# US 11,444,256 B2 · Filter-free tunable spectrum photodetectors > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,444,256 B2 - Document ID: US11444256B2 - Status: Granted - Kind: B2 - Application number: 16/908,694 - Filed: 2020-06-22 - Published: 2020-12-31 - Granted: 2022-09-13 - Earliest claimed: 2019-06-25 - Assignees: Hong Kong Baptist University - Applicants: Hong Kong Baptist University - Inventors: Furong Zhu; Zhaojue Lan - Web page: https://patentgrep.com/patent/US11444256B2 ## CPC - H10K 39/30: Devices controlled by radiation - H10K 30/352: {the inorganic nanostructures being nanotubes or nanowires, e.g. CdTe nanotubes in P3HT polymer} - H10K 30/82: Transparent electrodes, e.g. indium tin oxide [ITO] electrodes - H10K 85/113: {Heteroaromatic compounds comprising sulfur or selene, e.g. polythiophene} - H10K 85/1135: {Polyethylene dioxythiophene [PEDOT]; Derivatives thereof} - H10K 85/151: {Copolymers} - H10K 85/621: {Aromatic anhydride or imide compounds, e.g. perylene tetra-carboxylic dianhydride or perylene tetracarboxylic di-imide} - H10K 85/6576: {comprising only sulfur in the heteroaromatic polycondensed ring system, e.g. benzothiophene} - H10K 2102/103: {comprising indium oxides, e.g. ITO} - Y02E 10/549: Organic PV cells - Y02P 70/50: Manufacturing or production processes characterised by the final manufactured product - H10K: ORGANIC ELECTRIC SOLID-STATE DEVICES - Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION - Y02P: CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS ## Abstract This invention provides a filter-free tunable spectrum PD with a layered structure of at least two electrodes and two functional layers. Both functional layers can be a layer, a stack of inorganic semiconductors, an organic semiconductor, an organic/polymer donor/acceptor blend, a hybrid semiconductor or their combinations that has a good charge transport property. The first functional layer absorbs the shorter-wavelength EM waves and is transparent to the longer-wavelength EM waves. The second functional layer absorbs the longer-wavelength EM waves. The detection spectrum window is determined by the difference in wavelengths between the transmission cut-off wavelength of the first functional layer and absorbing edge of the second functional layer, or between the absorption edge of the first functional layer and that of the second functional layer. The present PDs can be used in imaging, thermal therapy, night-vision, Li-Fi, optical communication, environmental detection, agricultural, wellness, bioimage, food, automotive and security monitoring. ## Claims ### Claim 1 A filter-free tunable spectrum photodetector comprising a layered structure of at least two electrodes and at least two functional layers, wherein a first functional layer of the at least two functional layers comprises a shorter-wavelength electromagnetic wave depletion layer within a first wavelength range of 10 nm to 1000 μm, wherein the first functional layer absorbs electromagnetic radiation in the first wavelength range without generating photocurrent and is transparent to electromagnetic radiation in a longer-wavelength second wavelength range of 10 nm to 1000 μm, and wherein a second functional layer of the at least two functional layers comprises a longer-wavelength electromagnetic wave absorbing layer within the second wavelength range for generating photocurrent upon absorption of the longer-wavelength electromagnetic waves and wherein filter-free tunable spectral detection of the photodetector occurs by adjusting a selected spectral response window within a wavelength range determined by a difference in wavelength between a transmission cut-off wavelength of the first functional layer and an absorbing edge of the second functional layer. ### Claim 2 (depends on 1) The photodetector of claim 1, wherein the shorter-wavelength electromagnetic wave has a wavelength range from 10 nm to 1000 μm. ### Claim 3 (depends on 1) The photodetector of claim 1, wherein the longer-wavelength electromagnetic wave has a wavelength range from 10 nm to 1000 μm. ### Claim 4 (depends on 1) The photodetector according to claim 1 wherein the first functional layer and the second functional layer are made of materials comprising organic, polymer, perovskite, colloidal