Full-spectrum underwater optical communication (UOC) is of great significance for major strategic needs including resource development, scientific exploration, and homeland security. As the core of the full-spectrum UOC system, photodetectors (PDs) are plagued by stringent requirements including a broadband response, intrinsic water resistance, and a high detectivity. In this work, two-dimensional (2D) halide perovskites (HPs) and corresponding PDs are constructed by stearamine (SA), representing the rarely explored long-chain aliphatic amine series, to own waterproofness, ultralow noise, and superior optoelectronic performance, which consequently enable a high suitability for UOC. By dimensionality and composition modulations to extend the absorption onset down to 1.5 eV, a broadband response covering the entire transmission window of water (> 1.55 eV) for full- spectrum UOC can be obtained. Besides, featuring a high responsivity of 3.27 A·W⁻¹, a peak external quantum efficiency (EQE) of 630%, fast rise/decay times of 0.35 ms/0.54 ms, a superior detectivity up to 1.35 × 10¹² Jones and the capability to distinguish various waveforms and light intensities, the PDs present sensitive and persistent photoresponse underwater. As a result, proof-of-concept wireless transmission of ASCII codes in water is demonstrated.

全光谱水下光通信（UOC）对于包括资源开发，科学探索和国土安全在内的主要战略需求具有重要意义。作为全光谱UOC系统的核心，光电探测器（PD）受到严格要求的困扰，包括宽带响应，固有的耐水性和高检测率。在这项工作中，由硬脂胺（SA）构成二维（2D）卤化物钙钛矿（HPs）和相应的PD，代表了罕见的长链脂肪族胺系列，具有防水性，超低噪声和优越的光电性能，这些因此，对于UOC具有很高的适用性。通过尺寸和成分调制将吸收起始点扩展至1.5 eV，宽带响应覆盖了水的整个传输窗口（> 可获得全谱UOC的1.55 eV）。此外，具有3.27 A·W的高响应度^-1，峰值外部量子效率（EQE）为630％，快速上升/衰减时间为0.35 ms / 0.54 ms，高达1.35×10 ¹² Jones的出色检测能力，并能够区分各种波形和光强度，PD目前在水下敏感而持久的光响应。结果，证明了水中ASCII码的概念验证无线传输。