A method for synthesizing tetrapod-shaped HgTe quantum dots with sharp absorption band edges

Abstract

This application provides a method for synthesizing tetrapod-shaped HgTe quantum dots with sharp absorption band edges. The method includes: preparing a tellurium source solution of a first predetermined concentration; preparing a mercury precursor solution of a second predetermined concentration; injecting a predetermined volume of tellurium source solution into the mercury precursor solution using an injection pump at a predetermined injection rate to obtain a quantum dot solution; and growing the quantum dot solution for a predetermined time to obtain tetrapod-shaped HgTe quantum dots. This application synthesizes HgTe quantum dots using a simple injection pump method, with controllable injection rate, injection time, and other process conditions, and high reproducibility of the synthesis process.

Description

Technical Field

[0001] This application relates to the field of infrared optoelectronic materials and their preparation technology, specifically a method for synthesizing tetrapod-shaped HgTe quantum dots with sharp absorption band edges. Background Technology

[0002] Quantum dots are semiconductor nanocrystalline materials synthesized through chemical methods, with characteristic sizes ranging from a few nanometers to tens of nanometers. Compared with traditional semiconductor materials, the unique advantage of quantum dot materials lies in the fact that, by utilizing the quantum size effect, their band gap can be tuned by the particle size, thus meeting different spectral responses, spectral applications, and photoelectric detection requirements.

[0003] Mercury telluride (HgTe) is a special half-metal material with a relatively large exciton Bohr radius (~40 nm). By adjusting the size, the photoresponse of HgTe quantum dots can be extended into the infrared band. Figure 2 More importantly, HgTe quantum dots are binary components and are synthesized using low-temperature colloidal chemistry, so they do not have the component segregation problem present in HgCdTe materials. Therefore, they are considered ideal materials for preparing infrared photodetectors.

[0004] Currently, HgTe quantum dots are mainly synthesized using two methods: one involves injecting tri-n-octylphosphine telluride (TOPTe) into an oleylamine solution of mercuric chloride, and the other involves injecting bis(trimethylsilyl)telluride (TMSTe) into an oleylamine solution of mercuric chloride. When using TOPTTe as the tellurium source, the synthesized HgTe quantum dots exhibit sharp exciton absorption peaks, but quantum dot aggregation is severe, resulting in poor stability and hindering subsequent processing. Some researchers have also obtained monodisperse HgTe quantum dots by controlling the nucleation and growth process through ligand engineering, but this involves multi-step injection and growth time control, making process control difficult. The other mainstream method, using TMSTe as the tellurium source, produces HgTe quantum dots with good monodispersity and ease of processing, but the quantum dots exhibit poor exciton absorption characteristics. Meanwhile, TMSTe has poor stability, is difficult to store, and is expensive, making large-scale industrial production challenging. Therefore, developing a new, simple, controllable method for synthesizing HgTe quantum dots with sharp absorption band edges and good processability is particularly important.

[0005] Therefore, overcoming the shortcomings of the existing technology is an urgent problem to be solved in this technical field. Summary of the Invention

[0006] The main technical problem addressed in this application is to provide a method for synthesizing tetrapod-shaped HgTe quantum dots with sharp absorption band edges. By improving the key preparation method principles and process conditions of each growth reaction step, this application focuses on effectively solving the problems of smooth absorption band edges, poor synthesis reproducibility, and high cost of HgTe quantum dots compared with existing technologies.

[0007] To solve the above-mentioned technical problems, one technical solution adopted in this application is: a method for synthesizing tetrapod-shaped HgTe quantum dots with sharp absorption band edges, comprising:

[0008] Prepare a tellurium source solution of a first preset concentration;

[0009] Prepare a mercury precursor solution of a second preset concentration;

[0010] A predetermined volume of tellurium source solution is injected into the mercury precursor solution at a predetermined injection rate using an injection pump to obtain a quantum dot solution.

[0011] After a preset time, tetrapod-shaped HgTe quantum dots were obtained by reacting and growing quantum dot solution.

