Black titanium dioxide LiDAR reflective particles and vehicles containing same

Abstract

To provide black titanium dioxide.SOLUTION: Black titanium dioxide comprises: a crystalline titanium dioxide core; and an amorphous titanium dioxide shell that encompasses the crystalline titanium dioxide core, wherein the black titanium dioxide has a reflectivity of electromagnetic radiation in the visible spectrum that is less than or equal to 15% and a reflectivity for near-IR and LiDAR electromagnetic radiation that is greater than or equal to 10%. The black titanium dioxide has a band gap of 1.0 eV to 2.0 eV.SELECTED DRAWING: Figure 1B

Description

[Technical field]

[0001] This specification relates generally to black titanium dioxide (TiO2) particles, and more specifically to black TiO2 particles that reflect near-infrared electromagnetic radiation. [Background technology]

[0002] LiDAR systems using pulsed laser electromagnetic radiation with a wavelength of 905 nanometers have been proposed and tested for obstacle detection and avoidance systems in autonomous vehicles. However, the dark (e.g., black) pigments used in automotive paints to provide dark vehicles not only absorb visible electromagnetic radiation to provide a dark color, but also absorb near-infrared electromagnetic radiation having a wavelength of 905 nanometers, which includes LiDAR electromagnetic radiation. Summary of the Invention [Problem to be solved by the invention]

[0003] Therefore, there is a need for alternative dark pigments that absorb electromagnetic radiation in the visible spectrum but reflect near-infrared electromagnetic radiation, which has a wavelength of about 905 nanometers. [Means for solving the problem]

[0004] A first embodiment includes a black titanium dioxide comprising a crystalline titanium dioxide core; and an amorphous titanium dioxide shell encapsulating the crystalline titanium dioxide core, the black titanium dioxide having a reflectance of 15% or less for electromagnetic radiation in the visible spectrum, and a reflectance of 10% or more for near infrared electromagnetic radiation and LiDAR electromagnetic radiation.

[0005] A second embodiment includes the black titanium dioxide of the first embodiment, having a reflectance of 5% or less to electromagnetic radiation in the visible spectrum.

[0006] A third embodiment includes the black titanium dioxide of any one of the first to second embodiments, having a reflectance of 20% or greater to near infrared electromagnetic radiation and LiDAR electromagnetic radiation.

[0007] A fourth embodiment comprises the black titanium dioxide of any one of the first to third embodiments, having a reflectance of greater than or equal to 0.5% and less than or equal to 5% to electromagnetic radiation in the visible spectrum.

[0008] A fifth embodiment comprises the black titanium dioxide of any one of the first to fourth embodiments, having a reflectance of 15% or more and 65% or less for near-infrared electromagnetic radiation and LiDAR electromagnetic radiation.

[0009] A sixth embodiment comprises the black titanium dioxide according to any one of the first to fifth embodiments, which has a band gap of 1.0 eV or more and 2.0 eV or less.

[0010] A seventh aspect comprises the black titanium dioxide according to any one of the first to sixth aspects, having a band gap of 1.2 eV or more and 1.8 eV or less.

[0011] An eighth embodiment includes black titanium dioxide particles having a crystalline titanium dioxide core; and an amorphous titanium dioxide shell encapsulating the crystalline titanium dioxide core, the black titanium dioxide particles having a band gap of 1.0 eV or more and 2.0 eV or less.

[0012] A ninth embodiment includes the black titanium dioxide particles of the eighth embodiment, having a band gap of 1.2 eV or more and 1.8 eV or less.

[0013] A tenth aspect comprises the black titanium dioxide particles of any one of the eighth to ninth aspects, wherein the amorphous titanium dioxide shell has a thickness of 5.0 nm or less.

[0014] An eleventh aspect comprises the black titanium dioxide particles of any one of the eighth to tenth aspects, wherein the amorphous titanium dioxide shell has a thickness of 2.5 nm or less.

[0015] A twelfth aspect comprises the black titanium dioxide particles according to any one of the eighth to eleventh aspects, wherein the amorphous titanium dioxide shell has a thickness of 0.1 nm or more and 5.0 nm or less.

[0016] In a thirteenth aspect, the black titanium dioxide particles have an average particle size D of 5 nm or more and 200 nm or less. 50 The black titanium dioxide particles according to any one of the eighth to twelfth aspects include:

[0017] A fourteenth aspect comprises the black titanium dioxide particles of any one of the eighth to thirteenth aspects, wherein the black titanium dioxide particles have a reflectance of 15% or less for electromagnetic radiation in the visible spectrum, and a reflectance of 10% or more for near infrared electromagnetic radiation and LiDAR electromagnetic radiation.

[0018] A fifteenth aspect comprises the black titanium dioxide particles of any one of the eighth to fourteenth aspects, wherein the black titanium dioxide particles have a reflectance of 5% or less for electromagnetic radiation in the visible spectrum, and a reflectance of 20% or more for near-infrared electromagnetic radiation and LiDAR electromagnetic radiation.

[0019] A sixteenth embodiment includes a paint comprising a paint binder and black titanium dioxide, the black titanium dioxide comprising a crystalline titanium dioxide core and an amorphous titanium dioxide shell encapsulating the crystalline titanium dioxide core, the black titanium dioxide having a reflectance of 15% or less for electromagnetic radiation in the visible spectrum and a reflectance of 10% or more for near infrared electromagnetic radiation and LiDAR electromagnetic radiation, and the LiDAR reflective dark paint has a value of 40 or less in the CIELAB color space.

[0020] A seventeenth embodiment includes the coating material of the sixteenth embodiment, wherein the black titanium dioxide has a band gap of 1.0 eV or more and 2.0 eV or less.

[0021] An eighteenth aspect comprises the coating material of any one of the sixteenth to seventeenth aspects, wherein the amorphous titanium dioxide shell has a thickness of 5 nm or less.

[0022] A nineteenth embodiment includes a vehicle having a body panel coated with a LiDAR reflective dark paint, the LiDAR reflective dark paint comprising a paint binder and black titanium dioxide, the black titanium dioxide comprising a crystalline titanium dioxide core and an amorphous titanium dioxide shell encapsulating the crystalline titanium dioxide core, the black titanium dioxide having a reflectance of 15% or less for electromagnetic radiation in the visible spectrum and a reflectance of 10% or more for near infrared electromagnetic radiation and LiDAR electromagnetic radiation, and the LiDAR reflective dark paint having a value of 40 or less in the CIELAB color space.

[0023] A twentieth embodiment includes the vehicle of the nineteenth embodiment, wherein the black titanium dioxide has a band gap of 1.0 eV or more and 2.0 eV or less.

[0024] These and additional features provided by the embodiments described herein will be more fully understood by considering the following detailed description in conjunction with the drawings.

