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The photovoltaic effect whereby solar energy is converted to electrical energy was first discovered by Becquerel in a liquid electrolyte.
所有光伏材料都具有不连续性或标记的欧洲杯足球竞彩变化，从而产生电位，导致入射光产生电量载体。这就是太阳能电池如何产生功率的影响。
Silicon is the material that is used most commonly in these cells in two different forms - pure and amorphous silicon.
纯硅用于单晶和多晶形式，其中优选单晶硅是由于其太阳捕获效率约为25-30％，
Broad Issues with PV Cell Development
材料可用性和费用
Cost-effective manufacture, efficiency of solar energy capture, reliability of performance, and stability for at least 20 years are among the chief features required for a PV cell to be commercially viable. These ensure that less energy is used to produce the cell than it produces over its operating life.
The materials used to create semiconductors in PV cells must have a low energy band gap for efficient energy capture and to be able to regulate the energy conversion processes. These criteria are met only by a small number of materials, like Si, GaAs, InP, CdTe, and CuInSe2在单晶电池中，和氢化非晶硅（A-Si：H），CdTe和Cuinse2for thin films.
Availability and low cost of processing are important factors in material selection. An increasing volume of production has caused concerns about material availability.
Printing technologies could cut down the cost while keeping quality high.
硅电池
These are first-generation devices.
单晶GaAs可以与后触点单晶硅组合，以便更好地效率约为31％。通过昂贵且能量密集的Czochralski方法，通过诸如硅的高成本限制，使用单晶硅PV电池的使用。
多晶硅电池的制造更容易，更便宜，但重组损失将其效率降低至约17％。
硅太阳能电池也面对长波长光子吸收不良的吸收问题。
Modified Technologies
While it would be difficult to change the material properties of silicon such as absorption and grain boundaries, other suggested methods to improve the efficiency of silicon cells include:
- 单晶硅CZOCHRALSKI方法的修改
- Adopt wafer technology to use less silicon
- 使用定向凝固方法对于多晶硅的生长，这减少能量密集，在大约12千瓦时/千瓦时的电力与传统过程中的约100千瓦时/千克。
- 使用厚膜技术
- 用于易于自动化铝和银电触点的丝网印刷
- Introduction of more holes in the bottom of the PV cell to produce unidirectional movement of the generated holes towards the upper layers, avoiding recombinational losses – a costly approach
- Use newer antireflective coatings and glass materials, to reduce reflectance
Thin Films
Thin-film silicon devices are second-generation PV cells. They are mechanically improved, with greater flexibility, but less efficient.
The use of hydrogenated amorphous silicon in thin-film PV cells brings down production costs. On the other hand, drift collection reduces voltage-dependent current collection, thus lowering the efficiency. It also has a lower lifetime as a minority carrier, breakdown with long-term illumination, doping issues and low quality of alloys. Therefore thin film silicon cells are mostly constructed from monocrystalline silicon to maximize their efficiency.
正在探索可用欧洲杯足球竞彩作薄膜的其他材料，例如碲化镉，铜铟：碳化铈（CIS）和铜铟硒化镓（CIGS）。
CdTe具有高光吸收，易于产生多种方法，但其掺杂难以困难，并且其稳定性低，除了废CD的毒性。
CIS and CIGS in the form of polycrystalline thin films have a capture efficiency of about 19 percent. However, these are currently too unstable for use. Indium is also a costly and limited metal.
Other Materials
Third-generation PV materials are being explored to improve solar cell performance. Many reports show attractive concepts to achieve low operating and material costs. Concepts like multiple exciton generation (MEG), carrier multiplication (CM), hot carrier extraction, and intermediate band solar cell must first be replicated on the PV device itself, which involves a junction barrier. Currently, the III-V multijunction cells are the only third-generation devices to practically exceed the maximum efficiency of a silicon cell.
多结细胞
Multijunction cells exploit the fact that efficient solar-to-electrical energy capture occurs without thermalization and absorption issues when the light wavelength is identical to the bandgap. Different materials, typically III-V materials, are used with bandgaps varying from high to low as one moves from the top to the bottom of the device.
III-V materials show direct bandgaps in many cases. They are fabricated efficiently and when used for thinner cells, use less material. Low current matching and high material cost may limit their use, as with the Germanium/GaAs/InGaP cell.
