Composition exhibiting a narrow optical luminescence linewidth

Abstract

This semiconductor quantum dot composition exhibits a narrow optical luminescence linewidth and / or faster PL decay.

Description

[Technical Field]

[0001] The present invention relates to compositions exhibiting a narrow optical luminescence (PL) linewidth and / or faster PL attenuation. [Background technology]

[0002] Semiconductor quantum dots are attracting considerable interest in various applications due to their excellent optical and electronic properties. [Overview of the Initiative]

[0003] One aspect of the present invention relates to a composition AgInSe x S 2-x Regarding. Another aspect of the present invention relates to a composition CuInSe x S 2-x Regarding. Furthermore, another aspect of the present invention relates to a composition Cu having an emission spectrum with a full width at half maximum (FWHM) of less than about 0.20 eV and a peak optical luminescence wavelength in the range of 750 to 950 nm. y Ag 1-y InSe x S 2-x Regarding. [Brief explanation of the drawing]

[0004] [Figure 1] This graph shows (a) the photoluminescence (PL) peak position and (b) the full width at half maximum (FWHM) of a CuyAg1-yInSexS2-x core quantum dot (QD) when the copper-to-silver ratio of the quantum dot is changed. [Figure 2] This graph shows (a) the photoluminescence (PL) peak position and (b) the full width at half maximum (FWHM) of AgInSexS2-x core QDs when the silver-to-indium ratio of the quantum dots is changed. [Figure 3] This graph shows (a) the photoluminescence (PL) peak position and (b) the full width at half maximum (FWHM) of AgInSexS2-x core QDs when the selenium-to-silver-to-indium ratio of the quantum dots is varied. [Figure 4] This graph shows (a) the photoluminescence (PL) peak position and (b) the full width at half maximum (FWHM) of a CuInSexS2-x core QD when the copper-to-indium ratio of the quantum dot is varied. [Figure 5] This graph shows (a) the photoluminescence (PL) peak position and (b) the full width at half maximum (FWHM) of a CuInSexS2-x core QD when the selenium-to-copper-to-indium ratio of the quantum dot is varied. [Figure 6] This graph shows the photoluminescence (PL) peak position and full width at half maximum (FWHM) of CuInSexS2-x core QDs when the reaction time is varied for the preparation of quantum dots. [Figure 7] This figure shows the photoluminescence (PL) spectrum of CuyAg1-yInSexS2-xQD, exhibiting a variable full width at half maximum (FWHM). [Figure 8] This figure shows the X-ray diffraction (XRD) pattern of AgInSexS2-xQD, illustrating its orthorhombic structure. [Figure 9] This figure shows the absorption and photoluminescence spectra of AgInSexS2-xQD. The dashed line represents the second derivative of the absorption spectrum, indicating the presence of band edge states close to the photoluminescence (PL) peak, suggesting the presence of a higher density of states and direct recombination of the conduction and valence bands. [Figure 10] This graph shows the photoluminescence (PL) decay and average lifetime of I-III-VI QD compositions with various photoluminescence (PL) peak positions in the range of 800-900 nm. [Figure 11] This figure shows the absorption and photoluminescence spectra of AgInSexS2-xQD. The dashed line represents the second derivative of the absorption spectrum, indicating the presence of band edge states close to the photoluminescence (PL) peak, suggesting the presence of a higher density of states and direct recombination of the conduction and valence bands. [Modes for carrying out the invention]

[0005] Definitions and Abbreviations The following explanations of terms and abbreviations are provided to better describe this disclosure and to guide those skilled in the art in carrying out the systems, methodologies and compositions disclosed herein. In this specification, unless the context clearly indicates otherwise, “comprising” means “including,” and the singular forms “a,” “an,” or “the” include multiple references. Unless the context clearly indicates otherwise, the term “or” is inclusive and therefore refers to both a single element of the alternative elements listed and a combination of two or more of those elements.

[0006] Unless otherwise specified, all technical and scientific terms used herein have the same meaning as those generally understood by those skilled in the art in which this disclosure relates. Suitable methods and compositions are provided herein for the implementation or testing of the systems, methodologies and compositions described herein. However, it will be understood that other methods and materials similar or equivalent to those described herein may be used in the implementation or testing of these systems, methodologies and compositions disclosed herein. Consequently, the systems, methods, compositions and examples disclosed herein are illustrative and not intended to be limiting. Other features of this disclosure will be apparent to those skilled in the art from the following detailed description and the appended claims.

