CN201112423Y - Organic UV Optical Sensor Based on Phosphorescent Material Photovoltaic Diodes - Google Patents

Abstract

The utility model belongs to the technical field of ultraviolet light-sensitive optical sensors, and relates to an organic ultraviolet light optical sensor based on a phosphorescent material photovoltaic diode, which uses an existing compound with low ionization energy (IP) and high hole transport characteristics as a donor , the phosphorescent compound with high electron affinity (EA) and large electron transport characteristics is used as the acceptor, which makes the material selection range wider; the device is a multi-layer structure, and the film is formed by thermal evaporation, and the manufacturing process is simple and the cost is low; And because the thin organic layer and metal electrode layer are used, the device is small in size and light in weight; because the phosphorescent material has a long excited state lifetime and exciton diffusion length, it has a higher efficiency than the organic polymer photovoltaic diode of the fluorescent material. Efficiency means that it has higher sensitivity to ultraviolet light, and is only sensitive to ultraviolet light in the 300-400nm band and is blind to visible light. The utility model can be widely used in the fields of science, industry and commerce.

Description

Organic UV Optical Sensor Based on Phosphorescent Material Photovoltaic Diodes

technical field

The utility model belongs to the technical field of ultraviolet sensitive optical sensors, and relates to an organic ultraviolet optical sensor based on organic diodes of phosphorescent materials.

Background technique

The photon-electron conversion of organic materials requires the decomposition of excitons generated by optical absorption into charge carriers, and this optical absorption is different from ordinary solar cells. The light absorption spectrum of organic solar cells is required to mainly cover the visible region (400-700nm). The ultraviolet light irradiated by sunlight on the ground is mainly in the 300-400nm band, and the light irradiated on the ground is mainly in the visible light band, while the ultraviolet light optical sensor is required to be sensitive to a small amount of ultraviolet light, that is, the ultraviolet light in the band (300-400nm). At present, ultraviolet light optical sensors mainly use inorganic ultraviolet light sensitive devices as optical sensors. Fluorescent materials are used. If fluorescent materials are used as ultraviolet light sensitive devices, due to the short diffusion distance of their excitons, the response sensitivity to ultraviolet light is expected to be low.

Contents of the invention

Aiming at the problems of complex preparation process and high cost of using inorganic ultraviolet light sensitive devices as optical sensors in the prior art, and the spectral response of organic/polymer photovoltaic diodes mostly covers the visible region, and fluorescent materials are used, and fluorescent materials As a problem that the response sensitivity of ultraviolet light sensitive devices to ultraviolet light becomes low, the utility model provides an organic ultraviolet light optical sensor based on phosphorescent material photovoltaic diodes, which adopts the existing low ionization energy (IP) and high hole The compound with transport properties is used as the donor, and the phosphorescent compound with high electron affinity (EA) and high electron transport properties is used as the acceptor, which makes the material selection range wider; the device is a multi-layer structure, which is formed by thermal evaporation. The process is simple and the cost is low; and because the thin organic layer and the metal electrode layer are used, the device is small in size and light in weight.

Technical solution 1: The utility model has a layered structure, from the substrate (the side irradiated by ultraviolet light) to the electron collecting electrode, followed by the substrate, the hole collecting electrode layer, the electron donor layer, the electron donor and the electron acceptor mixed layer, electron acceptor layer, electron collection layer, electron collection electrode layer; 10nm, the material used for the electron donor is a diamine derivative (diamine derivative), the material used for the electron acceptor is a complex of iridium, platinum, osmium or rhenium, and the electron donor material in the mixed layer of the electron donor and electron acceptor The weight ratio to the electron acceptor material is 1:1; the material used for the electron collection layer is LiF or CsF, and the thickness of the electron collection layer is 0.8-3nm; the material used for the electron collection electrode layer is Al, and the thickness of the electron collection electrode layer is 100 ~150nm.

