Radiation detector

Abstract

Radiation detector. A device (1) for converting incident radiation into positive and negative charges, comprising a network (2) including a first semiconductor material for transporting positive charges and a second semiconductor material for transporting negative charges. The first and second semiconductor materials are dispersed within the network to provide a plurality of electrical junctions, wherein the network further comprises a plurality of nanostructure aggregates (3) dispersed within the network, the nanostructure aggregates (3) comprising a plurality of regions and / or interfaces having different relative permittivity that can generate dielectric heterogeneity within the nanostructure aggregates.

Description

Technical Field

[0001] The present invention relates to radiation detection, particularly radiation detection devices and related methods, etc. The present invention further relates to devices, apparatuses, and methods for converting incident radiation into positive and negative charges.

Background Art

[0002] Due to the widespread use of ionizing radiation (e.g., nuclear radiation) in a wide range of applications such as industrial applications like radiation therapy, security inspections, and non-destructive testing (NDT), the development of appropriate radiation detection technologies is required. Here, both the terms "ionizing radiation" and "nuclear radiation" are considered to include alpha particles, beta particles, X-rays, gamma rays, etc.

[0003] Common nuclear radiation detectors typically comprise semiconductor devices such as silicon (Si) or germanium (Ge). These solid devices detect nuclear radiation or ionizing radiation by measuring the number of charge carriers (electrons and holes) generated within the volume of the detector in response to incident radiation. When photons or particles of high-energy radiation collide with the active semiconductor material within the detector, ionization occurs and charge carriers are generated. Ionization occurs when external radiation frees electrons from the inner shell of an atom or when high-speed radiation interacts with a solid material, resulting in the generation of charges within the device structure. The generated charge carriers are accelerated under the action of an electric field generated by an applied voltage bias. This results in an electric current that can be easily collected by electrodes. The current can be found to be proportional to the amount of radiation deposited in the material.

[0004] Depending on the energy of the photons of the incident radiation and the atomic number (Z) of the material, there are three main mechanisms widely considered when a substance interacts with incident photons, namely, the photoelectric effect, Compton scattering, and pair production. Detectors typically measure the incident amount of radiation, spatial distribution, radiation spectrum, and other characteristics.

[0005] Solid-state inorganic radiation detectors based on silicon are known. However, despite their excellent performance, these inorganic detectors have major drawbacks due to the crystalline detector material used, such as poor manufacturability of curved shapes, brittle active materials, high manufacturing costs, and limited detector size.

[0006] Compared to more established inorganic counterparts, organic semiconductors (e.g., semiconductor polymers) offer several advantages that make them attractive candidates for large-area, low-cost electronics. Inks composed of these organic semiconductors can be prepared by dissolving conjugated polymers, oligomers, and low-molecular-weight compounds in common organic solvents. These inks can then be easily coated onto substrates using conventional wet process techniques, leading to the possibility of producing large-area devices at extremely low cost. Their flexible properties allow large-area organic semiconductor-based detector panels to be formed into curved shapes, such as tubes for placement around piping to monitor radioactive fluids. Flexible organic dosimeters can also be used as patient dosimeters for X-ray diagnosis or cancer treatment, for example, by forming large-area pixelated detection tubes around parts of a patient's body, such as limbs, to provide localized dose measurements with spatial resolution.

[0007] Some known characteristics of high-energy radiation detectors include low dark current (leakage current), good rectification behavior, high charge carrier mobility, and high radiation stopping power. Generally, radiation detectors are classified as either "direct" or "indirect" detectors.

[0008] To date, it has been shown that radiation-induced photocurrents can be achieved in metal, semiconductor polymer, and metal device architectures in direct radiation detectors using single homogeneous materials such as poly(triarylamine) (PTAA) and poly([9,9-dioctylfluorenyl-2,7-diyl]-coubithiophene) (F8T2). While such materials are active polymer materials, they can only transport one type of charge (electrons or holes). The monocarrier characteristics of devices incorporating a single homogeneous material (single organic semiconductor system) reduce the overall signal response that can be achieved.

[0009] Organic semiconductors are typically composed of carbon and hydrogen atoms with low atomic numbers (low Z), resulting in low stopping power (attenuation) to high-energy radiation. Therefore, for organic material detectors to operate efficiently, they need to be very thick to generate sufficient ionization events to produce a detectable current. However, because the mobility of detected carriers is very low within organic materials (polymer materials are typically insulators due to the lack of free carriers, resulting in low charge mobility), increasing thickness reduces the efficiency of charge sweeping, requiring very high electric fields. Such high electric fields can destroy the material, making it difficult to fabricate a compromise structure that achieves both high collection efficiency and high ionization.

[0010] In the case of typical semiconductor devices such as silicon, high charge mobility and a small ionization cross-section can be achieved in radiation detection. Therefore, silicon radiation detectors can be made very thick, but consequently, the detectors become very hard and brittle. Furthermore, due to the interaction of radiation throughout the device, a high electric field is required to sweep the ionized charge carriers, resulting in the creation of expensive devices with electric fields incompatible with standard CMOS ICs (complementary metal-oxide-semiconductor integrated circuits). In addition, the indirect band gap reduces the efficiency of radiation capture within these devices, and the footprint is inevitably smaller due to the additional processing required on the silicon wafer.

[0011] Current polymer and organic solar cells exhibit relatively low conversion efficiencies. However, these technologies have been developed over many years, and power conversion efficiencies of 10-20% are now routinely achieved.

[0012] Therefore, these solar cell devices may be able to achieve a certain level of efficiency if manufactured as thin films with a thickness of approximately 100 nm to 10 microns. Furthermore, the organic or polymer materials used to manufacture the majority of the devices offer advantages in terms of flexibility and large-area manufacturing. However, because organic / polymer materials have low efficiency in blocking X-rays or gamma rays, these devices are generally unsuitable for radiation detection.

[0013] In a previous patent application, the applicant demonstrated that by incorporating bismuth oxide nanoparticles (NPs) along with other nanoparticles and nanostructures having a much higher Z number (atomic number) compared to bulk heterojunction (BHJ) polymers into the active heterojunction region of organic or polymer solar cells, it is possible to attenuate X-ray radiation signals and generate enough electron-hole pairs to sweep the entire device, such as a diode, to fabricate an efficient X-ray detector.

[0014] Device efficiency improved with increasing nanoparticle content, demonstrating that higher detector currents could be obtained as radiation attenuation increased. However, increasing NP content had a negative effect, causing organic / polymer detectors to lose flexibility and become more rigid, meaning they were no longer considered flexible materials that could be processed using large-area solution-processable techniques. Therefore, detectors needed to find a compromise between increasing the cross-sectional depth of the active capture portion of the detection component and maintaining device flexibility and processability. [Overview of the project] [Problems that the invention aims to solve]

[0015] The present invention aims to solve at least some of the problems outlined above. [Means for solving the problem]

[0016] According to a first aspect, the present invention provides a device for converting incident radiation into positive and negative charges. The device comprises a network having a first semiconductor material for transporting positive charges and a second semiconductor material for transporting negative charges, wherein the first and second semiconductor materials are dispersed within the network to provide a plurality of electrical junctions, and the network further comprises a plurality of nanostructured aggregates dispersed within the network, the nanostructured aggregates comprising a plurality of regions and / or interfaces of different dielectric constants that can generate dielectric heterogeneity within the nanostructured aggregates.

[0017] Preferably, the nanostructure aggregate comprises multiple regions having different dielectric constants, and the interface regions between these regions are at or within the wavelength of the incident radiation.

[0018] Preferably, the nanostructure aggregate includes multiple regions with different dielectric constants that are substantially distributed throughout and / or across the aggregate.

[0019] Preferably, the nanostructure aggregate includes multiple interface regions substantially distributed throughout the aggregate and / or across the aggregate.

[0020] Preferably, the nanostructure aggregate includes an interface or interface region in at least one arbitrary direction that is approximately the same size as, or within the size of, the wavelength of the incident radiation.

[0021] Preferably, the nanostructured aggregate has a porosity or void ratio of about 0.01 to about 0.99, about 0.05 to about 0.7, or about 0.1 to about 0.3.

[0022] Preferably, the nanostructured aggregate includes one or more, or a plurality of solid nanoparticle structures, and one or more, or a plurality of voids provided between the one or more, or a plurality of solid nanoparticle structures.

