A lutetium-manganate-based near-infrared light detection film, a preparation method and application thereof

Abstract

The application discloses a lutetium manganate-based near-infrared light detection film, a preparation method and application thereof, and has a molecular formula of Lu (0.98‑x) Er 0.02 Yb x MnO3, wherein x is 0.04-0.10. The application is prepared by rare earth elements Er and Yb co-doping for regulation, and a Lu (0.98‑x) Er 0.02 Yb x MnO3 base film colloid, when x is 0.04-0.10, the optical absorption range is widened and the band gap is reduced, and due to efficient energy transmission between Er 3+ , Yb 3+ , efficient pumping of Er 3+ is realized, thereby enhancing the photovoltaic effect of the LMO film, greatly improving the photoelectric current density, and improving the responsivity and the detection rate by several times under 850 nm near-infrared wavelength. The up-conversion strategy based on multiple rare earth elements co-doping has positive multiple positive effects on the light detection performance, and promotes the development of the ferroelectric series in the field of light detection. Meanwhile, the material is expected to become a new generation of environment-friendly lead-free ferroelectric film material.

Description

TECHNICAL FIELD

[0001] The application relates to a lutetium manganate-based lead-free ferroelectric thin film material, in particular to a lutetium manganate-based near-infrared light detection thin film, a preparation method and application thereof. BACKGROUND

[0002] Since the 21st century, with the continuous reform and innovation in the field of optoelectronics, various new optoelectronic devices have emerged in an endless stream. Among them, photoelectric detectors have the ability to convert light into electrical signals, and are currently the most important type of optoelectronic device in the optoelectronic industry, playing an important role in automatic control, remote sensing, optical imaging, fire detection, environmental monitoring and military fields. Photoelectric detectors can detect all wavebands from the ultraviolet region to the infrared region, and its main working mechanism relies on the photovoltaic effect of the material. Due to the increasingly serious problems of current environmental pollution and overuse of non-renewable energy, the demand for new renewable clean energy in modern society is increasing, so researchers are also increasingly researching micro-sized, low-energy and high-performance photoelectric detectors, and therefore self-powered photoelectric detectors (photovoltaic type photoelectric detectors) are increasingly favored by them. It is urgent to develop new light detection materials to replace traditional semiconductor materials.

[0003] The lutetium manganate-based lead-free ferroelectric thin film material is considered to be an ideal material for preparing photoelectric devices due to its narrow optical band gap, good carrier transport and strong visible light and infrared absorption characteristics, mechanical, chemical and thermal stability and low manufacturing cost. Pure LuMnO3 (LMO) ferroelectric thin films exhibit a wide optical absorption range and weak absorption intensity. Under light, pure LMO ferroelectric thin films have a low photocurrent density, which greatly limits their application in the field of light detection. Therefore, in recent years, by doping chemical elements and constructing heterojunctions to pure LMO ferroelectric thin films, the ferroelectric thin film photocurrent density (J sc ) is improved, so as to optimize the light detection performance of the LMO ferroelectric thin film.

[0004] Tian et al. published in Chem. Eng. J. by Bi-doping YMnO3 to work in a wide waveband from ultraviolet to near-infrared, the maximum photocurrent density is 11.8 mA / cm 2 under standard sunlight (AM 1.5G, 100 mW / cm 2 ), the maximum responsivity and detectivity are as high as 0.07 A / W and 2.90 x 10 2 at 10 mW / cm 11Jones, fast response time is 0.5 / 0.6ms.V.Solanke et al published in Sensor Actuat.A-phys. by constructing p-GaN / alpha-In2Se3 vertical heterojunction structure near-infrared photodetector, the responsivity is 70mA / W at 850nm, the detection rate is 3.6*10 10 Jones. Obviously, the effect of these methods on the light detection performance is limited. In addition, there is singularity and uncertainty in improving the detection performance based on these methods. SUMMARY

[0005] In view of the problem that the effect of the traditional method on the light detection performance is limited, the present application provides a lutetium manganate-based near-infrared light detection film, a preparation method and application thereof, by co-doping erbium and ytterbium in the lutetium manganate-based lead-free ferroelectric film material, so as to obtain higher photocurrent density, responsivity, detection rate and fast response time.

