Near‐Infrared‐Activated Thermochromic Perovskite Smart Windows

Abstract

Perovskite‐based thermochromic smart windows that can change color have attracted much interest. However, the high transition temperature (>45 °C in air) hinders their practical application. Herein, a near‐infrared (NIR) activated thermochromic perovskite window that enables reversible transition cycles at room temperature is proposed. Under natural sunlight (>700 W m−2), it efficiently harvests 78% NIR light to trigger the thermochromism of perovskites, blocking the heat gain from both the visible and NIR light. Meanwhile, it also exhibits a low mid‐infrared emissivity of <0.3, suppressing thermal radiation to the indoor environment. A field test demonstrates that this smart window can reduce the indoor temperature by 8 °C compared to a normal glass window at noon. The near‐room‐temperature color change, multispectral thermal management, outstanding energy‐saving ability, and climate adaptability, and solution‐based process of this window make it unique and promising for real applications.

Vapor–Liquid Transition‐Based Broadband Light Modulation for Self‐Adaptive Thermal Management

“…In hot weather, the device was continuously tested from 10:00 to 14:00 under a relative humidity of ≈32% and a wind speed of ≈1.5 m s −1 (Figure S17a, Supporting Information). Under these conditions, the STMD exhibited excellent light blocking abilities and a reflectance >94.1% in the solar radiation region (Figure S18a, Supporting [11,12,[26][27][28][29][30][31][32][33][34][35][36][37][38][39] e,f) simulations of HVAC energy consumption in Guangzhou and Harbin for normal glass, low-E glass, and the developed STMD.…”

Sunlight-driven smart windows with polymer/liquid crystal composites for autonomous control of optical properties

“…[5][6][7] Organic, inorganic and their hybrid approaches have been developed for smart windows. Typical examples include hydrogels, [8][9][10][11][12][13][14] liquid crystals (LCs), [15][16][17][18] thermochromic vanadium dioxide (VO 2 ), [19][20][21][22] electrochromic metal oxides, [23][24][25] perovskites, [26][27][28] and ionic liquids. 29 These devices are driven by various external stimuli, such as heat, electricity, and light, depending on working mechanism of each system.…”

Concomitant Thermochromic and Phase‐Change Effect in a Switchable Spin Crossover Material for Efficient Passive Control of Day and Night Temperature Fluctuations

“…[3] Thus, the growing energy-saving demand and environmental protection have prompted the development and implementation of more energyefficient and environmentally friendly thermalization technology. In this regard, remarkable efforts have been focused on the implementation of passive thermal regulation systems, that can be incorporated directly into windows, [4][5][6][7][8][9] roofs, or walls of buildings and operate without the need for electricity. [10][11][12] Although to keep buildings cool the light absorption and reflection properties have been used for millennia, nowadays more sophisticated approaches are being explored for passive thermal regulation of buildings.…”

“…[ 3 ] Thus, the growing energy‐saving demand and environmental protection have prompted the development and implementation of more energy‐efficient and environmentally friendly thermalization technology. In this regard, remarkable efforts have been focused on the implementation of passive thermal regulation systems, that can be incorporated directly into windows, [ 4–9 ] roofs, or walls of buildings and operate without the need for electricity. [ 10–12 ]…”