Thermochromic Halide Perovskite Windows with Ideal Transition Temperatures

Abstract

Urban centers across the globe are responsible for a significant fraction of energy consumption and CO2 emission. As urban centers continue to grow, the popularity of glass as cladding material in urban buildings is an alarming trend. Dynamic windows reduce heating and cooling loads in buildings by passive heating in cold seasons and mitigating solar heat gain in hot seasons. Here, reduced energy consumption in highly glazed buildings in a mesoscopic building energy model is demonstrated when thermochromic windows are employed. Savings are realized across eight disparate climate zones of the United States. The model is used to determine ideal critical transition temperatures of 20–27.5 °C for thermochromic windows based on metal halide perovskite materials. Ideal transition temperatures are realized experimentally in composite metal halide perovskite films composed of perovskite crystals and an adjacent reservoir phase. The transition temperature is controlled by cointercalating methanol, instead of water, with methylammonium iodide and tailoring the hydrogen‐bonding chemistry of the reservoir phase. Thermochromic windows based on metal halide perovskites represent a clear opportunity to mitigate the effects of energy‐hungry buildings.

Thermochromic Printable and Multicolor Polymeric Composite Based on Hybrid Organic–Inorganic Perovskite

“…[ 60,61 ] Moreover, we can recognize the vibrational modes corresponding to the methylammonium (MAI) and butylammonium (BAI) organic cations: C─H asymmetric and symmetric stretching at 2970–2870 cm −1 , N─H stretching between 3000 and 3200 cm −1 , N─H bending at 1550–1650 cm −1 , and C─N stretching at 920–930 cm −1 . [ 52 ]…”

Can we make color switchable photovoltaic windows?

“…This expansion/contraction can lead to signicant morphological changes aer very few color change cycles. 50,52 Both of these instabilities remain challenging, but work is being done to template both materials 52 and device structures 62 to help relieve these stresses and offer improved device lifetime. Because of these two issues, while it addresses many aspects necessary for switchable photovoltaic windows, this switching mechanism's particular stability issues are likely to be a major hurdle to its development into a product.…”

Thermochromism in Bismuth Halide Perovskites with Cation and Anion Transmutation

“…[ 2 ] The change in temperature and pressure can tune perovskite's optoelectronic properties; [ 2a,b,3 ] for example, in some halide perovskite optical color changes are observed in response to temperature change, a phenomenon popularly known as thermochromism. [ 4 ] These thermochromic perovskites have numerous applications such as smart windows, temperature sensors, and color‐changing inks. [ 5 ]…”