Quantum dot solar cell

Last updated
Spin-cast quantum dot solar cell built by the Sargent Group at the University of Toronto. The metal disks on the front surface are the electrical connections to the layers below. Sargent Group quantum dot solar cell.jpg
Spin-cast quantum dot solar cell built by the Sargent Group at the University of Toronto. The metal disks on the front surface are the electrical connections to the layers below.

A quantum dot solar cell (QDSC) is a solar cell design that uses quantum dots as the captivating photovoltaic material. It attempts to replace bulk materials such as silicon, copper indium gallium selenide (CIGS) or cadmium telluride (CdTe). Quantum dots have bandgaps that are adjustable across a wide range of energy levels by changing their size. In bulk materials, the bandgap is fixed by the choice of material(s). [1] This property makes quantum dots attractive for multi-junction solar cells, where a variety of materials are used to improve efficiency by harvesting multiple portions of the solar spectrum.

Contents

As of 2022, efficiency exceeds 18.1%. [2] Quantum dot solar cells have the potential to increase the maximum attainable thermodynamic conversion efficiency of solar photon conversion up to about 66% by utilizing hot photogenerated carriers to produce higher photovoltages or higher photocurrents. [3]

Background

Solar cell concepts

In a conventional solar cell light is absorbed by a semiconductor, producing an electron-hole (e-h) pair; the pair may be bound and is referred to as an exciton. This pair is separated by an internal electrochemical potential (present in p-n junctions or Schottky diodes) and the resulting flow of electrons and holes creates an electric current. The internal electrochemical potential is created by doping one part of the semiconductor interface with atoms that act as electron donors (n-type doping) and another with electron acceptors (p-type doping) that results in a p-n junction. The generation of an e-h pair requires that the photons have energy exceeding the bandgap of the material. Effectively, photons with energies lower than the bandgap do not get absorbed, while those that are higher can quickly (within about 10−13 s) thermalize to the band edges, reducing output. The former limitation reduces current, while the thermalization reduces the voltage. As a result, semiconductor cells suffer a trade-off between voltage and current (which can be in part alleviated by using multiple junction implementations). The detailed balance calculation shows that this efficiency can not exceed 33% if one uses a single material with an ideal bandgap of 1.34 eV for a solar cell. [4]

The band gap (1.34 eV) of an ideal single-junction cell is close to that of silicon (1.1 eV), one of the many reasons that silicon dominates the market. However, silicon's efficiency is limited to about 30% (Shockley–Queisser limit). It is possible to improve on a single-junction cell by vertically stacking cells with different bandgaps – termed a "tandem" or "multi-junction" approach. The same analysis shows that a two layer cell should have one layer tuned to 1.64 eV and the other to 0.94 eV, providing a theoretical performance of 44%. A three-layer cell should be tuned to 1.83, 1.16 and 0.71 eV, with an efficiency of 48%. An "infinity-layer" cell would have a theoretical efficiency of 86%, with other thermodynamic loss mechanisms accounting for the rest. [5]

Traditional (crystalline) silicon preparation methods do not lend themselves to this approach due to lack of bandgap tunability. Thin-films of amorphous silicon, which due to a relaxed requirement in crystal momentum preservation can achieve direct bandgaps and intermixing of carbon, can tune the bandgap, but other issues have prevented these from matching the performance of traditional cells. [6] Most tandem-cell structures are based on higher performance semiconductors, notably indium gallium arsenide (InGaAs). Three-layer InGaAs/GaAs/InGaP cells (bandgaps 0.94/1.42/1.89 eV) hold the efficiency record of 42.3% for experimental examples. [7]

However, the QDSCs suffer from weak absorption and the contribution of the light absorption at room temperature is marginal. This can be addressed by utilizing multibranched Au nanostars. [8]

Quantum dots

Quantum dots are semiconducting particles that have been reduced below the size of the Exciton Bohr radius and due to quantum mechanics considerations, the electron energies that can exist within them become finite, much alike energies in an atom. Quantum dots have been referred to as "artificial atoms". These energy levels are tuneable by changing their size, which in turn defines the bandgap. The dots can be grown over a range of sizes, allowing them to express a variety of bandgaps without changing the underlying material or construction techniques. [9] In typical wet chemistry preparations, the tuning is accomplished by varying the synthesis duration or temperature.

