丙酮是工业上常见的一种化学溶剂，由于其价格低廉，化学性质活泼，在物理、化学和制药领域有着非常广泛的用途。丙酮易挥发、易燃且遇到明火易爆炸，具有一定的毒性，长期接触，会对人体造成一定的伤害，轻则头晕、恶心、无力等，重则对人体的中枢神经系统造成创伤甚至是永久性伤害。作为呼出气中的一种成分，丙酮在健康人中的浓度约为300-900ppb，而在糖尿病患者中的浓度大于900ppb，有的甚至高达1800ppb。因此，丙酮可作为一种标志物，用于初步判断患者是否患有糖尿病。无论是为了检测周围的丙酮气体的浓度，还是来判断糖尿病的存在，研发一种高效、准确的手段来检测丙酮的浓度是非常重要的。 在当代，有许多种检测丙酮浓度的方法，但是这些检测手段非常的不方便，需要去专门的检测机构或者医院进行检测且价格昂贵，无法做到随时随地的对人体周围的丙酮进行检测。据近几年的报道我们发现，气体传感器具有检测结果准确，成本较低，且体积较小，可以随时随地的进行检测目标气体的浓度等优点，非常符合我们的要求。对丙酮灵敏度比较高的材料如NiO，WO⁻²，ZnO，Co₃O₄和Fe₃O₄等，同时，我们也观察到，很多具有钙钛矿结构的氧化物材料对丙酮也有非常好的灵敏度，如LaFeO₃，SmFeO₃，SmMg〓Fe〓O₃，LaNi〓Ti〓O₃， La₀.₇₅Ba₀.₂₅FeO₃，La〓Pb〓FeO₃，Yb〓Ca〓FeO₃和NdFeO₃等，在本论文中，我们在已报道的材料的基础上进行了扩展，对丙酮气体进行了检测。 本论文的主要研究成果如下： 1.通过溶胶-凝胶法制备了SmCo〓Fe〓O₃，并在此基础上掺杂了质量分数为3wt％的贵金属Pd元素。实验结果证明，3wt％Pd:SmCo₀.₁Fe₀.₉O₃对丙酮有非常高的响应，且检测极限非常低，能检测极限浓度为0.01 ppm的丙酮。为了降低材料对丙酮的最佳工作温度，我们在测试过程中引入了紫外光，波长为365nm，功率为50mW，距传感器元件约为15㎝。经过测试我们发现，材料对丙酮的最佳工作温度得到降低，且材料对丙酮的响应得到了提高，不仅如此，在光照时，材料对丙酮的稳定性得到增强，同时，材料的选择性也得到了加强。通过对志愿者的呼出气的检测，我们发现3wt％Pd:SmCo₀.₁Fe₃O₄可以成为检测糖尿病的一种潜在材料。 2.通过溶胶-凝胶法制备了SmFe〓Mg〓O₃，并在随后的烧结过程中掺入了适量的Pd元素，制备成了3wt％Pd:SmFe〓Mg〓O₃。通过对丙酮气体的测试，我们发现当掺杂浓度x=0.1时，即3wt％Pd:SmFe₀.₉Mg₀.₁O₃对微量丙酮有非常高的灵敏度，对丙酮表现出响应的极限浓度可达0.01 ppm。为了降低材料的最佳工作温度，我们引入了不同波长的光照，即365、410和450nm的光照。我们发现，在测试过程中用不同波长的光对传感器进行照射，会增强材料对丙酮的响应，降低材料工作温度。而且我们发现，不同波长的光，对材料的气敏响应的促进作用影响不同，波长越短，对气敏性能的促进作用越大，最佳工作温度的降低程度也越明显。实验证明，光照下的材料的响应更稳定。 3.通过溶胶-凝胶法制备了LaFeO₃，并测试了对丙酮气体的响应。为了增强LaFeO₃对丙酮的灵敏度，我们在测量系统中引入了紫外光。实验发现，在照射过程中，材料的丙酮灵敏度大幅度提高。通过对材料的动态电阻变化的分析，我们发现，当光照被引入的同时，即当气敏元件被紫外光照射时，材料的电阻瞬时下降，经过短暂的变化之后，材料的电阻维持在一个较低的值，保持稳定。这是因为材料的禁带宽度小于入射光的光子能量，材料从光中吸收能量产生了电子空穴对，空穴的浓度升高导致了p型半导体的电阻降低。我们也通过材料对志愿者的呼出气的响应证实了材料可以初步判断区分出健康人群和糖尿病人群。经过一个月的不间断测试，我们发现，紫外光照下的材料对丙酮有非常好的气敏稳定性。 4.通过溶胶-凝胶法制备了SmFe₀.₉Zn₀.₁O₃，并在随后的烧结过程中掺入了适量的Au元素，制备成了Xwt％Au:SmFe₀.₉Zn₀.₁O₃。通过XPS表征，我们发现， Au元素在材料中有两种存在形式，即Au(4f〓)和Au(4f〓)。通过对丙酮的测试，我们发现，当X=2时，即2wt％Au:SmFeFe₀.₉Zn₀.₁O₃对丙酮的响应最大，对丙酮表现出响应的极限浓度可达10ppb。在测试环境中引入了365、410、450、535、590nm波长的光之后我们发现，材料的气敏响应得到增强，最佳工作温度得到一定程度的降低。入射光的波长越长，对材料的气敏响应的促进作用越弱，当波长增长到一定程度时，对材料的气敏响应的促进作用可以忽略不计。通过对材料电阻的动态变化的分析，我们发现，入射光可以降低材料的电阻，这对解释材料气敏性能增强的原因提供了新思路，对降低材料的电阻提供了新方法。实验证明，在光照条件下，材料的气敏性能更加稳定。 5.通过溶胶-凝胶法制备了SmFe〓Zn〓O₃，并在随后的烧结过程中掺入了适量的Pd元素，制备成了3wt％Pd:SmFe〓Zn〓O₃。通过对丙酮气体的测试，我们发现当掺杂浓度x=0.1时，即3wt％Pd:SmFe₀.₉Zn₀.₁O₃对微量丙酮有非常高的响应，对丙酮表现出响应的极限浓度可达10ppb。对比了波长λ=365，410，450 nm的光与λ=535，590，635 nm的光对材料气敏性能的各项影响之后，我们发现波长λ=365，410，450 nm的光对材料的气敏响应有增强作用，降低了材料的最佳工作温度；而波长λ=535，590，635 nm的光对材料气敏性能的各项影响几乎没有，这与材料的禁带宽度有关，我们得出结论：只有当入射光的光子能量大于材料的禁带宽度时，光照能影响材料的各项气敏参数，否则对材料没有任何的促进作用。通过对志愿者的呼出气的检测，我们发现3wt％Pd:SmFe₀.₉Zn₀.₁O₃可以通过检测呼出气中的丙酮浓度来初步诊断出健康人群和糖尿病人群。通过一个月的实验证明，短波长的光照更有利于材料的气敏响应的稳定性。 关键词：丙酮；光照；气体传感器；糖尿病

 Acetone is a common chemical solvent in industry. Because of its low price and active chemical properties, it has a very wide range of applications in the fields of physics, chemistry and pharmaceuticals. Acetone is volatile, flammable and explosive when exposed to open fire. It has certain toxicity. Long-term contact can cause certain harm to the human body, light dizziness, nausea, weakness, etc., and heavy injury to the human central nervous system, even permanent injury. As a component of exhaled air, acetone concentration in healthy people is about 300-900 ppb, while in diabetic patients, the concentration is more than 900 ppb, and some even as high as 1800 ppb. Therefore, acetone can be used as a marker to preliminarily determine whether a patient has diabetes or not. Whether it is to detect the concentration of acetone gas around or to judge the existence of diabetes mellitus, it is very important to develop an efficient and accurate method to detect the concentration of acetone. At present, there are several methods to detect acetone concentration, but these methods