PbSe Colloidal Quantum Dots Temperature Sensing Effect And Application Of Research

Quantum dots materials having excellent electrical and optical properties as a new type of temperature-sensitive material are broad prospects in physics, communications and other fields. In many quantum dots materials, IV-VI group semiconductor quantum dots have unique features, such as a high dielectric constant, large Bohr radius, mass of electrons and holes approximately the same and narrow band gap. PbSe colloidal quantum dots have the temperature-size-dependent properties, due to its strong quantum confinement effect(exciton Bohr radius 46nm). Therefore, PbSe colloidal quantum dots as the temperature sensors sensitive materials have the board prospects.Combining the experimental and theoretical can explain the size-temperature-dependent properties of PbSe colloidal quantum dots. According to the quantum dots energy structure and establishing a PbSe colloidal quantum dots exciton energy model. According to the proposed model to calculate the band gap of the quantum dots and gave its relatively consistent through the experimental values. Through measuring the absorption spectrum and photoluminescence spectrum of different sizes of PbSe colloidal quantum dots are proving temperature-size-dependent of its band gap, intensity and FWHM.Designed the temperature characteristics experiment and measured the photoluminescence spectrum of three sizes PbSe colloidal quantum dots with temperature changing(20℃~90℃). Then we carried out its reversibility experiments. Analyzing the above experimental results, finding the peak wavelength and intensity of the emission spectrum of PbSe colloidal quantum dots proved that it is temperature-dependent while having a good stability.The PbSe colloidal quantum dots are applied to detect the temperature on the PCB. Proposed an integrated circuit chip temperature detection method and constructing temperature detection system. Preparation temperature detection system is divided into the following steps: Synthesis of PbSe colloidal quantum dots; The purified PbSe colloidal quantum dots sample in solution was dropped on the partial surface position of IC chip; The laser beam emitted by the laser;The laser beam makes PbSe colloidal quantum dots of the chip surface photoluminescence; The image acquisition system collects the infrared light; IR spectrometer receives the infrared light signal and photoluminescence spectra obtained. Experimental results show that the measurement accuracy of the temperature detection system is ±3℃ and the relative error is less than 5%.Manufacturing PbSe colloidal quantum dots-filled liquid-core optical fiber is used for temperature detection. In the temperature detection, emitting optical signal of the temperature dependence liquid core optical fiber sensor is converted to an electrical signal by the photovoltaic device. And then through the amplifier, A/D converter, the computer acquisition and data processing, transmission to display readings. The temperature sensitivity is found to be 0.01 V/℃ and the relative deviation is less than 4%. The influencing factors of temperature detection are analyzed and the following conclusions are obtained:it is better stability and sensitivity of output intensity with the temperature changing which has the characteristics including the smaller size of PbSe colloidal quantum dots, the longer of quantum dots sensitive areas and the higher of quantum dots doping concentration.