The ability to tune the bandgap makes quantum dots desirable for solar cells. For the sun's photon distribution spectrum, the Shockley-Queisser limit indicates that the maximum solar conversion efficiency occurs in a material with a band gap of 1.34 eV. However, materials with lower band gaps will be better suited to generate electricity from lower-energy photons (and vice versa). Single junction implementations using lead sulfide (PbS) colloidal quantum dots (CQD) have bandgaps that can be tuned into the far infrared, frequencies that are typically difficult to achieve with traditional solar cells. Half of the solar energy reaching the Earth is in the infrared, most in the near infrared region. A quantum dot solar cell makes infrared energy as accessible as any other. [10]

Moreover, CQD offer easy synthesis and preparation. While suspended in a colloidal liquid form they can be easily handled throughout production, with a fumehood as the most complex equipment needed. CQD are typically synthesized in small batches, but can be mass-produced. The dots can be distributed on a substrate by spin coating, either by hand or in an automated process. Large-scale production could use spray-on or roll-printing systems, dramatically reducing module construction costs.

Production

Early examples used costly molecular beam epitaxy processes. However, the lattice mismatch results in accumulation of strain and thus generation of defects, restricting the number of stacked layers. Droplet epitaxy growth technique shows its advantages on the fabrication of strain-free QDs. [11] Alternatively, less expensive fabrication methods were later developed. These use wet chemistry (for CQD) and subsequent solution processing. Concentrated nanoparticle solutions are stabilized by long hydrocarbon ligands that keep the nanocrystals suspended in solution.

To create a solid, these solutions are cast down[ clarification needed ] and the long stabilizing ligands are replaced with short-chain crosslinkers. Chemically engineering the nanocrystal surface can better passivate the nanocrystals and reduce detrimental trap states that would curtail device performance by means of carrier recombination.[ clarification needed ] This approach produces an efficiency of 7.0%. [12]

A more recent study uses different ligands for different functions by tuning their relative band alignment to improve the performance to 8.6%. [13] The cells were solution-processed in air at room-temperature and exhibited air-stability for more than 150 days without encapsulation.

In 2014 the use of iodide as a ligand that does not bond to oxygen was introduced. This maintains stable n- and p-type layers, boosting the absorption efficiency, which produced power conversion efficiency up to 8%. [14]

History

The idea of using quantum dots as a path to high efficiency was first noted by Burnham and Duggan in 1989. [15] At the time, the science of quantum dots, or "wells" as they were known, was in its infancy and early examples were just becoming available.

DSSC efforts

Another modern cell design is the dye-sensitized solar cell, or DSSC. DSSCs use a sponge-like layer of TiO
2 as the semiconductor valve as well as a mechanical support structure. During construction, the sponge is filled with an organic dye, typically ruthenium-polypyridine, which injects electrons into the titanium dioxide upon photoexcitation. [16] This dye is relatively expensive, and ruthenium is a rare metal. [17]

Using quantum dots as an alternative to molecular dyes was considered from the earliest days of DSSC research. The ability to tune the bandgap allowed the designer to select a wider variety of materials for other portions of the cell. Collaborating groups from the University of Toronto and École Polytechnique Fédérale de Lausanne developed a design based on a rear electrode directly in contact with a film of quantum dots, eliminating the electrolyte and forming a depleted heterojunction. These cells reached 7.0% efficiency, better than the best solid-state DSSC devices, but below those based on liquid electrolytes. [12]

Multi-junction

Traditionally, multi-junction solar cells are made with a collection of multiple semiconductor materials. Because each material has a different band gap, each material's p-n junction will be optimized for a different incoming wavelength of light. Using multiple materials enables the absorbance of a broader range of wavelengths, which increases the cell's electrical conversion efficiency.

However, the use of multiple materials makes multi-junction solar cells too expensive for many commercial uses. [18] Because the band gap of quantum dots can be tuned by adjusting the particle radius, multi-junction cells can be manufactured by incorporating quantum dot semiconductors of different sizes (and therefore different band gaps). Using the same material lowers manufacturing costs, [19] and the enhanced absorption spectrum of quantum dots can be used to increase the short-circuit current and overall cell efficiency.

Cadmium telluride (CdTe) is used for cells that absorb multiple frequencies. A colloidal suspension of these crystals is spin-cast onto a substrate such as a thin glass slide, potted in a conductive polymer. These cells did not use quantum dots, but shared features with them, such as spin-casting and the use of a thin film conductor. At low production scales quantum dots are more expensive than mass-produced nanocrystals, but cadmium and telluride are rare and highly toxic metals subject to price swings.