are very inconvenient. It is necessary to go to a special testing institution or hospital for testing, and the price is expensive. It is impossible to detect acetone around human body at any time and anywhere. According to reports in recent years, we found that gas sensors have the advantages of accurate detection results, low cost, small volume, and can detect the concentration of target gas at any time and anywhere, which is very in line with our requirements. The materials with high sensitivity to acetone, such as TiO₂, NiO, SnO₂, WO₃, ZnO, Co₃O₄ and Fe₂O₃ are also very sensitive to acetone. At the same time, we also observed that many oxide materials with perovskite structure are also very sensitive to acetone, such as LaFeO₃, SmFeO₃, SmMg〓Fe〓O₃, LaNi〓Ti〓O₃, La₀.₇₅Ba₀.₂₅FeO₃, La〓Pb〓FeO₃, Yb〓Ca〓FeO₃ and NdFeO₃. On the basis of this, the acetone gas was detected. The main research results of this paper are as follows: 1.SmCo〓Fe〓O₃ was prepared by sol-gel method, and a precious metal Pd element with a mass fraction of 3wt% was doped on this basis. The experimental results show that 3wt% Pd: SmCo₀.₁Fe₀.₉O₃ has a very high response to acetone, and the detection limit is very low, and acetone with a limit concentration of 0.01 ppm can be detected. In order to reduce the optimum operating temperature of the material for acetone, we introduced UV light during the test with a wavelength of 365 nm, a power of 50 mW and a distance of 15 ㎝ from the sensor element. After testing, we found that the optimum working temperature of the material for acetone was reduced, and the response of the material to acetone was improved. Not only that, the stability of the material to acetone was enhanced during illumination, and the selectivity of the material was also obtained. Strengthened. By testing the exhaled breath of volunteers, we found that 3wt% Pd: SmCo₀.₁Fe₀.₉O₃ can be a potential material for detecting diabetes. 2.SmFe〓Mg〓O₃ was prepared by sol-gel method, and an appropriate amount of Pd element was added in the subsequent sintering process to prepare 3wt% Pd: SmFe〓Mg〓O₃. Through the test of acetone gas, we found that when the doping concentration x=0.1, 3wt% Pd: SmFeFe₀.₉Mg₀.₁O₃ has very high sensitivity to trace acetone, the limit concentration of response to acetone can reach 0.01 ppm. In order to reduce the optimum operating temperature of the material, we introduced different wavelengths of illumination, namely 365, 410 and 450 nm illumination. We have found that illuminating the sensor with different wavelengths of light during the test will enhance the material′s response to acetone and lower the material's operating temperature. Moreover, we have found that different wavelengths of light have different effects on the gas-sensitive response of the material. The shorter the wavelength, the greater the effect on the gas-sensitive performance, and the more the optimal working temperature is reduced. Experiments have shown that the response of materials under illumination is more stable. 3.LaFeO₃ was prepared by a sol-gel method and tested for its response to acetone gas. In order to enhance the sensitivity of LaFeO₃ to acetone, we introduced UV light into the measurement system. The experiment found that the acetone sensitivity of the material was greatly improved during the irradiation. Through the analysis of the dynamic resistance change of the material, we found that when the illumination is introduced, that is, when the gas sensor is irradiated by ultraviolet light, the resistance of the material instantaneously decreases. After a short change, the resistance