CN109148691B - Low-voltage multiplication type color organic photoelectric detector and preparation method thereof - Google Patents

Abstract

The invention discloses a low-voltage multiplication type color organic photoelectric detector, which comprises an ITO glass substrate, wherein an anode buffer layer, an active layer and an Al electrode layer are sequentially coated on one surface of the ITO glass substrate. The invention also discloses a preparation method of the low-voltage multiplication type color organic photoelectric detector, which comprises the steps of plating an ITO electrode layer on a glass substrate, coating an anode buffer layer on the blow-dried ITO electrode layer, coating an active layer on the anode buffer layer, and performing vacuum evaporation on the active layer to form an Al electrode layer, annealing, and cooling to room temperature. The detector of the invention has low working voltage, high external quantum efficiency and high specific detection rate, and the preparation method of the detector of the invention has simple process and low requirement on equipment.

Description

A kind of low-voltage multiplication type color organic photodetector and preparation method thereof

technical field

The invention belongs to the technical field of organic semiconductors, relates to a low voltage multiplication type color organic photodetector, and also relates to a preparation method of a low voltage multiplication type color organic photoelectric detector.

Background technique

Organic optoelectronic materials have the advantages of light weight, simple preparation process, easy processing into large areas, low cost, wide response spectrum range, and large light absorption coefficient, and can be widely used in photodetectors. The development of new device structures and their fabrication methods is the key technology to improve the photoresponsivity, quantum efficiency, and specific detectivity of photodetectors.

Although organic photodetectors with conventional structures have lower operating voltages, however, due to the low external quantum efficiency (generally less than 100%) and the low specific detection rate, the application of the detectors under weak light conditions is limited. Detection capability is critical. In recent years, people have taken advantage of the assisting effect of electron traps and the structure of flip-chip devices to introduce external circuit charge injection to improve the detection rate of organic detectors. Although several detectors reported so far have obtained high photoresponse and specific detection rate under some monochromatic light, there are still problems such as high operating voltage, incomplete three primary colors, and complex structure. In order to solve the above problems, this patent provides a multiplication type color organic photodetector with low operating voltage, high photosensitivity (R), high external quantum efficiency (EQE), high specific detection rate (D*), and simple process. device.

SUMMARY OF THE INVENTION

An object of the present invention is to provide a low-voltage multiplication type color organic photodetector with low operating voltage, high external quantum efficiency and high specific detection rate.

Another object of the present invention is to provide a method for preparing a low-voltage multiplier type color organic photodetector, which is simple and requires low equipment requirements.

The first technical solution adopted in the present invention is a low-voltage multiplication type color organic photodetector, comprising an ITO glass substrate, and one surface of the ITO glass substrate is sequentially coated with an anode buffer layer, an active layer and an Al electrode Floor.

The characteristics of the first technical solution of the present invention are:

The anode buffer layer is a PEDOT:PSS layer, and the thickness of the anode buffer layer is 32 nm-38 nm.

The active layer is a composite layer composed of P3HT, PBDTTT-F, PC ₆₁ BM and C ₆₀ , and the thickness of the active layer is 190 nm-210 nm.

The mass ratio of P3HT to PBDTTT-F was 11.8-12.2:7.8-8.2, the mass ratio of P3HT to _PC61 BM was 11.8-12.2:2.8-3.2, and the mass ratio of P3HT to _C60 was 11.8-12.2:0-0.5.

The thickness of the Al electrode layer is 90 nm to 110 nm.

Another technical solution adopted by the present invention is a preparation method of a low-voltage multiplier type color organic photodetector, which is specifically carried out according to the following steps:

Step 1, plating an ITO electrode layer on the glass substrate, cleaning, and blowing dry;

Step 2, coating an anode buffer layer on the dried ITO electrode layer;

Step 3, coating the active layer on the anode buffer layer;

In step 4, an Al electrode layer is vacuum-evaporated on the active layer, annealed, and the temperature is lowered to room temperature to obtain a low-voltage multiplication type color organic photodetector.