[0007] Unless otherwise specified, all numbers used herein or in the claims, such as amounts, percentages, temperatures, and times of components, should be understood to be modified by the term "about." Unless otherwise specified, non-numerical properties used herein or in the claims, such as colloidality, continuity, and crystallinity, should be understood to be modified by the term "substantially," meaning to a considerable extent or degree. Therefore, unless otherwise implicitly or explicitly indicated, the numerical parameters and / or non-numerical properties described herein are approximations, and the optimal values ​​of these properties and parameters may depend on the desired properties to be sought, the detection limits under standard test conditions or methods, the limitations of the processing method, and / or the nature of the properties or parameters. Where embodiments are directly and explicitly distinguished from the disclosed prior art, the figures of embodiments are not approximations unless the word "about" is enumerated.

[0008] Emission spectrum: The portion of the electromagnetic spectrum (in response to excitation by a light source) in which QD (or a composition containing them) exhibits PL whose amplitude is at least 1% of the peak PL emission. Nanoparticles: Nanoscale particles of solid materials. The nanoparticles disclosed herein are preferably crystalline and have a size of less than 500 nanometers. The nanoparticles disclosed herein may form colloidal suspensions. Embodiments of the disclosed nanoparticles may be of a single material or may include an inner core and an outer shell of different materials. The nanoparticles may further include multiple ligands bound to the outer surface of the nanoparticle. Exemplary nanoparticles that can be used in the compositions, systems and methodologies described herein may include metals, metal oxides, metal chalcogenides, semiconductors, and insulators.

[0009] Photoluminescence (PL): The emission of light after absorption (electromagnetic radiation, in the form of photons). It is a form of luminescence (light emission) and is initiated by photoexcitation (excitation by photons). Quantum dots: Nanoparticles that exhibit size-dependent electronic and optical properties due to quantum confinement. The quantum dots disclosed herein preferably have at least one dimension less than about 50 nanometers. The disclosed quantum dots may be colloidal quantum dots. Some of the quantum dots that can be utilized in the compositions, systems, and methodologies described herein are made from binary semiconductor materials having the formula MX, where M is a metal and X is typically selected from sulfur, selenium, tellurium, nitrogen, phosphorus, arsenic, antimony, or a mixture thereof. Exemplary binary quantum dots that can be used in the compositions, systems, and methodologies described herein include CdS, CdSe, CdTe, PbS, PbSe, PbTe, ZnS, ZnSe, ZnTe, InP, InAs, Cu2S, and In2S3. Other quantum dots that can be utilized in the compositions, systems, and methodologies described herein include, but are not limited to, ZnSSe, ZnSeTe, ZnSTe, CdSSe, CdSeTe, HgSSe, HgSeTe, HgSTe, ZnCdS, ZnCdSe, ZnCdTe, ZnHgS, ZnHgSe, ZnHgTe, CdHgS, CdHgSe, CdHgTe, ZnCdSe x S 2-x 、ZnCdSe x Te 2-x 、ZnHgSe x Te 2-x 、ZnHgSe x S 2-x 、CdHgSe x S 2-x 、CdHgSeTe, CuInS2, CuInSe2, CuInGaSe2, CuInZnS2, CuZnSnSe2, CuInSe x S 2-x 、CuInZnSe x S 2-x 、(CuyAg 1-y )InSe x S 2-x 、AgGaSe x S 2-x 、AgGa y In 1-y Se x S 2-x 、CuGaSe x S 2-x 、CuGay In 1-y Se x S 2-x AgInS2, AgInSe2, and AgInSe x S 2-x The disclosed quantum dots include ternary, quaternary, and / or alloyed quantum dots, although the use of non-toxic quantum dots may be preferred for certain uses or applications. The disclosed embodiments of quantum dots may be single materials or may include an internal core and an external shell of different materials. The internal core may also be a blend of the materials described for the quantum dot and / or core. The external shell may be a thin shell or layer formed by any preferred method, such as cation exchange. The external shell material, including its blend, may consist of various I-III-VI or II-VI semiconductor materials. The quantum dot may further include multiple ligands bound to the quantum dot surface.