Technical solution two: The utility model has a layered structure, from the substrate (the side irradiated by ultraviolet light) to the electron collection electrode, followed by the substrate, the hole collection electrode layer, the electron donor layer, the electron acceptor layer, and the electron collection electrode. layer, electron collecting electrode layer; the thickness of the electron donor layer is 5-20nm, and the material used for the electron donor is diamine derivative (diamine derivative); the thickness of the electron acceptor layer is 20-40nm, and the material used for the electron acceptor is Complexes of iridium, platinum, osmium or rhenium; the material used for the electron collection layer is LiF or CsF, and the thickness of the electron collection layer is 0.8-3nm; the material used for the electron collection electrode layer is Al, and the thickness of the electron collection electrode layer is 100-150nm .

The preparation method of the utility model: deposit an electron donor layer on the hole collecting electrode layer; deposit an electron acceptor layer on the electron donor layer, or deposit a layer of electron donor and electron acceptor layer on the electron donor layer The mixed layer of the body, and then deposit the electron acceptor layer on it, and then deposit the electron collection layer and the electron collection electrode layer in sequence; the above layers are deposited by thermal evaporation process.

The substrate is made of glass, and the hole collecting electrode layer (transparent conductive film) is made of ITO transparent conductive film; the electron donor layer is made of TPD (N, N'-diphenyl-N, N'-bis(3-methylphenyl)-[1, 1'-biphenyl]-4, 4'-diamine) or m-MTDATA

(4, 4', 4"-tris(3-methylphenyl-phenylaminojtriphenylamine;) material, the thickness is selected from 5 to 20nm; the electron acceptor layer is selected from Ir(ppy) ₃ : fac(tris～2-phenyl Pyridine)Iridium, or Btp ₂ Ir(acac), :bis(2-(2'8-benzo[4,5-a]thienyl)(pyridinato-N, C ³ ')iridium(acetylacetonate), the thickness is 20-40nm; electron donor and In the electron-acceptor mixed layer, the weight ratio of electron donor and electron acceptor is 1:1, and the thickness is 2-10nm; the electron collection material layer is LiF or CsF, and the thickness is 0.8-3nm; the electron collection electrode layer is made of Using Al or, the thickness can be 100-150nm.

The successfully manufactured device is first irradiated with ultraviolet light with a known power center wavelength of 365nm, changing the irradiation intensity or distance to measure the relationship between the electrical signal open circuit voltage (Voc) or short circuit current (Jsc) and the irradiation light intensity in the photovoltaic characteristics and draw it. The standard curve, and then use the ultraviolet light optical sensor to detect the electrical signal obtained by measuring the ultraviolet light with unknown intensity and compare it with the standard curve to calculate the sensitivity of the ultraviolet light to be measured.

Beneficial effects: Since the phosphorescent material has a long excited state lifetime and exciton diffusion length, the utility model has higher efficiency than the organic/polymer photovoltaic diode of the fluorescent material, that is, it has higher sensitivity to ultraviolet light, and only 300 The -400nm band is sensitive to ultraviolet rays and blind to visible light.

Compared with the prior art inorganic ultraviolet light sensitive device as the ultraviolet light optical sensor of the optical sensor, the utility model has the following advantages:

(1) Wide range of material sources

Since many hole-injection and hole-transport materials for organic light-emitting diodes (OLEDs) have low IP values and absorption in the 300-400 band, many electron-transport phosphorescent materials for OLEDs have high EA and absorption in the 300 band. -400 band, so that when selecting electron donor and electron acceptor materials, as long as they are good hole injection and hole transport materials and electron transport materials respectively, the combination of the two can be used to construct an ultraviolet light optical sensor. Compared with inorganic materials, there is no need for complex material synthesis, given their ionization energy and electron affinity parameters, as well as the absorption spectrum of phosphorescent material films, even if it contains ultraviolet light with a wavelength shorter than 300nm, due to the utility model The devices are all made of ITO conductive glass, which can filter ultraviolet light with a wavelength shorter than 300nm from entering the sensor device, so that materials already used in OLEDs can be selected.

(2) The production process is simple

Because the device structure of the utility model is a "sandwich" multilayer structure similar to many device structures of OLEDs, all materials are formed by vacuum thermal evaporation, and there is no need for complex semiconductors necessary for inorganic ultraviolet optical sensor devices. manufacturing process.