Another feature of the technical solution of the present invention is:

In step 1, after plating the ITO electrode layer on the glass substrate, mask and pattern etching the ITO electrode layer, then rinse and dry.

Step 2 is carried out according to the following method:

The PEDOT:PSS was spin-coated on the dried ITO electrode layer at a speed of 3300rpm-3700rpm for 50s-70s, and then annealed on a CNC hot plate at 95℃-105℃ for 10min-15min.

Step 3 is carried out according to the following method:

Step 3.1, weigh P3HT, PBDTTT-F, PC ₆₁ BM and C ₆₀ , wherein the mass ratio of P3HT to PBDTTT-F is 11.8-12.2:7.8-8.2, and the mass ratio of P3HT to PC ₆₁ BM is 11.8-12.2:2.8 -3.2, the mass ratio of P3HT to _C60 is 11.8-12.2:0-0.5;

In step 3.2, the weighed P3HT, PBDTTT-F, PC ₆₁ BM and C ₆₀ were all dissolved in 1 ml of chlorobenzene, and then fully stirred with a constant temperature magnetic stirrer at room temperature for 15 h to obtain an active layer solution;

Step 3.3, spin-coating the active layer solution on the anode buffer layer at a speed of 570rpm-630rpm, and the spin-coating time is 50s-70s;

Step 3.4, anneal on a CNC heating plate at 90℃~100℃ for 20min.

The vacuum evaporation in step 4 is monitored by a micro quartz oscillator, the rate of vacuum evaporation is controlled to be 0.3 nm·s ⁻¹ , and the thickness of the Al electrode layer of evaporation is controlled to be 90 nm-110 nm; Annealing at a temperature of 105℃~115℃ for 15min~20min.

The beneficial effects of the present invention are

The invention is a low-voltage multiplication type color organic photoelectric detector with low operating voltage, high external quantum efficiency and high specific detection rate;

The present invention is a low-voltage multiplication type color organic photodetector. The sex layer adopts the P3HT:PBDT-TT-F: _PC61BM three-phase bulk heterojunction, and the absorption spectrum of the active layer is broadened by spectral complementarity, and the full three-primary color is realized. absorb;

The invention is a low-voltage multiplication type color organic photoelectric detector. A small proportion of C ₆₀ is doped into the active layer as an electron energy level trap, and the electron assisting effect captured by the trap is used to cause hole injection, generate photomultiplier, and improve detection. The photoresponsivity and specific detection rate of the detector;

The present invention is a low-voltage multiplication type color organic photoelectric detector. There are two bulk heterojunctions, P3HT: PC ₆₁ BM and PBDTTT-F: PC ₆₁ BM, which satisfy the dissociation of photogenerated excitons, in the active layer, so as to ensure that the detector is in low work under bias;

The invention is a low-voltage multiplication type color organic photodetector, which has simple process, low requirements for equipment, and is suitable for industrial mass production.

Description of drawings

1 is a schematic structural diagram of a low-voltage multiplication type color organic photodetector of the present invention;

Fig. 2 is the absorption spectrum diagram of a kind of low voltage multiplication type color organic photodetector of the present invention;

Fig. 3 is the energy level diagram of a kind of low voltage multiplication color organic photodetector of the present invention;

Fig. 4 is a photomultiplier principle diagram of a low-voltage multiplier type color organic photodetector of the present invention;

5 is a schematic diagram of the C ₆₀ trap energy level of a low-voltage multiplication type color organic photodetector of the present invention after trapping;

6 is a J-V curve diagram of a low-voltage multiplication color organic photodetector of the present invention under different light;

Fig. 7 is the transient response curve of red light under -4V bias of a low-voltage multiplier type color organic photodetector of the present invention;

Fig. 8 is the transient response curve of green light under -4V bias of a low-voltage multiplication type color organic photodetector of the present invention;

FIG. 9 is a transient response curve of blue light under -4V bias of a low-voltage multiplier type color organic photodetector of the present invention.

