Water-resistant electroluminescent devices with temperature tolerance and mechanical cyclic stability based on...

Alternating current electroluminescent (ACEL) devices have propelled significant progress in areas such as flexible displays and human-machine interaction. Nanocellulose, a natural biomass material, has attracted widespread attention as a promising sustainable alternative to conventional plastic substrates. However, it remains a significant challenge to simultaneously achieve waterproofness, temperature tolerance and mechanical cycling stability in flexible ACEL devices constructed from green nanocellulose substrates. Herein, a type of ACEL device composing of a hydrophobically modified cellulose nanofibers (MCNF)-phosphor luminescent layer sandwiched between two hydrophobically modified cellulose nanocrystals with II crystalline allomorphs (MCNC II)‑silver nanowire (AgNWs) electrodes fabricated through a vacuum filtration-lamination assembly strategy is proposed. The transparent (transmittance ~81.1%) and conductive (sheet resistance ~4 Ω sq.^-1) electrodes demonstrate excellent wear resistance, bending cyclic stability (0.67-fold increase in sheet resistance after 10,000 cycles) and humidity resistance. The assembled devices exhibit high luminance (96.11 cd m^-2) and mechanical strength (25.92 MPa), along with stable performance across broad temperatures (-20-60 °C). Notably, the waterproof devices present remarkable mechanical stability (luminance retention 95% after 3000 cycles) and durability (luminance retention 97.8% after 10 h) under 99% relative humidity. The ACEL devices offer new perspectives for the development of future flexible display technologies.