[0023] Preferably, the void is air or vacuum.

[0024] Preferably, the aggregate can accelerate and decelerate the received radiation and generate one or more, or a plurality of positively or negatively charged charge accumulations within the surface structure of the aggregate.

[0025] Preferably, the surface structure of the aggregate, whether it is an external or / and internal surface structure, can interact with the incident radiation to attenuate the radiation and improve the conversion to positive and negative charges.

[0026] Preferably, the nanostructured aggregate is configured to act as a local inhomogeneity that can attract and concentrate an electric field.

[0027] Preferably, the nanostructured aggregate is configured to convert the radiation into positive and negative charges in the interaction event between the radiation and the aggregate.

[0028] Preferably, the nanostructured aggregate has a size in the range of 20 - 100 nm, which is preferable for the detection of X-ray radiation.

[0029] Preferably, the nanostructured aggregate is a doped nanostructured aggregate having an additional electron-containing element or hole-containing element.

[0030] Preferably, the nanostructured aggregate is doped with cesium (Cs) and / or lanthanum (La).

[0031] Preferably, the doped nanostructured aggregate is configured to increase and / or decrease the charge carriers within the nanostructured aggregate.

[0032] Preferably, the doped nanostructure aggregate contains dopant atoms ranging from light elements to heavy elements.

[0033] Preferably, the plurality of nanostructure aggregates have one or more optimized parameters selected from the group consisting of nanoparticle and / or aggregate size, nanoparticle and / or aggregate distribution, porosity of the nanostructure aggregates, and / or doping.

[0034] Preferably, the first and second semiconductor materials are organic-organic transport materials, inorganic-inorganic transport materials, or organic-inorganic transport materials.

[0035] Preferably, the nanoparticles include high-Z nanoparticles, organic nanoparticles, or a combination thereof.

[0036] Preferably, the particles of the first and / or second semiconductor material are of a size and configured to aggregate, and the first and / or second semiconductor material provides nanoparticles for aggregation without requiring the addition of (further) nanoparticles to form a matrix.

[0037] Preferably, the network is a bulk heterojunction.

[0038] Preferably, the incident radiation includes ionizing radiation. More preferably, the incident radiation includes one or more of alpha particles, beta particles, neutrons, X-rays, and gamma rays. Therefore, preferably, the multiple regions of different dielectric constants include regions and / or interfaces that are on the same wavelength as, or within, the wavelengths of, alpha particles, beta particles, neutrons, X-rays, and / or gamma rays.

[0039] Preferably, the parameters of the nanostructure aggregate are configured to be actively optimized for the detection of defined wavelengths or forms of radiation that are to be detected by the device.

[0040] Preferably, the first semiconductor material comprises P3HT, the second semiconductor material comprises PCBM, and the nanoparticles comprise Bi2O3 doped with cesium (Cs) and / or lanthanum (La) in an optional manner.

[0041] Preferably, multiple regions with different dielectric constants may be generated using plasmonic phenomena. Most preferably, plasmonics involves generating surface charge waves within a network, particularly within metal surfaces or microparticles having regions.

[0042] According to a second aspect, the present invention provides a radiation detector comprising a first electrode, a second electrode, and a device according to the first aspect, disposed between or sandwiched between the first and second electrodes.

[0043] Preferably, the radiation detector is equipped with a current measuring instrument.

[0044] Preferably, the radiation detector includes a voltage source.

[0045] More preferably, the radiation detector includes a wireless transmitter that enables real-time data transmission to a remote computer.

[0046] Preferably, the radiation detector includes a display for showing the radiation level.

[0047] According to a third aspect, the present invention provides a system comprising a plurality of radiation detectors according to the second aspect.

[0048] Preferably, the system comprises a plurality of radiation detectors according to a second embodiment, wherein at least a portion of the plurality of radiation detectors are configured to detect a single type of radiation, to detect a plurality of different types of radiation, and / or to identify different energies of a particular type of radiation.

[0049] Preferably, the device or radiation detector is integrated with either a rigid or flexible backing.

[0050] According to a fourth aspect, the present invention provides a method comprising using a device according to the first aspect, a radiation detector according to the second aspect, or a system according to the third aspect to convert incident radiation into positive and negative charges, and recording the properties generated by the positive and negative charges.

[0051] Preferably, the method further includes converting incident radiation into free positive and negative charges in an interaction event between radiation and aggregates.

[0052] Preferably, the current is generated in response to the application of a voltage to the device. More preferably, the method includes converting the recorded current into an estimate of the radiation level.

[0053] According to a fifth aspect, the present invention provides a process for providing a network for a device for converting incident radiation into positive and negative charges, the process comprising dissolving first and second semiconductors capable of transporting positive and negative charges, respectively, in one or more solvents; adding and dispersing a plurality of nanoparticles to form a matrix; and agglomerating the nanoparticles in the matrix to form a plurality of nanostructure aggregates, the nanostructure aggregates comprising a plurality of regions and / or interfaces with different dielectric constants capable of generating dielectric heterogeneity within the nanostructure aggregates.

[0054] Preferably, the method includes generating a plurality of regions and / or interfaces, one or more solid nanoparticle structures, and one or more voids between the one or more solid nanoparticle structures, which are at or within the wavelength of the incident radiation and have different dielectric constants.

[0055] Preferably, the nanostructure aggregates are formed at least partially within the matrix and / or during the lamination of the matrix onto the substrate, prior to coating the substrate.

[0056] Preferably, the method includes generating one or more solid nanoparticle structures and one or more voids between one or more solid nanoparticle structures.

[0057] Preferably, aggregation involves controlling the solvent, poor solvent, cations, anions, temperature and / or time at which different components are introduced, the rate at which the solvents are mixed, and / or the environment in which the solvents are mixed, in order to optimize the quality, distribution, size and / or other physical properties of the resulting nanostructure aggregates.

[0058] Preferably, forming nanostructured aggregates involves optimizing and controlling one or more parameters from the group including the size of nanoparticles and / or aggregates, the distribution of nanoparticles and / or aggregates, the porosity of the nanostructured aggregates, and / or doping.

[0059] Preferably, the process involves optionally adding a plurality of dopant atoms, including Cs and / or La atoms, before aggregation.

[0060] Preferably, the doped nanostructure aggregates increase and / or decrease the charge carriers within the nanostructure aggregates.

[0061] Preferably, the first and second semiconductor materials are organic-organic transport materials, inorganic-inorganic transport materials, or organic-inorganic transport materials.

[0062] Preferably, the nanoparticles include high-Z nanoparticles, organic nanoparticles, or a combination thereof.

[0063] Preferably, the nanostructured aggregate accelerates and decelerates the received radiation, generating one or more positive or negative charge reservoirs within the surface structure of the aggregate. Preferably, the surface structure of the aggregate, whether external or internal, interacts with the incident radiation to attenuate it and improve its conversion to positive and negative charges.

[0064] Preferably, the nanostructure aggregates act as local heterogeneities to attract and concentrate the electric field.

[0065] Preferably, the nanostructured aggregate converts the radiation into positive and negative charges in interaction events between the radiation and the aggregate.

[0066] Preferably, instead of separately adding nanoparticles, a matrix is ​​formed by dissolving and dispersing the first and second semiconductors in one or more solvents, where the first and / or second semiconductors include a plurality of nanoparticles.

[0067] Preferably, the particles of the first and / or second semiconductor material are of a size and configured to aggregate, and the first and / or second semiconductor material provides nanoparticles for aggregation without requiring the addition of (further) nanoparticles to form a matrix.

[0068] Preferably, the process further comprises coating a matrix onto a substrate, the method including one or more of the doctor blade method, slot die coating, inkjet printing, gravure printing, spray coating, spin coating, drop casting, and / or 3D printing.

[0069] More generally, interfacial layers, surface modifiers and modifiers, bulk modifiers, and passivators may be used to eliminate parts of the recombination pathway and improve device performance.

[0070] The radiation detector may also be equipped with a current measuring instrument.

[0071] The radiation detector may include a voltage source (such as a battery). The voltage source may be provided to apply an electric field to the radiation detector to assist in sweeping electrons and holes to their respective electrodes. As described elsewhere in this specification, such a voltage source may be omitted in some implementations.