In the figure, 1. ITO glass substrate, 2. anode buffer layer, 3. active layer, 4. Al electrode layer.

Detailed ways

The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

A low-voltage multiplication color organic photodetector, as shown in FIG. 1, includes an ITO glass substrate 1, and one surface of the ITO glass substrate 1 is sequentially coated with a PEDOT:PSS layer of 32nm-38nm, a layer of 190nm-210nm The active layer 3 and the Al electrode layer 4 of 90 nm-110 nm.

Among them, the active layer 3 is a composite layer composed of P3HT, PBDTTT-F, PC ₆₁ BM and C ₆₀ , and the mass ratio of P3HT and PBDTTT-F in the active layer 3 is 11.8-12.2:7.8-8.2, P3HT and PC ₆₁ The mass ratio of BM was 11.8-12.2:2.8-3.2, and the mass ratio of P3HT to _C60 was 11.8-12.2:0-0.5.

In a low-voltage multiplication type color organic photodetector of the present invention, the anode buffer layer 2 modifies the main active layer, which can effectively collect holes, increase the photo-generated current, and reduce the dark current at the same time;

As shown in Figure 2 and Figure 3, the active layer 3 is a mixed film of P3HT, PBDTTT-F, PC ₆₁ BM and C _60. The active layer 3 can absorb visible light of all wavelengths in the visible light spectrum range, and can be photogenerated excitons for effective solution. Two bulk heterojunctions, P3HT:PC ₆₁ BM and PBDTTT-F: PC ₆₁ BM, are provided separately, thereby ensuring the detector has a low operating voltage; through the assistance of a small proportion of C ₆₀ electron level traps, it induces hole injection, Generate photomultiplier to improve the detection ability of the detector.

As shown in Figure 3, when a forward voltage is applied to the low-voltage multiplication color organic photodetector, the electrons injected by the cathode overcome the smallest potential barrier among the three potential barriers formed by the organic material and the cathode of the Al electrode layer under the action of the electric field, which is 0.4 eV (PC ₆₁ BM△E 0.4 eV, PBDT-TT-F △E 0.76 eV, P3HT△E 1.1 eV) enters the LOMO level of PC ₆₁ BM, and is transported to the anode or recombined with the holes injected by the anode to form a current . Similarly, the holes injected from the anode do not need to overcome the potential barrier -0.1eV (P3HT △E-0.1eV, PBDTTT-F △E -0.05eV, PC ₆₁ BM△E0.9eV). A large number of holes are injected into the HUMO energy of P3HT. level, and recombine with the electrons injected by the cathode or be collected by the cathode to form a large current, and the current increases rapidly with the increase of voltage, similar to the characteristics of the forward-biased pn junction. When the reverse voltage is applied, the anode electrons have to overcome the larger potential barrier of 1.3eV to enter the LOMO energy level of PC ₆₁ BM, and the holes have to overcome the potential barrier of 0.8eV to enter the HUMO energy level of P3HT. The barrier forms the current, so the current is very small, similar to reverse biased pn junction characteristics.

As shown in Fig. 4 and Fig. 5, when irradiated under reverse voltage application, PC ₆₁ BM, P3HT and PBDTTT-F absorb photons of their respective wavelengths to generate excitons, which are separated at the heterojunction interface to form free carriers electrons and holes. Under the action of the electric field, holes and electrons pass through the interpenetrating network transport channels formed by PBDT-TT-F or P3HT, PC ₆₁ BM, respectively, and are collected by their respective electrodes to form a photogenerated current. At the same time, after part of the photogenerated electrons are captured by the C ₆₀ trap level in Fig. 5, the accumulation of electrons will cause the accumulation of holes on the side of the Al electrode, so a space charge region will be formed at the interface of the active layer 3/Al electrode layer. , resulting in the bending of the P3HT energy band, the Al work function will increase, and the potential barrier width will be reduced accordingly, which will cause the external circuit holes to be injected into the HOMO energy level of the P3HT through tunneling and then collected by the anode. The current is the sum of the photo-generated current and the hole injection current of the external circuit, and the device generates photomultiplier, so that the photoelectric characteristics of the low-voltage multiplication color organic photodetector can be greatly improved.