[0010] Detailed explanation This invention relates to the development of semiconductor nanocrystalline compositions characterized by having a narrow emission range. Such narrow emission can also be controlled over a wide range of wavelengths. Our research has shown that, in some cases, obtaining a narrow emission can result from selective control of changes in cations and anions. In other cases, we have found that increasing the overall particle size can narrow the photoluminescence (PL) full width at half maximum (FWHM) emission. In some cases, these materials can behave like phosphors in that they have an intermediate gap state that is involved in photoluminescence (PL). This can result in a large Stokes shift, a longer PL lifetime, and better stability. Surprisingly, the substitution of copper with silver has been shown to cause the material to behave more like a typical quantum dot than like a phosphor. The silver-indium-selenium composition exhibits a narrow emission range of 750nm to 950nm, and especially in the 800-900nm range, that has not been found with any known material.

[0011] The peak position of narrow PL emission may be in the wavelength range of 400 nm to 1400 nm. Depending on the application, the desired peak position can vary considerably. A peak position of approximately 750 nm to 950 nm, particularly in the 800 nm to 900 nm range, may be desirable for applications such as NIR light conversion and NIR sensors, while a peak position in the 400 nm to 650 nm range for displays may be desirable for applications such as security ink authentication, displays, agriculture, and solar energy.

[0012] CuInSe x S 2-x Controlling the Cu / In ratio in this context resulted in changes to both the peak position at the maximum wavelength and the narrowness of the FWHM. Much narrower emission was obtained at Cu / In ratios of approximately 0.4–0.7, with the narrowest emission observed at Cu / In ratios of approximately 0.45–0.65. The maximum wavelength at Cu / In ratios of 0.45–0.55 was observed in the range of approximately 880 nm–900 nm. Another technique for obtaining the desired narrow emission involves selecting anions and cations, as well as the ratio of specific anion-to-cation pairings. For example, the desired narrow emission results from a Se / Cu+In ratio of approximately 1.0–1.4, where the narrow photoluminescence (PL) full width at half maximum (FWHM) is less than approximately 0.21 eV at the maximum wavelength range of approximately 850 nm–990 nm, and approximately 0.19 eV at a Se / Cu+In ratio of approximately 1.2.

[0013] Another technique for obtaining the desired narrow emission is by using a mixture of cations, such as a blend of Ag and Cu. When studying the effect of the Ag:Cu ratio, it was found that compositions with a higher Ag content produce a narrower photoluminescence (PL) full width at half maximum (FWHM) emission, less than about 0.14 eV at an Ag:Cu ratio of about 0.8–1.0. As the Ag:Cu ratio increases, the maximum wavelength tends to decrease, for example, to about 880–920 nm at an Ag:Cu ratio of about 0.8–1.0, resulting in the narrowest emission. AgInSe x S 2-xControlling the Ag / In ratio in this sample resulted in changes to both the peak position at the maximum wavelength and the narrowness of the FWHM. Much narrower emission was obtained at Ag / In ratios of approximately 0.4–0.6, and the narrowest emission was observed at an Ag / In ratio of approximately 0.4–0.5. The maximum wavelength at an Ag / In ratio of 0.4–0.5 was observed in the range of approximately 830 nm–950 nm.

[0014] Another approach involves varying the ratio of Se to Ag and In combinations. A Se / (Ag+In) ratio of approximately 1.1–2.0 yields the narrowest emission, with a narrow photoluminescence (PL) full width at half maximum (FWHM) emission of approximately 0.1 eV. The maximum wavelength for Se / (Ag+In) ratios of 1.1–2.0 is generally observed in the range of approximately 830 nm–950 nm. The PL lifetimes of narrow-linewidth QDs vary over a wide range, from tens of nanoseconds to hundreds of nanoseconds (see Figure 10). Nevertheless, the majority of PL decay τ is characterized by several exponential components with the longest lifetimes of around 1300 ns, and the shortest components of around 10–20 ns. Surprisingly, the narrowest emission typically correlated with faster PL decays of less than 200 ns on average. The contribution (amplitude) of the faster component lifetimes was more pronounced for narrower-linewidth QDs, which may be partly due to their lower photoluminescence quantum yield (PLQY) and partly due to their narrower linewidths. [Examples]

