been developed as electrode modifiers for organic solar cells (OSCs), perovskite solar cells (PVSCs), and organic light-emitting devices (OLEDs), as well as electrolyte additives for lithium ion batteries (LIBs).With the rapid advances of zwitterionic materials, high-performan...

Zwitterionic Sulfobetaine Hydrogel Electrolyte Building Separated Positive/Negative Ion Migration Channels for Aqueous Zn‐MnO2 Batteries with Superior Rate Capabilities

“…Polyzwitterions are a type of charged polymer bearing unique zwitterionic groups in a repeat unit, which generally exhibit high water retention abilities and solubilities. [ 8,9 ] The polyzwitterions have attracted considerable interest as potential biocompatible materials. [ 10,11 ] Owing to their high hydration ability and neutral surface charge considering the zwitterionic structure, sulfobetaine polymers exhibit high resistances to nonspecific protein adsorptions.…”

Ion transport mechanisms in salt‐doped polymerized zwitterionic electrolytes

“…Zwitterions (ZIs) are small molecule ampholytes, or covalently bonded cations and anions, of zero net charge . Their ionic properties and hydrophilicity have made them targets for use in organic electronics, catalysis, battery electrolytes, surfactants, drug‐delivery, and antifouling coatings, among other applications .…”

“…Zwitterions (ZIs) are small molecule ampholytes, or covalently bonded cations and anions, of zero net charge . Their ionic properties and hydrophilicity have made them targets for use in organic electronics, catalysis, battery electrolytes, surfactants, drug‐delivery, and antifouling coatings, among other applications . ZI‐incorporated polymers (polyZIs) have also been investigated as novel materials for chromatography, drug‐delivery, self‐assembled microstructures, and battery electrolytes …”

A Short Review on Interface Engineering of Perovskite Solar Cells: A Self‐Assembled Monolayer and Its Roles

“…Additionally, the dipole formed by zwitterions is stable because the negative and positive ions are covalently bonded to each other . Given this interesting nature, the zwitterion offers a new approach that can be used to modify the interface and improve interfacial properties of various optoelectronic devices such as organic solar cells and PSCs . Thus, studies introducing zwitterionic SAMs into PSCs are being performed to improve organic and inorganic CTL electrical properties and form a desirable morphology for high‐efficiency devices.…”