[0072] The radiation detector may further include a wireless transmitter that enables real-time data transmission to a remote computer (for example, to enable the dosimeter user to maintain a record of radiation exposure over time and / or to enable the generation of a warning mechanism to notify the user of potential radiation hazards).

[0073] The radiation detector may be equipped with a display for showing the radiation level.

[0074] Incident radiation can be converted into positive and negative charges in interaction events between (single) radiation and aggregates.

[0075] Current can be generated in response to the application of voltage (from the battery) to the device, or, in the absence of an external voltage, by the device's built-in potential.

[0076] The method may further include converting the recorded current into an estimate of the radiation level.

[0077] The matrix may be applied to the substrate using one of several techniques, such as doctor blade method, slot die coating, inkjet printing, gravure printing, spray coating, spin coating, drop casting, and 3D printing. The matrix can be applied by any printing technique, including 3D printing. Printing techniques are not mandatory; the matrix can also be pressed into pellets or tiles, for example, by vapor deposition or sputtering.

[0078] Advantageously, higher attenuation of the X-ray signal can be achieved by reducing the absolute content of NP material. This can be achieved in two ways.

[0079] Firstly, this involves introducing aggregates of NPs that have pockets or air gaps within them. These aggregates still occupy the dimensional space / volume required or used for an apparently larger NP distribution. This can be achieved as a result of dielectric heterogeneity, where the dielectric constant of the material, i.e., relative epsilon, increases or decreases rapidly depending on the material's composition. This is described in detail below with reference to Figure 3a.

[0080] Such rapid increases or decreases in epsilon are due to the presence or absence of material interacting with the incident electromagnetic wave. NP aggregates (referred to in the claims as “nanostructure aggregates”) provide surface variations that interact more strongly with the electronic material, thereby providing larger structures with larger surfaces. This is very similar to the case of plasmonic structures, according to the invention, which have degrees of freedom for surface waves to propagate throughout the entire external volume of the aggregate particles, including gaps or voids of air or vacuum. Radiation of different wavelengths interacts differently with the dimensions of the generated aggregate surface, which can be tuned or adapted during generation to detect and resonate with different energy ranges (this is further elaborated in the exemplary embodiments).

[0081] Secondly, a route to create expanded and enhanced interaction volumes with radiation can be designed by doping NPs with additional electron-containing or hole-containing elements. By "doping," or by increasing / decreasing charge carriers within elemental aggregates loaded into nanocomposites, the interaction volume and plasmonic effects of the enhanced / reduced volume regions can be increased / decreased simply by controlling the dielectric heterogeneity of the structure.

[0082] See Figure 3b, which is described in more detail below. The abrupt change in the epsilon of a material linked to charge via Gauss's law can be given by ∇·D=ρ, where ∇ is the function div or divergence used in Maxwell's laws, Q is the total charge, and D is the electric flux. D is equal to εE, where ε is the dielectric constant or epsilon of the material (a physical parameter that controls the charge transfer field within an electron thin film), and E is the electric field of the entire film. This will be described in more detail in exemplary embodiments.

[0083] When considering mixed-phase materials having doped regions or regions of nanoparticles, advantageously, these high-density regions, aggregates, or portions are high-density "blobs" of the material and can act as local heterogeneities to attract and / or concentrate electric fields, thereby the collected charges acting as Mie scattering points that enhance the charges via plasmonic effects. Similarly, the absence of material or air gaps act as voids in dielectric regions where the epsilon drops sharply from the surrounding material, preferably composed of high-epsilon or high-atomic-density metals.

[0084] This causes abrupt fluctuations in the ∇·D function, generating negative or positive charge accumulations within the aggregate surface. These can act as dielectric heterogeneous points, creating disturbing volumes that interact extensively with radiation and act to attenuate the signal, providing more charge carriers for signal capture.

[0085] Advantageously, the aggregates, through the absence of continuous particulate matter as demonstrated in metasurfaces, possess a surface similar to appropriately sized radiation-destroyed nanoparticles, providing conversion to positive and negative charges. Even more advantageously, the aggregates act as appropriately sized nanoparticles to provide conversion to free positive and negative charges through direct radiation conversion.

[0086] Advantageously, detection is the result of charge ionization caused by the acceleration, deceleration, or both acceleration and deceleration of radiation when confined within heterogeneous regions of the aggregate, where heterogeneity is the absence of voids or solid nanoparticles / materials within the “active capture cross-section” of the detection component, which is nanostructured within the aggregate in the form of solid nanoparticles or structured into an electronically active device within the radiation detector system.

[0087] Advantageously, when using mixed organic-inorganic transport systems with materials such as lead-based perovskite as the inorganic component, power conversion efficiencies as high as 25% have been recorded.

[0088] Advantageously, in at least one embodiment, the present invention provides a plastic electron X-ray radiation detector that maintains flexibility and provides efficient radiation detection, while its properties can be optimized or tuned during manufacturing, at least through the size of the NP, to attenuate the incident X-ray signal.

[0089] Therefore, as those skilled in the art will understand, in the case of electromagnetic (EM) waves, a change in dielectric constant, i.e., "epsilon," generates a delta function of wave continuity, which forms the basis for perturbation of the EM wave, altering its propagation and causing signal attenuation. The presence or absence of another material, the presence of one or more voids, and / or multiple such embodiments throughout the aggregate provided to a region and / or interface of a size comparable to or within the wavelength of the EM wave, cause wave perturbation (in those regions), thereby first slowing or accelerating the group velocity of the wave, producing an effect detectable as an electric current.

[0090] The present invention is disclosed merely as an example with reference to the following drawings. [Brief explanation of the drawing]

[0091] [Figure 1] This is a schematic diagram of a device relating to one embodiment of the present invention. [Figure 2] Figure 1 is a schematic diagram of a radiation detector including the device. [Figure 3a] Figure 1 is a schematic diagram of the aggregate of the device. [Figure 3b] Figure 1 is a schematic diagram of the doped aggregate of the device. [Figure 4] Figure 2 is a flowchart showing the intended use of the radiation detector. [Figure 5] This graph shows the effect of Bi2O3NP content on sensitivity. [Figure 6] This graph shows the effect of Bi2O3 nanoparticle diameter on sensitivity. [Figure 7] This graph shows the effect of high-Z material thickness on sensitivity. [Figure 8] This graph shows the effect of BHJ thickness on sensitivity when using doped Bi2O3. [Modes for carrying out the invention]

[0092] Figure 1 shows a device, generally indicated by reference numeral 1, which comprises a bulk material 2 and a plurality of nanostructure aggregates 3 dispersed within the bulk material 2. The bulk material 2 provides a network having a first semiconductor material for transporting positive charges and a second semiconductor material for transporting negative charges, the first and second materials being dispersed within the network to form a plurality of electrical junctions.

[0093] The nanostructured aggregate 3, shown in detail in Figures 3a and 3b, consists of a plurality of aggregated primary particles 4 having interparticle pores 5 (voids or gaps) between them, the effect of which is to provide a dielectric constant different from that of the primary particles 4 in the gaps 5. Thus, the nanostructured aggregate 3 has multiple regions of different relative permittivity that can generate dielectric heterogeneity within the nanostructured aggregate 3. The multiple regions and / or interfaces of different relative permittivity can be configured and predetermined to have a size comparable to, or within, the wavelength of the incident radiation to be detected.

[0094] Figure 3a shows an undoped nanostructure aggregate 3, while Figure 3b shows a doped nanostructure aggregate 3', which additionally contains dopant atoms 6. Dopant 6 is shown in close proximity to the primary nanoparticle 4', transferring a negative charge 7 to the primary nanoparticle 4'. This is an example of electron transfer through doping. Of course, as explained above, other effects can also be provided through doping.

[0095] The first and second semiconductor materials may be organic-organic transport materials, inorganic-inorganic transport materials, or organic-inorganic transport materials. Interfaces 8 are provided between primary particles 4, dopant atoms 6, and / or interparticle pores 5. Interfaces are provided at junctions of adjacent primary particles 4 (for example, as shown in Figures 3a and 3b), junctions between primary particles 4 and interparticle pores 5, junctions between primary particles 4 and dopant atoms 6, and / or junctions between dopant atoms 6 and interparticle pores 5.