[0012] Optionally, the preparation of the mercury precursor solution of the second preset concentration includes:

[0013] The halogenated compounds of mercury are dissolved in an oleylamine solution to form a mixture;

[0014] Under an inert atmosphere, the mixture is kept at 80°C to 150°C for 20 min to 40 min, and then cooled to 35°C to 145°C to obtain a mercury precursor solution of the second preset concentration, wherein the second preset concentration is 20 mmol / L to 90 mmol / L.

[0015] Optionally, the mercury halogen compound is any one of mercuric chloride, mercuric bromide, or mercuric iodide.

[0016] Optionally, the preparation of the tellurium source solution of the first preset concentration includes:

[0017] Dissolve 0.127 g to 2.54 g of tellurium in 10 mL of organophosphorus solution;

[0018] Heat to 150°C under an inert atmosphere and maintain for 8 hours until the tellurium is completely dissolved;

[0019] The solution was allowed to cool naturally to room temperature, resulting in a tellurium source solution of the first preset concentration.

[0020] Optionally, the preset volume is 3 ml, and the first preset concentration is 0.05 mmol / L to 2 mmol / L.

[0021] Optionally, the organophosphorus solution is either trioctylphosphine (TOP) or tributylphosphine (TBP).

[0022] Optionally, the preset injection rate is 0.15 mL / min to 1.5 mL / min.

[0023] Optionally, the step of obtaining tetrapod-shaped HgTe quantum dots by reacting and growing the quantum dot solution for a preset time includes:

[0024] After maintaining the quantum dot solution for a preset growth time, a quenching agent is injected into the quantum dot solution to quench the reaction, and the solution is cooled to room temperature in an ice bath.

[0025] The quenched solution was poured into a centrifuge tube, and an antisolvent was added to the centrifuge tube to precipitate and centrifuge, resulting in black powdery tetrapod HgTe quantum dots.

[0026] Optionally, the antisolvent is any one of methanol, ethanol, isopropanol, and acetone; the quenching agent is any one of tetrachloroethylene, n-hexane, and n-octane.

[0027] Optionally, the tetrapod HgTe quantum dots have a tetrapod shape, an aspect ratio greater than 2, a length of 3 nm to 18 nm for the tetrapod branches, and an absorption cutoff band edge between 1.3 μm and 5 μm.

[0028] The beneficial effects of this application are as follows: A tellurium source solution of a first preset concentration is prepared; a mercury precursor solution of a second preset concentration is prepared; a tellurium source solution of a preset volume is injected into the mercury precursor solution using an injection pump at a preset injection rate to obtain a quantum dot solution; and tetrapod-shaped HgTe quantum dots are obtained by reacting and growing the quantum dot solution for a preset time. This application synthesizes HgTe quantum dots using a simple injection pump method, with controllable injection rate, injection time, and other process conditions, and high reproducibility of the synthesis process.

[0029] Furthermore, in this application, the tellurium source is added gradually dropwise into the mercury precursor solution at a constant injection rate. In the early stages of the injection process, the tellurium source reacts with excess mercury precursor to form nuclei, during which the number of quantum dot nuclei gradually increases. As more tellurium source is added, the subsequently added portion reacts on the surface of the already nucleated quantum dots, continuing to grow and causing the quantum dots to gradually form a tetrapod-like branched structure with progressively increasing branch length, resulting in the growth of tetrapod-like HgTe quantum dots. Therefore, this application can prepare HgTe quantum dots of different sizes without changing the ratio of mercury and tellurium sources, simply by adjusting the synthesis temperature.

[0030] Furthermore, the HgTe quantum dots prepared in this application exhibit excellent exciton absorption characteristics with sharp absorption band edges. By changing the size of the HgTe quantum dots, the absorption band edge can be adjusted from 1.3 μm to 5 μm.

[0031] Furthermore, this application uses TOPTTe and TPTTe as tellurium sources, which are cheaper, more stable, and easier to mass-produce than TMSTe. Attached Figure Description

[0032] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the embodiments of this application will be briefly described below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0033] Figure 1 This is a schematic flowchart of a method for synthesizing tetrapod-shaped HgTe quantum dots with sharp absorption band edges, provided in an embodiment of this application.

