LCD screen can collect light energy to solve the urgent need

Polarized organic photovoltaic film developed by the research team of UCLA.

When faced with outdoor work or long-distance travel, many people may have had such concerns: They could not find an external power supply, and shut down their smart phones or laptops due to the exhaustion of their power, thus missing a business opportunity. Even lost the only opportunity to survive. Recently, a technology developed by researchers at the Sabari Institute of Engineering and Applied Science at the University of California, Los Angeles has basically solved this thorny issue.

The school’s engineers have created a new concept for collecting and reusing energy for electronic devices: the liquid crystal displays (LCDs) for these devices are equipped with built-in photovoltaic polarizers that support their use of ambient light sources, sunlight, and electronic devices themselves. The backlight is converted into electricity. Related papers will be published in the magazine "Advanced Materials".

The LCD can be said to be a common item on today's electronic devices. It can be seen on smart phones, TV screens, computer monitors, and laptops and tablets. The LCD is mostly a layered structure composed of different parts and is composed of two glass plates separated by a space containing a liquid crystal material. Because the liquid crystal material does not emit light itself, it is necessary to configure the display screen with an additional light source. On the back of the liquid crystal display, there is a light guide plate and a reflective film. The main function of the light guide plate is to convert the line light source or the point light source into the display plane. Surface light source. The light from the backlight enters the liquid crystal layer after passing through the first polarisation filter layer. Crystal droplets in the liquid crystal layer are all contained in a fine cell structure, and one or more cells constitute a pixel on the screen. Between the glass plate and the liquid crystal material is a transparent electrode, the electrode is divided into rows and columns, at the intersection of the rows and columns, the liquid crystal's optical rotation state can be changed by the change of the voltage, the role of the liquid crystal material resembles a small one. Light valve. Around the liquid crystal material are the control circuit portion and the driver circuit portion. When the electrodes in the LCD generate an electric field, the liquid crystal molecules are distorted so that the light passing through them undergoes regular refraction and then passes through the second filter layer and is displayed on the screen.

The new energy collection polarizer developed by the research team of the University of California, Los Angeles is called a polarizing organic photovoltaic panel. It can promote the function of the LCD while playing the role of polarizers, photovoltaic devices, and ambient light sources or solar photovoltaic panels.

Professor Yang Yang, a research leader and professor of materials science, said: “I firmly believe that this is an invention that changes the rules of the game. It can significantly increase the performance of LCDs. In addition, this kind of polarizer can also be used as an ordinary solar cell. Collect light sources indoors or outdoors, so the next time you go to the beach, you can use the sun to charge your iPhone."

Researchers said that from the point of view of energy use, the current efficiency of LCD polarizers is low. The backlight of an electronic device can consume 80% to 90% of the energy of the device, and up to 75% of the light source is due to the loss of the polarizer. The polarized organic photovoltaic LCD can regain most of the unused energy.

Zhu Rui, the main author of the paper and a postdoctoral researcher in the university, also mentioned that their coating method is very simple and the technology will be expected to be applied to large-scale manufacturing processes in the future.