RU221988U1 - PIEZOELECTRIC NANOGENERATOR BASED ON TWO ARRAYS OF VERTICALLY ORIENTED CARBON NANOTUBES - Google Patents

Abstract

The utility model relates to electrical engineering. The technical result consists in increasing the output power of the piezoelectric nanogenerator due to the effective collection of the generated potential by increasing the contact area of the top electrode with the tops of vertically oriented carbon nanotubes. A piezoelectric nanogenerator based on two arrays of vertically oriented carbon nanotubes consists of a lower substrate with a lower contact electrode formed on it, on which vertically oriented carbon nanotubes are grown, which act as piezoelements. The tops of the nanotubes are not rigidly fixed on the upper contact electrode due to the presence of dielectric stops. An array of vertically oriented carbon nanotubes, which is grown on an upper substrate with a continuous conductive layer, is used as the upper contact electrode. Moreover, the length of the upper array of vertically oriented carbon nanotubes is from 10% to 30% of the length of the lower array of vertically oriented carbon nanotubes, acting as piezoelements. 2 ill.

Description

The utility model relates to the field of electrical power engineering, specifically to devices capable of converting mechanical energy into electrical energy due to the direct piezoelectric effect, and can be used to create low-power power supplies for electronics.

A functional analogue of the claimed object is a “Piezoelectric generator” [RU 2446551 C1 dated October 18, 2010], containing a dielectric substrate, vertical nano-sized piezoelectric columns acting as piezoelectric elements, and nano-sized current-collecting wire electrodes laid between rows of vertical nano-sized columns and in contact with them in the areas of their foundations. The electrodes are enclosed in a layer of elastic-plastic insulator, the height of which corresponds to the diameter of the electrodes, and there is a gap between each two electrodes. In this case, permanent nanosized magnetic elements are introduced into the tops of the nano-sized columns. The operating principle of this generator is based on converting the energy of an external alternating magnetic (electromagnetic) field into electrical energy by swinging nano-sized columns under the influence of reciprocating movements of nano-sized permanent magnetic elements. When rocking nano-sized columns, due to the occurrence of a piezoelectric effect, a potential difference is created on their surfaces, which is transferred to nano-sized current-collecting wire electrodes.

This generator allows you to generate electrical energy to power various micro- or nanodevices, and can also be used in the production of alternative long-term energy installations.

The characteristics of the analogue, which coincide with the essential characteristics of the claimed object, are:

a) top electrode;

b) bottom electrode;

c) vertical orientation of piezoelements;

d) nano-sized geometric parameters of piezoelements.

The reasons preventing the achievement of the technical result are: the need for precise positioning of wire electrodes between rows of vertical nano-sized pillars using lithography operations, the need for additional introduction of permanent nano-sized magnetic elements into the tops of nano-sized pillars to increase the energy efficiency of the nanogenerator.

There is a known analogue of the claimed object - a nanogenerator based on vertically oriented zinc oxide whiskers [article X. Wang, J. Song, J. Liu, Z.L. Wang, “Direct-Current Nanogenerator Driven by Ultrasonic Waves” (“DC nanogenerator controlled by ultrasonic waves” ) Science, 316, 2007, 102-105], containing a substrate made of dielectric or semiconductor material, a lower solid electrode, vertically oriented zinc oxide nanowhiskers acting as piezoelements, an upper profiled contact electrode held above the tops of the piezoelements using dielectric stops . The operating principle of this nanogenerator is based on the conversion of external influence in the form of an ultrasonic wave into an electrical signal (voltage and/or current) as a result of the manifestation of a direct piezoelectric effect in zinc oxide nanowhiskers.

This nanogenerator makes it possible to generate energy of 10 fW from each nanowhisker and with a total output power per unit area of up to 10 mW/cm ² . This nanogenerator does not require additional operations of introducing permanent nano-sized magnetic elements, and also makes it possible to increase the packing density of piezoelements due to the absence of wire electrodes between the rows of nanowhiskers and reducing the diameter of the piezoelement to the diameter of an individual nanowhisker.

The characteristics of the analogue, which coincide with the essential characteristics of the claimed object, are:

a) upper profiled electrode;

b) bottom solid electrode;

c) dielectric stops;

d) vertical orientation of piezoelements;

e) nano-sized geometric parameters of piezoelements.