[0025] The embodiments set forth in the drawings are exemplary and illustrative in nature and are not intended to limit the subject matter defined by the claims. The following detailed description of the exemplary embodiments can be understood when read in conjunction with the following drawings, in which like structure is indicated with like reference numerals and in which: [Brief description of the drawings]

[0026] [Figure 1A] FIG. 1A is a graph showing reflectance versus wavelength of electromagnetic radiation for conventional colorants. [Figure 1B] FIG. 1B is a graph showing electromagnetic radiation reflectance versus wavelength for a colorant according to embodiments disclosed and described herein. [Diagram 2]FIG. 2 is a bar graph showing the jetness of black TiO2 from commercially available materials and in accordance with embodiments disclosed and described herein. [Diagram 3] FIG. 3 is a schematic diagram showing the evolution of black TiO2 during hydrogenation and the band gap at each stage of the evolution. [Figure 4] FIG. 4 is a schematic cross-sectional view of a LiDAR reflective dark paint layer on an article according to one or more embodiments disclosed and described herein. [Diagram 5] FIG. 5 is a schematic diagram of a vehicle having side panels painted with LiDAR reflective dark paint according to one or more embodiments disclosed and described herein. [Figure 6] FIG. 6 is a schematic cross-sectional view of the side panel in FIG. 5 painted with LiDAR reflective dark paint. [Figure 7A] FIG. 7A is a scanning electron microscope (SEM) image of a TiO2 sample, with the near-infrared reflectance of the sample shown in the inset. [Figure 7B] FIG. 7B is a scanning electron microscope (SEM) image of the TiO2 sample, with the near-infrared reflectance of the sample shown in the inset. [Figure 7C] FIG. 7C is a scanning electron microscope (SEM) image of the TiO2 sample, with the near-infrared reflectance of the sample shown in the inset. [Figure 8A] FIG. 8A is a photograph showing the color of the TiO2 sample. [Figure 8B] FIG. 8B is a photograph showing the color of the TiO2 sample. [Figure 8C] FIG. 8C is a photograph showing the color of the TiO2 sample. [Figure 9] FIG. 9 is a photograph of a black TiO2 powder according to an embodiment disclosed and described herein. [Figure 10] FIG. 10 is a photograph showing the near infrared reflectance of black TiO powder according to embodiments disclosed and described herein. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0027] According to one or more embodiments described herein, the black titanium dioxide comprises a crystalline titanium dioxide core and an amorphous titanium dioxide shell that encases the crystalline titanium dioxide core, and the black titanium dioxide has a reflectance of 15% or less for electromagnetic radiation in the visible spectrum, and a reflectance of 10% or more for near-infrared electromagnetic radiation and LiDAR electromagnetic radiation. Thus, the LiDAR reflective black TiO2 particles disclosed and described herein exhibit a dark color and reflect near-infrared electromagnetic waves, including LiDAR, having wavelengths of 850 nm and 1550 nm and therebetween. In some embodiments, the black TiO2 particles disclosed and described herein can be included in a paint system to form a LiDAR reflective dark paint, which can be applied to an object, such as a part of a vehicle, so that the LiDAR system can detect the object coated with the LiDAR reflective dark paint.

[0028] As used herein, the term "near infrared electromagnetic radiation" refers to electromagnetic radiation with wavelengths of 750 nm and 950 nm and therebetween, and LiDAR refers to electromagnetic radiation with wavelengths of 905 nm and 1550 nm and therebetween.

[0029] As used herein, the term "visible spectrum" refers to electromagnetic radiation having wavelengths between 350 nm and 750 nm and therebetween.

[0030] LiDAR reflective dark paint may be disposed on a surface to provide a LiDAR reflective dark surface. Non-limiting examples include surfaces of vehicle body panels, such as vehicle door panels and vehicle quarter panels. The use of LiDAR reflective black TiO2 particles allows dark vehicles to be detected by a LiDAR system. Various embodiments of LiDAR reflective black TiO2 and methods of use thereof are described in further detail herein with specific reference to the accompanying drawings.

[0031] One difficulty in forming a dark colored (e.g., black) particle and paint system that reflects LiDAR or near-infrared electromagnetic radiation is the close proximity of the visible spectrum of electromagnetic radiation to the near-infrared or LiDAR electromagnetic radiation. Materials that provide a dark color, such as black, do not reflect electromagnetic radiation that is within the visible spectrum of electromagnetic radiation. Such materials will generally not reflect electromagnetic radiation, such as near-infrared and LiDAR, that is just outside the visible spectrum of electromagnetic radiation. Thus, a material that does not reflect electromagnetic radiation within the visible spectrum but does reflect near-infrared or LiDAR electromagnetic radiation requires a very steep increase in reflectance just outside the visible spectrum of electromagnetic radiation.

[0032] Referring to FIG. 1A, the reflectance of materials commonly used as colorants in paint systems is shown. The reflectance percentages are measured by a Perkin Elmer Lambda 1050 UV-Vis NIR analyzer. The reflectance percentages are presented along the y-axis of FIG. 1A, and the wavelengths of electromagnetic radiation are provided along the x-axis of FIG. 1A. Along the bottom of the graph is shown the reflectance of a conventional black colorant, such as carbon black. As shown in FIG. 1A, the carbon black colorant does not reflect electromagnetic radiation in the visible spectrum (left side of the graph). As shown in FIG. 1A, the reflectance of this black colorant is approximately zero percent within the visible spectrum of electromagnetic radiation. This indicates that the colorant provides a dark, nearly pure black color. However, these conventional colorants also reflect approximately zero percent of electromagnetic radiation outside of the visible spectrum (right side of the graph), such as in near infrared electromagnetic radiation or LiDAR electromagnetic radiation (e.g., from about 905 nanometers (nm) to about 1050 nm). Similarly, near the top of the graph is shown the reflectance of white TiO2, which is used as a conventional white colorant. As shown in FIG. 1A, white TiO2 reflects near infrared electromagnetic radiation and LiDAR electromagnetic radiation, as shown on the right side of the graph (e.g., about 905 nm to 1050 nm), with the reflection of near infrared electromagnetic radiation and LiDAR electromagnetic radiation being greater than 40 percent (at 1550 nm) and about 60 percent (at 905 nm). However, white TiO2, as the name suggests, also reflects electromagnetic radiation in the visible spectrum. As shown in FIG. 1A, white TiO2 reflects nearly 80% of electromagnetic radiation in the visible spectrum. Therefore, none of these colorants are suitable as dark particles that also reflect near infrared electromagnetic radiation or LiDAR electromagnetic radiation.