[0015] The following examples are non-limiting and are intended only to further illustrate the compositions, systems, and methodologies described herein. (Example 1) Narrow line width AgInSe x S 2-x Core QD synthesis In a three-necked flask, indium acetate (1-6 mmol) and silver acetate (1-6 mmol) were added together with octadecene, dodecanethiol, and oleylamine. Separately, a selenium solution was prepared by dissolving metallic selenium (0-20 mmol) in oleylamine and dodecanethiol and pouring it into an indium flask at a temperature of 20°C to 250°C (see typical XRD in Figure 8). The reaction was maintained at 130°C to 250°C for approximately 5 to 300 minutes or more. In these reactions, AgInSe emits light at 780-900 nm and has a narrow PL linewidth of approximately 0.087 eV. x S 2-x QDs are generated that have a core and satisfy 0 ≤ x ≤ 2 (see Figures 7 and 9). Furthermore, these QDs exhibit more interband recombination due to a higher density of states near the band edges and a correlation between the second derivative of the absorption spectrum and the PL peak position (see Figures 9 and 11). The average PL lifetime of these QDs is less than 200 ns, or even less than 100 ns (see Figure 10). (Example 2) Narrow line width Cu y Ag 1-y InSe x S 2-x Core QD synthesis This embodiment was carried out in the same manner as in Embodiment 1, and a series of different experiments were conducted by varying the copper-to-silver ratio from 0 to 1. The results of these various experiments are shown in Figure 1.

[0016] In these reactions, Cu emits light at 890-1000 nm and has a PL linewidth of approximately 0.100 eV FWHM. y Ag 1-y InSe x S 2-x A QD is generated that has a core and satisfies 0≦x≦2 and 0≦y≦1. (Example 3) Narrow line width AgInSe x S 2-x Core QD synthesis This example was carried out in the same manner as in Example 1, with a series of different experiments conducted by varying the silver-to-indium ratio from 0.2 to 1. In these reactions, AgInSe x S 2-xA QD is generated that has a core and satisfies 0 ≤ x ≤ 2. The results of various experiments are shown in Figure 2. (Example 4) Narrow line width AgInSe x S 2-x Core QD synthesis This example was carried out in the same manner as in Example 1, with a series of different experiments conducted by varying the selenium-to-silver-to-indium ratio from 0.2 to 2. In these reactions, AgInSe x S 2-x A QD is generated that has a core and satisfies 0 ≤ x ≤ 2. The results of various experiments are shown in Figure 3. (Example 5) Narrow line width CuInSe x S 2-x Core QD synthesis In a three-necked flask, indium acetate (1-4 mmol) and copper iodide (1-4 mmol) were added together with octadecene, dodecanethiol, and oleylamine. Separately, a selenium solution was prepared by dissolving metallic selenium (1-4 mmol) in oleylamine and dodecanethiol and pouring it into an indium flask at a temperature of 60°C to 250°C. The reaction was maintained at 130°C to 250°C for approximately 1 to 60 minutes or longer.