quantum dots, and inorganic compounds, or any combination thereof. ### Claim 5 (depends on 4) The photodetector according to claim 4 wherein the short-wavelength electromagnetic wave depletion layer is selected from a P3HT layer, a PTB7-Th layer, a CH3NH3Pb0.5Sn0.5I3 perovskite layer or a CH3NH3PbI3 perovskite layer. ### Claim 6 (depends on 4) The photodetector according to claim 4 wherein the longer-wavelength electromagnetic wave absorbing layer is selected from a PBDB-T:m-ITIC blended layer, a PDPP3T:m-ITIC blended layer, PTB7-Th:COi8DFIC:PC70BM blended layer, a PTB7-Th:PC70BM blended layer or a PCPDTBT:PC70BM blended layer. ### Claim 7 (depends on 1) The photodetector according to claim 1 wherein the first functional layer and/or the second functional layer is/are selected from at least one of a functional layer, a stack of blended layers, or a combination of functional layers and blended layers. ### Claim 8 (depends on 1) The photodetector according to claim 1 is prepared using solution fabrication, vacuum evaporation, printing processes, nanoimprinting, transfer processes, or any combination thereof. ### Claim 9 (depends on 1) The photodetector according to claim 1, wherein the first functional layer is a charge transporting layer. ### Claim 10 (depends on 1) The photodetector according to claim 1, wherein the second functional layer is an absorption layer absorbing shorter-wavelength electromagnetic waves. ### Claim 11 (depends on 1) The photodetector according to claim 1, wherein the second functional layer is an absorption layer absorbing longer-wavelength electromagnetic waves. ### Claim 12 (depends on 1) The photodetector according to claim 1, wherein a first electrode of the at least two electrodes which is more proximal to incident light is transparent or semi-transparent. ### Claim 13 (depends on 1) The photodetector according to claim 1, wherein a second electrode of the at least two electrodes which is more distal to incident light is transparent, semi-transparent or opaque. ### Claim 14 (depends on 1) The photodetector according to claim 1, wherein the at least two electrodes comprise transparent conducting oxides, thin metal layer, conducting polymers, organic semiconductors, nanostructured transparent electrode, metal nanoparticles, metal nanowires, graphene sheets, or any combination thereof. ### Claim 15 (depends on 14) The photodetector according to claim 14, wherein a first electrode of the at least two electrodes being more proximal to incident light is selected from a PEDOT:PSS layer, an ITO layer, a surface modified PEDOT:PSS layer or a surface modified ITO layer, and wherein a second electrode of the at least two electrodes being more distal to incident light is selected from an Al layer or an Ag layer or a ZnO-modified Al layer or a ZnO-modified Ag layer. ### Claim 16 (depends on 1) The photodetector according to claim 1, wherein the layered structure further comprises an interlayer sandwiched between a first functional layer and a second functional layer of the at least two functional layers. ### Claim 17 (depends on 1) The photodetector according to claim 1, wherein the at least two electrodes include a first, proximal electrode, and a second, distal electrode with respect to the incident light, the photodetector further comprising an interlayer to the layered structure, the interlayer being configured to assist charge exchange and comprising conducting polymer, metal oxide, self-assembled monolayer, metal nanoparticles, metal nanowires, graphene sheets, or any combination thereof. ### Claim 18 (depends on 1) The photodetector according to claim 1, wherein the photodetector has a photoresponse to a selected spectrum window within a wavelength range from 10 nm to 1000 μm and is operable with or without bias. ### Claim 19 (depends on 1) The photodetector according to claim 1, wherein the spectrum window of the electromagnetic waves detected by the photodetector is tunable based on optical properties of the selected materials for a first functional layer and a second functional layer of the at least two functional layers, which is determined by the difference in wavelengths between transmission cut-off wavelength of the first functional layer and an absorbing edge of the second functional layer.