[0033] FIG. 1B is a graph showing the target conditions for a particle that does not reflect light in the visible spectrum of electromagnetic radiation, but reflects near-infrared electromagnetic radiation and LiDAR electromagnetic radiation. It should be understood that FIG. 1B shows the theoretical reflectance of a material that does not reflect light in the visible spectrum, but reflects near-infrared electromagnetic radiation and LiDAR electromagnetic radiation. As in FIG. 1A, the percentage of reflectance is measured along the y-axis, and the wavelength of electromagnetic radiation is provided along the x-axis. Along the bottom of the graph, the reflectance of a conventional black colorant is shown, which is identical to the reflectance of the conventional black colorant shown in FIG. 1A. As shown in FIG. 1B, a particle that does not reflect electromagnetic waves in the visible spectrum, but reflects near-infrared electromagnetic radiation and LiDAR electromagnetic radiation, has at least two distinct regions of reflection. The first region of reflection is in the visible spectrum of electromagnetic radiation, and is shown as "1" on the left side of the graph in FIG. 1B. In this region of reflection, particles that do not reflect electromagnetic waves in the visible spectrum, but reflect near-infrared electromagnetic radiation and LiDAR electromagnetic radiation, will behave in the same way as a traditional black colorant (such as carbon black) by not reflecting electromagnetic radiation in the visible spectrum. As shown in FIG. 1B, particles that do not reflect electromagnetic waves in the visible spectrum, but reflect near-infrared and LiDAR electromagnetic radiation, will reflect approximately zero percent of the electromagnetic radiation in the visible spectrum. However, particles that do not reflect electromagnetic waves in the visible spectrum, but reflect near-infrared and LiDAR electromagnetic radiation, have a second region of reflection that is outside the visible spectrum of electromagnetic radiation.

[0034] The second region of reflection encompasses electromagnetic radiation having wavelengths between 750 nm and 1050 nm, including near-infrared electromagnetic radiation and LiDAR electromagnetic radiation. In the second reflection region, the particles that do not reflect electromagnetic waves in the visible spectrum and reflect near-infrared electromagnetic radiation and LiDAR electromagnetic radiation function similarly to white TiO2 by reflecting a large amount of electromagnetic radiation in the second reflection region. As shown in FIG. 1B, the particles that do not reflect electromagnetic waves in the visible spectrum and reflect near-infrared electromagnetic radiation and LiDAR electromagnetic radiation, for example, reflect about 60% of LiDAR electromagnetic radiation having a wavelength of 905 nm and reflect more than 40% of LiDAR electromagnetic radiation having a wavelength of 1550 nm. By having a reflectivity similar to white TiO2 in the second reflection region, the particles can reflect a sufficient amount of near-infrared electromagnetic radiation and LiDAR electromagnetic radiation, and the particles can be detected by the LiDAR system.

[0035] The theoretical reflectance of a black near-infrared electromagnetic radiation and LiDAR electromagnetic radiation reflective pigment, shown in FIG. 1B, shows that it is difficult to create particles that do not reflect electromagnetic waves in the visible spectrum and that reflect near-infrared electromagnetic radiation and LiDAR electromagnetic radiation. In particular, FIG. 1B shows a steep increase in reflectance just outside the visible spectrum of electromagnetic radiation. In an embodiment, this steep increase in reflectance is at or about 905 nm, a wavelength of electromagnetic radiation that is commonly used in LiDAR systems. As shown in FIG. 1B, the reflectance increases from about zero percent to nearly 60 percent at a wavelength of electromagnetic radiation that is about 905 nm. Creating particles with such a precise and steep increase in reflectance is difficult to achieve and there is very little room for error. For example, if a material reflects too much electromagnetic radiation in the visible spectrum, the color appearance will not be pure black, but will have a slight red or purple color, for example. However, if a material does not reflect a sufficient amount of near-infrared electromagnetic radiation or LiDAR electromagnetic radiation, the material is not suitable for detection by a LiDAR system.

[0036] Some materials do not reflect electromagnetic radiation within most of the visible spectrum, but do reflect near-infrared and LiDAR electromagnetic radiation. However, these materials have not been able to replicate the visible appearance of carbon black (i.e., have approximately 0 percent reflectance for electromagnetic radiation in the visible spectrum). One such material that has attracted interest is the class of complex inorganic pigments (CIPs) based on mixed metal oxides such as chrome iron oxide, chrome green black hematite, and chrome iron nickel black. Although CIP materials can generally reflect near-infrared and LiDAR electromagnetic radiation, colorants made from CIP materials are generally referred to as "cool blacks" because colorants made from CIPs or their derivatives have a slight red or blue color. Figure 2 is a bar graph showing the jetness of various materials on the y-axis. Jetness is measured by an X-Rite spectrophotometer. At the far left of Figure 2 is carbon black, a material commonly used as a black colorant, but does not reflect near-infrared or LiDAR electromagnetic radiation. As shown in FIG. 2, carbon black has a jetness of about 165. Materials 1-7 are one typical CIP-containing material that reflects near-infrared electromagnetic radiation and LiDAR electromagnetic radiation, but as seen in FIG. 2, these materials have a jetness of about 142 or less. This difference in jetness is noteworthy because materials 1-7 have a red or blue tint. Thus, this substantial gap in jetness between carbon black and materials 1-7 indicates that materials 1-7 are generally not suitable for use in applications where a pure black color is desired, such as paints for automotive applications.

[0037] Black TiO2 is another material that has been considered for use as a black colorant. As shown in FIG. 2, black TiO2 has a jetness close to 165, which is comparable to that of carbon black. Black TiO2 generally does not exhibit red and brown hues and is a good alternative to carbon black. However, standard black TiO2 does not reflect near-infrared or LiDAR electromagnetic radiation. In addition, black TiO2 is more expensive to prepare than carbon black. This is because TiO2 is naturally white and must be treated, for example, by hydrogenation, to form black TiO2, as presented in more detail below. White TiO2 reflects near-infrared and LiDAR electromagnetic radiation, but when processed to become black TiO2, it loses its ability to reflect near-infrared and LiDAR electromagnetic radiation. Thus, although black TiO2 is visually similar to carbon black in terms of its jetness, carbon black is generally preferred over black TiO2 for economic reasons. However, according to the embodiments disclosed and described herein, white TiO2 may be converted to black TiO2, which theoretically does not reflect electromagnetic radiation in the visible spectrum, but reflects near-infrared electromagnetic radiation and LiDAR electromagnetic radiation.

[0038] TiO2 is a widely used oxide material. It has attracted great interest in the fields of catalysis, solar cells, energy storage, and semiconductor devices. It is also used as a white pigment material due to its relatively wide band gap (3.0 eV for rutile phase TiO2 and 3.2 eV for anatase phase TiO2). As a photocatalyst, the photoconversion rate of TiO2 is limited by its large band gap characteristics. These wide band gap characteristics limit the absorption of TiO2 in ultraviolet (UV) electromagnetic radiation and electromagnetic radiation with wavelengths shorter than UV. Therefore, efforts have been made to increase the visible and infrared light absorbance of TiO2 by band engineering such as hydrogenation, metal doping, and nonmetal doping. For photocatalytic applications, high absorption is desired in both the infrared and visible spectrum. Thus, in previous uses of black TiO2, it was desired that TiO2 absorb near-infrared electromagnetic radiation and LiDAR electromagnetic radiation. It was not previously recognized that black TiO2 could be used to reflect near-infrared electromagnetic radiation and LiDAR electromagnetic radiation.

