Solar‐driven interfacial evaporation is an emerging technology with a strong potential for applications in water distillation and desalination. However, the high‐cost, complex fabrication, leaching, and disposal of synthetic materials remain the major roadblocks toward large‐scale applications. Herein, the benefits offered by renewable bacterial cellulose (BC) are considered and an all‐cellulose‐based interfacial steam generator is developed. In this monolithic design, three BC‐based aerogels are fabricated and integrated to endow the 3D steam generator with well‐defined hybrid structures and several self‐contained properties of lightweight, efficient evaporation, and good durability. Under 1 sun, the interfacial steam generator delivers high water evaporation rates of 1.82 and 4.32 kg m−2 h−1 under calm and light air conditions, respectively. These results are among the best‐performing interfacial steam generators, and surpass a majority of devices constructed from cellulose and other biopolymers. Importantly, the first example of integrating solar‐driven interfacial evaporation with water wave detection is also demonstrated by introducing a self‐powered triboelectric nanogenerator (TENG). This work highlights the potential of developing biopolymer‐based, eco‐friendly, and durable steam generators, not merely scaling up sustainable clean water production, but also discovering new functions for detecting wave parameters of surface water.

Solar‐driven interfacial evaporation has emerged as an innovative and sustainable technology for efficient, clean water production. Real‐world applications depend on new classes of low‐cost, lightweight, and robust materials that can be integrated into one monolithic device, which withstands a variety of realistic conditions on open water. Self‐repairing building blocks are highly desired to prevent permanent failures, recover original functions and maintain the lifetime of interfacial steam generators, although related studies are scarce to date. For the first time, a monolithic, durable, and self‐floating interfacial steam generator with well‐defined structures is demonstrated by integrating self‐healing hydrogels through facile processes in surface modulation and device fabrication. High and stable water evaporation rates over 2.0 kg m−2 h−1 are attained under 1 sun on both fresh water and brine with a broad range of salinity (36–210 g kg−1). The solar evaporation and desalination performance are among the best‐performing interfacial steam generators and surpass a majority of devices that are constructed by composite polymers as structural components. This study provides a perspective and highlights the future opportunities in self‐healing and damage‐tolerant materials that can simultaneously improve the performance, durability, and lifetime of interfacial steam generators in real‐world applications.

Solar-driven interfacial evaporation has emerged as an innovative and sustainable technology for clean water production. Rational fabrication of monolithic three-dimensional (3D) steam generators has accordingly become a topic of growing...

The development of efficient and biocompatible organic near-infrared emitters is attractive for many applications, spanning from photodynamic therapy [1] to light fidelity (Li-Fi) all-optical networking systems. [2][3][4] In particular, the range 700-1000 nm is interesting for medical applications, given the semitransparency of biological tissue in this spectral interval, [5] and we will specifically refer to this range as near-infrared (NIR) in the following text. Compared to conventional inorganic materials, organic NIR emitters are interesting also for their mechanical conformability, which makes them appealing for the integration in flexible and stretchable devices. [6] Furthermore, the metal-free organic light-emitting materials can be a cheap and biocompatible alternative to inorganic ones for application in wearable, implantable, or in vivo medical applications, such as for sensing of body temperature, heart and respiration rates, blood pressure, glucose level, and oxygenation. [7] In the search for ever-higher efficiencies, several classes of materials have been investigated, such as perovskite-structured methylammonium lead halides, [8][9][10] quantum dots, [11] and organometallic phosphorescent complexes. [12][13][14][15][16][17][18][19] However, although such hybrid materials afford substantial electroluminescence (EL) external quantum efficiency (EQE) in the NIR, in some cases exceeding 10% [8,10] or even 20% or so, [13] their use of heavy, toxic, and/or costly metals is not ideal for manufacturing, sustainability, environmental impact, and, in perspective, biocompatibility. Furthermore, in such hybrid systems, and in general in materials that leverage triplet excitons to boost the EQE, [20,21] exciton recombination dynamics typically fall in the hundreds of nanoseconds or even in the microsecond (or longer) range, which intrinsically limits the bandwidth when integrated in devices for telecommunications. For Li-Fi applications, [2][3][4] fluorescent molecular and polymeric materials are preferred, given that the typical fluorescence lifetime of these materials is of the order of few nanoseconds or less, thereby ideally allowing data transmission rates up to the Gb s −1 regime.In the last decade, scientists have attempted different strategies to develop heavy-metal-free NIR fluorescent organic light-emitting diodes (OLEDs), with chemical design essentially revolving around the careful combination of donor and acceptor groups to both tune the spectral range (up to 1000 nm) and maximize the EQE. [22][23][24][25][26][27][28][29][30][31][32][33] Very recently, we have, for Due to the so-called energy-gap law and aggregation quenching, the efficiency of organic light-emitting diodes (OLEDs) emitting above 800 nm is significantly lower than that of visible ones. Successful exploitation of triplet emission in phosphorescent materials containing heavy metals has been reported, with OLEDs achieving remarkable external quantum efficiencies (EQEs) up to 3.8% (peak wavelength > 800 nm). For OLEDs incorporating f...