High-Efficiency Infrared Quantum Dot LEDs And Their Application For Apple Near-Infrared Detection

The existing mostly agricultural product testing technology testing time is long and is complex,many agricultural products can not be quickly graded after production,resulting in good products and defective products mixed seriously affect the sales of China’s agricultural products,so that the market competitiveness of China’s agricultural products declined,value-added space shrinked,so in China’s national development outline of the development of agricultural products modern processing and storage and transportation technology is listed as a priority theme,so the rapid detection technology of agricultural products has become a major demand for China’s agricultural development.In recent years,infrared detection has been widely used in the detection of agricultural products due to its fast and convenient detection characteristics.Infrared light source has always been an important part of the agricultural products detection system,at this stage most of the agricultural products detection system light source is mainly tungsten halogen lamp,the main reason for the use of tungsten halogen lamp is tungsten halogen lamp wavelength range coverage,but tungsten halogen lamp shortcomings are also obvious: its heat generation,large volume,low photoelectric conversion power,complex driving circuit is not conducive to the miniaturization of detection instruments,the traditional semiconductor LED light-emitting half-peak width is narrow,and the new LED currently studied is generally less than 1500 nm,therefore,There is an urgent need for an infrared light source that can cover most of the near-infrared detection band.The synthesis process of near-infrared quantum dots is simple and low-cost,especially Pb Se quantum dots,its luminous range can cover the near-infrared spectral region of 800 nm-2000 nm,and its luminous peak can change with the change of quantum dot size,so it can cover most of the detection area in infrared detection.In the LED preparation process,Pb Se quantum dot LEDs can be prepared by photoluminescence,and blue gallium nitride chips can be used as the excitation light source,and ultra-wideband infrared LEDs can be prepared when different sizes of quantum dots are mixed together to meet the use of near-infrared detection.However,the luminous efficiency of Pb Se quantum dot near-infrared LED is low,so in order to meet the needs of near-infrared detection,it is necessary to adopt methods to improve the luminous efficiency of near-infrared quantum dots.In addition to optimizing the near-infrared quantum dot LED,we also built a near-infrared detection system to test the detection effect of quantum dot LED as a light source,the specific research content is as follows:(1)Pb Se quantum dots were prepared by thermal injection,and two Pb Se quantum dots of different sizes were synthesized by adjusting the synthesis time and precursor type and precursor injection temperature,and the photoluminescence spectra and absorption spectra and XRD characterization of these two different sizes of quantum dots were tested,and the size distribution and morphology of these two quantum dots were obtained by TEM.(2)Three Pb Se quantum dot near-infrared LEDs with different luminescence wavelengths were prepared using two different sizes of quantum dots,one of which was a hybrid LED using two different sizes of quantum dots,the luminous band covered900 nm-1800 nm,and two single-size quantum dots,and SBA-15 mesoporous molecular sieve was incorporated in the preparation process to improve the luminous efficiency of Pb Se quantum dot LED.(3)A set of near-infrared detection system based on Pb Se quantum dot LED was built,the sugar content of apple slices was detected,a modeling algorithm based on partial least squares method was written,and the detection performance of the detection system based on these three different bands of LEDs was tested.In summary,we synthesized two Pb Se quantum dots of different sizes by thermal injection,and added mesoporous zeolite to improve the luminescence performance of quantum dot LEDs,and on this basis,we tested the performance of apple slice sugar detection system of three different bands of quantum dot LEDs,which provided a feasible idea for the application of Pb Se quantum near-infrared LED in infrared detection technology for agricultural products.In summary,we synthesized two Pb Se quantum dots of different sizes by thermal injection,and added SBA-15 mesoporous zeolite to the preparation process to improve the luminescence performance of quantum dot LEDs,and on this basis,the performance of apple slice sugar detection system of three different bands of quantum dot LEDs was tested,which provided a feasible idea for the application of Pb Se quantum near-infrared LED in infrared detection technology of agricultural products.