[0039] As discussed above in connection with FIG. 2, white TiO2 can be treated to turn it into a dark color with a jetness close to that of carbon black. Among these treatments, hydrogenation of white TiO2 is an exemplary treatment that can be used to turn white TiO2 into black TiO2. As hydrogenation proceeds, it has been found that the defect band of TiO2 rises to near the valence band, while the conduction band of TiO2 remains almost unchanged. This provides a band gap believed to be close to 1.8 eV. It is believed that by exploiting the stability of the conductor of TiO2 and the instability of the defect band of TiO2, the band gap of TiO2 can be controlled to provide unique and desirable properties of TiO2.

[0040] Band gap generally refers to the energy difference (in electron volts or eV) between the top of the valence band (VB) and the bottom of the conduction band (CB). Band gap is the energy required for an electron to move from the valence band to the conduction band. In optics, band gap correlates to the threshold at which photons can be absorbed by a material. Thus, the band gap determines what portion of the electromagnetic spectrum the material can absorb. Generally, a material with a large band gap absorbs a larger portion of the electromagnetic spectrum with short wavelengths, and a material with a small band gap absorbs a larger portion of the electromagnetic spectrum with long wavelengths. However, it has been found that by manipulating the band gap of a material, it is possible to control the type of electromagnetic spectrum absorbed by the material. TiO2 is a material that is particularly suitable for band gap manipulation, as will be described below.

[0041] Referring to FIG. 3, white TiO2 with a relatively pure crystal structure is widely available. White crystalline TiO2 has a band gap of about 3.2 eV and has high reflectance of electromagnetic radiation in the visible spectrum, as well as high reflectance of near-infrared electromagnetic radiation and LiDAR electromagnetic radiation (as shown in FIG. 1A). However, it has been found that the valence band of TiO2 can be manipulated by various methods, such as hydrogenation. As hydrogenation proceeds, the crystal structure of TiO2 changes and a disordered shell begins to form on the TiO2 particles, forming crystalline-amorphous core-shell black TiO2. The formation of this disordered shell on TiO2 changes the valence band, but the conduction band remains constant. When the amorphous phase begins to form on the TiO2 particles, TiO2 transitions from white to gray, and the change in the valence band reduces the band gap. As shown in FIG. 3, gray TiO2 reflects less electromagnetic radiation in the visible spectrum than white TiO2, and still reflects near-infrared electromagnetic radiation and LiDAR electromagnetic radiation. However, gray TiO2 still reflects a significant amount of electromagnetic radiation in the visible spectrum and is not suitable for applications where a pure black color is desired.

[0042] As hydrogenation continues, an amorphous shell is more completely formed on the surface of the TiO2 particles, so that H-doping creates lattice disorder at the surface and introduces electronic states that shift the valence band, narrowing the band gap to about half of the original band gap. The disordered shell contains other defects, such as oxygen vacancies or Ti 3+ It was observed that no band gap exists in the visible spectrum. It was hypothesized that in this structure, electromagnetic radiation in the visible spectrum is not reflected (i.e., absorbed), but near-infrared electromagnetic radiation and LiDAR electromagnetic radiation are reflected due to the reduced band gap. Thus, a TiO2 particle having an amorphous TiO2 shell and a crystalline TiO2 core would not reflect electromagnetic radiation in the visible spectrum, but would reflect near-infrared electromagnetic radiation and LiDAR electromagnetic radiation.

[0043] However, if the hydrogenation of TiO2 particles is not properly controlled, the entire TiO2 particle will become amorphous TiO2, as shown in Figure 3. In this state, a significant amount of oxygen vacancies and Ti 3+ It has been observed that the band gap of the TiO2 particles is essentially zero, and the amorphous TiO2 particles reflect electromagnetic radiation in the visible spectrum or near infrared electromagnetic radiation and LiDAR electromagnetic radiation. Previously, amorphous black TiO2 was the desired product, and the process would ignore the stage where the TiO2 particles have a well-formed amorphous TiO2 shell and a crystalline TiO2 core. The unique nature of TiO2 particles with a well-formed disordered shell and a crystalline TiO2 core was not recognized. In fact, it is difficult to control the hydrogenation process in such a way that TiO2 particles with a well-formed disordered TiO2 shell and a crystalline TiO2 core are achieved.

[0044] According to the embodiments disclosed and described herein, the TiO2 particles contain a granular TiO3 core and a disordered TiO2 shell. In one or more embodiments, the disordered TiO2 shell has a thickness of 5.0 nm or less, such as 4.5 nm or less, 4.0 nm or less, 3.5 nm or less, 3.0 nm or less, 2.5 nm or less, 2.0 nm or less, 1.5 nm or less, 1.0 nm or less, or 0.5 nm or less. In one or more embodiments, the disordered TiO2 shell has a thickness of 0.1 nm to 5.0 nm, such as 0.5 nm to 5.0 nm, 1.0 nm to 5.0 nm, 1.5 nm to 5.0 nm, 2.0 nm to 5.0 nm, 2.5 nm to 5.0 nm, 3.0 nm to 5.0 nm, 3.5 nm to 5.0 nm, 4.0 nm to 5 nm, or 4.5 nm to 5.0 nm. In one or more embodiments, the disordered TiO2 shell has a thickness of 0.1 to 5.0 nm, e.g., 0.1 to 4.5 nm, 0.1 to 4.0 nm, 0.1 to 3.5 nm, 0.1 to 3.0 nm, 0.1 to 2.5 nm, 0.1 to 2.0 nm, 0.1 to 1.5 nm, 0.1 to 1.0 nm, or 0.1 to 0.5 nm. In one or more embodiments, the disordered TiO2 shell has a thickness of 0.1 to 5.0 nm, e.g., 0.5 to 4.5 nm, 1.0 to 4.0 nm, 1.5 to 3.5 nm, 2.0 to 3.0 nm, or 2.5 to 3.0 nm.

[0045] The overall particle size of the TiO2 particles is not particularly limited. However, in one or more embodiments, the TiO2 particles have an average particle size D of 5 nm to 200 nm, for example, 20 nm to 180 nm, 40 nm to 200 nm, 60 nm to 200 nm, 80 nm to 200 nm, 100 nm to 200 nm, 120 nm to 200 nm, 140 nm to 200 nm, 160 nm to 200 nm, or 180 nm to 200 nm. 50In one or more embodiments, the TiO2 particles have an average particle size D of 10 nm to 180 nm, e.g., 10 nm to 160 nm, 10 nm to 140 nm, 10 nm to 120 nm, 10 nm to 100 nm, 10 nm to 80 nm, 10 nm to 60 nm, 10 nm to 40 nm, or 10 nm to 20 nm. 50 In one or more embodiments, the TiO2 particles have an average particle size D of 20 nm to 180 nm, e.g., 40 nm to 160 nm, 60 nm to 140 nm, or 80 nm to 120 nm. 50 has.

