Smart Windows: Electro‐, Thermo‐, Mechano‐, Photochromics, and Beyond

TLDR

Smart windows that dynamically modulate light transmittance are essential for building energy efficiency and on‑demand optical devices, and recent technological advances have produced electro‑, thermo‑, mechano‑, and photochromic variants with distinct transmittance mechanisms. This review surveys recent progress in each smart‑window category and offers a perspective on future developments. The review outlines strategies for each smart‑window type, emphasizing functional materials, device design, performance enhancement, and integration with solar cells, triboelectric nanogenerators, actuators, energy storage, and electrothermal devices. The review summarizes the advantages and disadvantages of each smart‑window category and discusses emerging dual‑stimulus and multifunctional integrated technologies.

Abstract

Abstract A smart window that dynamically modulates light transmittance is crucial for building energy efficiently, and promising for on‐demand optical devices. The rapid development of technology brings out different categories that have fundamentally different transmittance modulation mechanisms, including the electro‐, thermo‐, mechano‐, and photochromic smart windows. In this review, recent progress in smart windows of each category is overviewed. The strategies for each smart window are outlined with particular focus on functional materials, device design, and performance enhancement. The advantages and disadvantages of each category are summarized, followed by a discussion of emerging technologies such as dual stimuli triggered smart window and integrated devices toward multifunctionality. These multifunctional devices combine smart window technology with, for example, solar cells, triboelectric nanogenerators, actuators, energy storage devices, and electrothermal devices. Lastly, a perspective is provided on the future development of smart windows.