Upconversion Luminescence from Ln<sup>3+</sup>(Ho<sup>3+</sup>,Pr<sup>3+</sup>) Ion-Doped BaCl<sub>2</sub> Particles via NIR Light of Sun Excitation JiaHong LiuZhongli LiaoLamei GuYanhong DingChaoliang ZhaoJianguo ZhangWeiying HuXiaoke FengXun ChenZhi LiuXiaofeng QiuJianrong 2018 Generation of visible photons by upconverting materials under excitation by the near-infrared part of sunlight is very attractive for complete utilization of solar energy. Visible upconversion luminescence is efficiently generated in BaCl<sub>2</sub>:Ln<sup>3+</sup> (Ho<sup>3+</sup> or Pr<sup>3+</sup>) particles via excitation with broad band near-infrared part of sunlight. We observed greatly enhanced photocurrent response from the thin-film hydrogenated amorphous silicon solar cell covered with the upconversion layer of BaCl<sub>2</sub>:Ho<sup>3+</sup> phosphor, which demonstrates a prospective application for near-infrared photoresponse devices.