(3) Small size and light weight

Since the utility model adopts thin organic layers and metal electrode layers, except for the thickness of the hole-collecting electrode layer (0.3-1.1 mm), the thickness of all functional layers is not more than 1 micron.

The organic ultraviolet optical sensor of the utility model can be widely used in the fields of science, industry and commerce.

Description of drawings

Fig. 1 is the structural representation of the utility model, also is abstract accompanying drawing. In the figure 1, substrate, 2, hole collecting electrode layer (transparent conductive film), 3, electron donor layer, 4, electron donor and electron acceptor mixed layer, 5, electron acceptor layer, 6, electron collection Layer, 7, electron collecting electrode layer.

Fig. 2 is a structural schematic diagram of another technical solution of the utility model. 1. Substrate, 2. Hole collecting electrode layer (transparent conductive film), 3. Electron donor layer, 5. Electron acceptor layer, 6. Electron collecting layer, 7. Electron collecting electrode layer.

Detailed ways:

Below in conjunction with accompanying drawing and embodiment the utility model is described further, but the utility model is not limited to these embodiments.

Technical solution one:

Example 1:

The device structure shown in FIG. 1 is selected: in this embodiment, firstly, the hole-collecting electrode layer 2 selects the ITO film on the glass substrate 1 as the transparent conductive film. After cleaning the transparent conductive film on the substrate 1, at first under high vacuum (3-2×10 ⁴ Pa), deposit a layer of thickness on the transparent conductive film and be 10nm electron donor layer 3, the electron donor layer 3 TPD is used as the material; then a mixed layer 4 of electron donor and electron acceptor is deposited on the electron donor layer 3 with a thickness of 5nm, the electron donor material is TPD, the electron acceptor material is Ir(ppy) ₃ , TPD and Ir The weight ratio of (ppy) ₃ is 1: 1; The electron acceptor layer 5 is deposited on the mixed layer 4 of the electron donor and the electron acceptor, and the material of the electron acceptor layer 5 is Ir(ppy) ₃ , and the thickness is selected 20nm or 30nm or 40nm; after that, an electron collection layer 6 is deposited on the electron acceptor layer 5, the material of the electron collection layer 6 is LiF, and its thickness is 0.8nm; finally, an electron collection electrode 7 is deposited on the electron collection layer 6, The electron collecting electrode 7 is made of metal Al with a thickness of 100nm. All of the above films were deposited using thermal evaporation processes. The thickness of each layer was monitored using a film thickness monitoring instrument. The successfully fabricated device is first irradiated with a UV irradiant of known power, and the irradiation intensity or distance is changed to measure the relationship between the electrical signal open circuit voltage (Voc) or short circuit current (Jsc) and the irradiation intensity in the photovoltaic characteristics and draw a standard curve, and then The sensitivity of the ultraviolet light to be measured is calculated by comparing the electrical signal obtained by measuring the ultraviolet light with an unknown intensity with the ultraviolet optical sensor to the standard curve. The sensitivity of the device in this embodiment to detect ultraviolet light is: the power of the ultraviolet light to be measured is 0.017mW/cm ² , the _ISC signal of the UV optical sensor is 1.8μA/cm ²

Example 2:

The hole collecting electrode layer 2 selects the ITO film on the glass substrate 1 as a transparent conductive film, and the electron donor layer 3 selects m-MTDATA material with a thickness of 6nm; The mixed layer 4 of the acceptor has a thickness of 5nm, the material of the electron donor is m-MTDATA, the material of the electron acceptor is _Btp2Ir (acac), and the weight ratio of m-MTDATA to _Btp2Ir (acac) is 1: 1; Deposition electron acceptor layer 5 on the mixed layer 4 of electron donor and electron acceptor again, electron acceptor layer 5 selects material as Btp ₂ Ir (acac), and thickness selects 20nm or 30nm or 35nm; An electron collection layer 6 is deposited on the acceptor layer 5, and the material of the electron collection layer 6 is LiF, and its thickness is 0.8nm; finally, an electron collection electrode layer 7 is deposited on the electron collection layer 6, and the electron collection electrode layer 7 is made of a metal Al material , and its thickness is 120nm. Each of the above layers is deposited using a thermal evaporation process. The thickness of the film was monitored using a film thickness monitoring instrument. Adopt the measuring method described in embodiment 1 to measure result as follows:

