Publication detail

Local optical and electric characteristics of solar cells

TOMÁNEK, P. ŠKARVADA, P. GRMELA, L.

Original Title

Local optical and electric characteristics of solar cells

Czech Title

Lokální optické a elektrické vlastnosti solárních článků

English Title

Local optical and electric characteristics of solar cells

Type

conference paper

Language

en

Original Abstract

Today photovoltaic cells are divided into two principal types: higher-efficiency but quite expensive crystalline silicon solar cells (either monocrystalline or multicrystalline), and lower-cost thin-film solar cells, usually composed of amorphous silicon, polycrystalline silicon, cadmium telluride, or copper indium gallium diselenide. In both cases their operation is based on a large-area pn junction. Their efficiency is generally limited by defects and impurities, which include grain boundaries, dislocations, and transition metals. A wide variety of defects can be formed in a silicon crystals during and after their growth. Some of defects arise on cell surface during its life-time such as scratches. These surface damages are origin of lower light-trapping efficiency. Many of defects do not cause cell malfunction, but generate local microplasmas, which are conductive and hence reduce overall cell efficiency. A number of defects of various kinds, some of them being of local character only, can not be observed with classical methods in such large-area junctions. Therefore a use of more precise scanning probe microscopes represents a novel approach to surface investigations with superresolving features. The paper presents results of experimental study of high resolution map of induced photocurrent and local electroluminescence in monocrystalline silicon solar cells. Photovoltaic solar cells are evaluated by I-V electric measurement, Far-field and Near-field Optical Beam Induced photocurrent (NOBIC), as well as by Scanning Near-field Optical Microscope (SNOM) topography and reflection. The correlation between reflection and transport characteristics indicates power of this diagnostic tool.

Czech abstract

Současné fotovoltalické články se dšělí na dvě významné skupiny: vysoceúčinné, dosti nákladné články z monokrystalického křemíku a laciné tenkovrstvé, obvykle složené z amorfního či polykrystalického křemíku, CdTe, či dalších. V obou případech je jejich funkce založena na pn přechodu. Účinnost je obvykle limitována defekty nebo nečistotami jako hranice zrn, dislokace, přítomnost přechodových kovů. K mnoha typům defektů může dojít při růstu krystalu i poté. Některé defekty se mohou objevit v průběhu života článku jaké jsou např. škábance, což může vést ke snížení účinnost článku. Mnohé defekty generují mikroplasmu, jsou vodivé a tím opět dochází ke snížení účinnosti. MNohé defekty není možné pozorovat obvyklými metodami, musí se k jejich studiu použít metody optického blízkého pole. Skenovací sondové mikroskopy reprezentují nový nástroj zkoumání povrchů se superrozlišením. Článek přináší experimentální výsledky lokálně indukovaného fotoproudu a lokální elektroluminiscence v solárním článku s monokrystalickým křemíkem. Články jsou zkoumány pomocí I-V elektrického měření a mikroskopie ve vzdáleném i blízkém poli a pomocí lokálně indukovaných fotoproudů (NOBIC) Korelace mezi odrazivostí a transportními charakteristikami je významným diagnostickým nástrojem zkoumání solárních článků.

English abstract

Today photovoltaic cells are divided into two principal types: higher-efficiency but quite expensive crystalline silicon solar cells (either monocrystalline or multicrystalline), and lower-cost thin-film solar cells, usually composed of amorphous silicon, polycrystalline silicon, cadmium telluride, or copper indium gallium diselenide. In both cases their operation is based on a large-area pn junction. Their efficiency is generally limited by defects and impurities, which include grain boundaries, dislocations, and transition metals. A wide variety of defects can be formed in a silicon crystals during and after their growth. Some of defects arise on cell surface during its life-time such as scratches. These surface damages are origin of lower light-trapping efficiency. Many of defects do not cause cell malfunction, but generate local microplasmas, which are conductive and hence reduce overall cell efficiency. A number of defects of various kinds, some of them being of local character only, can not be observed with classical methods in such large-area junctions. Therefore a use of more precise scanning probe microscopes represents a novel approach to surface investigations with superresolving features. The paper presents results of experimental study of high resolution map of induced photocurrent and local electroluminescence in monocrystalline silicon solar cells. Photovoltaic solar cells are evaluated by I-V electric measurement, Far-field and Near-field Optical Beam Induced photocurrent (NOBIC), as well as by Scanning Near-field Optical Microscope (SNOM) topography and reflection. The correlation between reflection and transport characteristics indicates power of this diagnostic tool.

Keywords

solar cell, optical characteristics, electric characteristics, local measurement

RIV year

2010

Released

01.01.2010

Publisher

SPIE

Location

Bellingham, USA

ISBN

978-0-8194-7671-5

Book

Ninth International Conference on Correlation Optics

Pages from

73880L1

Pages to

73880L9

Pages count

9

BibTex


@inproceedings{BUT29152,
  author="Pavel {Tománek} and Pavel {Škarvada} and Lubomír {Grmela}",
  title="Local optical and electric characteristics of solar cells",
  annote="Today photovoltaic cells are divided into two principal types: higher-efficiency but quite expensive crystalline silicon solar cells (either monocrystalline or multicrystalline), and lower-cost thin-film solar cells, usually composed of amorphous silicon, polycrystalline silicon, cadmium telluride, or copper indium gallium diselenide. In both cases their operation is based on a large-area pn junction. Their efficiency is generally limited by defects and impurities, which include grain boundaries, dislocations, and transition metals. A wide variety of defects can be formed in a silicon crystals during and after their growth. Some of defects arise on cell surface during its life-time such as scratches. These surface damages are origin of lower light-trapping efficiency. Many of defects do not cause cell malfunction, but generate local microplasmas, which are conductive and hence reduce overall cell efficiency. A number of defects of various kinds, some of them being of local character only, can not be observed with classical methods in such large-area junctions. Therefore a use of more precise scanning probe microscopes represents a novel approach to surface investigations with superresolving features. The paper presents results of experimental study of high resolution map of induced photocurrent and local electroluminescence in monocrystalline silicon solar cells. Photovoltaic solar cells are evaluated by I-V electric measurement, Far-field and Near-field Optical Beam Induced photocurrent (NOBIC), as well as by Scanning Near-field Optical Microscope (SNOM) topography and reflection. The correlation between reflection and transport characteristics indicates power of this diagnostic tool.",
  address="SPIE",
  booktitle="Ninth International Conference on Correlation Optics",
  chapter="29152",
  howpublished="print",
  institution="SPIE",
  journal="Proceedings of SPIE",
  number="7388",
  year="2010",
  month="january",
  pages="73880L1--73880L9",
  publisher="SPIE",
  type="conference paper"
}