Study on spectral fitting method of quantum dot white LED
Liu Yuanhai1, Liu Wen1, He Siyu1, Jiang Fuchun1, Chai Guangyue1,2, Zhang Wang2     
1. College of Photoelectric Engineering, Shenzhen University, Shenzhen, Guangdong 518061, China;
2. College of New Energy and New Materials, Shenzhen Technology University, Shenzhen, Guangdong 518118, China

Overview: Quantum dot material is a new semiconductor luminescent material which has the characteristics of narrow luminescent spectrum, adjustable luminescent wavelength and high quantum yield. Because of its narrow fluorescence spectrum, the light-emitting device is very helpful to improve the color gamut and saturation in the backlight field. Quantum dot materials are used as backlight devices to improve the color gamut and saturation which need to match the white light to meet the requirements through the principle of three primary colors. At present, there are many studies on the fitting method of white light spectrum, but it is not verified by the quality ratio of fluorescent materials in actual production. Based on the CIE 1931 XYZ surface color system, a new white light spectrum fitting method is developed in this paper.

The ratio of red and green QDs to glue was (1: 60) and (1: 10). The test range of the glue content was 1.4 μL~2.2 μL and 3.0 μL~5.0 μL. In the experiment, the traditional LED manufacturing method is used and the red green quantum dots are excited by the characteristics of blue light short wavelength and high energy to obtain the red green blue three colors which are mixed into white light. At the same time, due to the more stable nature of red quantum dots, the layered structure of red quantum dots under green quantum dots is adopted. Make samples according to the above-mentioned manufacturing method, test the absorption and conversion ratio of different samples to blue light, get the functional relationship between glue amount and absorption and conversion ratio through Matlab fitting, and then substitute it into the calculation formula to get the white light area. In the experiment, it is found that the amount of red-green quantum dots with layered structure will affect each other's absorption conversion; therefore, when fitting the functional relationship between the amount of glue and the absorption conversion, it is necessary to take the amount of red-green quantum dots as an independent variable at the same time.

According to the spectral fitting method, the white light region of each sample in the color coordinate is calculated, and a point (0.34, 0.3) in the region is taken. The corresponding red and green quantum dots are 1.9 μL and 4.55 μL by the inverse use of the spectral fitting method, so the corresponding theoretical spectrum is obtained. Then, according to the above-mentioned amount of glue, the white light spectrum is obtained, which basically coincides with the theoretical spectrum, and the color coordinate points (0.3409, 0.2992) obtained from the actual spectrum are also basically close. The fitting method of white light spectrum introduced in this paper is combined with the actual production and verified, which has a certain reference value for the preparation of white light of photoluminescent products.

Supported by National Fund Committee-Shenzhen Unite Fund Key Support Project (U1613212)