A preparation method of a low-voltage multiplication type color organic photodetector is specifically carried out according to the following steps:

Step 1, plating an ITO electrode layer on a glass substrate to obtain an ITO glass substrate 1, performing mask and pattern etching on the ITO electrode layer, and then cleaning the mask and pattern etched ITO electrode layer with a large amount of pure water, Then wash and dry;

Then use deionized water to ultrasonically clean the ITO glass substrate 1 for 15 minutes, then use acetone to ultrasonically clean the ITO glass substrate 1 for 15 minutes, continue to ultrasonically clean the ITO glass substrate 1 with absolute ethanol for 15 minutes, and finally dry the ITO glass substrate with pure nitrogen. 1;

Step 2, coating the anode buffer layer on the dried ITO electrode layer 2: spin-coating PEDOT:PSS on the dried ITO electrode layer at a speed of 3300rpm-3700rpm, the spin coating time is 50s-70s, Then anneal for 10min~15min on the CNC heating plate at 95℃-105℃;

Step 3, coating the active layer 3 on the anode buffer layer 2 is carried out according to the following method:

Step 3.1, weigh P3HT, PBDTTT-F, PC ₆₁ BM and C ₆₀ , wherein the mass ratio of P3HT to PBDTTT-F is 11.8-12.2:7.8-8.2, and the mass ratio of P3HT to PC ₆₁ BM is 11.8-12.2:2.8 -3.2, the mass ratio of P3HT to _C60 is 11.8-12.2:0-0.5;

In step 3.2, the weighed P3HT, PBDTTT-F, PC ₆₁ BM and C ₆₀ were all dissolved in 1 ml of chlorobenzene, and then fully stirred with a constant temperature magnetic stirrer at room temperature for 15 h to obtain an active layer solution;

Step 3.3, spin-coating the active layer solution on the anode buffer layer 2 at a speed of 570rpm-630rpm, and the spin-coating time is 50s-70s;

Step 3.4, annealing for 18min-22min on a CNC heating plate at 90℃~100℃;

In step 4, the Al electrode layer 4 is vacuum-evaporated on the active layer 3 at a speed of 0.3 nm·s ⁻¹ under the monitoring of a micro-quartz oscillator, until the thickness of the Al electrode layer 4 is 90 nm-110 nm, and the process is carried out under vacuum. Annealing at 105℃~115℃ for 15min~20min, then lowering the temperature to room temperature to obtain a low-voltage multiplication color organic photodetector.

Example 1

A preparation method of a low-voltage multiplication type color organic photodetector is specifically carried out according to the following steps:

Step 1, plating an ITO electrode layer on a glass substrate to obtain an ITO glass substrate 1, performing mask and pattern etching on the ITO electrode layer, and then cleaning the mask and pattern etched ITO electrode layer with a large amount of pure water, Then wash and dry;

Then use deionized water to ultrasonically clean the ITO glass substrate 1 for 15 minutes, then use acetone to ultrasonically clean the ITO glass substrate 1 for 15 minutes, continue to ultrasonically clean the ITO glass substrate 1 with absolute ethanol for 15 minutes, and finally dry the ITO glass substrate with pure nitrogen. 1;

Step 2, coating the anode buffer layer on the dried ITO electrode layer 2: Spin-coat PEDOT:PSS on the dried ITO electrode layer at a speed of 3300 rpm for 50 s, and then at 95°C Annealed on the CNC heating plate for 10min;

Step 3, coating the active layer 3 on the anode buffer layer 2 is carried out according to the following method:

Step 3.1, weigh P3HT, PBDTTT-F and PC ₆₁ BM, wherein the mass ratio of P3HT to PBDTTT-F is 11.8:7.8, and the mass ratio of P3HT to PC ₆₁ BM is 11.8:2.8;

