CaTiO3:Er3+, Ni2+ broadband‐sensitive upconverter: An effective way to harvest unused NIR solar irradiation for crystalline silicon solar cells. Issue 8 (9th June 2017)

• Record Type: Journal Article
• Authors: Luitel, Hom Nath; Mizuno, Shintaro; Takeda, Yasuhiko
• Is Part Of: Physica status solidi. Volume 214:Issue 8(2017)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2017-06-09
• Subjects: CaTiO3 -- energy transfer -- erbium -- photon upconversion -- Ni2+‐sensitization -- solar cells; Solid state physics -- Periodicals; Solids -- Industrial applications -- Periodicals; 530.41
• DOI: 10.1002/pssa.201600899
• Languages: English
• ISSNs: 1862-6300

Abstract

Abstract : We have realized broadband‐sensitive upconversion (UC) in CaTiO3 :Er 3+, Ni 2+ that can harvest 1060–1630 nm photons, which are not utilized by present crystalline silicon (c‐Si) solar cells, and upconvert to 980 nm. The Ni 2+ sensitizers absorb 1060–1450 nm photons and efficiently transfer the energies to the Er 3+ emitters. In addition to 1450–1630 nm photons that are directly absorbed by the Er 3+ ions, 1060–1450 nm photons are also upconverted to 980 nm by the Er 3+, Ni 2+ codoped upconverter, leading to a more remarkably enhanced conversion efficiency of c‐Si solar cells compared to conventional Er 3+ ‐only doped upconverters. Codoping with Nb 5+ to compensate for the charge imbalance caused by the Ni 2+ doping at the Ti 4+ sites intensified the UC emission. Similarly, charge imbalance caused by the Er 3+ doping at the Ca 2+ sites was compensated by codoping with alkali ions (Li +, Na +, K + ), resulting in a significant improvement in the UC emission intensity. Nearly 6.5‐fold intense UC emission was realized in the newly developed CaTiO3 :Er, Ni upconverter compared to the previously reported CaZrO3 :Er, Ni one. It is explained on the basis of higher Ni → Er energy transfer efficiency and a more efficient Er 3+ UC emission. If these upconverters are applied at the rear‐face of a bifacial c‐Si solar cell, ∼4.8% absolute efficiency improvement is possible.