Conjugated polyelectrolytes: Interlayers for perovskite optoelectronic devices

Metal halide perovskites (MHPs) have attracted significant interest in optoelectronic research due to their exceptional magnetic, electrical, and optical properties. These materials are widely used in various applications such as photovoltaics, light-emitting diodes (LEDs), lasers, photodetectors, field-effect transistors, and solar concentrators. Particularly notable is their application in light-emitting devices, offering high color purity, extensive color tunability, cost-effective manufacturing, and compatibility with solution processing. Perovskite LEDs (PeLEDs) utilizing MHPs exhibit remarkable external quantum efficiencies (EQEs) exceeding 20% in the green, red, and near-infrared spectra. Additionally, perovskite solar cells (PeSCs) have gained attention for their solution processability, customizable band gaps, high absorption coefficients, and long carrier diffusion lengths, resulting in power conversion efficiencies (PCEs) surpassing 26%, comparable to crystalline silicon solar cells. To enhance the performance and stability of PeLEDs and PeSCs, the incorporation of appropriate charge transport layers (CTLs) and/or interlayers is crucial. These layers require suitable energy levels to facilitate efficient charge injection and transport while blocking opposite charges. Moreover, an interlayer based on ionic conjugated molecules can mitigate ion migration by chemically capturing halide and metal ions through electrostatic coulombic interactions. Heat dissipation during device operation is also an important theme to further optimize the perovskite optoelectronic devices. This presentation introduces a series of interfacial layers and CTLs for perovskite optoelectronic devices.