[0096] By creating aggregates of NP4 3, 3' that have internal air gaps (voids) 5 and solid NP regions, but still occupy a dimensional space or volume of an apparently larger NP distribution, a volume is generated that has the absence or presence of material interacting with the incident electromagnetic wave. This volume has surface variations that interact more strongly with the electronic material, thereby generating a larger apparent surface (very similar to the case of plasmonic structures) and providing a degree of freedom for surface waves to propagate throughout the larger "external volume" of the aggregated particles, including air or vacuum gaps. Alternatively, similar results can be achieved by generating charge reservoirs using, at least, different NP sizes, different NP distributions, different dopings, or different void distributions within the aggregates. Dielectric heterogeneity generates rapidly changing delta electric flux, altering the statistical behavior of the charge.

[0097] Figure 2 shows a radiation detector, collectively indicated by reference numeral 10, which comprises the device 1 described above with reference to Figure 1. The detector 10 comprises a first electrode 11, a second electrode 12, a substrate 13, a current meter 14, and a voltage source 15 (such as a battery). As shown in Figure 2, the device 1 is sandwiched between the first and second electrodes 11 and 12.

[0098] As indicated by arrow 16 in Figure 2, radiation is incident on the detector 10. The radiation interacts with device 1, generating a current detectable by the current meter 14. The bulk material 2 forms a bulk heterojunction (BHJ) 2. In this example, the BHJ 2 is an interpenetration network of organic hole transporters / p-type semiconductors / electron donors and organic electron transporters / n-type semiconductors / electron acceptors. The interaction between these electron donor and electron acceptor materials results in the formation of an electrical junction (or nanoscale diode) that exists throughout the entire volume of the device.

[0099] The proximity of the electrical junction to the aggregate 3 maximizes the number of charge carriers 17a;17b extracted as current (and therefore detected by the current meter 14). In other words, the aggregate is located in an essentially built-in depletion region. BHJ2 assists in the extraction of charge carriers from the entire active polymer layer. Thus, these systems can operate at very low voltages (<10V) or even 0V. Such low-voltage operation is particularly ideal for portable radiation monitors that generally require a low-voltage source (e.g., voltage source 15), such as a battery, to enable the operation of the detector 10. The thickness of the active layer may be increased (in the range of approximately 1–100 μm) to capture the maximum proportion of incident radiation, while still providing efficient extraction of charge to the electrodes.

[0100] Therefore, it will be understood that the size of nanoparticles and / or aggregates, the distribution of nanoparticles and / or aggregates, the porosity of the nanostructured aggregates, and / or doping are factors that can be tuned to provide nanostructured aggregates with performance characteristics optimized for specific detection purposes. Such tuning can produce a number of different aggregates with different dielectric heterogeneities, or having different dielectric heterogeneities.

[0101] Such adjustments can also provide regions and / or interfaces of different dielectric constants where the size characteristics or dimensions in any given direction are on or within the wavelength of the radiation to be detected. Furthermore, this offers great flexibility, including the possibility of adjusting nanoscale structures on a surface by either bottom-up nanostructure design, which can be fabricated on large-area substrates using 3D additive or subtractive lithography, or top-down design using lithographic block copolymers.

[0102] It should be noted that the use of a voltage source is not essential in all embodiments. Furthermore, since the determination of charge generation can be performed by other means, the use of a current detector is not essential in all embodiments.

[0103] Because organic materials (i.e., low-Z components such as carbon and hydrogen) have low radiation attenuation coefficients, BHJ active organic material 2 alone hardly attenuates incident radiation. However, the presence of aggregates 3, 3' assists in the attenuation of incident radiation and enables the generation of charge carriers for producing a detectable current. Generally, the term “nanoparticles” as used herein conforms to the definition given in at least ASTM E2456-06 standard (ASTM E2456-06 (2012), Standard Terminology Relating to Nanotechnology, ASTM International, West Conshohocken, PA, 2012, www.astm.org.), and therefore the term “nanoparticles” generally means particles having at least one dimension less than 100 nm.

[0104] The performance of the detector typically depends on the formation of denser regions or aggregates 3,3'. When the particle sizes of the first and / or second organic semiconductors are in the quantum domain, i.e., the range of particle sizes in which quantum mechanical effects are dominant over bulk properties, radiation interactions with the organic semiconductor itself provide little charge generation, as organic semiconductors generally attenuate only low levels of radiation.

[0105] Aggregates 3, 3' may also result from the mixing of solutions used to produce the donor layer, acceptor layer, or both, by solution or evaporation, as in the case of the manufacture of halide perovskite solar cells, for example. In this case, a single-step or two-step process may be used to produce the layered material.

[0106] In a single-step process, a material such as PbI2 (lead iodide) is mixed with a solvent and, while in a liquid state, is further mixed with molecular cations such as FA (formamidinium lead bromide), MA (methylammonium lead bromide), or a combination of the two. The mixture is coated onto a surface that allows the solvent to evaporate, thereby forming aggregates that can be mixed with microcrystalline perovskite or other organic layered materials, which can act as a monolayer of such NP formations.

[0107] In a two-step process, a secondary interaction with the solution occurs after the above process, generally called a "poor solvent" step, surface modifier, or interface modifier, which further precipitates microcrystals. This helps to produce more controlled nucleation of inorganic microcrystals in this layer formation stage. The solvents and modifiers in a two-step process can be added in a single step for single-step nucleation, but this reduces the controllability and uniformity of the layer aggregates / NPs produced from that process. Controlling the solvent, poor solvent, cations, anions, temperature and / or time at which different components are introduced, the rate at which the solvents are mixed, and the environment in which the solvents are mixed all contribute to controlling the final quality, distribution, size, and physical properties of the material produced and used to attenuate X-ray radiation in the fabricated X-ray device.

[0108] Furthermore, if the particle size of the aggregates is too large, packing within the active material becomes inefficient, resulting in a decrease in the number of junction diodes in BHJ2 near the aggregates, thereby reducing the efficiency of the detector. Larger aggregates can also affect the diode-like behavior of the device, potentially causing it to behave as a resistor. Therefore, the size of the aggregates 3,3' must be optimized so that charge generation and extraction occur most efficiently.

[0109] Because the dimensions of the aggregates are large compared to the wavelength of ionizing radiation, the latter undergo Mie scattering, resulting in a longer optical path length. This scattering effect increases as the aggregate size increases. However, since charge extraction generally occurs at a depth of 10-15 nm, for larger aggregates, most of the deposited energy, i.e., the X-ray energy, is converted into heat. Furthermore, as the aggregate size decreases, charge extraction becomes more efficient, while the scattering effect is significantly reduced. Therefore, aggregate sizes in the range of 20-100 nm may be preferable (for example, for X-ray radiation). The use of aggregates as defined herein also enables broadband sensing of X-rays (i.e., detection of X-rays above 1 keV) due to the ionizing radiation scattering effect, which is an improvement over current direct X-ray detectors that are limited to a very narrow energy range (for example, amorphous selenium, one of the most widely used direct X-ray detector materials, cannot detect X-rays with energies above 50 keV).

[0110] The radiation detector 10 preferably directly converts incident high-energy radiation into a detectable electrical signal, preferably in a single step. In other words, this detection does not involve additional conversion steps such as the generation of visible light, as in the case of scintillator detectors, or the generation of excitons, as seen in scintillator detectors and quantum nanoparticle detectors.

[0111] As a first example, a single detector may be connected to the following: • A wireless transmitter that enables real-time data transmission to a remote computer. This allows (i) the dosimeter user to maintain a record of the radiation dose they are exposed to over time, and / or (ii) to generate a warning mechanism to inform the user of potential radiation hazards. A system integrated with a detector, consisting of a detector that generates a warning signal (sound) and / or a display that shows the ambient radiation level. • A system that combines both of the above features.

[0112] Examples of powering such systems include indoor solar cells that capture light from ambient lighting conditions, batteries (e.g., coin cells, flexible or rigid batteries), or energy storage devices such as supercapacitors. This is expected to be extendable to situations where power is supplied via wired connections.

[0113] The configuration of a dosimeter can be extended to integrate multiple detectors, each capable of detecting different types of radiation (e.g., neutrons or X-rays), or distinguishing between different energies of a particular type of radiation or a mixture of both.

[0114] The entire system can be integrated into either a rigid backing material or a flexible backing material, particularly a plastic sheet or adhesive bandage.