[0046] As described herein, by controlling the hydrogenation treatment, the band gap of the TiO2 particles having a disordered TiO2 shell and a crystalline TiO2 core affects the reflectance of electromagnetic radiation. Thus, in one or more embodiments, the target band gap of the TiO2 particles having a disordered TiO2 shell and a crystalline TiO2 core measured by a UV-Vis-NIR analyzer is 1.0 eV to 2.0 eV, for example, 1.1 eV to 2.0 eV, 1.2 eV to 2.0 eV, 1.3 eV to 2.0 eV, 1.4 eV to 2.0 eV, 1.5 eV to 2.0 eV, 1.6 eV to 2.0 eV, or 1.7 eV to 2.0 eV. In one or more embodiments, the target band gap of the TiO2 particles having a TiO2 shell and a crystalline TiO2 core is 1.0 eV to 1.8 eV, such as 1.0 eV to 1.7 eV, 1.0 eV to 1.6 eV, 1.0 eV to 1.5 eV, 1.0 eV to 1.4 eV, 1.0 eV to 1.3 eV, 1.0 eV to 1.2 eV, or 1.0 eV to 1.1 eV. In one or more embodiments, the target band gap of the TiO2 particles having a disordered TiO2 shell and a crystalline TiO2 core is 1.1 eV to 1.9 eV, such as 1.2 eV to 1.8 eV, 1.3 eV to 1.7 eV, 1.4 eV to 1.6 eV, or about 1.5 eV.

[0047] The TiO2 particles according to embodiments disclosed and described herein have a target reflectance to electromagnetic radiation in the visible spectrum as measured by a UV-Vis-NIR spectrophotometer that is 15% or less, e.g., 14% or less, 13% or less, 12% or less, 11% or less, 10% or less, 9% or less, 8% or less, 7% or less, 6% or less, 5% or less, 4% or less, 3% or less, 2% or less, or 1% or less. In one or more embodiments, the TiO2 particles have a target reflectance to electromagnetic radiation in the visible spectrum that is 0.5% to 15%, e.g., 0.5% to 14%, 0.5% to 13%, 0.5% to 12%, 0.5% to 11%, 0.5% to 10%, 0.5% to 9%, 0.5% to 8%, 0.5% to 7%, 0.5% to 6%, 0.5% to 5%, 0.5% to 4%, 0.5% to 3%, 0.5% to 2%, or 0.5% to 1%.

[0048] The TiO2 particles according to embodiments disclosed and described herein have a target reflectance for near infrared electromagnetic radiation and LiDAR electromagnetic radiation of 10% or more, 15% or more, 20% or more, 25% or more, 30% or more, 35% or more, 40% or more, 45% or more, 50% or more, 60% or more, or 65% or more. In one or more embodiments, the TiO2 particles have a target reflectance for near infrared electromagnetic radiation and LiDAR electromagnetic radiation of 10% or more and 65% or less, such as 10% or more and 60% or less, 10% or more and 55% or less, 10% or more and 50% or less, 10% or more and 45% or less, 10% or more and 40% or less, 10% or more and 35% or less, 10% or more and 30% or less, 10% or more and 25% or less, 10% or more and 10% or less and 20% or less, or 10% or less and 15% or less.

[0049] A method for forming black TiO2 according to embodiments disclosed and described herein is described herein. Generally, hydrogenation is performed by exposing white TiO2 to a hydrogen (H2) atmosphere at high temperature and pressure for an extended period of time. However, if the temperature and pressure are not properly balanced, black TiO2 particles having a disordered TiO2 shell and a crystalline TiO2 core will not be formed. As used herein, the term "disordered TiO2" and similar terms refer to TiO2 that does not have an ordered crystal structure and may include amorphous TiO2. However, if the proper balance of time, temperature, and pressure is not achieved, completely disordered TiO2 particles or TiO2 particles having disordered and crystalline shells will be formed.

[0050] According to an embodiment, a method for forming black TiO2 particles having a disordered TiO2 shell and a crystalline TiO2 core includes exposing white TiO2 to a hydrogen atmosphere (e.g., greater than 99% H2) in the gas phase at a temperature between 200°C and 600°C, a pressure between 20 bar and 90 bar, and a duration between 12 hours and 10 days.

[0051] In one or more embodiments, the temperature is from 200° C. to 600° C., e.g., from 200° C. to 575° C., from 200° C. to 550° C., from 200° C. to 525° C., from 200° C. to 500° C., from 200° C. to 475° C., from 200° C. to 450° C., from 200° C. to 425° C., from 200° C. to 400° C., from 200° C. to 375° C., from 200° C. to 350° C., from 200° C. to 325° C., from 200° C. to 300° C., from 200° C. to 275° C., from 200° C. to 250° C., or from 200° C. to 225° C. In one or more embodiments, the temperature is 225° C. to 600° C., 250° C. to 600° C., 275° C. to 600° C., 300° C. to 600° C., 325° C. to 600° C., 350° C. to 600° C., 375° C. to 600° C., 400° C. to 600° C., 425° C. to 600° C., 450° C. to 600° C., 475° C. to 600° C., 500° C. to 600° C., 525° C. to 600° C., 550° C. to 600° C., or 575° C. to 600° C. In one or more embodiments, the temperature is 225°C or higher and 575°C or lower, e.g., 250°C or higher and 550°C or lower, 275°C or higher and 525°C or lower, 300°C or higher and 500°C or lower, 325°C or higher and 475°C or lower, 350°C or higher and 450°C or lower, or 375°C or higher and 425°C or lower.

[0052] In one or more embodiments, the pressure is from 20 to 90 bar, e.g., from 25 to 90 bar, from 30 to 90 bar, from 35 to 90 bar, from 40 to 90 bar, from 45 to 90 bar, from 50 to 90 bar, from 55 to 90 bar, from 60 to 90 bar, from 65 to 90 bar, from 70 to 90 bar, from 75 to 90 bar, from 80 to 90 bar, or from 85 to 90 bar. In one or more embodiments, the pressure is from 20 to 85 bar, e.g., from 20 to 80 bar, from 20 to 75 bar, from 20 to 70 bar, from 20 to 65 bar, from 20 to 60 bar, from 20 to 55 bar, from 20 to 50 bar, from 20 to 45 bar, from 20 to 40 bar, from 20 to 35 bar, from 20 to 30 bar, from 20 to 25 bar. In one or more embodiments, the pressure is from 25 to 85 bar, e.g., from 30 to 80 bar, from 35 to 75 bar, from 40 to 70 bar, from 45 to 65 bar, or from 50 to 60 bar.

[0053] In one or more embodiments, the duration is from 12 hours to 10 days, e.g., from 1 day to 10 days, e.g., from 12 hours to 9 days, from 12 hours to 8 days, from 12 hours to 7 days, from 12 hours to 6 days, from 12 hours to 5 days, from 12 hours to 4 days, from 12 hours to 3 days, from 12 hours to 2 days, or from 12 hours to 1 day. In one or more embodiments, the duration is from 1 day to 10 days, e.g., from 2 days to 10 days, from 3 days to 10 days, from 4 days to 10 days, from 5 days to 10 days, from 6 days to 10 days, from 7 days to 10 days, from 8 days to 10 days, or from 9 days to 10 days. In one or more embodiments, the duration is from 1 day to 9 days, e.g., from 2 days to 8 days, from 3 days to 7 days, or from 4 days to 6 days.