The reasons preventing the achievement of the technical result are: low output power due to energy dissipation due to the lack of high-quality conducting channels from each piezoelectric element, as well as the low current value generated by one piezoelectric element, caused by the high resistivity of zinc oxide nanowhiskers (0.3 Ohm m).

Of the known analogues, the closest in technical essence to the claimed object is the “Nanogenerator based on vertically oriented carbon nanotubes” [RU 211606 U1 dated February 16, 2022], containing a substrate made of dielectric or semiconductor material, with a formed solid bottom contact electrode, on in which vertically oriented carbon nanotubes are grown using the method of plasma-chemical deposition from the gas phase, which act as piezoelectric elements, an upper contact profiled electrode, dielectric stops that ensure the positioning of the upper contact electrode above the tops of vertically oriented carbon nanotubes. The nanogenerator operates as follows: in the initial state, vertically oriented carbon nanotubes are in an undeformed state, and their tops should not be rigidly fixed on the upper contact electrode to maintain the mobility of the tops of the nanotubes under external mechanical influences. Then, under external mechanical influence, the tops of vertically oriented carbon nanotubes deviate from their axis, become deformed and come into contact with the upper profiled electrode. Due to the fact that vertically oriented nanotubes have a piezoelectric effect, as a result of external mechanical influences they are deformed, and a potential difference arises between the tops of vertically oriented carbon nanotubes, which experience elastic nanoscale deformations, and the grounded upper contact profiled electrode. The magnitude of the generated potential is determined by the magnitude of the piezoelectric modulus of vertically oriented carbon nanotubes, the magnitude of which depends on the concentration of defects in the substitution of carbon atoms by nitrogen atoms with a pyrrole structure. The magnitude of the generated current is determined by the resistivity of vertically oriented carbon nanotubes and their packing density on the substrate, which can reach values of up to 100 μm-2. The proposed device can be used to generate electrical energy by converting external mechanical influences, such as wind, vibrations and movements of the human body, including nano-sized deformations and vibrations.

The features of the prototype that coincide with the essential features of the claimed object are:

a) substrate;

b) upper profiled electrode;

c) bottom solid electrode;

d) dielectric stops;

e) nano-sized geometric parameters of piezoelements

f) vertically oriented carbon nanotubes.

The reasons preventing the achievement of the technical result are: a decrease in output power due to ineffective collection of the generated potential on the surface of vertically oriented carbon nanotubes.

The technical result of the proposed utility model is to increase the output power of a piezoelectric nanogenerator due to more efficient collection of the generated potential by increasing the contact area of the top electrode with the tops of vertically oriented carbon nanotubes.

To achieve the required technical result in a piezoelectric nanogenerator based on two arrays of vertically oriented carbon nanotubes, consisting of a lower substrate with a lower contact electrode formed on it, on which vertically oriented carbon nanotubes are grown, which act as piezoelements, the tops of the nanotubes are not rigidly fixed to upper contact electrode due to the presence of dielectric stops, an array of vertically oriented carbon nanotubes is used as the upper contact electrode, which is grown on the upper substrate with a continuous conductive layer, and the length of the upper array of vertically oriented carbon nanotubes is from 10% to 30% of the length of the lower an array of vertically oriented carbon nanotubes acting as piezoelements.

In this case, the length of the upper array of vertically oriented carbon nanotubes should be from 10% to 30% of the length of the lower array of vertically oriented carbon nanotubes, acting as piezoelements, in order to provide a sufficient contact area to the tops of the vertically oriented carbon nanotubes for effective collection of the generated potential the lower massif, experiencing the greatest deformation due to external mechanical influences. The minimum length of the upper array of vertically oriented carbon nanotubes, 10% of the length of the lower array of vertically oriented carbon nanotubes, is determined by the maximum permissible deviation from the height of the dielectric stops, which ensure the positioning of the upper contact electrode above the tops of vertically oriented carbon nanotubes, acting as piezoelements, as well as the need to increase the area contact of the upper electrode to the tops of vertically oriented carbon nanotubes of the lower array for efficient collection of the generated potential. The maximum length of the upper array of vertically oriented carbon nanotubes, 30% of the length of the lower array of vertically oriented carbon nanotubes, is due to the need to form contact primarily with the vertices of the lower array of vertically oriented carbon nanotubes, which experience the greatest deformation due to external mechanical influences, as well as the need to exclude the possibility of touching the vertices of the upper an array of vertically oriented carbon nanotubes of the lower contact electrode.

