Recent advances on passivation and morphology engineering approaches adopted to obtain high efficiency and stability in perovskite solar cells are thoroughly reviewed.

An overview on recent advances in the fundamental understanding of how interfaces of mesoscopic perovskite solar cells (mp-PSCs) with different architectures, upon incorporating various charge transport layers, influence their performance.

The presence of defects formed during the growth and crystallization of perovskite films is a limiting factor to achieve high efficiency and stability in perovskite solar cells. Here, we present a robust route to passivate bulk and surface defects in perovskite films by using an amino-functionalized BODIPY fluorophore. The addition of amino-BODIPY into the prototype methyl ammonium lead iodide (MAPbI₃) perovskite solution significantly altered the nanomorphology of the perovskite film and alleviated the defect formation leading to efficiency enhancement and prolonged stability of perovskite solar cells with a regular structure. Similar results were obtained when using the BODIPY fluorophore in chlorobenzene (CB)-based antisolvent treatment of spin-coated perovskite films in inverted perovskite solar cells. In addition, reduction in the electron extraction barrier was evidenced. Our approach represents a universal passivation methodology for boosting the efficiency and stability in both regular and inverted perovskite solar cells.

Charge injection and transport interlayers play a crucial role in many classes of optoelectronics, including organic and perovskite ones. Here, we demonstrate the beneficial role of carbon nanodots, both pristine and nitrogen-functionalized, as electron transport materials in organic light emitting diodes (OLEDs) and organic solar cells (OSCs). Pristine (referred to as C-dots) and nitrogen-functionalized (referred to as NC-dots) carbon dots are systematically studied regarding their properties by using cyclic voltammetry, Fourier-transform infrared (FTIR) and UV–Vis absorption spectroscopy in order to reveal their energetic alignment and possible interaction with the organic semiconductor’s emissive layer. Atomic force microscopy unravels the ultra-thin nature of the interlayers. They are next applied as interlayers between an Al metal cathode and a conventional green-yellow copolymer—in particular, (poly[(9,9-dioctylfluorenyl-2,7-diyl)-alt-co-(1,4-benzo-{2,1′,3}-thiadiazole)], F8BT)—used as an emissive layer in fluorescent OLEDs. Electrical measurements indicate that both the C-dot- and NC-dot-based OLED devices present significant improvements in their current and luminescent characteristics, mainly due to a decrease in electron injection barrier. Both C-dots and NC-dots are also used as cathode interfacial layers in OSCs with an inverted architecture. An increase of nearly 10% in power conversion efficiency (PCE) for the devices using the C-dots and NC-dots compared to the reference one is achieved. The application of low-cost solution-processed materials in OLEDs and OSCs may contribute to their wide implementation in large-area applications.

Although organic light-emitting diodes (OLEDs) are considered a mature technology, further enhancements in their efficiency are of paramount importance for advancing their incorporation in high-quality displays and flexible, wearable, electronic devices. In this regard, we propose an innovative approach, focusing on strategic modifications to the hole transport layer (HTL) through the integration of core-shell nanoparticles. Silver nanoparticles (Ag-NPs) encapsulated in a tungsten polyoxometalate compound (POM) are embedded within the prototype poly(3,4-ethylenedioxythiophene)-poly(styrenesulphonate) (PEDOT:PSS) to form the modified HTL. Our work reveals the pivotal plasmonic role of Ag-NPs in enhancing OLED device performance based on commercially available conjugated polymers. Comprehensive analyses, including UV–Vis absorption spectroscopy, atomic force microscopy, photoluminescence spectroscopy, and electrical measurements, confirm the influence of the POM encapsulated Ag-NPs on improving the device efficiency. This is attributed to the synergistic influence of enhanced hole injection and conductivity and beneficial optical effects (i.e. the Localized Surface Plasmon Resonance (LSPR) and, likely, light scattering of the POM-Ag NPs in the core-shell configuration, depending on their diameter), contributing to enhanced carrier balance and exciton recombination rate. Comparison with POM gold NPs (POM-Au NPs) highlights the distinct advantages of POM-Ag NPs. Our work reveals the potential of this innovative approach to contribute to the evolution of high-performance OLEDs, ensuring a visually compelling and efficient future.