In step 3.2, the weighed P3HT, PBDTTT-F, PC ₆₁ BM and C ₆₀ were all dissolved in 1 ml of chlorobenzene, and then fully stirred with a constant temperature magnetic stirrer at room temperature for 15 h to obtain an active layer solution;

Step 3.3, spin-coating the active layer solution on the anode buffer layer 2 at a speed of 570rpm, and the spin-coating time is 50s;

Step 3.4, annealing on a CNC heating plate at 90°C for 18min-22min;

In step 4, the Al electrode layer 4 is vacuum-evaporated on the active layer 3 at a speed of 0.3 nm·s ⁻¹ under the monitoring of a micro-quartz oscillator. After the thickness of the Al electrode layer 4 is 90 nm, the process is carried out under vacuum at 105° C. After annealing for 15 min, the temperature was lowered to room temperature to obtain a low-voltage multiplication color organic photodetector.

Example 2

A preparation method of a low-voltage multiplication type color organic photodetector is specifically carried out according to the following steps:

Step 1, plating an ITO electrode layer on a glass substrate to obtain an ITO glass substrate 1, performing mask and pattern etching on the ITO electrode layer, and then cleaning the mask and pattern etched ITO electrode layer with a large amount of pure water, Then wash and dry;

Then use deionized water to ultrasonically clean the ITO glass substrate 1 for 15 minutes, then use acetone to ultrasonically clean the ITO glass substrate 1 for 15 minutes, continue to ultrasonically clean the ITO glass substrate 1 with absolute ethanol for 15 minutes, and finally dry the ITO glass substrate with pure nitrogen. 1;

Step 2, coating the anode buffer layer on the dried ITO electrode layer 2: Spin-coat PEDOT:PSS on the dried ITO electrode layer at a speed of 3700 rpm for 70 s, and then spin at 105 s. Annealed on a numerically controlled heating plate at ℃ for 15min;

Step 3, coating the active layer 3 on the anode buffer layer 2 is carried out according to the following method:

Step 3.1, weigh P3HT, PBDTTT-F, PC ₆₁ BM and C ₆₀ , wherein the mass ratio of P3HT to PBDTTT-F is 12.2: 8.2, the mass ratio of P3HT to PC ₆₁ BM is 12.2: 3.2, and the mass ratio of P3HT to C ₆₀ is 12.2: 3.2. The mass ratio is 12.2: 0.5;

In step 3.2, the weighed P3HT, PBDTTT-F, PC ₆₁ BM and C ₆₀ were all dissolved in 1 ml of chlorobenzene, and then fully stirred with a constant temperature magnetic stirrer at room temperature for 15 h to obtain an active layer solution;

Step 3.3, spin-coating the active layer solution on the anode buffer layer 2 at a speed of 630 rpm, and the spin-coating time is 70s;

Step 3.4, annealing on a CNC heating plate at 100°C for 22min;

In step 4, the Al electrode layer 4 is vacuum-evaporated on the active layer 3 at a speed of 0.3 nm·s ⁻¹ under the monitoring of a micro-quartz oscillator. After the thickness of the Al electrode layer 4 is 110 nm, the process is carried out under vacuum at 115° C. After annealing for 20 min, the temperature was lowered to room temperature to obtain a low-voltage multiplication color organic photodetector.