The Sargent Group[ who? ] used lead sulfide as an infrared-sensitive electron donor to produce then record-efficiency IR solar cells. Spin-casting may allow the construction of "tandem" cells at greatly reduced cost. The original cells used a gold substrate as an electrode, although nickel works just as well. [20]

Hot-carrier capture

Another way to improve efficiency is to capture the extra energy in the electron when emitted from a single-bandgap material. In traditional materials like silicon, the distance from the emission site to the electrode where they are harvested is too far to allow this to occur; the electron will undergo many interactions with the crystal materials and lattice, giving up this extra energy as heat. Amorphous thin-film silicon was tried as an alternative, but the defects inherent to these materials overwhelmed their potential advantage. Modern thin-film cells remain generally less efficient than traditional silicon.

Nanostructured donors can be cast as uniform films that avoid the problems with defects. [21] These would be subject to other issues inherent to quantum dots, notably resistivity issues and heat retention.

Multiple excitons

The Shockley-Queisser limit, which sets the maximum efficiency of a single-layer photovoltaic cell to be 33.7%, assumes that only one electron-hole pair (exciton) can be generated per incoming photon. Multiple exciton generation (MEG) is an exciton relaxation pathway which allows two or more excitons to be generated per incoming high energy photon. [22] In traditional photovoltaics, this excess energy is lost to the bulk material as lattice vibrations (electron-phonon coupling). MEG occurs when this excess energy is transferred to excite additional electrons across the band gap, where they can contribute to the short-circuit current density.

Within quantum dots, quantum confinement increases coulombic interactions which drives the MEG process. [23] This phenomenon also decreases the rate of electron-phonon coupling, which is the dominant method of exciton relaxation in bulk semiconductors. The phonon bottleneck slows the rate of hot carrier cooling, which allows excitons to pursue other pathways of relaxation; this allows MEG to dominate in quantum dot solar cells. The rate of MEG can be optimized by tailoring quantum dot ligand chemistry, as well as by changing the quantum dot material and geometry.

In 2004, Los Alamos National Laboratory reported spectroscopic evidence that several excitons could be efficiently generated upon absorption of a single, energetic photon in a quantum dot. [24] Capturing them would catch more of the energy in sunlight. In this approach, known as "carrier multiplication" (CM) or "multiple exciton generation" (MEG), the quantum dot is tuned to release multiple electron-hole pairs at a lower energy instead of one pair at high energy. This increases efficiency through increased photocurrent. LANL's dots were made from lead selenide.

In 2010, the University of Wyoming demonstrated similar performance using DCCS cells. Lead-sulfur (PbS) dots demonstrated two-electron ejection when the incoming photons had about three times the bandgap energy. [25]

In 2005, NREL demonstrated MEG in quantum dots, producing three electrons per photon and a theoretical efficiency of 65%. [26] In 2007, they achieved a similar result in silicon. [27]

Non-oxidizing

In 2014 a University of Toronto group manufactured and demonstrated a type of CQD n-type cell using PbS with special treatment so that it doesn't bind with oxygen. The cell achieved 8% efficiency, just shy of the current QD efficiency record. Such cells create the possibility of uncoated "spray-on" cells. [28] [29] However, these air-stable n-type CQD were actually fabricated in an oxygen-free environment.

Also in 2014, another research group at MIT demonstrated air-stable ZnO/PbS solar cells that were fabricated in air and achieved a certified 8.55% record efficiency (9.2% in lab) because they absorbed light well, while also transporting charge to collectors at the cell's edge. [30] These cells show unprecedented air-stability for quantum dot solar cells that the performance remained unchanged for more than 150 days of storage in air. [13]

Market Introduction

Commercial Providers

Although quantum dot solar cells have yet to be commercially viable on the mass scale, several small commercial providers have begun marketing quantum dot photovoltaic products. Investors and financial analysts have identified quantum dot photovoltaics as a key future technology for the solar industry. [31]

Safety Concerns

Many heavy-metal quantum dot (lead/cadmium chalcogenides such as PbSe, CdSe) semiconductors can be cytotoxic and must be encapsulated in a stable polymer shell to prevent exposure. Non-toxic quantum dot materials such as AgBiS2 nanocrystals have been explored due to their safety and abundance; exploration with solar cells based with these materials have demonstrated comparable conversion efficiencies (> 9%) and short-circuit current densities (> 27 mA/cm2). [35] [36] UbiQD's CuInSe2−X quantum dot material is another example of a non-toxic semiconductor compound.

