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Robust Smart Windows: Reversible Switching from Transparent to Color

Description:

Inventor

Shu Yang, PhD , Professor of Materials Science and Engineering

 

Problem

Commercial buildings in the United States alone account for nearly 40% of the total

energy consumption. Among them, electricity is the largest energy source for buildings.

Therefore, the design of new energy efficient materials and technologies is crucial to meet

goals such as the Net-Zero Energy Commercial Building Initiative (CBI) put forward by

the U.S. Department of Energy (DOE). Approaches to block or reflect intense sunlight

when needed, and to capture the sun’s light and heat when desirable, remain complex and

expensive to fabricate.

 

Solution

A low cost, durable composite film used as a window “shade” where the transparency can

be tailored to adjust heat and light. The film could also be mounted between two panes of

glass and motor controlled.

 

Technology Overview

A composite film consisting of a thin layer of quasi-amorphous array of silica nanoparticles

(NPs) is embedded in a bulk elastomeric polymer film.

• It is highly transparent (>90% transmittance in the visible wavelength) in the initial state.

• Upon mechanical stretching, the transmittance is dramatically reduced to 30% and

displays angle-independent structural color at a strain >30%.

• The displayed reflective color is a so-called structural color, which could be tuned by the

silica NP size; the color displayed is invariant with the applied strain.

• The switch between transparency and colored states has been reversibly cycled over

1000 times without losing the film’s structural and optical integrity.

 

 

Advantages

The initial state is transparent vs. technologies such as polymer dispersed liquid crystals and electrochromic displays.

• The switch between transparency and colored states has been reversibly cycled at least 1000 times without losing the film’s structural and optical integrity.

• The “window” can be massproduced using low-cost methods from abundant materials.

• In addition to light blocking smart windows, it can also be used for display or security applications.

   

Intellectual Property

US provisional patent application

 

Reference Media

Advanced Materials

Volume 27 Issue 15, pages 2489-2495, 2 MAR 2015 DOI: 10.1002/adma.201500281 

 

Desired partnerships

• License

Co-development

 

 

Download PDF

 

Docket #  15-7442 


Patent Information:
For Information, Contact:
Pamela Beatrice
Director, SEAS/SAS Licensing Group
University of Pennsylvania
215-573-4513
beatricp@upenn.edu
Inventors:
Shu Yang
Keywords:
Nanotechnology