Example 3

A preparation method of a low-voltage multiplication type color organic photodetector is specifically carried out according to the following steps:

Step 1, plating an ITO electrode layer on a glass substrate to obtain an ITO glass substrate 1, performing mask and pattern etching on the ITO electrode layer, and then cleaning the mask and pattern etched ITO electrode layer with a large amount of pure water, Then wash and dry;

Then use deionized water to ultrasonically clean the ITO glass substrate 1 for 15 minutes, then use acetone to ultrasonically clean the ITO glass substrate 1 for 15 minutes, continue to ultrasonically clean the ITO glass substrate 1 with absolute ethanol for 15 minutes, and finally dry the ITO glass substrate with pure nitrogen. 1;

Step 2, coating the anode buffer layer on the dried ITO electrode layer 2: Spin-coat PEDOT:PSS on the dried ITO electrode layer at a speed of 3500 rpm for 60 s, and then at 100 °C Annealed on the CNC heating plate for 12min;

Step 3, coating the active layer 3 on the anode buffer layer 2 is carried out according to the following method:

Step 3.1, weigh P3HT, PBDTTT-F, PC ₆₁ BM and C ₆₀ , wherein the mass ratio of P3HT to PBDTTT-F is 12:8, the mass ratio of P3HT to PC ₆₁ BM is 12:3, and the mass ratio of P3HT to C ₆₀ is 12:8. The mass ratio is 12:0.2;

In step 3.2, the weighed P3HT, PBDTTT-F, PC ₆₁ BM and C ₆₀ were all dissolved in 1 ml of chlorobenzene, and then fully stirred with a constant temperature magnetic stirrer at room temperature for 15 h to obtain an active layer solution;

Step 3.3, spin-coating the active layer solution on the anode buffer layer 2 at a speed of 600 rpm, and the spin-coating time is 60s;

Step 3.4, annealing on a CNC heating plate at 95°C for 20min;

In step 4, the Al electrode layer 4 is vacuum-evaporated on the active layer 3 at a speed of 0.3 nm·s ⁻¹ under the monitoring of a micro-quartz oscillator. After the thickness of the Al electrode layer 4 is 100 nm, the process is carried out under vacuum at 110° C. After annealing for 15min-20min, the temperature was lowered to room temperature to obtain a low-voltage multiplier color organic photodetector.

Example 4

A preparation method of a low-voltage multiplication type color organic photodetector is specifically carried out according to the following steps:

Step 1, plating an ITO electrode layer on a glass substrate to obtain an ITO glass substrate 1, performing mask and pattern etching on the ITO electrode layer, and then cleaning the mask and pattern etched ITO electrode layer with a large amount of pure water, Then wash and dry;

Then use deionized water to ultrasonically clean the ITO glass substrate 1 for 15 minutes, then use acetone to ultrasonically clean the ITO glass substrate 1 for 15 minutes, continue to ultrasonically clean the ITO glass substrate 1 with absolute ethanol for 15 minutes, and finally dry the ITO glass substrate with pure nitrogen. 1;

Step 2: Coating the anode buffer layer on the dried ITO electrode layer 2: Spin-coat PEDOT:PSS on the dried ITO electrode layer at a speed of 3400 rpm for 55 s, and then at 98 °C Annealed on the CNC heating plate for 12min;

Step 3, coating the active layer 3 on the anode buffer layer 2 is carried out according to the following method:

Step 3.1, weigh P3HT, PBDTTT-F, PC ₆₁ BM and C ₆₀ , wherein the mass ratio of P3HT to PBDTTT-F is 11.8: 8.2, the mass ratio of P3HT to PC ₆₁ BM is 11.8: 3.2, and the mass ratio of P3HT to C ₆₀ is 11.8: 3.2. The mass ratio is 11.8: 0.5;

In step 3.2, the weighed P3HT, PBDTTT-F, PC ₆₁ BM and C ₆₀ were all dissolved in 1 ml of chlorobenzene, and then fully stirred with a constant temperature magnetic stirrer at room temperature for 15 h to obtain an active layer solution;

Step 3.3, spin-coating the active layer solution on the anode buffer layer 2 at a speed of 580 rpm, and the spin-coating time is 55s;

Step 3.4, annealing on a CNC heating plate at 93°C for 19min;

In step 4, the Al electrode layer 4 is vacuum-evaporated on the active layer 3 at a speed of 0.3 nm·s ⁻¹ under the monitoring of a micro-quartz oscillator. After the thickness of the Al electrode layer 4 is 92 nm, the process is carried out under vacuum at 108° C. After annealing for 16 min, the temperature was lowered to room temperature to obtain a low-voltage multiplication color organic photodetector.