[0006] In order to achieve the above-mentioned purpose, one aspect of the present application provides a lutetium manganate-based near-infrared light detection film, characterized in that the molecular formula is Lu (0.98-x) Er 0.02 Yb x MnO3, wherein the value of x is 0.04-0.10.

[0007] The present application is regulated by the up-conversion strategy of co-doping two rare earth elements erbium and ytterbium, which widens the light absorption range of the LMO film and enhances the absorption intensity, and at the same time, enhances the efficient energy transfer, so as to obtain high light detection performance under light, and the specific principle is as follows:

[0008] The pure LMO ferroelectric film shows a wide optical absorption range and weak absorption intensity, and with the introduction of Er 3+ , Yb 3+ ions, the absorption range is expanded to the near-infrared light region, and the optical band gap of the film after doping is reduced, thereby improving the light absorption capacity of the film material. However, only relying on the enhancement of light absorption capacity is not enough to make the light detection performance improve by one order of magnitude. Therefore, by using the efficient energy transfer between Er 3+ , Yb 3+ ions, efficient pumping of Er 3+ ions can be realized. The enhancement of light absorption capacity and efficient energy transfer greatly optimize the light detection performance of the lead-free ferroelectric film material.

[0009] According to the experimental results, it is found that the rare earth elements Er and Yb are selected for co-doping, and the stimulated absorption spectrum of Yb 3+ is wider than that of Er 3+ and has a large amplitude, so that Yb 3+The high absorption of Yb enables the expansion of its optical absorption range in the ultraviolet-near infrared region (365nm~1200nm); 3+ With increasing doping content, Er... 3+ Yb 3+ Co-doping reduces the optical band gap of the thin film; simultaneously, Er 3+ Yb 3+ The efficient transfer of energy between them enables the transfer of energy to Er 3+ The efficient pumping enhances the photovoltaic effect of the LMO thin film, significantly increasing the photocurrent density and thus improving detection performance. This results in a responsivity and detectivity of 0.5 mW / cm² at an 850 nm near-infrared wavelength under illumination intensity. 2 The rise and fall times of the fast response at 900nm wavelength are significantly shortened, with improvements of several times.

[0010] Specifically, the thin film has a hexagonal phase structure with P63cm spatial groups, and its average surface roughness R a The wavelength ranges from 0.8 to 1.0 nm.

[0011] A second aspect of the present invention provides a method for preparing the above-mentioned lutetium manganate-based near-infrared optical detection film, the method comprising the following steps:

[0012] S1. A mixture of soluble manganese salt, lutetium salt, erbium salt, and ytterbium salt yields Lu. (0.98-x) Er 0.02 Yb x MnO3 precursor solution, after standing, yields colloid;

[0013] S2. Coat the colloid obtained in step S1 onto the substrate to form a wet gel film;

[0014] S3. The wet gel membrane obtained in step S2 is subjected to heat treatment to obtain the detection film.

[0015] Soluble manganese salts, lutetium salts, erbium salts, and ytterbium salts can be nitrates, sulfates, chlorides, etc.

[0016] Preferably, in step S1, the preparation environment of the precursor solution is: room temperature and humidity not exceeding 30%.

[0017] Preferably, in step S1, the settling time is 24 to 36 hours.

[0018] Specifically, in step S2, the coating method is as follows: spin coating at 500-600 rpm for 5-10 seconds, and then spin coating at 2500-3000 rpm for 20-30 seconds.

[0019] Specifically, in step S3, the heat treatment method is as follows: first, hold at 120-180℃ for 4-8 minutes, then hold at 400-450℃ for 10-15 minutes, and finally hold at 550-650℃ for 3-5 minutes.

[0020] Preferably, steps S2 and S3 are repeated multiple times.

[0021] A third aspect of the present invention provides a lutetium manganate-based near-infrared light detection film prepared by the above-described method.

[0022] The fourth aspect of the present invention provides an application of the above-mentioned lutetium manganate-based near-infrared light detection film in the preparation of near-infrared light detectors.