[0115] Furthermore, since the material of the detector 10 can be flexible, the dosimeter can be fixed to the position of the object of interest, for example, by being wrapped around a pipe.

[0116] An optimized detector signal relies on charge collection. Considering radiation attenuation across the entire detector, charges must be collected from the entire active device layer. Single-carrier organic semiconductor systems generate only electrical junctions favorable to charge extraction at one electrode. Consequently, carriers are extracted only at this interface, as the opposite electrode acts as a barrier to the extraction of the opposite charge (this is only true if the two junctions have different work functions). The BHJ2 system described above generates electrical junctions throughout the active material, and charges are extracted through both electrodes. This increases the probability of extracting both types of charge carriers generated by high-energy radiation.

[0117] The effects of these mechanisms described above can be seen in the decay of typical materials at different photon energies (<0.1 MeV: photoelectric effect, 0.1–10 MeV: Compton scattering, and >10 MeV: electron-pair production). These effects are further enhanced by Mie scattering of ionizing radiation, resulting from aggregates 3, 3', high-density regions, or parts thereof that are slightly larger than the wavelength of ionizing radiation, as well as from multiple regions of different dielectric constants that are tuned and configured to generate dielectric heterogeneity within the nanostructure aggregates.

[0118] Figure 4 is a flowchart showing an exemplary use of the radiation detector 10 of Figure 2, with the algorithm collectively indicated by reference numeral 40. Thus, the radiation detector 10 may operate as follows:

[0119] Algorithm 40 begins in step 41, where device 1 is used to attenuate incident radiation. In this example, aggregates 3, 3' in the bulk material 2 / BHJ2 (of device 1) attenuate the incident high-energy radiation. In step 42, radiation interaction with aggregates 3, 3' generates free charge carriers of electrons 17b and holes 17a. In step 43, the generated free charges of electrons 17b and holes 17a are swept through the BHJ2 toward electrodes 11 and 12 with the assistance of an applied voltage bias (e.g., applied by a voltage source 15, if provided). Note that the charges can also be swept by the detector's built-in potential, allowing operation under a 0V bias, i.e., omitting the voltage source 15. The charges 17a, 17b described above, referring to step 42, are collected at electrodes 11 and 12, and the current is recorded (step 44). Calibration or other processing may be performed to relate the current output to the incident radiation dose. Finally, in step 45, an estimate of the incident radiation is determined based on the current detected in step 44.

[0120] Radiation detectors like radiation detector 10 have many potential applications, one such example being portable dosimeters.

[0121] <Example of experiment> The following experimental example uses a direct radiation detector fabricated from an organic donor and organic acceptor-based BHJ system. In this exemplary system, poly(3-hexylthiophene-2,5-diyl):[6,6]-phenyl C71 methyl butyrate (P3HT:PCBM) constitutes the bulk heterojunction active material (bulk material 2), and bismuth oxide (Bi2O3) constitutes the high-z NPs (nanoparticles 4). Aluminum (Al) and indium tin oxide (ITO) are used as the cathode electrode and anode electrode (electrodes 11 and 12 of detector 10), respectively.

[0122] As a variation, the Bi2O3 used above may be substituted with other types of high-Z NP4s, or with other types of aggregates 3,3', including organic or inorganic components, perovskite nanocrystals, perovskite aggregates, etc.

[0123] Regioregular poly(3-hexylthiophene-2,5-diyl) (P3HT, 40 mg, Rieke 4002 EE) and [6,6]-phenyl C71 butyrate methyl ester (PC71BM, 40 mg, purity 99%; Solenne) were added to 1 ml of dichlorobenzene to prepare a P3HT:PC71BM(Bi2O3-0) solution. Bi2O3 nanoparticles 4 (β phase with tetragonal crystal structure; diameter 38 nm; surface area 18 m²) were prepared. 2 g -1 Disperse Alfa Aesar in P3HT:PC71BM solution and add 40 mg / ml (Bi2O3-40). -1 The Bi2O3 concentration was obtained. The weight percentage (wt%) of NP is 33%. Since the NP is not completely dispersed, aggregation may occur initially when the NP is dispersed.

[0124] An electron-blocking and hole-transport layer (HTL) of poly(3,4-ethylenedioxythiophene)-poly(styrene sulfonic acid) (PEDOT:PSS;Al 4083;Heraeus)—or, in variations, a Spiro-OMeTAD, P3HT, or PTAA layer (see table of materials shown)—was spin-coated in air (5000 rpm for 40 seconds) and annealed at high temperature for 10 minutes to obtain a thickness of 40 nm. 90 μl volumes of Bi2O3-0 and Bi2O3-40 solutions were spread and annealed at 60°C for 20-40 minutes under a covered Petri dish. In addition to or separately from the above, aggregates form within the Bi2O3-0 and Bi2O3-40 layers before annealing due to the non-uniform dispersion of NPs.

[0125] Following this, the device was annealed in a dry nitrogen glove box at 140°C for 10 minutes. During the second annealing step, the device was not placed under a covered Petri dish. To remove residual solvent, the device was 3 × 10⁻⁶ -6 The sample was held under vacuum at a pressure of less than mbar. This was followed by the deposition of 1,2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP; sublimation grade, Sigma Aldrich, 99.99% purity, 5 nm thick), which is an electron transport (ETL) and hole blocking layer, as well as the deposition of an Al cathode (approximately 120 nm) by vapor deposition. In a modified example, BCP was made of TiO2, ZnO, C 60 It can be replaced by PCBM or another ETL layer with equivalent functionality.

[0126] Device sealing was performed by using a sealing glass slide and UV photocurable adhesive (Ossila) and irradiating it with a UV lamp for 5 minutes. The HTL, ETL, and electrode materials can be replaced with any materials suitable for the application that optimize the extraction of charge carriers from the BHJ active material. For illustrative purposes, the mixture is often referred to as the matrix before annealing and during the formation stage. On the other hand, the term network is often used to describe the mixture after annealing or after energy input to the matrix, when a higher order is introduced.

[0127] Following further analysis and testing, the following results were obtained.

[0128] As shown in Figure 5, this data indicates that for each of the different particle sizes and their distributions, there exists a peak sensitivity that can be adjusted based on the type of material (single or multiple), its size, and the energy to be detected. This forms the basis for understanding that a range of different NP sizes is more sensitive to different energy ranges, particularly to the energy for which the detector is designed to detect, and allows for further optimization of the distribution and aggregation of NPs according to the desired detection target of the detector. Furthermore, based on this principle, holographic and tomographic imaging for the hyperspectral range can be obtained in a single detector configuration. These aggregates may also include families of different particle sizes, where the configuration of particle size and "aggregate-surface-volume" density gives different attenuation to radiation incident on the device, structure, or detector.

[0129] As shown in Figure 6, which illustrates the variation in detection sensitivity, sensitivity is affected by the NP size. This is a feature that can be controlled and tuned to match the X-ray energy to be detected, four of which are exemplified in Figure 6. Based on the diameter and distribution of the NPs, different sweet spots or specific sensitivities can be obtained in the detector due to local dielectric heterogeneity generated within the composite detector material.

[0130] Figure 7 shows the sensitivity to the volume of high-Z nanomaterials present in the detector material. Those skilled in the art will understand that Figure 7 shows that there is no simple linear relationship with respect to X-ray signal attenuation, as seen in standard X-ray bulk detectors. The data shows that the volume of high-Z NPs that attenuate X-ray radiation and convert it into current in each detector does not have a simple volume coefficient relationship with the high-Z material content. Therefore, it will be understood that while attenuation is an important factor, it is not the only relevant factor; charge transport and the mode in which charge is generated are also important factors.

[0131] Referring to Figure 8, this illustrates the effect of doping Bi2O3 nanoparticles with Cs to alter the charge particles available for conduction upon excitation by irradiated X-rays. This figure also shows that carrier doping, which affects dielectric heterogeneity by altering the dielectric constant ε within the material, is equally (or in some cases more influential) important for the sensitivity as an X-ray detector by also providing free carriers. Figure 8 shows, on the one hand, the effect of dopant La (lanthanum) on X-ray detection within a device structure, and on the other hand, the effect of dopant Cs (cesium) on X-ray detection within the same device structure.

