[21p-S423-1~19] 13.9 Optical properties and light-emitting devices

[21p-S423-13] Broadband-sensitive upconverters for crystalline silicon solar cells

〇Yasuhiko Takeda¹, Shintaro Mizuo¹, Hom Nath Luitel¹, Toshihiko Tani¹ (1.Toyota Central R&D Labs.)

Keywords:upconverter,crystalline silicon solar cell,Er3+

Er³⁺-doped uconverters used for crystalline silicon solar cells convert photons at around 1.55 um to 0.98 um photons. However, the absorption band of Er³⁺ ions is narrow, and hence only a small portion of the solar spectrum can be utilized. We introduced sensitizers that absorb 1.1-1.45 um photons, which are not absorbed by either crystalline silicon or Er³⁺ ions, and transfer the energies to Er³⁺ ions, and then designed suitable combinations of host materials for co-doping with Er³⁺ ions and sensitizers. Eventually we have demonstrated broadband-sensitive upconversion.