See also

Related Research Articles

<span class="mw-page-title-main">Band gap</span> Energy range in a solid where no electron states exist

In solid-state physics and solid-state chemistry, a band gap, also called a bandgap or energy gap, is an energy range in a solid where no electronic states exist. In graphs of the electronic band structure of solids, the band gap refers to the energy difference between the top of the valence band and the bottom of the conduction band in insulators and semiconductors. It is the energy required to promote an electron from the valence band to the conduction band. The resulting conduction-band electron are free to move within the crystal lattice and serve as charge carriers to conduct electric current. It is closely related to the HOMO/LUMO gap in chemistry. If the valence band is completely full and the conduction band is completely empty, then electrons cannot move within the solid because there are no available states. If the electrons are not free to move within the crystal lattice, then there is no generated current due to no net charge carrier mobility. However, if some electrons transfer from the valence band to the conduction band, then current can flow. Therefore, the band gap is a major factor determining the electrical conductivity of a solid. Substances having large band gaps are generally insulators, those with small band gaps are semiconductor, and conductors either have very small band gaps or none, because the valence and conduction bands overlap to form a continuous band.

<span class="mw-page-title-main">Quantum dot</span> Zero-dimensional, nano-scale semiconductor particles with novel optical and electronic properties

Quantum dots (QDs) or semiconductor nanocrystals are semiconductor particles a few nanometres in size with optical and electronic properties that differ from those of larger particles via quantum mechanical effects. They are a central topic in nanotechnology and materials science. When a quantum dot is illuminated by UV light, an electron in the quantum dot can be excited to a state of higher energy. In the case of a semiconducting quantum dot, this process corresponds to the transition of an electron from the valence band to the conductance band. The excited electron can drop back into the valence band releasing its energy as light. This light emission (photoluminescence) is illustrated in the figure on the right. The color of that light depends on the energy difference between the conductance band and the valence band, or the transition between discrete energy states when the band structure is no longer well-defined in QDs.

<span class="mw-page-title-main">Quantum well</span> Concept in quantum mechanics

A quantum well is a potential well with only discrete energy values.

<span class="mw-page-title-main">Solar cell</span> Photodiode used to produce power from light on a large scale

A solar cell or photovoltaic cell is an electronic device that converts the energy of light directly into electricity by means of the photovoltaic effect. It is a form of photoelectric cell, a device whose electrical characteristics vary when it is exposed to light. Individual solar cell devices are often the electrical building blocks of photovoltaic modules, known colloquially as "solar panels". The common single-junction silicon solar cell can produce a maximum open-circuit voltage of approximately 0.5 to 0.6 volts.

Thermophotovoltaic (TPV) energy conversion is a direct conversion process from heat to electricity via photons. A basic thermophotovoltaic system consists of a hot object emitting thermal radiation and a photovoltaic cell similar to a solar cell but tuned to the spectrum being emitted from the hot object.

Hybrid solar cells combine advantages of both organic and inorganic semiconductors. Hybrid photovoltaics have organic materials that consist of conjugated polymers that absorb light as the donor and transport holes. Inorganic materials in hybrid cells are used as the acceptor and electron transporter in the structure. The hybrid photovoltaic devices have a potential for not only low-cost by roll-to-roll processing but also for scalable solar power conversion.

Third-generation photovoltaic cells are solar cells that are potentially able to overcome the Shockley–Queisser limit of 31–41% power efficiency for single bandgap solar cells. This includes a range of alternatives to cells made of semiconducting p-n junctions and thin film cells. Common third-generation systems include multi-layer ("tandem") cells made of amorphous silicon or gallium arsenide, while more theoretical developments include frequency conversion,, hot-carrier effects and other multiple-carrier ejection techniques.

<span class="mw-page-title-main">Multi-junction solar cell</span> Solar power cell with multiple band gaps from different materials

Multi-junction (MJ) solar cells are solar cells with multiple p–n junctions made of different semiconductor materials. Each material's p-n junction will produce electric current in response to different wavelengths of light. The use of multiple semiconducting materials allows the absorbance of a broader range of wavelengths, improving the cell's sunlight to electrical energy conversion efficiency.