[0023] Through the above technical solution, the present invention achieves the following beneficial effects:

[0024] 1. This invention prepares Lu by co-doping with rare earth elements erbium and ytterbium. (0.98-x) Er 0.02 Yb x MnO3-based thin film colloids, when x is 0.04–0.10, broaden the optical absorption range and reduce the band gap, while Er 3+ Yb 3+ The efficient transfer of energy between them enables the transfer of energy to Er 3+ The efficient pumping enhances the photovoltaic effect of the LMO thin film, significantly increasing the photocurrent density and improving responsivity and detectivity by several times at the 850nm near-infrared wavelength. This upconversion strategy based on the co-doping of multiple rare earth elements has generated multiple positive effects on photodetection performance, promoting the development of ferroelectric materials in the field of photodetection. At the same time, it also makes this material a promising candidate for a new generation of environmentally friendly lead-free ferroelectric thin film materials.

[0025] 2. The materials prepared in this invention do not contain lead, are not harmful to the environment, and the preparation process is simple, highly operable, and has a low overall cost. Attached Figure Description

[0026] Figure 1 These are XRD patterns of the lutetium manganate-based lead-free ferroelectric thin film materials and the pure LMO ferroelectric thin film materials prepared in Examples 1-4 of this invention, wherein (a) is the pure LMO ferroelectric thin film material and (b) is the lutetium manganate-based lead-free ferroelectric thin film material prepared in Examples 1-4.

[0027] Figure 2 These are SEM images of the lutetium manganate-based lead-free ferroelectric thin film materials and the pure LMO ferroelectric thin film materials prepared in Examples 1-4 of this invention, wherein (a) is the pure LMO ferroelectric thin film material and (b) is the lutetium manganate-based lead-free ferroelectric thin film material prepared in Examples 1-4.

[0028] Figure 3 are AFM images of LuMnO3-based lead-free ferroelectric thin film materials prepared in Examples 1-4 of the present application, wherein (a)-(d) represent Examples 1-4 in sequence;

[0029] Figure 4 are ultraviolet-visible absorption spectra, (αhv) 2 -hv curves of LuMnO3-based lead-free ferroelectric thin film materials prepared in Examples 1-4 of the present application and pure LMO ferroelectric thin film materials, wherein (a) is the ultraviolet-visible absorption spectrum, (b) is the (αhv) 2 -hv curve of pure LMO ferroelectric thin film materials, and (c) is the (αhv) 2 -hv curve of LuMnO3-based lead-free ferroelectric thin film materials prepared in Examples 1-4 of the present application;

[0030] Figure 5 are J-V graphs of LuMnO3-based lead-free ferroelectric thin film materials prepared in Examples 1-4 of the present application, wherein (a) is the J-V graph under different polarization conditions, and (b) is the J-V graph under different doping amounts;

[0031] Figure 6 are response and detectivity graphs of LuMnO3-based lead-free ferroelectric thin film materials prepared in Examples 1-4 of the present application corresponding to near-infrared wavelengths, wherein (a) and (c) are the detection performance of pure LMO and the response time at 900 nm, and (b) and (d) are the detection performance of Lu 0.90 Er 0.02 Yb 0.08 MnO3and the response time at 900 nm. DETAILED DESCRIPTION

[0032] The specific embodiments of the present application are described in detail below with reference to the examples. It should be understood that the specific embodiments described herein are merely intended to illustrate and explain the present application, and are not intended to limit the present application.

[0033] Example 1

[0034] S1, according to the stoichiometric ratio, Lu 0.94 Er 0.02 Yb 0.04MnO3thin film, the raw materials are weighed. 0.5123 g of MnN2O6·4H2O with a purity of 98%, 0.8818 g of Lu(NO3)3·5H2O with a purity of 99.99%, 0.0177 g of Er(NO3)3·5H2O with a purity of 99.9%, and 0.0359 g of YbN3O9·5H2O with a purity of 99.99% are weighed into a beaker and uniformly mixed using a magnetic stirrer with ethylene glycol methyl ether as the solvent and citric acid as the dispersant. The preparation is carried out at room temperature (20-25°C) and a humidity of no more than 30%, and stirring is carried out for 2 hours to obtain a Lu 0.94 Er 0.02 Yb 0.04 MnO3base thin film precursor solution;

[0035] S2, the Lu 0.94 Er 0.02 Yb 0.04 MnO3base thin film precursor solution is allowed to stand for 24 hours to allow it to fully react and form a colloid. The colloid is uniformly spin-coated on a Si substrate at a low rotation speed of 600 rpm for 6 s and a high rotation speed of 3000 rpm for 20 s to form a Lu 0.94 Er 0.02 Yb 0.04 MnO3wet gel film.