The ultraviolet light detection sensitivity of the device in this embodiment is: when the ultraviolet light power to be tested is 0.009mW/ ^cm2 , _{the ISC} signal of the ultraviolet light optical sensor is 1.0μA/ ^cm2

Example 3:

The hole collecting electrode layer 2 selects the ITO film on the glass substrate 1 as a transparent conductive film; the electron donor layer 3 selects m-MTDATA material with a thickness of 15nm; the thickness of the mixed layer 4 of the electron donor and electron acceptor is 5nm, The electron donor material is m-MTDATA, the electron acceptor is Ir(ppy) ₃ , the weight ratio of m-MTDATA and Ir(ppy) ₃ is 1:1; the electron acceptor layer 5 is Ir(ppy) ₃ , the thickness Select 20nm or 25nm or 30nm; then deposit an electron collection layer 6 on the electron acceptor layer 5, the material of the electron collection layer 6 is LiF, and its thickness is 1.5nm; finally deposit an electron collection electrode layer 7 on the electron collection layer 6 , The electron collecting electrode layer 7 is made of metal Al material, and its thickness is 120nm.

Adopt the measuring method described in embodiment 1 to measure result as follows:

The ultraviolet light detection sensitivity of the device in this embodiment is: when the ultraviolet light power to be tested is 0.010mW/ ^cm2 , _{the ISC} signal of the ultraviolet light optical sensor is 1.6μA/ ^cm2

Example 4:

The hole collecting electrode layer 2 selects the ITO film on the glass substrate 1 as the transparent conductive film; the electron donor layer 3 selects the m-MTDATA material with a thickness of 20nm, and the electron donor of the mixed layer 4 of the electron donor and the electron acceptor The material is m-MTDATA, the electron acceptor is Btp ₂ Ir (acac), the weight ratio of m-MTDATA to Btp ₂ Ir (acac) is 1:1, and the thickness of the mixed layer 4 of electron donor and electron acceptor is 7nm; Deposition electron acceptor layer 5 on the mixed layer 4 of electron donor and electron acceptor again, electron acceptor layer 5 selects Btp ₂ Ir (acac) for use, and thickness selects 20nm or 25nm or 30nm; Electron collection layer 6 is deposited on it, and the material of electron collection layer 6 adopts CsF, and its thickness is 2.5nm; Finally, electron collection electrode layer 7 is deposited on electron collection layer 6, and electron collection electrode layer 7 adopts metal Al material, and its thickness is 120nm.

Effect: adopt the measuring method described in embodiment 1 to measure result as follows:

The ultraviolet light detection sensitivity of the device in this embodiment is: when the ultraviolet light power to be tested is 0.010mW/ ^cm2 , _{the ISC} signal of the ultraviolet light optical sensor is 1.6μA/ ^cm2

Example 5:

The hole collecting electrode layer 2 selects the ITO film on the glass substrate 1 as a transparent conductive film; the electron donor layer 3 selects the material m-MTDATA with a thickness of 10nm; Select m-MTDATA, the electron acceptor selects the mixture of Btp ₂ Ir(acac) and Ir(ppy) ₃ , the weight ratio of Btp ₂ Ir(acac) and Ir(ppy) ₃ is 1:1, m-MTDATA and Btp ₂ The weight ratio of the mixture of Ir(acac) and Ir(ppy) ₃ is 1:1, and the thickness of the mixed layer 4 of electron donor and electron acceptor is 10 nm; above the mixed layer 4 of electron donor and electron acceptor Re-deposition electron acceptor layer 5, electron acceptor layer 5 is selected the mixture of Btp ₂ Ir (acac) or Ir (ppy) ₃ , the weight ratio of Btp ₂ Ir (acac) and Ir (ppy) ₃ is 1: 1, thickness 20nm or 30nm or 40nm; after that, an electron collection layer 6 is deposited on the electron acceptor layer 5, the material of the electron collection layer 6 is CsF, and its thickness is 2.5nm; finally, an electron collection electrode layer 7 is deposited on the electron collection layer 6 , The electron collecting electrode layer 7 is made of metal Al material, and its thickness is 150nm. Effect: adopt the measuring method described in embodiment 1 to measure result as follows:

