Ionic Liquid Bridging Buried Interface for High-Performance Flexible Self-Powered Perovskite Nanowire Photodetectors with Excellent Mechanical Stability

Abstract

Flexible, self-powered, carbon-based perovskite nanowire (PNW) photodetectors (PDs) are promising candidates for next-generation optoelectronics because they are lightweight, bendable, low-cost, and operate without external power.However, device performance and mechanical durability are often limited by the buried SnO₂/PNW interface, where interfacial defects, unfavorable band alignment, and residual strain impede charge extraction and hinder stress relaxation, leading to enhanced non-radiative recombination and accelerated degradation under bending.Here, we report, for the first time, an ionic-liquid "molecular bridge" strategy using 1butyl-3-methylimidazolium hydrogen sulfate (BMIMHSO₄) to engineer the buried interface in carbon-based self-powered PNW PDs. The BMIMHSO₄ interlayer effectively passivates interfacial defects, suppresses non-radiative recombination, improves energy-level alignment, and promotes interfacial stress release, thereby simultaneously enhancing device performance and flexibility stability. Rigid devices with a Glass/FTO/SnO₂/BMIMHSO₄/MAPbI₃ PNWs/PMMA/Carbon architecture deliver an outstanding linear dynamic range of 190 dB, a high responsivity of 11.52 A W⁻¹, and a detectivity of 5.45 × 10¹³ Jones, ranking among the best reported carbonbased self-powered perovskite PDs to date. Notably, the flexible BMIMHSO₄-modified carbon-based devices retain 95% of their initial performance after 2000 bending cycles, outperforming most flexible perovskite PDs employing precious-metal electrodes. This work provides a simple, air-processable buried-interface engineering route for low-cost, high-performance, and mechanically reliable flexible PNW photodetectors, accelerating their practical deployment in wearable and flexible optoelectronic applications.