Example 5

A preparation method of a low-voltage multiplication type color organic photodetector is specifically carried out according to the following steps:

Step 1, plating an ITO electrode layer on a glass substrate to obtain an ITO glass substrate 1, performing mask and pattern etching on the ITO electrode layer, and then cleaning the mask and pattern etched ITO electrode layer with a large amount of pure water, Then wash and dry;

Then use deionized water to ultrasonically clean the ITO glass substrate 1 for 15 minutes, then use acetone to ultrasonically clean the ITO glass substrate 1 for 15 minutes, continue to ultrasonically clean the ITO glass substrate 1 with absolute ethanol for 15 minutes, and finally dry the ITO glass substrate with pure nitrogen. 1;

Step 2, coating the anode buffer layer on the dried ITO electrode layer 2: Spin-coat PEDOT:PSS on the dried ITO electrode layer at a speed of 3600 rpm for 55 s, and then at 10 2 Annealed on a numerically controlled heating plate at ℃ for 14min;

Step 3, coating the active layer 3 on the anode buffer layer 2 is carried out according to the following method:

Step 3.1, weigh P3HT, PBDTTT-F, PC ₆₁ BM and C ₆₀ , wherein the mass ratio of P3HT to PBDTTT-F is 12.2:7.8, the mass ratio of P3HT to PC ₆₁ BM is 12.2:2.8, and the mass ratio of P3HT to C ₆₀ is 12.2:2.8. The mass ratio is 12.2:0.1;

In step 3.2, the weighed P3HT, PBDTTT-F, PC ₆₁ BM and C ₆₀ were all dissolved in 1 ml of chlorobenzene, and then fully stirred with a constant temperature magnetic stirrer at room temperature for 15 h to obtain an active layer solution;

Step 3.3, spin-coating the active layer solution on the anode buffer layer 2 at a speed of 620rpm, and the spin-coating time is 65s;

Step 3.4, annealing on a CNC heating plate at 98°C for 21min;

In step 4, the Al electrode layer 4 is vacuum-evaporated on the active layer 3 at a speed of 0.3 nm·s ⁻¹ under the monitoring of a micro-quartz oscillator. After the thickness of the Al electrode layer 4 is 115 nm, the process is carried out under vacuum at 112° C. After annealing for 19 min, the temperature was lowered to room temperature to obtain a low-voltage multiplication color organic photodetector.

The low voltage multiplication type color organic photodetector obtained by the preparation method of the low voltage multiplication type color organic photodetector of the present invention is tested. /cm ² ; green LED light, wavelength is 530nm, optical power is 0.19mW/cm ² ; blue LED light, wavelength is 460nm, light power is 0.21mW/cm ² , the current density and voltage as shown in Figure 5 are obtained From the JV characteristic curve, it can be obtained from FIG. 5 that the low-voltage multiplication type color organic photodetector of the present invention has a good detection effect for different light sources.

The transient photoresponse rise and fall times of the detector's three primary colors were tested under −4 V bias. As shown in Figure 7, when the red light is tested, the rising time from 10%−90% of Vrp is 120 μs, and the time of falling from 90%−10% of Vrp is 817 μs;

As shown in Figure 8, when the green light is tested, the time to rise from 10%−90% of Vrp is 138 μs, and the time to fall from 90%−10% of Vrp is 833 μs;

As shown in Figure 9, when the blue light is tested, the rising time from 10%−90% of Vrp is 175 μs, and the falling time from 90%−10% of Vrp is 175 μs;

Therefore, the low voltage multiplication type color organic photodetector obtained by the preparation method of the low voltage multiplication type color organic photodetector of the present invention has a faster detection speed when detecting different light sources.