of the material is maintained at a relatively low level. This is because the forbidden band width of the material is smaller than the photon energy of the incident light, and the material absorbs energy from the light to generate electron-hole pairs, and the increase in the concentration of the holes causes the resistance of the p-type semiconductor to decrease. We also confirmed through the material's response to the exhaled breath of the volunteers that the material can be initially judged to distinguish between healthy people and diabetics. After a month of uninterrupted testing, we found that the material under UV light has very good gas-sensitive stability to acetone. 4.SmFe₀.₉Zn₀.₁O₃ was prepared by sol-gel method, and an appropriate amount of Au element was added in the subsequent sintering process to prepare Xwt% Au: SmFe₀.₉Zn₀.₁O₃. By XPS characterization, we found that the Au element has two forms of existence in the material, namely Au (4f7/2) and Au (4f5/2). By testing acetone, we found that when X = 2, 2 wt% Au: SmFe₀.₉Zn₀.₁O₃ has the highest response to acetone, and the limit concentration for acetone is 10 ppb. After introducing light of 365, 410, 450, 535, and 590 nm wavelengths in the test environment, we found that the gas-sensitive response of the material was enhanced and the optimal operating temperature was reduced to some extent. The longer the wavelength of the incident light, the weaker the promotion of the gas-sensitive response of the material. When the wavelength is increased to a certain extent, the promotion of the gas-sensitive response of the material is negligible. Through the analysis of the dynamic change of the material resistance, we found that the incident light can reduce the resistance of the material, which provides a new idea for explaining the reason for the enhancement of the gas sensitivity of the material, and provides a new method for reducing the resistance of the material. Experiments have shown that the gas sensitivity of the material is more stable under light conditions. 5.SmFe〓Zn〓O₃ was prepared by sol-gel method, and an appropriate amount of Pd element was added in the subsequent sintering process to prepare 3wt% Pd: SmFe〓Zn〓O₃. By testing the acetone gas, we found that when the doping concentration x = 0.1, that is, 3 wt% Pd: SmFe₀.₉Zn₀.₁O₃ has a very high response to a trace amount of acetone, and the limit concentration to the acetone exhibits a concentration of 10 ppb. After comparing the effects of light with wavelengths λ=365, 410, 450 nm and light with λ=535, 590, 635 nm on the gas sensitivity of the material, we found light-pair materials with wavelengths λ=365, 410, 450 nm. The gas-sensitive response has an enhancement effect, which reduces the optimal working temperature of the material; while the light with wavelength λ=535, 590, 635 nm has little effect on the gas-sensitivity of the material, which is related to the forbidden band width of the material. We conclude that only when the photon energy of the incident light is greater than the forbidden band width of the material, the illumination can affect the various gas sensing parameters of the material, otherwise there is no promotion to the material. Through the detection of exhaled breath of volunteers, we found that 3wt% Pd: SmFe₀.₉Zn₀.₁O₃ can initially diagnose healthy people and diabetics by detecting the concentration of acetone in exhaled breath. A month's experiment proves that short-wavelength illumination is more conducive to the stability of the gas-sensitive response of the material. Keywords: Acetone; Light; Gas Sensor; Diabetes