A broadband- sensitive upconverter La(Ga0.5Sc0.5)O-3:Er,Ni,Nb for crystalline silicon solar cells

作者：Takeda Yasuhiko; Mizuno Shintaro; Luitel Hom Nath; Tani Toshihiko

来源：Applied Physics Letters, 2016, 108(4): 043901.

DOI：10.1063/1.4940442

<jats:p>We have developed an upconverter that significantly broadens the sensitive range, to overcome the shortcoming that conventional Er3+-doped upconverters used for crystalline silicon solar cells can utilize only a small portion of the solar spectrum at around 1.55 μm. We have designed the combination of the sensitizers and host material to utilize photons not absorbed by silicon or Er3+ ions. Ni2+ ions have been selected as the sensitizers that absorb photons in the wavelength range between the silicon absorption edge (1.1 μm) and the Er3+ absorption band and transfer the energies to the Er3+ emitters, with La(Ga,Sc)O3 as the host material. The Ga to Sc ratio has been optimized to tune the location of the Ni2+ absorption band for sufficient energy transfer. Co-doping with Nb5+ ions is needed for charge balance to introduce divalent Ni2+ ions into the trivalent Ga3+ and Sc3+ sites. In addition to 1.45–1.58 μm photons directly absorbed by the Er3+ ions, we have demonstrated upconversion of 1.1–1.35 μm photons in the Ni2+ absorption band to 0.98 μm photons, using 10% Er, 0.5% Ni, and 0.5% Nb-doped La(Ga0.5Sc0.5)O3. The broadband-sensitive upconverter developed here can improve conversion efficiency of crystalline silicon solar cells more notably than conventional ones.</jats:p>

• 出版日期2016-1-25