[0034] Figure 2 This is a schematic diagram illustrating the principle of a method for synthesizing tetrapod-shaped HgTe quantum dots with sharp absorption band edges, as provided in an embodiment of this application.

[0035] Figure 3 This application provides a method for synthesizing tetrapod-shaped HgTe quantum dots with sharp absorption band edges, which yields TEM images of tetrapod-shaped HgTe quantum dots of different sizes.

[0036] Figure 4 This is an infrared absorption spectrum of HgTe quantum dots obtained by a method for synthesizing tetrapod-shaped HgTe quantum dots with sharp absorption band edges provided in an embodiment of this application;

[0037] Figure 5 This is an XRD pattern of HgTe quantum dots obtained by a method for synthesizing tetrapod-shaped HgTe quantum dots with sharp absorption band edges, as provided in an embodiment of this application. Detailed Implementation

[0038] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0039] In the description of this application, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings, are used only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include one or more features. In the description of this application, "a plurality of" means two or more, unless otherwise explicitly specified.

[0040] In this application, the term "exemplary" is used to mean "used as an example, illustration, or description." Any embodiment described as "exemplary" in this application is not necessarily to be construed as being more preferred or advantageous than other embodiments. The following description is provided to enable any person skilled in the art to make and use this application. Details are set forth in the following description for purposes of explanation. It should be understood that those skilled in the art will recognize that this application can be made without using these specific details. In other instances, well-known structures and processes are not described in detail to avoid obscuring the description of this application with unnecessary detail. Therefore, this application is not intended to be limited to the embodiments shown, but is consistent with the broadest scope of the principles and features disclosed in this application.

[0041] Example 1:

[0042] To address the aforementioned problems, this embodiment provides a method for synthesizing tetrapod-shaped HgTe quantum dots with sharp absorption band edges, comprising:

[0043] Step 101: Prepare a tellurium source solution of the first preset concentration.

[0044] In this embodiment of the application, the preparation of a tellurium source solution of the first preset concentration includes: dissolving 0.127g of tellurium material in 10mL of tri-n-octylphosphine solution; heating to 150°C under an inert atmosphere and maintaining it for 8 hours until the tellurium material is completely dissolved; and allowing it to cool naturally to room temperature to obtain a tellurium source solution of the first preset concentration.

[0045] The preset volume is 3 ml, and the first preset concentration is 0.1 mmol / L.

[0046] The tellurium source solution can be either TOPTTe or TPTTe.

[0047] Step 102: Prepare a mercury precursor solution of a second preset concentration.

[0048] In this embodiment, the second preset concentration is 20 mmol / L to 90 mmol / L. The concentration of the mercury precursor in the mercury precursor solution is 20 mmol / L to 90 mmol / L.

[0049] In this embodiment of the application, preparing a mercury precursor solution of a second preset concentration may include:

[0050] (1) Dissolve mercury halogens in an oleylamine solution to form a mixture.

[0051] Among them, the halogenated compounds of mercury are any one of mercuric chloride, mercuric bromide or mercuric iodide.

[0052] (2) Under an inert atmosphere, the mixture is kept at 80°C to 150°C for 20 min to 40 min, and then cooled to 35°C to 145°C to obtain a mercury precursor solution of the second preset concentration.

[0053] That is, under an inert atmosphere, the mixture is kept at 80°C to 150°C for 20 to 40 minutes, and then cooled to 35°C to 145°C to obtain a mercury precursor solution with a concentration of 20 mmol / L to 90 mmol / L. The inert atmosphere can be a nitrogen or argon atmosphere, etc.

[0054] Specifically, 0.271 g of mercuric chloride and 20 mL of oleylamine were weighed into a reaction flask. The mixture was heated to 90 °C under an inert atmosphere and kept at that temperature for 30 min. Then, it was cooled to 95 °C to obtain a 50 mmol / L mercury precursor solution.

[0055] Step 103: Using an injection pump, inject a preset volume of tellurium source solution into the mercury precursor solution at a preset injection rate to obtain a quantum dot solution.

[0056] The preset injection rate is 0.15 mL / min to 1.5 mL / min.