The ultraviolet light detection sensitivity of the device in this embodiment is: when the ultraviolet light power to be measured is 0.009mW/cm ² , the _ISC signal of the ultraviolet light optical sensor is 0.8μA/cm ²

Embodiment 6:

The device structure shown in FIG. 1 is selected: in this embodiment, firstly, the hole-collecting electrode layer 2 selects the ITO film on the glass substrate 1 as the transparent conductive film. After cleaning the transparent conductive film on the substrate 1, at first under high vacuum (3-2×10 ^-4 Pa), deposit a layer of electron donor layer 3 with a thickness of 10nm on the transparent conductive film, and the electron donor layer 3 TPD is used as the material; an electron acceptor layer 5 is deposited on the electron donor layer 3, the material of the electron acceptor layer 5 is Ir(ppy) ₃ , and the thickness is selected as 20nm or 30nm or 40nm; after that, between the electron acceptor layer 5 An electron collection layer 6 is deposited on it, and the material of the electron collection layer 6 is LiF, and its thickness is 0.8nm; finally, an electron collection electrode 7 is deposited on the electron collection layer 6, and the electron collection electrode 7 is made of metal Al material, and its thickness is 100nm. All of the above films were deposited using thermal evaporation processes. The thickness of each layer was monitored using a film thickness monitoring instrument. The successfully manufactured device is first irradiated with a UV irradiant of known power, and the irradiation intensity or distance is changed to measure the relationship between the electrical signal open circuit voltage (Voc) or short circuit current (Jsc) and the irradiation intensity in the photovoltaic characteristics and draw a standard curve, and then The sensitivity of the ultraviolet light to be measured is calculated by comparing the electrical signal obtained by measuring the ultraviolet light with an unknown intensity with the ultraviolet optical sensor to the standard curve. The sensitivity of the device in this embodiment to detect ultraviolet light is: the power of the ultraviolet light to be measured is 0.017mW/cm ² , the _ISC signal of the UV optical sensor is 1.8μA/cm ² .

Claims (6)

1. An organic ultraviolet optical sensor based on a phosphorescent material photovoltaic diode, characterized in that it is a layered structure, from the substrate to the electron collection electrode, followed by the substrate, the hole collection electrode layer, the electron donor layer, and the electron acceptor layer. Body layer, electron collection layer, electron collection electrode layer; the thickness of the electron donor layer is 5-20nm, and the material used for the electron donor is a diamine derivative; the thickness of the electron acceptor layer is 20-40nm, and the material used for the electron acceptor is It is a complex of iridium, platinum, osmium or rhenium; the material used for the electron collection layer is LiF or CsF, and the thickness of the electron collection layer is 0.8~3nm; the material used for the electron collection electrode layer is Al, and the thickness of the electron collection electrode layer is 100~ 150nm. 2. the organic ultraviolet light optical sensor based on phosphorescent material photovoltaic diode according to claim 1 is characterized in that electron donor material selects TPD or m-MTDATA for use; Electron acceptor material selects Ir(ppy) for use ₃ or Btp ₂ Ir( acac). 3. The organic ultraviolet optical sensor based on phosphorescent material photovoltaic diode according to claim 1, characterized in that the electron donor layer thickness is 10nm, 6nm, 15nm or 20nm. 4. The organic ultraviolet optical sensor based on phosphorescent material photovoltaic diode according to claim 1, characterized in that the electron acceptor layer thickness is 20nm, 30nm, 40nm, 25nm or 35nm. 5. The organic ultraviolet optical sensor based on phosphorescent material photovoltaic diode according to claim 1, characterized in that the thickness of the electron collection layer is 0.8nm, 1.5nm, 2.5nm. 6. The organic ultraviolet optical sensor based on phosphorescent material photovoltaic diode according to claim 1, characterized in that the thickness of the electron collecting electrode is 100nm, 120nm, 150nm.

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