[0017] In this reaction, CuInSe is emitted at 996 nm and has a PL linewidth of 0.17 eV FWHM. x S 2-x A QD is generated that has a core and satisfies 0 ≤ x ≤ 2. The average PL lifetime of these QDs is less than 300 ns, sometimes even around 200 ns (see Figure 10). (Example 6) Narrow line width CuInSe x S 2-x Core QD synthesis This example was carried out in the same manner as in Example 5, with a series of different experiments conducted by varying the copper-to-indium ratio from 0.2 to 0.8. In these reactions, CuInSe x S 2-x A QD is generated that has a core and satisfies 0 ≤ x ≤ 2. The results of various experiments are shown in Figure 4. (Example 7) Narrow line width CuInSe x S2-x Core QD synthesis This example was carried out in the same manner as in Example 5, with a series of different experiments conducted by varying the selenium-to-copper-to-indium ratio from 0.2 to 2.0. In these reactions, CuInSe x S 2-x A QD is generated that has a core and satisfies 0 ≤ x ≤ 2. The results of various experiments are shown in Figure 5. (Example 8) Narrow line width CuInSe x S 2-x Core QD synthesis This example was carried out in the same manner as in Example 5, and a series of different experiments were conducted by varying the reaction time. In these reactions, CuInSe x S 2-x The core is generated, and a QD is created where 0 ≤ x ≤ 2. The results of these various experiments are shown in Figure 6. (Example 9) Narrow line width AgAlSe x S 2-x Core QD synthesis In a three-necked flask, aluminum acetate (1-4 mmol) and silver acetate (1-4 mmol) were added together with octadecene, dodecanethiol, and oleylamine. Separately, a selenium solution was prepared by dissolving metallic selenium (1-4 mmol) in oleylamine and dodecanethiol and pouring it into an indium flask at a temperature of 60°C to 250°C. The reaction was maintained at 130°C to 250°C for approximately 1 to 60 minutes or more. In these reactions, AgAlSe x S 2-x A QD is generated that has a core and satisfies 0 ≤ x ≤ 2. (Example 10) Narrow line width AgIn y Ga 1-y Se x S 2-x Core QD synthesis Gallium acetate (1 - 4 mmol), indium acetate (1 - 4 mmol), and silver acetate (1 - 4 mmol) were added to a three-neck flask together with octadecene, dodecanethiol, and oleylamine. Separately, metal selenium (0 - 20 mmol) was dissolved in oleylamine and dodecanethiol, and a selenium solution was prepared by injecting it into an indium flask at a temperature of 60°C - 250°C. The reaction was maintained at 130°C - 250°C for about 1 - 60 minutes or more. In these reactions, AgIn y Ga 1-y Se x S 2-x core - containing QDs with 0 ≤ x ≤ 2 and 0 ≤ y ≤ 1 are produced. (Example 11) Narrow - linewidth CuAlSe x S 2-x Synthesis of core QDs Aluminum acetate (1 - 4 mmol) and copper iodide (1 - 4 mmol) were added to a three - neck flask together with octadecene, dodecanethiol, and oleylamine. Separately, metal selenium (1 - 4 mmol) was dissolved in oleylamine and dodecanethiol, and a selenium solution was prepared by injecting it into an indium flask at a temperature of 60°C - 250°C. The reaction was maintained at 130°C - 250°C for about 1 - 60 minutes or more. In these reactions, CuAlSe x S 2-x core - containing QDs with 0 ≤ x ≤ 2 are produced. (Example 12) Narrow - linewidth CuGaSe x S 2-x Synthesis of core QDs Gallium acetate (1 - 4 mmol) and copper iodide (1 - 4 mmol) were added to a three - neck flask together with octadecene, dodecanethiol, and oleylamine. Separately, metal selenium (1 - 4 mmol) was dissolved in oleylamine and dodecanethiol, and a selenium solution was prepared by injecting it into an indium flask at a temperature of 60°C - 250°C. The reaction was maintained at 130°C - 250°C for about 1 - 60 minutes or more. In these reactions, CuGaSe x S 2-x core - containing QDs with 0 ≤ x ≤ 2 are produced. (Example 13) ZnS shell on narrow-linewidth core QD The core solutions from Examples 1-12 were mixed with octadecene, dodecanethiol, and zinc oleate, and heated at 130°C to 300°C, maintaining the temperature for approximately 5 minutes to 12 hours or more. The mixture was cooled to 25°C to isolate it.

[0018] The addition of shells increased PLQY to over 70%, sometimes above 80%, and even above 90%. The increased average PL lifetime of these core / shell QDs was less than 700 ns, sometimes less than 200 ns. (Example 14) CdS shell on narrow-linewidth core QD The core solutions from Examples 1-12 were mixed with octadecene, dodecanethiol, and cadmium oleate, and heated at 130°C to 300°C, maintaining the temperature for approximately 5 minutes to 12 hours or more. The mixture was cooled to 25°C to isolate it.

[0019] The addition of shells increases the PLQY to over 70%, sometimes above 80%, or even above 90%. The increased average PL lifetime of these core / shell QDs is less than 500 ns, sometimes less than 200 ns. (Example 15) CdSe shell on narrow-linewidth core QD The core solutions from Examples 1-12 were first mixed with octadecene, cadmium oleate, and selenium dissolved in either a) trioctylphosphine; b) oleylamine and dodecanethiol; or c) oleic acid, and then heated to about 130°C to about 300°C and maintained for about 5 minutes to about 12 hours or more as desired. The mixture was cooled to 25°C to isolate it. The resulting shell is CdSe.

[0020] The addition of shells increases the PLQY to over 70%, sometimes above 80%, or even above 90%. The increased average PL lifetime of these core / shell QDs is less than 500 ns, sometimes less than 200 ns. (Example 16) ZnSe on narrow-linewidth core QD x S 1-xshell The core solutions from Examples 1-12 were first mixed with octadecene, dodecanethiol, zinc oleate, and selenium dissolved in either a) trioctylphosphine; b) oleylamine and dodecanethiol; or c) oleic acid. The mixture was then heated to approximately 130°C to approximately 300°C and maintained for approximately 5 minutes to approximately 12 hours or more as desired. The mixture was cooled to 25°C to isolate it. The resulting shell was ZnSe x S 1-x Therefore, 0 ≤ x ≤ 1.