Other methods such as inverted stacks, wafer bonding, dilute nitride and metamorphic growth, are being explored to achieve optimal multijunction cell architecture.
Ultrathin Cells
超薄细胞降低成本and time of production by epitaxial growth. This also caters to the complex arrangements required for current concepts, which would make it difficult to grow cells once the crystallinity exceeds 100 nm. Ultrathin cells use only enough to absorb most incident photons and generate excitons.
In the case of III-V semiconductors, the required thickness is only a few microns. Because of higher absorption in this limited thickness, efficiency is higher.
In intermediate band solar cells (IBSCs) the two-photon absorption and other similarly non-linear processes are also enhanced, while recombination losses are limited.
Hot-carrier solar cells (HCSCs) must be thin to minimize extraction time and keep thermalization low. However, numerous practical problems remain even at the experimental stage.
Tandem Cells
Tandem cell architecture consists of two distinct PV devices which soak up the light not absorbed by the other, having different band gaps. This is designed to maximize efficiency.
Perovskite Cells
A perovskite is any material that has a crystal structure identical to that of calcium titanium oxide, (XIIA2+VIB4+ X.2−3) with the oxygen in the edge center.
PEROVSKITE PV器件便宜且易于生产，具有许多潜在的结构，可以使用多样性的材料。欧洲杯足球竞彩它们具有非常良好的光电性能，并获得更好的功率转换效率。然而，它们在I-V曲线上显示滞后，在暴露于水分，光线和热量的情况下是不稳定的，提供环境毒性问题，因此在这些方面需要更多的工作，因为它们可以在更广泛的应用方面变得可行。与仔细工程的界面钝化的形态可能有助于克服这些问题。
纳米粒子在欧洲杯猜球平台PV.
Nanoparticles offer customization of the band gap since varying shapes and sizes of nanoparticles absorb light across the spectrum. Control of production, better impact ionization, and multiple charge carrier generation from one photon of light are other theoretical advantages.
While an efficiency of 44 percent has been reported in the laboratory, the applicability of such materials to real PV devices is still to be proved.
Organic, Dye-Sensitized and Hybrid Cells
Organic PV (OPV) and dye-sensitized cells are being intensively researched. These depend on one or more organic molecules or semiconductors like PCBM (phenyl-C61-butyric acid methyl ester) for the PV effect.
Dye-sensitized solar cells (DSCs) are easy to produce at low cost and have high theoretical efficiency. In hybrid cells, organic or metallo-organic dyes are used.
通过使用不同的染料可以调谐DSC和杂化细胞，但是长波长光子捕获仍然是困难的任务，因为这种染料难以创造。毒性和老化仍然存在限制有机光伏电池的发育的烦恼问题。
OPV问题包括退化反应，不稳定性和降低性能。较低的电子迁移率，电极触点差和材料中的缺陷负责低效率。
量子点太阳能电池
Printable colloidal quantum dot solar cells exploit the smallness of the material, which causes the quantum confinement effect to become active, leading to different optoelectronic properties like size-dependent emission and optical absorption bands.
Specialized polymer- and fullerene-based cells are being explored. However, material changes affect the morphology and hence the efficiency. To combat this, cross-linkable molecules or polymers are being studied to prevent any shift in morphology.
材料老化
浅色亮度的材料老化和劣化是其他问题，使技术在广泛的范围内不适用。在这方面涉及结构材料和内在稳定欧洲杯足球竞彩性。
Life Cycle Issues
The life cycle may also offer limiting constraints caused by the toxicity and recycling potential of the materials, including supply chain and environmental problems.
Once the volume of application in the power sector becomes large enough to increase the number and variety of situations of PV use, it becomes a challenge to integrate the novel PV system to the global power scenario and to store the generated energy, along with the architectural and aesthetic aspects.
尽管PV器件的理论能量转换限制很高，但大多数光伏电池的效率仍然是不合格的。
结论
总之，在电流散装和薄膜半导体之外的第三代PV器件的生产中仍有待解决的主要问题。目前，薄膜PV电池的制造过程的尺寸和改进的降低负责用于发电的太阳能电池的持续吸引力。
来源和进一步阅读
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