[0036] S3, the obtained wet gel film is subjected to a flow casting and multiple heat treatment process. The wet gel film is subjected to a first heat treatment at 150°C for 5 min, a second heat treatment at 410°C for 10 min, and a third heat treatment at 600°C for 3 min to crystallize the thin film.

[0037] S4, the spin-coating process of step S2 and the heat treatment process of step S3 are repeated 9 times to obtain a Lu 0.94 Er 0.02 Yb 0.04 MnO3ferroelectric thin film material.

[0038] Example 2

[0039] According to the stoichiometric ratio, the raw materials for the Lu 0.92 Er 0.02 Yb 0.06 MnO3thin film are weighed. 0.5123 g of MnN2O6·4H2O with a purity of 98%, 0.8818 g of Lu(NO3)3·5H2O with a purity of 99.99%, 0.0177 g of Er(NO3)3·5H2O with a purity of 99.9%, and 0.0359 g of YbN3O9·5H2O with a purity of 99.99% are weighed into a beaker and uniformly mixed using a magnetic stirrer with ethylene glycol methyl ether as the solvent and citric acid as the dispersant. The preparation is carried out at room temperature (20-25°C) and a humidity of no more than 30%, and stirring is carried out for 2 hours to obtain a Lu 0.92 Er 0.02Yb 0.06 MnO3 ferroelectric thin film material.

[0040] Example 3

[0041] According to the stoichiometric ratio for Lu 0.90 Er 0.02 Yb 0.08 MnO3 thin film, MnN2O6·4H2O 0.5123g with purity of 98%, Lu(NO3)3·5H2O 0.8443g with purity of 99.99%, Er(NO3)3·5H2O 0.0177g with purity of 99.9%, YbN3O9·5H2O 0.0718g with purity of 99.99% were weighed respectively, and other steps were the same as Example 1, to obtain Lu 0.90 Er 0.02 Yb 0.08 MnO3 ferroelectric thin film material.

[0042] Example 4

[0043] According to the stoichiometric ratio for Lu 0.88 Er 0.02 Yb 0.10 MnO3 thin film, MnN2O6·4H2O 0.5123g with purity of 98%, Lu(NO3)3·5H2O 0.8256g with purity of 99.99%, Er(NO3)3·5H2O 0.0177g with purity of 99.9%, YbN3O9·5H2O 0.0898g with purity of 99.99% were weighed respectively, and other steps were the same as Example 1, to obtain Lu 0.88 Er 0.02 Yb 0.10 MnO3 ferroelectric thin film material.

[0044] Figure 1 is the XRD pattern of the ferroelectric thin film sample prepared under the process of Examples 1-4, and the XRD pattern shows that the ferroelectric thin film samples of Examples 1-4 all obtain obvious hexagonal perovskite structure, indicating that the co-doping of rare earth elements Er 3+ , Yb 3+ does not change the crystal structure of the LMO thin film.

[0045] Figure 2 is the SEM pattern of the ferroelectric thin film sample prepared under the process of Examples 1-4, and it can be seen that the thickness of the thin film is about 150nm, indicating that the element doping does not affect the thickness of the thin film.

[0046] Figure 3is the AFM image of the ferroelectric thin film sample prepared by the process of Examples 1-4. It can be seen that the surface particles of the doped ferroelectric thin film are uniform and small, and the density is good, and the average surface roughness R a = 0.9 nm.