[0132] It will be understood that adding La to Bi2O3NP generates oxygen vacancies and negatively charged superoxide radicals. This is facilitated by the La intermediate doping band in Bi2O3, which promotes an increase in positively charged holes. It will also be understood that adding Cs to Bi2O3NP does not potentially provide many free carriers, but rather results in a more Coulombic interaction of Cs with oxygen vacancies, thereby inhibiting (reducing) the free charge. This is also evident from the observation of higher detection sensitivity in La-doped Bi2O3NP compared to Cs-doped Bi2O3NP.

[0133] The above illustrates the importance of selecting the appropriate dopant, along with the appropriate concentration and optimal dielectric, to generate the best heterogeneity for fabricating an X-ray detector. Naturally, such factors can be optimized differently to detect different types of radiation.

[0134] The device or radiation detector is mechanically flexible and therefore can be folded. Thus, the use of multiple layers of polymer / organic semiconductor / aggregate films can further attenuate incident radiation. Improved charge generation and collection from these lightweight, flexible organic semiconductor / polymer / aggregate materials could enable integration into disposable adhesive bandages, potentially allowing for rapid and real-time detection / imaging of radiation beams.

[0135] Organic semiconductor diodes are suitable for high spatial resolution and can accommodate directional dependence. Organic semiconductor or polymer diodes can be fabricated in sub-micrometer dimensions, over large areas, and on flexible substrates. The combination of these techniques makes it possible to position them three-dimensionally within an incident radiation beam. Since dose is a one-dimensional quantity, dosimeters with small volume have high spatial resolution. The ability to "fold" a single polymer-organic semiconductor detector so that the incident beam passes through it multiple times enables higher detector sensitivity. Finally, robust solid-state semiconductor organic diodes offer the advantages of direct-readable, real-time electrical response and low operating voltage, which allows for battery operation and increased portability.

[0136] It should be noted that other materials that can be used as cathodes include n-type graphene, n-type carbon nanotubes, chromium, titanium, calcium, barium, or similar low work function materials. Also included are two-layer cathode systems involving metal / metal oxide combinations where the metal oxide may be zinc oxide, titanium oxide, or chromium oxide, or metal / organic combinations where the organic system may be bathocuproine, polyethyleneimine or its derivatives, or polyfluorene such as (PFN).

[0137] Other materials that can be used as anodes include high work function materials such as gold, nickel, and graphene; metal / metal oxide combinations in which the metal oxide may be based on tungsten, molybdenum, or nickel; or metal / organic combinations in which the organic material may be PEDOT:PSS, PTAA, F8T2, Spiro-OMeTAD, P3HT, or any p-type polymer. Here, the SAM may be 2PACz, 4PACz, or any high work function type SAM.

[0138] Regarding manufacturing, the deposition of active materials for large-area production can be carried out using various roll-to-roll or sheet-to-sheet coating techniques such as spray coating, slot die coating, inkjet printing, gravure printing, flexographic printing, and power press. It should be noted that the present invention is also applicable to the detection of other ionizing (e.g., nuclear) radiation such as alpha particles, beta particles, neutrons, and gamma rays, while maintaining the same configuration. This can be achieved by using appropriate aggregates. For neutron detection, a layer of gadolinium, or doped diamond and nanocrystalline diamond films can be used.

[0139] For gamma-ray detection, high-z NPs (NPs) with a z-value greater than 13, such as bismuth, tantalum, tungsten, lead, gold, and platinum, can be used. Alloys such as cadmium telluride (CdTe), perovskites (lead-based and others), and compound high-z NPs such as Bi2O3, as well as nanodiamonds, can also be used. For the detection of alpha and beta particles, any carbon-based material, including graphene, amorphous carbon, carbon nanotubes, and all allotropes of carbon, can be used. Si-based NPs and nanowires, silver (Ag)-based NPs and nanowires, zinc (Zn) NPs, and any type of metal and alloy (NPs or micron-sized particles) can be used for the detection of alpha and beta particles.

[0140] As described above, the radiation detector described herein comprises a network having a first material for transporting positive charges and a second material for transporting negative charges, wherein aggregates are dispersed within the network.

[0141] In some embodiments, a radiation detector may be referred to as a radiation imager. This radiation imager may include appropriate readout electronics. Such a radiation imager has many potential applications, as shown below.

[0142] The imager may be fabricated on a flexible backing material (e.g., a substrate, a bandage) and can be used, for example, in wearable health monitoring applications. For example, a patch that the user wears over an area with a wound, an area where bone damage has been detected, or an area where cancerous tissue is present. Due to the extremely sensitive nature of each detector pixel, a small X-ray source can be used to periodically observe wound healing, fractures, or any changes in cancerous tissue.

[0143] Imagers can also be used to monitor for metallic objects in environments where they should not be present. For example, these imagers can be used in the food packaging industry to identify potential metallic contaminants in food. Furthermore, through the use of multi-channel analysis techniques or other appropriate techniques, imagers can also be used to map which elements are present where.

[0144] This technology can be applied, for example, to security inspection activities at airports, ports, and locations where the presence of bombs is suspected.

[0145] This technology can be used for non-destructive evaluation of mechanical parts during manufacturing or operation over a predetermined evaluation period, or for real-time monitoring of the integrity of mechanical parts through integration into the system itself. The potential flexibility of the imager allows for the utilization of the advantages of X-ray film (with few limitations on the shape that can be imaged), but in a digital format (where real-time imaging may be possible, in contrast to film where real-time imaging is not possible).

[0146] The detectors and imagers would be suitable for academic research.

[0147] The above applications are not limited to the use of X-rays, but can also be applied when other forms of ionizing radiation are used.

[0148] In the manufacture of the detector, the solution consisting of a mixture of a first material and a second material (such as a hole-transporting organic semiconductor (or multiple hole-transporting semiconductors) and an electron-transporting semiconductor (or multiple electron-transporting semiconductors)) and aggregates can be as follows:

[0149] • These inks may be deposited directly from a solution onto flexible or rigid substrates using solution printing and coating techniques such as (but not limited to) slot die coating, doctor blade method, gravure printing, flexographic printing, drop casting, 3D printing, inkjet printing, spray coating, or dip coating. Furthermore, these inks may also be used to coat wires or filaments;

[0150] • Can be deposited directly onto a substrate using thermal deposition, chemical vapor deposition, pulsed laser ablation, or sputter coating techniques;

[0151] The following process can be used to form self-supporting pellets or tiles: an antisolvent (in which the organic semiconductor is soluble but at least partially miscible with the organic solvent used) is introduced into the ink, thereby causing the material to precipitate from the system. The remaining solvent can then be evaporated to obtain a dry powder, which can be pressed and, if necessary, sintered to form solid self-supporting pellets;

[0152] • A semiconductor-containing ink can be sprayed under high pressure into a low-vacuum system maintained at an appropriate pressure, where the solvent can be evaporated and the powder collected. The powder can then be pressed to form self-supporting pellets; or,

[0153] The pellet can be pressed onto a substrate consisting of a suitable electrical contact material or backplane, as described in the section on X-ray imagers.

[0154] The physical properties of the ink can also be adjusted to allow the filament of this X-ray detector to be formed by methods such as extrusion molding or electrospinning.

[0155] A table of first and second organic semiconductor materials (i.e., hole transport materials and electron transport materials) and exemplary materials for use as nanoparticles is provided below.

[0156] Exemplary hole transport materials: [Table 1-1] [Table 1-2]

[0157] Exemplary electron transport materials: [Table 2]

[0158] Exemplary radiation-attenuating materials (i.e., as nanostructured aggregates): [Table 3]

[0159] The following description summarizes at least some interesting aspects of the embodiments described herein.

[0160] The performance of a detector typically depends on the size, distribution, and arrangement of aggregates within the detector. Because the aggregate size is large compared to the wavelength of ionizing radiation, the latter undergoes scattering (e.g., Mie scattering), resulting in a longer optical path length. Aggregate particle sizes in the range of 20–100 nm may be preferred (e.g., for X-ray radiation). The use of aggregates as defined herein also enables broadband sensing of X-rays (i.e., detection of X-rays above 1 keV) due to the ionizing radiation scattering effect. For comparison, those skilled in the art will know that the sensitivity of current direct X-ray detectors is limited to a very narrow energy range (e.g., amorphous selenium, one of the most widely used direct X-ray detector materials, cannot detect X-rays with energies above 50 keV). However, according to the present invention, where appropriate dielectric heterogeneity is imparted to the aggregates, the detector can be used to detect X-ray energies below 50 keV, and it is understood that, based on the principles of the present invention, the efficiency and sensitivity of the detector in any energy range can be improved.