[0054] According to an embodiment, a method for forming black TiO2 particles having a white TiO2 shell and a crystalline TiO2 core includes exposing white TiO2 to NaBH4 at a temperature of 250°C to 400°C, at atmospheric pressure, and for a duration of 0.5 hours to 48 hours.

[0055] In one or more embodiments, the temperature is from 250° C. to 400° C., such as from 275° C. to 400° C., from 300° C. to 400° C., from 325° C. to 400° C., from 350° C. to 400° C., or from 375° C. to 400° C. In one or more embodiments, the temperature is from 250° C. to 375° C., from 250° C. to 350° C., from 250° C. to 325° C., from 250° C. to 300° C., or from 250° C. to 275° C. In one or more embodiments, the temperature is from 275° C. to 375° C., such as from 300° C. to 350° C.

[0056] In one or more embodiments, the duration is from 0.5 to 48 hours, e.g., from 2 to 48 hours, from 5 to 48 hours, from 7 to 48 hours, from 10 to 48 hours, from 12 to 48 hours, from 15 to 48 hours, from 17 to 48 hours, from 20 to 48 hours, from 22 to 48 hours, from 25 to 48 hours, from 27 to 48 hours, from 30 to 48 hours, from 32 to 48 hours, from 35 to 48 hours, from 37 to 48 hours, from 40 to 48 hours, from 42 to 48 hours, or from 45 to 48 hours. In one or more embodiments, the duration is from 0.5 to 45 hours, e.g., from 0.5 to 42 hours, from 0.5 to 40 hours, from 0.5 to 37 hours, from 0.5 to 35 hours, from 0.5 to 32 hours, from 0.5 to 30 hours, from 0.5 to 27 hours, from 0.5 to 25 hours, from 0.5 to 22 hours, from 0.5 to 20 hours, from 0.5 to 17 hours, from 0.5 to 15 hours, from 0.5 to 12 hours, from 0.5 to 10 hours, from 0.5 to 7 hours, from 0.5 to 5 hours, or from 0.5 to 2 hours. In one or more embodiments, the duration is from 2 to 45 hours, e.g., from 5 to 42 hours, from 7 to 40 hours, from 10 to 37 hours, from 12 to 35 hours, from 15 to 32 hours, from 18 to 30 hours, or from 20 to 28 hours.

[0057] In one or more embodiments, the ratio of TiO2 to NaBH4 is 1.0 or more:1.0-5.0 or less:1.0, such as 1.5 or more:1.0-5.0 or less:1.0, 2.0 or more:1.0-5.0 or less:1.0, 2.5 or more:1.0-5.0 or less:1.0, 3.0 or more:1.0-5.0 or less:1.0, 3.5 or more:1.0-5.0 or less:1.0, 4.0 or more:1.0-5.0 or less:1.0, or 4.5 or more:1.0-5.0 or less:1.0. In one or more embodiments, the ratio of TiO2 to NaBH4 is 1.0 or more:1.0-4.5:1.0, for example, 1.0 or more:1.0-4.0:1.0, 1.0 or more:1.0-3.5:1.0, 1.0 or more:1.0-3.0:1.0, 1.0 or more:1.0-2.5:1.0, 1.0 or more:1.0-2.0:1.0, or 1.0 or more:1.0-1.5:1.0. In one or more embodiments, the ratio of TiO2 to NaBH4 is 1.5 or more:1.0-4.5:1.0, for example, 2.0 or more:1.0-4.0:1.0, or 2.5 or more:1.0-3.5:1.0.

[0058] In one embodiment, the black TiO2 of the embodiment is formed by exposing white TiO2 to NaBH4 at a ratio of TiO2 to NaBH4 of ≥3.0:1.0-≤4.5:1.0, at a temperature of ≥250°C and ≤300°C, for a duration of ≥1 hour and ≤14 hours, and at atmospheric pressure.

[0059] Now referring to FIG. 4, an embodiment of a LiDAR reflective dark layer 12 (e.g., paint layer) having a plurality of black TiO2 particles 10 according to the embodiments disclosed and described herein is shown. Specifically, the LiDAR reflective dark layer 12 includes a plurality of black TiO2 particles 10 according to the embodiments disclosed and described herein disposed in a binder 150 (e.g., paint binder). Non-limiting examples of binders include enamel paint binder, urethane paint binder, and enamel-urethane mixed paint binder. The LiDAR reflective dark layer 12 appears dark to an observer looking at the LiDAR reflective dark layer 12 and reflects near infrared electromagnetic radiation and LiDAR electromagnetic radiation having a wavelength of, for example, 905 nm or 1550 nm. That is, the LiDAR reflective dark layer 12 exposed to sunlight and observed by an observer has a color with a value of 20 or less in the CIELAB color space and reflects an average of 20% or more of near infrared electromagnetic radiation and LiDAR electromagnetic radiation having a wavelength of 905 nm or 1550 nm. In an embodiment, the LiDAR reflective dark layer 12 exposed to sunlight reflects an average of less than 10% of electromagnetic radiation in the visible spectrum and has a value of 15 or less in the CIELAB color space. In such an embodiment, the LiDAR reflective dark layer 12 exposed to sunlight can have a value of 10 or less in the CIELAB color space. As used herein, the term "average" refers to the average of 10 reflectance values ​​equally spaced along a particular reflectance spectrum for the dark pigment or LiDAR reflective dark layer described herein. Also, as used herein, the terms "more reflective" and "less reflective" refer to "more reflective on average" and "less reflective on average", respectively, unless otherwise specified.

[0060] 5 and 6, an embodiment of a vehicle "V" painted with a LiDAR reflective dark paint is shown. In particular, FIG. 5 shows a vehicle V having a side panel "S" coated with a LiDAR reflective dark paint 50, and FIG. 6 shows a cross-section of one of the side panels S having the LiDAR reflective dark paint 50. The LiDAR reflective dark paint 50 can include multiple layers that provide surface protection and a desired color. For example, the LiDAR reflective dark paint 50 can include a phosphate layer 122, an electrodeposition layer 124, a primer layer 126, a color layer 112 or 114 (also known as a base coat or base coat layer), and a clear coat layer 128. Non-limiting examples of the phosphate layer include a manganese phosphate layer, an iron phosphate layer, a zinc phosphate layer, and combinations thereof. Non-limiting examples of the electrodeposition layer include an anodic electrodeposition layer and a cathodic electrodeposition layer. Non-limiting examples of the primer layer include an epoxy primer layer and a urethane primer layer. Non-limiting examples of the clear coat layer include a urethane clear coat layer and an acrylic lacquer clear coat layer. It should be understood that the LiDAR reflective dark paint 50 appears dark to an observer looking at the LiDAR reflective dark paint and reflects near infrared electromagnetic radiation and LiDAR electromagnetic radiation with wavelengths of 905 nm or 1550 nm. That is, the LiDAR reflective dark paint exposed to sunlight and observed by an observer has a color with a color value of 20 or less in the CIELAB color space and reflects more than 40% of the near infrared electromagnetic radiation or LiDAR electromagnetic radiation with wavelengths of 905 nm or 1550 nm. In some embodiments, the LiDAR reflective dark paint 50 exposed to sunlight reflects an average of less than 10% of electromagnetic radiation in the visible spectrum and has a color value of 15 or less in the CIELAB color space. In such embodiments, the LiDAR reflective dark paint 50 exposed to sunlight can have a color value of 10 or less in the CIELAB color space.

