Fully Inkjet-Printed Green-Emitting PEDOT:PSS/NiO/Colloidal CsPbBr3/SnO2 Perovskite Light-Emitting Diode on Rigid and Flexible Substrates

After establishing themselves as promising active materials in the field of solar cells, halide perovskites are currently being explored for fabrication of low-cost, easily processable, and highly efficient light-emitting diodes (LEDs). Despite this, the highest efficiencies reported for perovskite-based LEDs (PeLEDs) are achieved through spin coating or vacuum evaporation deposition techniques, which are not adequate, in most of the cases, for an industrial-scale production. Additionally, the long-term stability is still a big handicap, even though all inorganic perovskites, such as CsPbBr3, are found to be more stable to external variables. In this context, herein, the fabrication of fully inkjet-printed (IJP) CsPbBr3-based PeLEDs in ambient conditions, on rigid and flexible substrates, on a proof-of-concept basis, with the successful incorporation of NiO and SnO2 as hole- and electron-selective contacts, respectively, is reported. Despite the moderate luminance (324 cd m−2) value obtained, this result paves the way toward the development of upscalable fabrication of PeLEDs based on deposition techniques with controlled spatial resolution.The authors wish to thank the financial support from the European Commission via FET Open Grant (862656, DROP-IT), MINECO (Spain) for grant PID2019-105658RB-I00 (PRITES project), Ministry of Science and Innovation of Spain under Project STABLE (PID2019-107314RB-I00), and Generalitat Valenciana via Prometeo Grant Q-Devices (Prometeo/2018/098)

Inkjet-Printed Red-Emitting Flexible LEDs Based on Sustainable Inks of Layered Tin Iodide Perovskite

Inkjet printing has emerged as a promising technique for the fabrication of halide perovskite (HP) thin films, as it enables precise and controlled deposition of the perovskite ink on a variety of substrates. One main advantage of inkjet printing for the fabrication of HP thin films is its ability to produce uniform films with controlled thickness and high coverage, which is critical for achieving high-performance devices. Additionally, inkjet printing allows for the deposition of patterned thin films, enabling the fabrication of complex device architectures such as light-emitting diodes (LEDs). In this work, flexible LEDs based on inkjet printed Pb-free HP thiophene-ethylammonium tin iodide (TEA₂SnI₄) are produced that has gained attention as a potential alternative to Pb-based HPs in optoelectronic devices due to its lower toxicity, environmental impact, and high performance. The role of ink solutions is compared using pure solvents: toxic dimethyl formamide (DMF) and more eco-friendly dimethyl sulfoxide (DMSO). Red-emitting devices (λₘₐₓ = 633 nm) exhibit, in ambient conditions, a maximum external quantum efficiency (EQEₘₐₓ) of 0.5% with a related brightness of 21 cd m⁻² at 54 mA cm⁻² for DMSO-based LEDs. The environmental impacts of films prepared with DMSO-based solvents ensure only 40% of the impact caused by DMF.ISSN:2366-748