Ferroelectric Layer‐Assisted Asymmetric Heterojunction Boosts Power Output in Silicon Hydrovoltaic Device

Abstract Hydrovoltaic devices (HDs) that convert ubiquitous environmental energy via water evaporation serves as a prospective technology for renewable power schemes. However, it remains a grand challenge to perform controllable and stable modulation of hydrovoltaic power generation for multi‐scenario practical applications. Here, a ferroelectric‐field assisted silicon HD is proposed, which sandwiches an ultrathin polarizable polymer between nanostructured silicon and the top electrode, constituting an asymmetric heterojunction designed to clinch well‐regulated and robust electrical signal output. Tunable modulation of the internal electric field at the silicon/top electrode interface can be realized by facilely aligning the polarization orientation of the ferroelectric domains, thus dominating the silicon energy band bending and controlling the ultimate electrical signal. Upon effective forward polarization, the interfacial dipoles can build a stronger asymmetric electric field, which allows an efficient sweep of the charges out of the heterojunction. Accordingly, the resulting device clinches to yield a considerably modulated voltage of 1.04 V, nearly three‐fold modulation over the reverse polarization one. As prospective applications, multifunctional sensing platforms including the self‐sufficient environmental temperature detector, intelligent water‐level alarm system, and automatic‐manual dual‐mode irrigation control system are demonstrated. This work exhibits the unique characteristics of ferroelectric HDs with tunable electrical performance.