[0061] As mentioned above, the LiDAR reflective black TiO2 particles according to the embodiments disclosed and described herein can be used in paints to provide LiDAR reflective dark articles that can be detected by LiDAR systems using near infrared electromagnetic radiation or LiDAR electromagnetic radiation, such as 905 nm or 1550 nm. That is, articles that are desired to be detected by LiDAR systems, such as automobiles, motorcycles, bicycles, etc., can be painted with the LiDAR reflective dark paints described herein, thereby providing the dark articles with the desired arc color, and further being detectable by LiDAR systems using near infrared electromagnetic radiation, such as 905 nm or 1550 nm wavelengths. EXAMPLES

[0062] The following examples will further clarify the embodiments.

[0063] Example 1 Three samples were prepared as follows: Sample 1 was commercial white TiO2. Sample 2 was prepared by exposing commercial white TiO2 to NaBH4 at a ratio of TiO2 to NaBH4 of 4.0:1.0. The TiO2 was exposed to NaBH4 at 375°C and atmospheric pressure for 1 hour. Sample 3 was prepared by exposing commercial TiO2 to a hydrogen atmosphere at 250°C and 20 bar pressure for 5 days.

[0064] FIG. 7A is a scanning electron microscope (SEM) image of Sample 1 showing white TiO2 particles, which are crystalline TiO2. The inset of FIG. 7A is the reflectance of Sample 1 to near-infrared electromagnetic radiation. As can be seen from the image, no core-shell structure is formed, and Sample 1 is a good reflector of near-infrared electromagnetic radiation. FIG. 8A shows that Sample 1 has a very bright white color.

[0065] FIG. 7B is an SEM image of Sample 2, showing that the TiO2 particles are completely amorphized. The inset of FIG. 7B is the reflectance of Sample 2 to near-infrared electromagnetic radiation. As can be seen from the image, no core-shell structure is formed, and Sample 2 does not reflect near-infrared electromagnetic radiation. FIG. 8B shows that Sample 2 has a very black color.

[0066] FIG. 7C is an SEM image of sample 3, showing that the TiO2 particles formed a disordered shell encapsulating a crystalline TiO2 core. The inset of FIG. 7C is the reflectance of sample 3 to near-infrared electromagnetic radiation. Sample 3 is a good reflector of near-infrared electromagnetic radiation. FIG. 8B shows that sample 3 has a grayish color.

[0067] Example 2 A sample was prepared by exposing the commercially available white TiO2 of Example 1 to NaBH4 at a temperature of 275°C at ambient pressure for 12 hours with TiO2 to NaBH4 at a ratio of 4.0:1.0. The sample had a good black color with a slight blue tint, as shown in Figure 9. Figure 10 is a photograph taken with a camera capable of detecting near infrared reflectance, showing that the sample is good at reflecting near infrared electromagnetic radiation.

[0068] Directional terms used herein (e.g., up, down, right, left, front, back, top, bottom, vertical, horizontal) are intended to refer to the drawings only and are not intended to imply absolute orientation unless otherwise specified. The terms "generally," "approximately," and "about" may be used herein to express the inherent degree of uncertainty that may result from any quantitative comparison, value, measurement, or other representation. These terms may also be used herein to express the degree to which a quantitative representation may vary from the stated reference without causing a change in the basic functionality of the subject matter at issue. In general, any quantitative comparison, value, measurement, or other representation is "approximately" or "about," whether or not expressly stated. Also, the beginning and end points of the ranges are disclosed herein and are intended to be used with any given end point and range, and include the beginning and end points unless otherwise stated. For example, the range "greater than or equal to 50 nm, 75 nm, 100 nm, 125 nm, 150 nm or 175 nm, and less than or equal to 200 nm, 175 nm, 150 nm, 125 nm, or 100 nm" includes any combination between a starting point, including 50 nm, 75 nm, 100 nm, 125 nm, 150 nm or 175 nm, and an ending point, including 200 nm, 175 nm, 150 nm, 125 nm, 100 nm or 75 nm, so long as the end point is greater than the starting point.