[0161] The radiation detectors described herein may use an ink consisting of at least two organic semiconductors. One preferentially transports positive charges (holes) when processed into a solid semiconductor, while the other transports negative charges (electrons) to separate electrical junctions. Mixtures of such organic semiconductors are used in the fields of organic photovoltaic (OPV) and photodetectors (detecting the ultraviolet to near-infrared portion of the electromagnetic spectrum). Inorganic NPs and aggregates can also be used in such detectors due to their dielectric heterogeneity. This mixture is often referred to as a bulk heterojunction (BHJ). The interaction of photons in the energy range of the ultraviolet to near-infrared portion of the electromagnetic spectrum results in the formation of bound electrons and holes known as excitons.

[0162] In organic photovoltaics and photodetectors, this BHJ architecture is required to separate (or dissociate) excitons into free charges before they are swept through electron- and hole-transporting organic semiconductors (often referred to as acceptor and donor phases, particularly only in exciton systems). Although the mixtures of organic semiconductors and aggregates described herein may not directly participate in the dissociation of excitons in radiation detectors, given the formation of a built-in electric field, such mixtures can still be referred to as providing a bulk heterojunction. Alternatively, similar bulk heterojunctions may also be referred to as pn junctions, interpenetrating pn junctions, interpenetrating networks of percolated electron- and hole-transporting phases, or donor (referring to a hole-transporting organic semiconductor)-acceptor (referring to an electron-transporting organic semiconductor) systems.

[0163] The number of organic semiconductors used can be increased, as long as it does not interfere with the charge transport highlighted above. Furthermore, the organic semiconductors specified herein may be polymers, small molecules, or have zero, one, two, or three-dimensional structures.

[0164] The semiconductors described herein, whether organic semiconductors, inorganic semiconductors, or combinations of organic and inorganic semiconductors with aggregates, may be selected to result in the formation of a built-in electric field. This built-in electric field drives free electrons and holes generated during the interaction of incident X-rays with the aggregate to separate electrical contacts, resulting in an electrical signal (even in the absence of an external voltage bias). In other words, the use of the above semiconductor combinations enables a fully depleted diode even in the absence of an external electric field. The mixture of electron-transporting and hole-transporting materials used (such as organic semiconductors) allows for the extraction of free carriers generated by X-rays (even in the absence of an external bias).

[0165] The nanoparticles used may be of a single material type or a mixture of nanoparticles made of different high-Z materials. A single nanoparticle may be composed of two high-Z materials (provided that the materials are selected so as not to hinder the extraction of either electrons or holes). Lamination of one high-Z material onto another high-Z material may be carried out in such a manner that an electric field acts to efficiently extract charges directly generated during interaction with ionizing radiation, even within the nanoparticles themselves.

[0166] Solid-state detectors can be fabricated by direct coating of ink using techniques such as doctor blade method, slot die coating, inkjet printing, gravure printing, spray coating, spin coating, and drop casting. Furthermore, solid-state detectors can be manufactured by preparing organic, inorganic, or mixtures of organic and inorganic semiconductor powders. These powders are obtained by adding a poor solvent to the ink to precipitate the organic semiconductor-aggregate mixture, followed by removal of the solvent using rotary evaporation, air drying, or vacuum drying. This powder can be pressed to any required size to form solid disks / pellets / slabs / tiles / wafers. These can then be combined with appropriate electrical contacts for selectively extracting electrons and holes on separate surfaces, in separate regions within the same surface, or a combination thereof, enabling them to function as ionizing radiation detectors as a whole.

[0167] Some of the interesting aspects of the embodiments described herein include: • Formation of nanostructured aggregates to provide conversion to positive and negative charges. Formation of nanostructured aggregates to provide conversion to positive and negative free charges through direct conversion of radiation. • Improvement of radiation energy attenuation through the formation of dielectric heterogeneity in the formed nanostructure aggregates. • The detector's broadband response is due to a dominant scattering effect at all X-ray energies above 1 keV. • Use of at least two organic semiconductors, one of which preferentially transports holes and the other which transports electrons. • Use of at least two inorganic semiconductors, or an inorganic-organic pair, in which one semiconductor preferentially transports holes and the other transports electrons. • Use of semiconductor systems as described herein that provide a built-in electric field within the device, enabling the detector to operate even in the absence of an external voltage bias.

[0168] (Note) (Note 1) A device for converting incident radiation into positive and negative charges, The system comprises a network including a first semiconductor material for transporting positive charges and a second semiconductor material for transporting negative charges. The first and second semiconductor materials are distributed within the network to provide multiple electrical junctions. The network further comprises a plurality of nanostructure aggregates dispersed within the network, The nanostructure aggregate is a device comprising a plurality of regions and / or interfaces having different dielectric constants, which can generate dielectric heterogeneity within the nanostructure aggregate.

[0169] (Note 2) The aforementioned nanostructure aggregate is a) Multiple regions and / or interfaces having different relative permittivity, which are at or within the wavelength of the incident radiation; and / or b) The device described in Appendix 1, having a porosity or void ratio of approximately 0.01 to approximately 0.99, approximately 0.05 to approximately 0.7, or approximately 0.1 to approximately 0.3.

[0170] (Note 3) The aforementioned nanostructure aggregate is One or more solid nanoparticle structures, The device according to Appendix 1 or Appendix 2, comprising one or more voids between one or more solid nanoparticle structures.

[0171] (Note 4) The device according to any one of the appendices 1 to 3, wherein the nanostructured aggregate is configured to accelerate and decelerate incident radiation and generate one or more positively or negatively charged reservoirs within the surface structure of the aggregate.

[0172] (Note 5) The device according to any one of Annexes 1 to 4, wherein the surface structure of the nanostructure aggregate, whether an external surface structure or / or an internal surface structure, is configured to interact with incident radiation to attenuate the radiation and to provide improved conversion to positive and negative charges.

[0173] (Note 6) The plurality of nanostructure aggregates are It acts as a local heterogeneity that can attract and concentrate electric fields; and / or, A device according to any one of the appendices 1 to 5, configured to convert radiation into positive and negative charges in a radiation-aggregate interaction event.

[0174] (Note 7) The device according to any one of the appendices 1 to 6, wherein the plurality of nanostructure aggregates are doped nanostructure aggregates having additional electron-containing elements or hole-containing elements.

[0175] (Note 8) The device according to Appendix 7, wherein the plurality of nanostructure aggregates are doped with cesium (Cs) and / or lanthanum (La).

[0176] (Note 9) The plurality of nanostructure aggregates are Size of nanoparticles and / or aggregates, Distribution of nanoparticles and / or aggregates, The porosity of the nanostructure aggregate, and doping A device according to any one of the appendices 1 to 8, having one or more optimized parameters selected from the group including the above.

[0177] (Note 10) The first and second semiconductor materials are, organic-organic transport materials, Inorganic-inorganic transport materials, or, A device as described in any one of the appendices 1 to 9, including organic-inorganic transport materials.

[0178] (Note 11) The aforementioned nanoparticles High-Z nanoparticles, Organic nanoparticles, or, A device as described in any one of the appendices 1 to 10, including any combination thereof.

[0179] (Note 12) The device according to any one of Annexes 1 to 11, wherein the parameters of the nanostructure aggregate are configured to be actively optimized for detecting radiation of a defined wavelength or form, which is configured to be detected by the device.

[0180] (Note 13) The device according to any one of the appendices 1 to 12, wherein the first semiconductor material comprises P3HT, the second semiconductor material comprises PCBM, and the nanoparticles optionally comprise Bi2O3 doped with cesium (Cs) and / or lanthanum (La).

[0181] (Note 14) The first electrode and The second electrode and A radiation detector comprising a device described in any one of the appendices 1 to 13, which is positioned between or sandwiched between the first and second electrodes.

[0182] (Note 15) A system comprising multiple radiation detectors as described in Appendix 14, At least some of the aforementioned multiple radiation detectors are Detects multiple different types of radiation, To detect one type of radiation, and / or, A system configured to identify or detect different energies of specific radiation.