[0057] Step 104: After the quantum dot solution is reacted and grown for a preset time, tetrapod-shaped HgTe quantum dots are obtained.

[0058] In this embodiment of the application, tetrapod-shaped HgTe quantum dots are obtained by reacting and growing a quantum dot solution for a preset time, including:

[0059] (1) After maintaining the quantum dot solution for a preset growth time, inject a quenching agent into the quantum dot solution to quench the reaction and cool it to room temperature in an ice bath.

[0060] The preset duration is 2 minutes.

[0061] (2) Pour the quenched solution into a centrifuge tube, add antisolvent to the centrifuge tube to precipitate and centrifuge, and obtain black powdery tetrapod HgTe quantum dots.

[0062] The antisolvent is any one of methanol, ethanol, isopropanol, and acetone. The quenching agent is any one of tetrachloroethylene, n-hexane, and n-octane. The tetrapod HgTe quantum dots have a tetrapod shape with an aspect ratio greater than 2, the length of the tetrapod branches is between 3 nm and 18 nm, and the absorption cutoff band edge is between 1.3 μm and 5 μm.

[0063] Steps 101 to 104 are all performed under nitrogen or argon protection.

[0064] Example 2:

[0065] To address the aforementioned problems, this embodiment provides a method for synthesizing tetrapod-shaped HgTe quantum dots with sharp absorption band edges, comprising:

[0066] (1) Preparation of a tellurium source solution with a first preset concentration: Weigh 1.27 g of tellurium material and dissolve it in 10 mL of organophosphorus solution. Heat the solution to 150 °C under an inert atmosphere and maintain the temperature for 8 hours until the tellurium material is completely dissolved. Then allow it to cool naturally to room temperature to obtain a 1 mol / mL TOPTe solution. The organophosphorus solution is either trioctylphosphine (TOP) or tributylphosphine (TBP).

[0067] (2) Preparation of a second preset concentration of mercury precursor solution: Weigh 0.45 g of mercuric chloride and measure 20 mL of oleylamine in a reaction flask. Place the mixture in an inert atmosphere and heat it to 80 °C, keeping the temperature stable.

[0068] (3) Using an injection pump, inject 3 mL of TOPTe solution at a rate of 1 mL / min.

[0069] (4) After maintaining growth for 2 min, inject 10 mL of octane solvent to quench the reaction and cool to room temperature in an ice bath;

[0070] (5) Pour the quenched solution into a centrifuge tube, add anhydrous ethanol as an antisolvent to the centrifuge tube to precipitate, and the resulting black powder is HgTe quantum dots.

[0071] Example 3:

[0072] To address the aforementioned problems, this embodiment provides a method for synthesizing tetrapod-shaped HgTe quantum dots with sharp absorption band edges, comprising:

[0073] (1) Preparation of tellurium source solution of the first preset concentration: Weigh 2.54g of tellurium material and dissolve it in 10mL of tri-n-octylphosphine solution. Heat it to 150℃ under an inert atmosphere and maintain it for 8 hours until the tellurium material is completely dissolved. Then let it cool naturally to room temperature to obtain a 2mol / mL TOPTTe solution.

[0074] (2) Preparation of a mercury precursor solution of a second preset concentration: Weigh 2.71 g of mercuric chloride and measure 20 mL of oleylamine in a reaction flask. Heat the mixture to 90 °C under an inert atmosphere and keep the temperature stable.

[0075] (3) Using an injection pump, inject 3 mL of TOPTe solution at a rate of 0.3 mL / min;

[0076] (4) After maintaining growth for 2 min, inject 10 mL of octane solvent to quench the reaction and cool to room temperature in an ice bath;

[0077] (5) Pour the quenched solution into a centrifuge tube, add anhydrous ethanol as an antisolvent to the centrifuge tube to precipitate, and the resulting black powder is HgTe quantum dots.

[0078] Example 4:

[0079] (1) Preparation of tellurium source solution of the first preset concentration: Weigh 1.27g of tellurium material and dissolve it in 10mL of tri-n-octylphosphine solution. Heat it to 150℃ under an inert atmosphere and maintain it for 8 hours until the tellurium material is completely dissolved. Then let it cool naturally to room temperature to obtain a 1mol / mL TOPTTe solution.