[0021] The addition of shells increases the PLQY to over 70%, sometimes above 80%, or even above 90%. The increased average PL lifetime of these core / shell QDs is less than 700 ns, sometimes less than 200 ns. (Example 17) Zn on narrow-linewidth core QD x CD 1-x S shell The core solutions from Examples 1-12 were mixed with octadecene, dodecanethiol, zinc oleate, and cadmium oleate, and heated at 130°C to 300°C for approximately 5 minutes to 12 hours or more. The mixture was cooled to 25°C to isolate it. The resulting shell was Zn x CD 1-x S is such that 0 ≤ x ≤ 1.

[0022] The addition of shells increases the PLQY to over 70%, sometimes above 80%, or even above 90%. The increased average PL lifetime of these core / shell QDs is less than 700 ns, sometimes less than 200 ns. (Example 18) Wet lamination of narrow-wire width QD into plastics In a flask, the QDs from Examples 1-16 were mixed at room temperature with isobornyl acrylate monomer, styrene-β-ethylene-butadiene-styrene, butyl acrylate, and omnirad 4265. The resulting mixture was coated between two metallized polyethylene terephthalate (PET) barrier films using a drawdown coater and then photocured using 320-390 nm UV light to prepare a laminated film. The laminated films are expected to exhibit PL emission with an FWHM of 0.09 eV to 0.35 eV, which is 0.01 to 0.03 eV narrower than that of QDs alone (in a diluted solvent, not in polymer). The polymer helps protect the QDs, increasing PLQY to over 70%, sometimes over 80%, or even over 90%. The average PL lifetime of these composites is less than 500 ns, sometimes less than 200 ns. (Example 19) Extrusion molding of narrow line width QD in polyolefins In an extruder, polyolefin (POE) pellets were mixed with QDs from Examples 1-16 and introduced through a hopper at a feed rate of 220 grams per hour at a temperature of 130°C-220°C. The resulting strands were shredded to produce pellets of the blended material. The pellets were hot-pressed to form films with a thickness of approximately 50-100 μm for optical property evaluation.

[0023] The linewidth of the resulting composites was 0.01–0.03 eV narrower in FWHM than that of QD alone (in dilution solvent, not polymer). The polymer helps protect the QD, increasing PLQY to over 70%, sometimes over 80%, or even over 90%. The average PL lifetime of these composites is less than 500 ns, sometimes less than 200 ns. (Example 20) Extrusion molding of narrow line width QD in ethylene vinyl acetate In an extruder, ethylene vinyl acetate (EVA) pellets were mixed with QDs from Examples 1-16 and introduced through a hopper at a feed rate of 250 grams per hour at a temperature of 130°C-220°C. The resulting strands were shredded to produce pellets of the blended material. The pellets were hot-pressed to form films with a thickness of approximately 50-100 μm for optical property evaluation.

[0024] The linewidth of the resulting composites was 0.01–0.03 eV narrower in FWHM than that of QD alone (in dilution solvent, not polymer). The polymer helps protect the QD, increasing PLQY to over 70%, sometimes over 80%, or even over 90%. The average PL lifetime of these composites is less than 500 ns, sometimes less than 200 ns. (Example 21) Cu y Ag 1-y InSe x S 2-x Narrow density of states in semiconductor nanocrystals Semiconductor nanocrystals emit photons as a pathway for excited state recombination, and excited electrons recombine with holes (electron vacancies). In semiconductors, typically, excited electrons move from the valence band to the conduction band, but this is the case with CuInSe x S 2-x In nanocrystals or quantum dots, the presence of intermediate gap states can be modified. Such excited states are formed when photons interact with intermediate gap states or electrons in the valence band. These materials may have intermediate gap states that donate electrons to the valence band, and the conduction band can supply photoexcited electrons to the same intermediate gap state at a narrow energy range of less than 300 meV, preferably less than 200 meV, or potentially even less than 100 meV in FWHM. In some cases, nanocrystals may not have intermediate gap states involved in recombination, and instead Cu y Ag 1-y InSe x S 2-xA semiconductor nanocrystal having the composition and 0≦x≦2 and 0≦y≦1 may have a distribution of the lowest conduction band state and the highest valence band state with transition energies in a narrow range of less than 300 meV, preferably less than 200 meV, or potentially even less than 100 meV in FWHM. In any case, the distribution of recombination states is relatively narrow, and conventionally, CuInSe x S 2-x This distribution is narrower than that seen in nanocrystals or quantum dots. A narrow range of transition energies will manifest in various useful ways, including, but not limited to, narrow photoluminescence linewidths.

