# From Structural Design to Molecular Mechanisms: The Evolution of Solar Evaporators

## TL;DR

This review explores how solar evaporators have evolved to efficiently purify water using sunlight, focusing on both structural and molecular improvements.

## Contribution

The paper provides a comprehensive overview of the synergy between structural and molecular innovations in solar evaporators.

## Key findings

- Advanced solar evaporators achieve water transport rates up to 0.091 g min–1 and evaporation rates up to 6.92 kg m–2 h–1.
- Salt rejection efficiencies above 99.99% are attainable with optimized molecular interactions.
- Challenges remain in scaling up fabrication and understanding interfacial evaporation mechanisms.

## Abstract

To address global water scarcity,
solar-driven interfacial evaporation
has emerged as a promising solution that minimizes energy consumption
and environmental impact by harvesting solar energy directly at the
air–water interface. Recent advances show that performance
breakthroughs depend on the synergistic interplay between macroscopic
structural designs and molecular-level mechanisms. This review traces
the evolution of solar evaporators, from buoyancy-driven floating
architectures and enhanced water transport enabled by capillary and
osmotic pressure differences, to state-of-the-art regulation of water
association states through hydrophobic interaction, hydrogen-bonding,
and electrostatic interaction. These strategies accelerate mass transport,
optimize solar energy utilization, lower evaporation enthalpy, and
enhance long-term stability, achieving water transport rates up to
0.091 g min–1, evaporation rates up to 6.92 kg m–2 h–1 under 1 kW m–2 illumination, and salt rejection efficiencies above 99.99%. Despite
these advances, challenges remain in achieving a precise mechanistic
understanding of interfacial evaporation, scaling up fabrication,
and standardized performance evaluation. This review highlights these
issues and outlines future research directions to accelerate the practical
deployment of solar-driven interfacial evaporation technologies for
sustainable desalination and water purification.