[0080] (2) Preparation of a mercury precursor solution of a second preset concentration: Weigh 0.271 g of mercuric chloride and measure 20 mL of oleylamine in a reaction flask. Heat the mixture to 100 °C under an inert atmosphere and keep the temperature stable.

[0081] (3) Using an injection pump, inject 3 mL of TOPTe solution at a rate of 1.2 mL / min;

[0082] (4) After maintaining growth for 2 min, inject 10 mL of tetrachloroethylene solvent to quench the reaction and cool to room temperature in an ice bath;

[0083] (5) Pour the quenched solution into a centrifuge tube, add the antisolvent isopropanol to the centrifuge tube to precipitate, and the resulting black powder is HgTe quantum dots.

[0084] Example 5:

[0085] (1) Preparation of tellurium source solution of the first preset concentration: Weigh 2.54g of tellurium material and dissolve it in 10mL of tri-n-octylphosphine solution. Heat it to 150℃ under an inert atmosphere and maintain it for 8 hours until the tellurium material is completely dissolved. Then let it cool naturally to room temperature to obtain a 1mol / mL TOPTTe solution.

[0086] (2) Preparation of a mercury precursor solution of a second preset concentration: Weigh 0.271 g of mercuric chloride and measure 20 mL of oleylamine in a reaction flask. Heat the mixture to 110 °C under an inert atmosphere and keep the temperature stable.

[0087] (3) Using an injection pump, inject 3 mL of TOPTe solution at a rate of 0.8 mL / min;

[0088] (4) After maintaining growth for 2 min, inject 10 mL of octane solvent to quench the reaction and cool to room temperature in an ice bath;

[0089] (5) Pour the quenched solution into a centrifuge tube, add the antisolvent acetone to the centrifuge tube to precipitate, and the resulting black powder is HgTe quantum dots.

[0090] Example 6:

[0091] (1) Preparation of tellurium source solution of the first preset concentration: Weigh 1.27g of tellurium material and dissolve it in 10mL of tributylphosphine solution. Heat it to 150℃ under an inert atmosphere and maintain it for 8 hours until the tellurium material is completely dissolved. Then let it cool naturally to room temperature to obtain a 1mol / mL TPTe solution.

[0092] (2) Preparation of a mercury precursor solution of a second preset concentration: Weigh 0.271 g of mercuric chloride and measure 20 mL of oleylamine in a reaction flask. Heat the mixture to 80 °C under an inert atmosphere and keep the temperature stable.

[0093] (3) Using an injection pump, inject 3 mL of TBPTe solution at a rate of 0.8 mL / min;

[0094] (4) After maintaining growth for 2 min, inject 10 mL of octane solvent to quench the reaction and cool to room temperature in an ice bath;

[0095] (5) Pour the quenched solution into a centrifuge tube, add anhydrous ethanol as an antisolvent to the centrifuge tube to precipitate, and the resulting black powder is HgTe quantum dots.

[0096] This application prepares a tellurium source solution of a first preset concentration; prepares a mercury precursor solution of a second preset concentration; injects a preset volume of tellurium source solution into the mercury precursor solution using an injection pump at a preset injection rate to obtain a quantum dot solution; and grows the quantum dot solution for a preset time to obtain tetrapod-shaped HgTe quantum dots. This application synthesizes HgTe quantum dots using a simple injection pump method, with controllable injection rate, injection time, and other process conditions, and high reproducibility of the synthesis process.

[0097] Furthermore, in this application, the tellurium source is added gradually dropwise into the mercury precursor solution at a constant injection rate. In the early stages of the injection process, the tellurium source reacts with excess mercury precursor to form nuclei, during which the number of quantum dot nuclei gradually increases. As more tellurium source is added, the subsequently added portion reacts on the surface of the already nucleated quantum dots, continuing to grow and causing the quantum dots to gradually form a tetrapod-like branched structure with progressively increasing branch length, resulting in the growth of tetrapod-like HgTe quantum dots. Therefore, this application can prepare HgTe quantum dots of different sizes without changing the ratio of mercury and tellurium sources, simply by adjusting the synthesis temperature.