[0047] Figure 4 is the UV-visible absorption spectrum of the ferroelectric thin film sample prepared by the process of Examples 1-4, (αhv) 2 -hv curve. It can be seen from the figure that the light absorption capacity of the Er 3+ , Yb 3+ co-doped thin film is almost the same, and both have higher light absorption capacity than the pure LMO thin film, especially in the visible and near-infrared wavelength range. The thin film after element doping has obviously higher light absorption. With the increase of Yb 3+ element content, compared with the optical band gap of 1.46 eV of the pure LMO thin film, the optical band gap of the Er 3+ , Yb 3+ co-doped thin film is reduced to about 1.14 eV. The results show that the thin film after doping has excellent optical performance.

[0048] Figure 5 is the J-V graph of the ferroelectric thin film sample prepared by the process of Examples 1-4. It can be seen that the ferroelectric thin film has a switching effect, that is, the direction of the photovoltaic current of the ferroelectric photovoltaic material can be converted with the change of the polarization direction. When the thin film is positively polarized, the direction of the photovoltaic current is positive, and when it is negatively polarized, the direction of the photovoltaic current changes to negative. This unique characteristic broadens the application field of ferroelectric photovoltaic materials. In the initial state without polarization, it has obvious photovoltaic performance under light, indicating that it can be directly applied to self-powered photodetectors. When x = 0.08, the thin film obtains the maximum current density under standard sunlight (100 mW / cm 2 ), about 27.69 mA / cm 2 , which is 2.6 times the current density of the pure LMO thin film.

[0049] Figure 6 is the response and detection rate and response time graph of the near-infrared wavelength corresponding to the ferroelectric thin film sample prepared by the process of Examples 1-4. It can be seen from the figure that the maximum response reaches 1.30 A / W and the detection rate reaches 2.31 x 10 2 Jones under the light intensity of 0.5 mW / cm 12 at 850 nm near-infrared wavelength. The rise time and fall time of the fast response at 900 nm wavelength are 0.28 ms and 21.38 ms, respectively.

[0050] The preferred embodiments of the present application are described in detail above in combination with the embodiments, but the present application is not limited to the specific details in the above-described embodiments, and various simple modifications can be made to the technical solutions of the present application within the technical concept of the present application, and these simple modifications all belong to the protection scope of the present application.

[0051] In addition, it should be noted that each specific technical feature described in the above specific embodiments can be combined in any appropriate manner without contradiction, and in order to avoid unnecessary repetition, various possible combinations are not described again by the present application.

[0052] In addition, various different embodiments of the present application can also be combined in any manner, as long as it does not deviate from the idea of the present application, and it should also be considered as disclosed by the present application.

Claims

1. A method for preparing a lutetium manganate-based near-infrared optical detection thin film, characterized in that, Comprising the following steps: S1, mixing soluble manganese salt, lutetium salt, erbium salt, ytterbium salt to obtain a precursor solution, and obtaining a colloid after standing; S2, coating the colloid obtained in step S1 on a substrate to form a wet gel film; S3, heat treating the wet gel film obtained in step S2 to obtain the detection film with the molecular formula of Lu （0.98-x） Er 0.02 Yb x MnO3, wherein x is 0.04-0.

10.

2. The production method according to claim 1, characterized by, The thin film has P 63 cm The hexagonal phase structure of the space group has an average surface roughness R a of 0.8 to 1.0 nm.

3. The preparation method according to claim 1, characterized in that, In step S1, the preparation environment of the precursor solution is: room temperature and humidity not more than 30%.

4. The method of claim 1, wherein, In step S1, the standing time is 24-36h.

5. The preparation method according to claim 1, characterized in that, In step S2, the coating method is: spin coating at 500-600rpm for 5-10s, and then spin coating at 2500-3000rpm for 20-30s.

6. The method of claim 1, wherein, In step S3, the heat treatment method is: first heat preservation at 120-180℃ for 4-8min, then heat preservation at 400-450℃ for 10-15min, and finally heat preservation at 550-650℃ for 3-5min.

7. The preparation method according to claim 1, characterized in that, Steps S2 and S3 are repeated multiple times.

8. The lutetium orthomanganate-based near-infrared light detection film prepared by the method of any one of claims 1 to 7.

9. The use of the lutetium orthomanganate-based near-infrared light detection film of claim 8 in the preparation of a near-infrared light detector.

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