<span class="mw-page-title-main">Multiple exciton generation</span> A concept in quantum electronics

In solar cell research, carrier multiplication is the phenomenon wherein the absorption of a single photon leads to the excitation of multiple electrons from the valence band to conduction band. In the theory of a conventional solar cell, each photon is only able to excite one electron across the band gap of the semiconductor, and any excess energy in that photon is dissipated as heat. In a material with carrier multiplication, high-energy photons excite on average more than one electron across the band gap, and so in principle the solar cell can produce more useful work.

<span class="mw-page-title-main">Shockley–Queisser limit</span> Maximum theoretical efficiency of a solar cell

In physics, the radiative efficiency limit is the maximum theoretical efficiency of a solar cell using a single p-n junction to collect power from the cell where the only loss mechanism is radiative recombination in the solar cell. It was first calculated by William Shockley and Hans-Joachim Queisser at Shockley Semiconductor in 1961, giving a maximum efficiency of 30% at 1.1 eV. The limit is one of the most fundamental to solar energy production with photovoltaic cells, and is one of the field's most important contributions.

<span class="mw-page-title-main">Thin-film solar cell</span> Type of second-generation solar cell

Thin-film solar cells are made by depositing one or more thin layers of photovoltaic material onto a substrate, such as glass, plastic or metal. Thin-film solar cells are typically a few nanometers (nm) to a few microns (µm) thick–much thinner than the wafers used in conventional crystalline silicon (c-Si) based solar cells, which can be up to 200 µm thick. Thin-film solar cells are commercially used in several technologies, including cadmium telluride (CdTe), copper indium gallium diselenide (CIGS), and amorphous thin-film silicon.

<span class="mw-page-title-main">Solar cell research</span> Research in the field of photovoltaics

There are currently many research groups active in the field of photovoltaics in universities and research institutions around the world. This research can be categorized into three areas: making current technology solar cells cheaper and/or more efficient to effectively compete with other energy sources; developing new technologies based on new solar cell architectural designs; and developing new materials to serve as more efficient energy converters from light energy into electric current or light absorbers and charge carriers.

<span class="mw-page-title-main">Nanocrystal solar cell</span>

Nanocrystal solar cells are solar cells based on a substrate with a coating of nanocrystals. The nanocrystals are typically based on silicon, CdTe or CIGS and the substrates are generally silicon or various organic conductors. Quantum dot solar cells are a variant of this approach which take advantage of quantum mechanical effects to extract further performance. Dye-sensitized solar cells are another related approach, but in this case the nano-structuring is a part of the substrate.

Thermodynamic efficiency limit is the absolute maximum theoretically possible conversion efficiency of sunlight to electricity. Its value is about 86%, which is the Chambadal-Novikov efficiency, an approximation related to the Carnot limit, based on the temperature of the photons emitted by the Sun's surface.

<span class="mw-page-title-main">Core–shell semiconductor nanocrystal</span>

Core–shell semiconducting nanocrystals (CSSNCs) are a class of materials which have properties intermediate between those of small, individual molecules and those of bulk, crystalline semiconductors. They are unique because of their easily modular properties, which are a result of their size. These nanocrystals are composed of a quantum dot semiconducting core material and a shell of a distinct semiconducting material. The core and the shell are typically composed of type II–VI, IV–VI, and III–V semiconductors, with configurations such as CdS/ZnS, CdSe/ZnS, CdSe/CdS, and InAs/CdSe Organically passivated quantum dots have low fluorescence quantum yield due to surface related trap states. CSSNCs address this problem because the shell increases quantum yield by passivating the surface trap states. In addition, the shell provides protection against environmental changes, photo-oxidative degradation, and provides another route for modularity. Precise control of the size, shape, and composition of both the core and the shell enable the emission wavelength to be tuned over a wider range of wavelengths than with either individual semiconductor. These materials have found applications in biological systems and optics.

Two-photon photovoltaic effect is an energy collection method based on two-photon absorption (TPA). The TPP effect can be thought of as the nonlinear equivalent of the traditional photovoltaic effect involving high optical intensities. This effect occurs when two photons are absorbed at the same time resulting in an electron-hole pair.