When the bias voltage is -4V, the responsivity R, external quantum efficiency (EQE) and specific detection rate (D*) of the three primary colors of the low-voltage multiplier color organic photodetector obtained in Examples 1-5 of the present invention are as follows: As shown in Table 1, the dark currents of the low-voltage multiplier color organic photodetectors of Examples 1 to 5 are all 10 ^-5 A/cm ² , and the dark currents for red light with a wavelength of 630 nm, blue light with a wavelength of 460 nm, and For green light with a wavelength of 530 nm, the specific detection rates are all above 7×10 ¹¹ Jones and between 7×10 ¹¹ -10 ¹² Jones, and the low voltage multiplication color organic photodetector obtained by this method has good stability.

Table 1 Responsivity, external quantum efficiency and specific detection rate of the three primary colors of the detector

Claims (3)

1. A low-voltage multiplication color organic photodetector, characterized in that it comprises an ITO glass substrate (1), one surface of the ITO glass substrate (1) is sequentially coated with an anode buffer layer (2) , an active layer (3) and an Al electrode layer (4), the anode buffer layer (2) is a PEDOT:PSS layer, and the thickness of the anode buffer layer (2) is 32 nm to 38 nm, and the active layer (3) is A composite layer composed of P3HT, PBDTTT-F, PC ₆₁ BM and C ₆₀ , the thickness of the active layer (3) is 190nm-210nm, and the mass ratio of the P3HT to PBDTTT-F is 11.8-12.2:7.8-8.2 , the mass ratio of P3HT to PC ₆₁ BM is 11.8-12.2:2.8-3.2, the mass ratio of P3HT to C ₆₀ is 11.8-12.2: 0.1-0.5, and the thickness of the Al electrode layer (4) is 90 nm-110 nm. 2. a preparation method of a low-voltage multiplier type color organic photodetector, is characterized in that, is specifically carried out according to the following steps: Step 1, plating an ITO electrode layer on the glass substrate, cleaning, and blowing dry; Step 2, coating an anode buffer layer (2) on the dried ITO electrode layer; specifically, according to the following method: Spin-coat PEDOT:PSS on the dried ITO electrode layer at a speed of 3300rpm-3700rpm, spin-coating time is 50s-70s, and then anneal on a CNC hot plate at 95℃-105℃ for 10min-15min; Step 3, coating the active layer (3) on the anode buffer layer (2); specifically, according to the following method: Step 3.1, weigh P3HT, PBDTTT-F, PC ₆₁ BM and C ₆₀ , wherein the mass ratio of P3HT to PBDTTT-F is 11.8-12.2:7.8-8.2, and the mass ratio of P3HT to PC ₆₁ BM is 11.8-12.2:2.8 -3.2, the mass ratio of P3HT to _C60 is 11.8-12.2:0.1-0.5; In step 3.2, the weighed P3HT, PBDTTT-F, PC ₆₁ BM and C ₆₀ were all dissolved in 1 ml of chlorobenzene, and then fully stirred with a constant temperature magnetic stirrer at room temperature for 15 h to obtain an active layer solution; Step 3.3, spin-coating the active layer solution on the anode buffer layer (2) at a speed of 570rpm-630rpm, and the spin-coating time is 50s-70s; Step 3.4, annealing on a CNC heating plate at 90℃~100℃ for 20min; Step 4, vacuum evaporation of the Al electrode layer (4) on the active layer (3), annealing, and temperature reduction to room temperature to obtain a low voltage multiplication type color organic photodetector; The vacuum evaporation was monitored by a micro-quartz oscillator, the rate of vacuum evaporation was controlled to be 0.3 nm·s ⁻¹ , and the thickness of the Al electrode layer (4) to be evaporated was controlled to be 90 nm-110 nm; Anneal at 105℃~115℃ for 15min~20min. 3. the preparation method of a kind of low-voltage multiplier color organic photodetector according to claim 2, is characterized in that, in described step 1, after plating ITO electrode layer on glass substrate, carry out mask to ITO electrode layer , pattern etching, and then rinse and dry.

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