[0069] While particular embodiments have been illustrated and described herein, it should be understood that various other changes and modifications can be made without departing from the spirit and scope of the claimed subject matter. Moreover, although various aspects of the claimed subject matter have been described herein, such aspects need not be utilized in combination. Accordingly, the scope of the appended claims is intended to encompass all such changes and modifications that are within the scope of the claimed subject matter. The present disclosure further includes the following aspects: Aspect 1 A crystalline titanium dioxide core; and An amorphous titanium dioxide shell encapsulating the crystalline titanium dioxide core. and has a reflectance of 15% or less for electromagnetic radiation in the visible spectrum and a reflectance of 10% or more for near infrared electromagnetic radiation and LiDAR electromagnetic radiation; Black titanium dioxide. Aspect 2 2. The black titanium dioxide of embodiment 1, having a reflectance of 5% or less to electromagnetic radiation in the visible spectrum. Aspect 3 2. The black titanium dioxide of embodiment 1, having a reflectance of 20% or more to near infrared electromagnetic radiation and LiDAR electromagnetic radiation. Aspect 4 2. The black titanium dioxide of embodiment 1, having a reflectance of greater than or equal to 0.5% and less than or equal to 5% to electromagnetic radiation in the visible spectrum. Aspect 5 2. The black titanium dioxide of embodiment 1, having a reflectance of greater than or equal to 15% and less than or equal to 65% for near infrared electromagnetic radiation and LiDAR electromagnetic radiation. Aspect 6 2. The black titanium dioxide of embodiment 1, having a band gap of 1.0 eV or more and 2.0 eV or less. Aspect 7 2. The black titanium dioxide of embodiment 1, having a band gap of 1.2 eV or greater and 1.8 eV or less. Aspect 8 A crystalline titanium dioxide core; and An amorphous titanium dioxide shell encapsulating the crystalline titanium dioxide core. It has It has a band gap of 1.0 eV or more and 2.0 eV or less. Black titanium dioxide particles. Aspect 9: 9. The black titanium dioxide particles according to embodiment 8, having a band gap of 1.2 eV or more and 1.8 eV or less. Aspect 10 9. The black titanium dioxide particles according to embodiment 8, wherein the amorphous titanium dioxide shell has a thickness of 5.0 nm or less. Aspect 11 9. The black titanium dioxide particles according to embodiment 8, wherein the amorphous titanium dioxide shell has a thickness of 2.5 nm or less. Aspect 12 9. The black titanium dioxide particles according to embodiment 8, wherein the amorphous titanium dioxide shell has a thickness of 0.1 nm or more and 5.0 nm or less. Aspect 13 9. The black titanium dioxide particles according to embodiment 8, wherein the black titanium dioxide particles have an average particle size D50 of 5 nm or more and 200 nm or less. Aspect 14 9. The black titanium dioxide particles of embodiment 8, wherein the black titanium dioxide particles have a reflectance of 15% or less for electromagnetic radiation in the visible spectrum and a reflectance of 10% or more for near infrared electromagnetic radiation and LiDAR electromagnetic radiation. Aspect 15 9. The black titanium dioxide particles of embodiment 8, wherein the black titanium dioxide particles have a reflectance of 5% or less for electromagnetic radiation in the visible spectrum and a reflectance of 20% or more for near-infrared electromagnetic radiation and LiDAR electromagnetic radiation. Aspect 16 Paint binders, and Black titanium dioxide, A paint containing The black titanium dioxide comprises a crystalline titanium dioxide core and an amorphous titanium dioxide shell encapsulating the crystalline titanium dioxide core, the black titanium dioxide has a reflectance of 15% or less for electromagnetic radiation in the visible spectrum and a reflectance of 10% or more for near infrared electromagnetic radiation and LiDAR electromagnetic radiation; The LiDAR reflective dark paint has a value of 40 or less in the CIELAB color space. Aspect 17 17. The coating material of embodiment 16, wherein the black titanium dioxide has a band gap of 1.0 eV or more and 2.0 eV or less. Aspect 18 17. The coating of embodiment 16, wherein the amorphous titanium dioxide shell has a thickness of 5 nm or less. Aspect 19 It has body panels coated with LiDAR-reflective dark paint. The LiDAR reflective dark paint is Paint binders, and Black Titanium Dioxide It contains The black titanium dioxide is A crystalline titanium dioxide core and an amorphous titanium dioxide shell encapsulating the crystalline titanium dioxide core. It contains the black titanium dioxide has a reflectance of 15% or less for electromagnetic radiation in the visible spectrum and a reflectance of 10% or more for near infrared electromagnetic radiation and LiDAR electromagnetic radiation; The LiDAR reflective dark paint has a brightness of 40 or less in the CIELAB color space; vehicle. Aspect 20 20. The vehicle of embodiment 19, wherein the black titanium dioxide has a band gap of 1.0 eV or greater and 2.0 eV or less.

Claims

1. A crystalline titanium dioxide core; and An amorphous titanium dioxide shell encapsulating the crystalline titanium dioxide core. and has a reflectance of 15% or less for electromagnetic radiation in the visible spectrum and a reflectance of 10% or more for near infrared electromagnetic radiation and LiDAR electromagnetic radiation; Black titanium dioxide.

2. 10. The black titanium dioxide of claim 1 having a reflectance of 5% or less to electromagnetic radiation in the visible spectrum.

3. 2. The black titanium dioxide of claim 1 having a reflectance of 20% or greater to near infrared electromagnetic radiation and LiDAR electromagnetic radiation.

4. 2. The black titanium dioxide of claim 1 having a reflectance of greater than or equal to 0.5% and less than or equal to 5% to electromagnetic radiation in the visible spectrum.

5. 2. The black titanium dioxide of claim 1, having a reflectance of 15% or more and 65% or less for near infrared electromagnetic radiation and LiDAR electromagnetic radiation.

6. 2. The black titanium dioxide according to claim 1, having a band gap of 1.0 eV or more and 2.0 eV or less.

7. 2. The black titanium dioxide of claim 1, having a band gap of 1.2 eV or more and 1.8 eV or less.

8. A crystalline titanium dioxide core; and An amorphous titanium dioxide shell encapsulating the crystalline titanium dioxide core. It has It has a band gap of 1.0 eV or more and 2.0 eV or less, has a reflectance of 15% or less for electromagnetic radiation in the visible spectrum and a reflectance of 10% or more for near infrared electromagnetic radiation and LiDAR electromagnetic radiation; Black titanium dioxide particles.

9. 9. The black titanium dioxide particles according to claim 8, having a band gap of 1.2 eV or more and 1.8 eV or less.

10. 9. The black titanium dioxide particle of claim 8, wherein the amorphous titanium dioxide shell has a thickness of 5.0 nm or less.

11. 9. The black titanium dioxide particle of claim 8, wherein the amorphous titanium dioxide shell has a thickness of 2.5 nm or less.

12. 9. The black titanium dioxide particle of claim 8, wherein the amorphous titanium dioxide shell has a thickness of 0.1 nm or more and 5.0 nm or less.

13. 9. The black titanium dioxide particles according to claim 8, wherein the black titanium dioxide particles have an average particle size D50 of 5 nm or more and 200 nm or less.

14. 9. The black titanium dioxide particles of claim 8, wherein the black titanium dioxide particles have a reflectance of 5% or less for electromagnetic radiation in the visible spectrum and a reflectance of 20% or more for near infrared electromagnetic radiation and LiDAR electromagnetic radiation.

15. Paint binders, and Black titanium dioxide, A paint containing The black titanium dioxide comprises a crystalline titanium dioxide core and an amorphous titanium dioxide shell encapsulating the crystalline titanium dioxide core, the black titanium dioxide has a reflectance of 15% or less for electromagnetic radiation in the visible spectrum and a reflectance of 10% or more for near infrared electromagnetic radiation and LiDAR electromagnetic radiation; A LiDAR reflective dark paint having a lightness in the CIELAB color space of 40 or less.

16. 16. The LiDAR reflective dark paint of claim 15, wherein the black titanium dioxide has a band gap of 1.0 eV or greater and 2.0 eV or less.

17. 16. The LiDAR reflective dark paint of claim 15, wherein the amorphous titanium dioxide shell has a thickness of 5 nm or less.

18. The vehicle has body panels coated with LiDAR reflective dark paint. The LiDAR reflective dark paint is Paint binders, and Black Titanium Dioxide It contains The black titanium dioxide is A crystalline titanium dioxide core and an amorphous titanium dioxide shell encapsulating the crystalline titanium dioxide core. It contains the black titanium dioxide has a reflectance of 15% or less for electromagnetic radiation in the visible spectrum and a reflectance of 10% or more for near infrared electromagnetic radiation and LiDAR electromagnetic radiation; The LiDAR reflective dark paint has a lightness of 40 or less in the CIELAB color space; vehicle.

19. 20. The vehicle of claim 18, wherein said black titanium dioxide has a band gap of 1.0 eV or greater and 2.0 eV or less.

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