Blinking colloidal nanocrystals is a phenomenon observed during studies of single colloidal nanocrystals that show that they randomly turn their photoluminescence on and off even under continuous light illumination. This has also been described as luminescence intermittency. Similar behavior has been observed in crystals made of other materials. For example, porous silicon also exhibits this affect.

Intermediate band photovoltaics in solar cell research provides methods for exceeding the Shockley–Queisser limit on the efficiency of a cell. It introduces an intermediate band (IB) energy level in between the valence and conduction bands. Theoretically, introducing an IB allows two photons with energy less than the bandgap to excite an electron from the valence band to the conduction band. This increases the induced photocurrent and thereby efficiency.

Quantum dots (QDs) are semiconductor nanoparticles with a size less than 10 nm. They exhibited size-dependent properties especially in the optical absorption and the photoluminescence (PL). Typically, the fluorescence emission peak of the QDs can be tuned by changing their diameters. So far, QDs were consisted of different group elements such as CdTe, CdSe, CdS in the II-VI category, InP or InAs in the III-V category, CuInS2 or AgInS2 in the I–III–VI2 category, and PbSe/PbS in the IV-VI category. These QDs are promising candidates as fluorescent labels in various biological applications such as bioimaging, biosensing and drug delivery.

Light-emitting diodes (LEDs) produce light by the recombination of electrons and electron holes in a semiconductor, a process called "electroluminescence". The wavelength of the light produced depends on the energy band gap of the semiconductors used. Since these materials have a high index of refraction, design features of the devices such as special optical coatings and die shape are required to efficiently emit light. A LED is a long-lived light source, but certain mechanisms can cause slow loss of efficiency of the device or sudden failure. The wavelength of the light emitted is a function of the band gap of the semiconductor material used; materials such as gallium arsenide, and others, with various trace doping elements, are used to produce different colors of light. Another type of LED uses a quantum dot which can have its properties and wavelength adjusted by its size. Light-emitting diodes are widely used in indicator and display functions, and white LEDs are displacing other technologies for general illumination purposes.

