カルコパイライト系薄膜太陽電池の開発の現状と将来展望

摘要

Chalcopyrite Cu (In, Ga) Se_2 (CIGS) and related compounds belong to the semiconducting I-III-VI_2 materials family and are most promising thin film solar cells which have demonstrated up to 20% cell efficiencies and over 15% module efficiencies to date. Many CIGS companies in EU, US, and Japan have started several ten MW/year scale commercial production and have announced to increase their production capacities further within a couple of years. In this review, recent developments in highly efficient CIGS module technologies and issues to be solved for further development are discussed. Recent progress in the development of reliable alkali incorporation control techniques which is required to demonstrate high cell efficiencies from flexible CIGS cells fabricated on alkali-free substrates is also introduced. The mechanism behind the beneficial effects of alkali doping into CIGS absorber layers is also discussed.%現在まで，太陽電池市場のシェアのはとんどは結晶系シリrnコンによって占められている．一方で薄膜太陽電池のシェアrnはまだ小さいが，カルコパイライト系Cu（In，Ga）Se_2rn（CIGS）太陽電池に関しては多くの企業が小規模生産の段階rnから着実に生産量を増やし，さらなる増産とシェア拡大に前rn進している．国内のCIGS系太陽電池企業としては，すでにrn昭和シェルソーラーが80MW/年，ホンダソルテックが27.5rnMW/年規模の生産段階にある．