[0098] Furthermore, the HgTe quantum dots prepared in this application exhibit excellent exciton absorption characteristics with sharp absorption band edges. By changing the size of the HgTe quantum dots, the absorption band edge can be adjusted from 1.3 μm to 5 μm.

[0099] Furthermore, this application uses TOPTTe and TPTTe as tellurium sources, which are cheaper, more stable, and easier to mass-produce than TMSTe.

[0100] The above are merely embodiments of this application and do not limit the scope of this patent application. Any equivalent structural or procedural changes made using the content of this application's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the scope of patent protection of this application.

Claims

1. A method for synthesizing tetrapod-shaped HgTe quantum dots with sharp absorption band edges, characterized in that, include: Prepare a tellurium source solution of a first preset concentration; Prepare a mercury precursor solution of a second preset concentration; A predetermined volume of tellurium source solution is injected into the mercury precursor solution at a predetermined injection rate using an injection pump to obtain a quantum dot solution. After a preset time, tetrapod-shaped HgTe quantum dots were obtained by reaction growth of quantum dot solution. The preparation of the mercury precursor solution of the second preset concentration includes: The halogenated compounds of mercury are dissolved in an oleylamine solution to form a mixture; Under an inert atmosphere, the mixture is kept at 80°C to 150°C for 20 min to 40 min, and then cooled to 35°C to 145°C to obtain a mercury precursor solution of the second preset concentration, wherein the second preset concentration is 20 mmol / L to 90 mmol / L. The tetrapod-shaped HgTe quantum dots are tetrapod-shaped with an aspect ratio greater than 2. The length of the tetrapod branches is 3nm to 18nm, and the absorption cutoff band edge is 1.3μm to 5μm.

2. The method for synthesizing tetrapod-shaped HgTe quantum dots with sharp absorption band edges as described in claim 1, characterized in that, The halogenated mercury compound is any one of mercuric chloride, mercuric bromide, or mercuric iodide.

3. The method for synthesizing tetrapod-shaped HgTe quantum dots with sharp absorption band edges as described in claim 1, characterized in that, The preparation of the tellurium source solution of the first preset concentration includes: Dissolve 0.127 g to 2.54 g of tellurium in 10 mL of organophosphorus solution; Heat to 150°C under an inert atmosphere and maintain for 8 hours until the tellurium is completely dissolved; The solution was allowed to cool naturally to room temperature, resulting in a tellurium source solution of the first preset concentration.

4. The method for synthesizing tetrapod-shaped HgTe quantum dots with sharp absorption band edges as described in claim 3, characterized in that, The preset volume is 3 ml, and the first preset concentration is 0.05 mmol / L to 2 mmol / L.

5. The method for synthesizing tetrapod-shaped HgTe quantum dots with sharp absorption band edges as described in claim 3, characterized in that, The organophosphorus solution is either trioctylphosphine (TOP) or tributylphosphine (TBP).

6. The method for synthesizing tetrapod-shaped HgTe quantum dots with sharp absorption band edges as described in claim 1, characterized in that, The preset injection rate is 0.15 mL / min to 1.5 mL / min.

7. The method for synthesizing tetrapod-shaped HgTe quantum dots with sharp absorption band edges as described in claim 1, characterized in that, The process of obtaining tetrapod-shaped HgTe quantum dots by reacting and growing a quantum dot solution for a predetermined time includes: After maintaining the quantum dot solution for a preset growth time, a quenching agent is injected into the quantum dot solution to quench the reaction, and the solution is cooled to room temperature in an ice bath. The quenched solution was poured into a centrifuge tube, and an antisolvent was added to the centrifuge tube to precipitate and centrifuge, resulting in black powdery tetrapod HgTe quantum dots.

8. The method for synthesizing tetrapod-shaped HgTe quantum dots with sharp absorption band edges as described in claim 7, characterized in that, The antisolvent is any one of methanol, ethanol, isopropanol, and acetone; the quenching agent is any one of tetrachloroethylene, n-hexane, and n-octane.

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