References

  1. ↑ Shishodia, Shubham; Chouchene, Bilel; Gries, Thomas; Schneider, Raphaël (2023-10-31). "Selected I-III-VI2 Semiconductors: Synthesis, Properties and Applications in Photovoltaic Cells". Nanomaterials. 13 (21): 2889. doi: 10.3390/nano13212889 . ISSN   2079-4991. PMC   10648425 . PMID   37947733.
  2. ↑ "Best Research Cell Efficiency Chart". National Renewable Energy Laboratory. Retrieved 22 May 2022.
  3. ↑ Nozik, A. J (2002-04-01). "Quantum dot solar cells". Physica E: Low-dimensional Systems and Nanostructures. 14 (1): 115–120. Bibcode:2002PhyE...14..115N. doi:10.1016/S1386-9477(02)00374-0. ISSN   1386-9477.
  4. ↑ Shockley, William; Queisser, Hans J. (1961). "Detailed Balance Limit of Efficiency of p-n Junction Solar Cells". Journal of Applied Physics. 32 (3): 510. Bibcode:1961JAP....32..510S. doi:10.1063/1.1736034.
  5. ↑ Brown, A; Green, M (2002). "Detailed balance limit for the series constrained two terminal tandem solar cell". Physica E. 14 (1–2): 96–100. Bibcode:2002PhyE...14...96B. doi:10.1016/S1386-9477(02)00364-8.
  6. ↑ Uni-Solar holds the record using a three-layer a-Si cell, with 14.9% initial production, but falling to 13% over a short time. See Yang et al., "Triple-junction amorphous silicon alloy solar cell with 14.6% initial and 13.0% stable conversion efficiencies", Applied Physics Letters, 1997
  7. ↑ SPIE Europe Ltd. "Spire pushes solar cell record to 42.3%". Optics.org. Retrieved 2014-06-22.
  8. ↑ Wu, Jiang; Yu, Peng; Susha, Andrei S.; Sablon, Kimberly A.; Chen, Haiyuan; Zhou, Zhihua; Li, Handong; Ji, Haining; Niu, Xiaobin (2015-04-01). "Broadband efficiency enhancement in quantum dot solar cells coupled with multispiked plasmonic nanostars". Nano Energy. 13: 827–835. doi:10.1016/j.nanoen.2015.02.012. S2CID   98282021.
  9. ↑ Baskoutas, Sotirios; Terzis, Andreas F. (2006). "Size-dependent band gap of colloidal quantum dots". Journal of Applied Physics. 99 (1): 013708–013708–4. Bibcode:2006JAP....99a3708B. doi:10.1063/1.2158502.
  10. ↑ H. Sargent, E. (2005). "Infrared Quantum Dots" (PDF). Advanced Materials. 17 (5): 515–522. Bibcode:2005AdM....17..515H. doi:10.1002/adma.200401552. S2CID   247707535.
  11. ↑ Yu, Peng; Wu, Jiang; Gao, Lei; Liu, Huiyun; Wang, Zhiming (2017-03-01). "InGaAs and GaAs quantum dot solar cells grown by droplet epitaxy" (PDF). Solar Energy Materials and Solar Cells. 161: 377–381. doi:10.1016/j.solmat.2016.12.024.
  12. 1 2 Ip, Alexander H.; Thon, Susanna M.; Hoogland, Sjoerd; Voznyy, Oleksandr; Zhitomirsky, David; Debnath, Ratan; Levina, Larissa; Rollny, Lisa R.; Carey, Graham H.; Fischer, Armin; Kemp, Kyle W.; Kramer, Illan J.; Ning, Zhijun; Labelle, André J.; Chou, Kang Wei; Amassian, Aram; Sargent, Edward H. (2012). "Hybrid passivated colloidal quantum dot solids". Nature Nanotechnology. 7 (9): 577–582. Bibcode:2012NatNa...7..577I. CiteSeerX   10.1.1.259.9381 . doi:10.1038/nnano.2012.127. PMID   22842552.
  13. 1 2 Chuang, Chia-Hao M.; Brown, Patrick R.; Bulović, Vladimir; Bawendi, Moungi G. (2014). "Improved performance and stability in quantum dot solar cells through band alignment engineering". Nature Materials. 13 (8): 796–801. Bibcode:2014NatMa..13..796C. doi:10.1038/nmat3984. PMC   4110173 . PMID   24859641.
  14. ↑ Mitchell, Marit (2014-06-09). "New nanoparticles bring cheaper, lighter solar cells outdoors". Rdmag.com. Retrieved 2014-08-24.
  15. ↑ Barnham, K. W. J.; Duggan, G. (1990). "A new approach to high-efficiency multi-band-gap solar cells". Journal of Applied Physics. 67 (7): 3490. Bibcode:1990JAP....67.3490B. doi: 10.1063/1.345339 .
  16. ↑ B. O’Regan and M. Gratzel (1991). "A low-cost, high efficiency solar cell based on dye-sensitized colloidal TiO2 films". Nature. 353 (6346): 737–740. Bibcode:1991Natur.353..737O. doi:10.1038/353737a0. S2CID   4340159.
  17. ↑ Emsley, John (25 August 2011). Nature's Building Blocks: An A-Z Guide to the Elements. Oxford University Press. pp. 368–370. ISBN   978-0-19-960563-7.
  18. ↑ Semonin, O. E., Luther, J. M., & Beard, M. C. (2012). Quantum dots for next-generation photovoltaics. Materials Today,15 (11), 508-515. doi:10.1016/s1369-7021(12)70220-1