In fig. 1, 2 show a general view and section of a piezoelectric nanogenerator based on two arrays of vertically oriented carbon nanotubes.

The piezoelectric nanogenerator (Fig. 1, 2) contains a lower substrate 1 made of dielectric or semiconductor material with a formed solid lower contact electrode 2, on which vertically oriented carbon nanotubes are grown using plasma-chemical vapor deposition in flows of carbon and nitrogen precursors 3, acting as piezoelectric elements, an upper contact electrode based on an array of vertically oriented carbon nanotubes 4 grown on an upper substrate 5 with a continuous conductive layer 6 by plasma-chemical vapor deposition in flows of carbon and hydrogen precursors, dielectric stops 7 ensuring the positioning of the upper contact electrode 4 over the tops of vertically oriented carbon nanotubes 3.

The piezoelectric nanogenerator works as follows.

In the initial state, vertically oriented carbon nanotubes 3 are in an undeformed state. In this case, the tops of the oriented carbon nanotubes should not be rigidly fixed on the upper contact electrode based on an array of vertically oriented carbon nanotubes 4 in order to maintain the mobility of the tops of the nanotubes under external mechanical influences. Under external mechanical influence, such as wind, vibration or human body movements, the tops of vertically oriented carbon nanotubes 3 deviate from their axis, deform and contact the upper electrode based on an array of vertically oriented carbon nanotubes 4 grown on the upper substrate 5 with a continuous conductive layer 6. Due to the fact that vertically oriented nanotubes 3 grown on the lower contact electrode 2 located on the lower substrate 1 have a piezoelectric effect, as a result of external mechanical influences they are deformed, and a potential difference arises between the tops of vertically oriented carbon nanotubes 3 experiencing elastic nanoscale deformations, and a grounded upper contact electrode based on an array of vertically oriented carbon nanotubes 4. Moreover, due to the fact that contact is provided to each vertically oriented carbon nanotube 3, the efficiency of collecting the generated potential tends to 100%. In this case, the value of the generated potential is determined by the value of the piezoelectric modulus of vertically oriented carbon nanotubes 3, the value of which depends on the concentration of defects in the substitution of carbon atoms by nitrogen atoms with a pyrrole structure. The value of the piezoelectric modulus of vertically oriented carbon nanotubes of the upper contact electrode 4 should be close to zero, which is achieved by their growth by plasma-chemical vapor deposition in flows of carbon and hydrogen precursors. The proposed device can be used to generate electrical energy by converting external mechanical influences, such as wind, vibrations and movements of the human body, including nano-sized deformations and vibrations.

Thus, the proposed device is a piezoelectric nanogenerator based on two arrays of vertically oriented carbon nanotubes, one of which acts as an array of piezoelements, allowing efficient conversion of nanoscale mechanical deformations and vibrations into electrical energy, the second - as an upper contact electrode, allowing efficient collection generated energy sufficient to create on their basis autonomous power sources for wearable and implantable electronics.

Compared with similar devices, the proposed piezoelectric nanogenerator makes it possible to increase the output power per unit area to tens of W/ ^cm2 due to more efficient collection of the generated potential by increasing the contact area of the top electrode with the tops of vertically oriented carbon nanotubes, acting as piezoelements.

Claims (1)

Piezoelectric nanogenerator based on two arrays of vertically oriented carbon nanotubes, consisting of a lower substrate with a lower contact electrode formed on it, on which vertically oriented carbon nanotubes are grown, which act as piezoelements; the tops of the nanotubes are not rigidly fixed on the upper contact electrode due to the presence of dielectric stops, characterized in that an array of vertically oriented carbon nanotubes is used as the upper contact electrode, which is grown on the upper substrate with a continuous conductive layer, and the length of the upper array of vertically oriented carbon nanotubes is from 10% to 30% of the length of the lower array of vertically oriented carbon nanotubes nanotubes acting as piezoelectric elements.