[0183] (Note 16) To convert incident radiation into positive and negative charges, use the device described in any one of the appendices 1 to 13, the radiation detector described in appendice 14, or the system described in appendice 15; and, A method comprising recording the properties generated by the aforementioned positive and negative charges.

[0184] (Note 17) The method according to Appendix 16, further comprising converting the incident radiation into positive and negative free charges in a radiation-aggregate interaction event.

[0185] (Note 18) To generate a current in response to the application of a voltage to the device, and The method according to Appendix 16 or Appendix 17, including converting the recorded current into an estimate of the level of incident radiation.

[0186] (Note 19) A process for providing a network for a device for converting incident radiation into positive and negative charges, Dissolving first and second semiconductors, each capable of transporting positive and negative charges respectively, in one or more solvents, Adding multiple nanoparticles and dispersing the multiple nanoparticles to form a matrix, and This includes agglomerating the nanoparticles in the matrix to form a plurality of nanostructure aggregates, The process comprising a nanostructure aggregate comprising a plurality of regions and / or interfaces having different dielectric constants, which can generate dielectric heterogeneity within the nanostructure aggregate.

[0187] (Note 20) Multiple regions and / or interfaces having different relative permittivity, which are on the same wavelength as or within the wavelength of the incident radiation, One or more solid nanoparticle structures, and, The process according to Appendix 19, comprising generating one or more voids between the one or more solid nanoparticle structures.

[0188] (Note 21) The aforementioned nanostructure aggregate is Before coating the substrate, at least partially within the matrix, and / or The process described in Appendix 19 or Appendix 20, which is formed during the lamination of the matrix onto the substrate.

[0189] (Note 22) Aggregation is To optimize the quality, distribution, size, and / or other physical properties of the generated nanostructure aggregates, Size of nanoparticles and / or aggregates, Distribution of nanoparticles and / or aggregates, Porosity of nanostructure aggregates, doping, Solvent, poor solvent, cation, anion, temperature and / or time at which different components are introduced, The rate at which the solvent is mixed, and, A process according to any one of the appendices 19 to 21, including optimizing and controlling the environment in which the solvents are mixed.

[0190] (Note 23) The process according to any one of the appendices 19 to 22, comprising optionally adding multiple dopant atoms, including Cs or La atoms, before aggregation.

[0191] (Note 24) The process according to any one of the appendices 19 to 23, comprising forming a matrix by dissolving and dispersing the first and / or second semiconductors, which comprise a plurality of nanoparticles, in one or more solvents.

Claims

1. A device for converting incident radiation into positive and negative charges, The system comprises a network including a first semiconductor material for transporting positive charges and a second semiconductor material for transporting negative charges. The first and second semiconductor materials are distributed within the network to provide a plurality of electrical junctions. The network further comprises a plurality of nanostructure aggregates dispersed within the network, The nanostructure aggregate is a device comprising a plurality of regions and / or interfaces having different dielectric constants that can generate dielectric heterogeneity within the nanostructure aggregate.

2. The aforementioned nanostructure aggregate is a) Multiple regions and / or interfaces having different relative permittivity, which are at or within the wavelength of the incident radiation; and / or b) The device according to claim 1, having a porosity or void ratio of about 0.01 to about 0.99, about 0.05 to about 0.7, or about 0.1 to about 0.

3.

3. The aforementioned nanostructure aggregate is One or more solid nanoparticle structures, The device according to claim 1 or claim 2, comprising one or more voids between one or more solid nanoparticle structures.

4. The device according to any one of claims 1 to 3, wherein the nanostructure aggregate is configured to accelerate and decelerate incident radiation and generate one or more positively or negatively charged reservoirs within the surface structure of the aggregate.

5. The device according to any one of claims 1 to 4, wherein the surface structure of the nanostructure aggregate, whether an external surface structure or / or an internal surface structure, is configured to interact with incident radiation to attenuate the radiation and to provide improved conversion to positive and negative charges.

6. The plurality of nanostructure aggregates are It acts as a local heterogeneity that can attract and concentrate electric fields; and / or, The device according to any one of claims 1 to 5, configured to convert radiation into positive and negative charges in a radiation-aggregate interaction event.

7. The device according to any one of claims 1 to 6, wherein the plurality of nanostructure aggregates are doped nanostructure aggregates having additional electron-containing elements or hole-containing elements.

8. The device according to claim 7, wherein the plurality of nanostructure aggregates are doped with cesium (Cs) and / or lanthanum (La).

9. The plurality of nanostructure aggregates are Size of nanoparticles and / or aggregates, Distribution of nanoparticles and / or aggregates, The porosity of the nanostructure aggregate, and doping The device according to any one of claims 1 to 8, having one or more optimized parameters selected from the group including the following.

10. The first and second semiconductor materials are, organic-organic transport materials, Inorganic-to-inorganic transport materials, or A device according to any one of claims 1 to 9, comprising an organic-inorganic transport material.

11. The aforementioned nanoparticles High Z nanoparticles, Organic nanoparticles, or, A device according to any one of claims 1 to 10, including a combination thereof.

12. The device according to any one of claims 1 to 11, wherein the parameters of the nanostructure aggregate are configured to be actively optimized for detecting radiation of a defined wavelength or form, which is configured to be detected by the device.

13. The first semiconductor material comprises P3HT, the second semiconductor material comprises PCBM, and the nanoparticles are optionally doped with cesium (Cs) and / or lanthanum (La). ２ O ３ A device according to any one of claims 1 to 12, including the device described in any one of claims 1 to 12.

14. The first electrode and The second electrode and A radiation detector comprising a device according to any one of claims 1 to 13, which is positioned between or sandwiched between the first and second electrodes.

15. A system comprising a plurality of radiation detectors as described in claim 14, At least some of the aforementioned multiple radiation detectors are Detects multiple different types of radiation, To detect one type of radiation, and / or, A system configured to identify or detect different energies of specific radiation.

16. To convert incident radiation into positive and negative charges, use the device according to any one of claims 1 to 13, the radiation detector according to claim 14, or the system according to claim 15; and, A method comprising recording the properties generated by the aforementioned positive and negative charges.

17. The method according to claim 16, further comprising converting the incident radiation into positive and negative free charges in a radiation-aggregate interaction event.

18. To generate a current in response to the application of a voltage to the device, and The method according to claim 16 or 17, comprising converting the recorded current into an estimate of the level of incident radiation.

19. A process for providing a network for a device for converting incident radiation into positive and negative charges, Dissolving first and second semiconductors, each capable of transporting positive and negative charges respectively, in one or more solvents, Adding multiple nanoparticles and dispersing the multiple nanoparticles to form a matrix, and This includes agglomerating the nanoparticles in the matrix to form a plurality of nanostructure aggregates, The process comprising a nanostructure aggregate comprising a plurality of regions and / or interfaces having different dielectric constants, which can generate dielectric heterogeneity within the nanostructure aggregate.

20. Multiple regions and / or interfaces having different relative permittivity, which are on the same wavelength as or within the wavelength of the incident radiation, One or more solid nanoparticle structures, and, The process according to claim 19, comprising generating one or more voids between the one or more solid nanoparticle structures.

21. The aforementioned nanostructure aggregate is Before coating the substrate, at least partially within the matrix, and / or The process according to claim 19 or claim 20, wherein the matrix is ​​formed during lamination onto a substrate.

22. Aggregation is To optimize the quality, distribution, size, and / or other physical properties of the generated nanostructure aggregates, Size of nanoparticles and / or aggregates, Distribution of nanoparticles and / or aggregates, Porosity of nanostructure aggregates, doping, Solvent, poor solvent, cation, anion, temperature and / or time at which different components are introduced, The rate at which the solvent is mixed, and, The process according to any one of claims 19 to 21, comprising optimizing and controlling the environment in which the solvents are mixed.

23. The process according to any one of claims 19 to 22, further comprising adding a plurality of dopant atoms, optionally containing Cs or La atoms, before aggregation.

24. The process according to any one of claims 19 to 23, comprising forming a matrix by dissolving and dispersing the first and / or second semiconductors, wherein the first and / or second semiconductors comprise a plurality of nanoparticles, in one or more solvents.

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