  19. ↑ Kerestes, C., Polly, S., Forbes, D., Bailey, C., Podell, A., Spann, J., . . . Hubbard, S. (2013). Fabrication and analysis of multijunction solar cells with a quantum dot (In)GaAs junction. Progress in Photovoltaics: Research and Applications,22 (11), 1172-1179. doi:10.1002/pip.2378
  20. ↑ "New Inexpensive Solar Cell Design is Pioneered" Archived January 28, 2011, at the Wayback Machine , University of Toronto, 3 August 2010
  21. ↑ Prashant Kamat, "Quantum Dot Solar Cells: Semiconductor Nanocrystals As Light Harvesters", Workshop on Nanoscience for Solar Energy Conversion, 27–29 October 2008, p. 8
  22. ↑ Goodwin, H., Jellicoe, T. C., Davis, N. J., & Böhm, M. L. (2018). Multiple exciton generation in quantum dot-based solar cells. Nanophotonics,7 (1), 111-126. doi:10.1515/nanoph-2017-0034
  23. ↑ Beard, M. C. (2011). Multiple Exciton Generation in Semiconductor Quantum Dots. The Journal of Physical Chemistry Letters,2 (11), 1282-1288. doi:10.1021/jz200166y
  24. ↑ Schaller, R.; Klimov, V. (2004). "High Efficiency Carrier Multiplication in PbSe Nanocrystals: Implications for Solar Energy Conversion". Physical Review Letters. 92 (18): 186601. arXiv: cond-mat/0404368 . Bibcode:2004PhRvL..92r6601S. doi:10.1103/PhysRevLett.92.186601. PMID   15169518. S2CID   4186651.
    Ellingson, Randy J.; Beard, Matthew C.; Johnson, Justin C.; Yu, Pingrong; Micic, Olga I.; Nozik, Arthur J.; Shabaev, Andrew; Efros, Alexander L. (2005). "Highly Efficient Multiple Exciton Generation in Colloidal PbSe and PbS Quantum Dots" (PDF). Nano Letters. 5 (5): 865–71. Bibcode:2005NanoL...5..865E. CiteSeerX   10.1.1.453.4612 . doi:10.1021/nl0502672. PMID   15884885.
    "Quantum Dot Materials Can Reduce Heat, Boost Electrical Output", NREL Press Release, 23 May 2005
  25. ↑ Jeff Hecht, "Work light twice as hard to make cheap solar cells", Newscientist, 1 October 2010
  26. ↑ Quantum Dots May Boost Photovoltaic Efficiency To 65%
  27. ↑ "Unique Quantum Effect Found in Silicon Nanocrystals", NREL Press Release, 24 July 2007
  28. ↑ Borghino, Dario (2014-06-10). "Quantum dot breakthrough could lead to cheap spray-on solar cells". Gizmag.com. Retrieved 2014-06-22.
  29. ↑ Ning, Z.; Voznyy, O.; Pan, J.; Hoogland, S.; Adinolfi, V.; Xu, J.; Li, M.; Kirmani, A. R.; Sun, J. P.; Minor, J.; Kemp, K. W.; Dong, H.; Rollny, L.; Labelle, A.; Carey, G.; Sutherland, B.; Hill, I.; Amassian, A.; Liu, H.; Tang, J.; Bakr, O. M.; Sargent, E. H. (2014). "Air-stable n-type colloidal quantum dot solids". Nature Materials. 13 (8): 822–828. Bibcode:2014NatMa..13..822N. doi:10.1038/nmat4007. PMID   24907929.
  30. ↑ Jeffrey, Colin (May 27, 2014). "New record efficiency for quantum-dot photovoltaics". Gizmag.com. Retrieved 2014-06-22.
  31. ↑ Chatsko, M. (2018, July 19). 3 Wild Solar Power Technologies That Could Secure the Industry's Future. Retrieved from https://www.fool.com/investing/2018/07/19/3-wild-solar-power-technologies-that-could-secure.aspx
  32. ↑ Johnson, T. (n.d.). "This Company's 'Tiny Dots' Promise to Turn the ENTIRE Renewable Energy Industry on its Head". Retrieved from https://www.stockgumshoe.com/reviews/cutting-edge-the/this-companys-tiny-dots-promi se-to-turn-the-entire-renewable-energy-industry-on-its-head/
  33. ↑ "ML System zawarła z firmą Servitech umowę wartą 26,7 mln zł netto" (in Polish). 2019-10-30. Retrieved 2020-02-06.
  34. ↑ "Kolejny krok milowy ML System w ramach projektu Quantum Glass" (in Polish). 2019-11-05. Retrieved 2020-02-06.
  35. ↑ Bernechea, M., Miller, N. C., Xercavins, G., So, D., Stavrinadis, A., & Konstantatos, G. (2016). Solution-processed solar cells based on environmentally friendly AgBiS2 nanocrystals. Nature Photonics,10( 8), 521-525. doi:10.1038/nphoton.2016.108
  36. ↑ Wang, Y., Kavanagh, S.R., Burgués-Ceballos, I. et al. Cation disorder engineering yields AgBiS2 nanocrystals with enhanced optical absorption for efficient ultrathin solar cells. Nat. Photon. 16, 235–241 (2022). https://doi.org/10.1038/s41566-021-00950-4.
This page is based on this Wikipedia article
Text is available under the CC BY-SA 4.0 license; additional terms may apply.
Images, videos and audio are available under their respective licenses.