[0025] Although the present invention has been described with reference to certain details, such details should not be considered as limiting the scope of the invention. Various modifications, substitutions, combinations, and parameters may be made or utilized in the compositions and methodologies described herein.

Claims

1. A composition AgInSe having an emission spectrum with a full width at half maximum (FWHM) of less than approximately 0.20 eV and a peak optical luminescence wavelength in the range of 750 nm to 950 nm. x S 2-x A composition such that 0 ≤ x ≤ 2.

2. The composition according to claim 1, having an emission spectrum with a full width at half maximum (FWHM) of less than about 0.10 eV.

3. The composition according to claim 1, wherein the PL attenuation is less than approximately 200 ns.

4. The composition according to claim 1, wherein the PL attenuation is approximately 100 ns.

5. The composition according to claim 1, having a crystal structure that exhibits photoluminescence emission FWHM of less than 0.2 eV.

6. The composition according to claim 1, which is partially or completely covered by a second shell material.

7. CuInSe x S 2-x , AgInSe x S 2-x , and Cu y Ag 1-y InSe x S 2-x A composition selected from the group consisting of, having an emission spectrum with a full width at half maximum (FWHM) of less than about 0.20 eV and a wavelength tunable peak optical luminescence wavelength in the range of 400 nm to 1400 nm, and 0 ≦ x ≦ 2 and 0 ≦ y ≦ 1, the composition.

8. The composition according to claim 7, wherein the photoluminescence peak is at a wavelength of 750 to 950 nm.

9. A semiconductor nanocrystal containing at least silver or copper or both in combination with indium, having an intermediate gap state that gives electrons to the valence band, and the conduction band capable of supplying photoexcited electrons to the same intermediate gap state at a narrow energy range of less than 300 meV in FWHM.

10. CuInSe x S 2-x AgInSe x S 2-x , and Cu y Ag 1-y InSe x S 2-x A polymer film containing quantum dots in a mass percent of about 0.05% to 50% selected from the group consisting of the following, having an emission spectrum with a full width at half maximum (FWHM) of less than about 0.20 eV, wherein the polymer film is composed of polyolefins, ethylene vinyl acetate, polyethylene, polyurethane, polyvinyl butyral, ionomers, acrylics and polymers selected from the group consisting of the following, and 0 ≤ x ≤ 2 and 0 ≤ y ≤ 1.

11. The quantum dot has an emission spectrum with a full width at half maximum (FWHM) of less than approximately 0.20 eV and a peak optical luminescence wavelength in the range of 750 nm to 950 nm. x S 2-x The polymer film according to claim 10, wherein 0 ≤ x ≤ 2.

12. CuInSe x S 2-x AgInSe x S 2-x , and Cu y Ag 1-y InSe x S 2-x A polymer film containing a certain proportion of quantum dots selected from the group consisting of the following, wherein the quantum dots have an emission spectrum in which the full width at half maximum (FWHM) is less than about 0.20 eV and the wavelength-tunable peak optical luminescence wavelength is in the range of 530 nm to 1400 nm, and the polymer film is composed of polyolefins, ethylene vinyl acetate, polyethylene, polyurethane, polyvinyl butyral, ionomers, acrylics and polymers selected from the group consisting of the following, wherein 0 ≤ x ≤ 2 and 0 ≤ y ≤ 1.

13. The polymer film according to claim 10, wherein the photoluminescence peak is at a wavelength of 750 to 950 nm.

14. A semiconductor nanocrystal having an intermediate gap state that donates electrons to the valence band, and in which the conduction band can supply photoexcited electrons to the same intermediate gap state at a narrow energy range of less than 300 meV in FWHM.

15. Composition Cu y Ag 1-y InSe x S 2-x A semiconductor nanocrystal having 0 ≤ x ≤ 2 and 0 ≤ y ≤ 1, and having a distribution of the lowest conduction band state and the highest valence band state with transition energies in a narrow range of less than 300 meV in FWHM.

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