Efficient near-infrared quantum cutting in NaYF_4: Ho^3+, Yb^3+ for solar photovoltaics

Abstract

Quantum cutting converting a ultraviolet photon into two near-infrared photons has been demonstrated by spectroscopic measurements in NaYF4:Ho3+,Yb3+ synthesized by hydrothermal method. Evidence is provided to confirm the occurrence of quantum cutting. Upon excitation of Ho3+ 5G4 level, near-infrared quantum cutting could occur through a two-step resonance energy transfer from Ho3+ to Yb3+ by cross relaxation, with a maximum quantum efficiency of 155.2%. This result reveals the possibility of violet to near-infrared quantum cutting with a quantum efficiency larger than 100% in Ho3+/Yb3+ codoped fluorides, suggesting the possible application in modifying the solar spectrum to enhance the efficiency of silicon solar cells.

Enhanced three-photon near-infrared quantum splitting in β-NaYF4:Ho3+ by codoping Yb3+

“…1(b)), NIR emission at 850 nm disappears expectedly. 21 18,19 whereas that of 985 nm PL rises before Yb 3+ content reaching the concentration quenching threshold 10 mol.% and that of 1180 nm emission increases monotonically. In comparison, PL spectrum of β-NaYF 4 :Ho 3+ excited at 880 nm ( Fig.…”

“…Noted that, as Yb 3+ content increases, PL intensity of ∼850 nm for Ho 3+ : 3 D 3 → 3 K 8 , 5 F 2 also decreases monotonically but that of 1180 nm for Ho 3+ : 5 I 6 → 5 I 8 enhances gradually. 19 In order to further investigate the NIR emission schemes in β-NaYF 4 :Ho 3+ ,Yb 3+ , NIR PL spectra (Figs. 1(b)-1(c)) were recorded for 535 and 880 nm excitation, respectively.…”

“…[7][8][9][10] A well-known example is Gd 3+ -Eu 3+ couple that features the interesting and appreciable QY 190% for LiGdF 4 :Eu 3+ and 194% for BaF 2 :Gd 3+ ,Eu 3+ in the visible spectral region. 7,9 Recently, near-infrared (NIR) downconversion has been studied in numerous materials, practically for Ln 3+ -Yb 3+ (Ln = Tb, Tm, Pr, Er, Nd, and Ho) couples, [11][12][13][14][15][16][17][18][19] where one Ln 3+ donor ion is proposed to cooperatively or resonantly excite two neighboring Yb 3+ acceptor ions. However, in most of these cases where NIR luminescence originates only from Yb 3+ through the first-order energy transfer (ET) from Ln 3+ , 18,19 QS does actually not occur.…”

“…7,9 Recently, near-infrared (NIR) downconversion has been studied in numerous materials, practically for Ln 3+ -Yb 3+ (Ln = Tb, Tm, Pr, Er, Nd, and Ho) couples, [11][12][13][14][15][16][17][18][19] where one Ln 3+ donor ion is proposed to cooperatively or resonantly excite two neighboring Yb 3+ acceptor ions. However, in most of these cases where NIR luminescence originates only from Yb 3+ through the first-order energy transfer (ET) from Ln 3+ , 18,19 QS does actually not occur. Moreover, for the cooperative NIR QS, it always become efficient only at rather high Yb 3+ content, which may induced serious concentration quenching.…”

Advances in Rare Earth Spectroscopy and Applications

“…With 359 nm excitation, nearinfrared QC could occur through cross-relaxation in a twostep resonance energy transfer from Ho to Yb, with a maximum QE of 155.2%. Yu et al 80 observed QC in hexagonal beta-NaYF 4 doped with Ho:Yb by exciting with 300-550 nm, yielding two NIR photons. It was found that NIR-QC can occur via two energy transfer mechanisms: through the simultaneous excitation of two Yb ions via cooperative energy transfer and via resonant energy transfer followed by a sequential 5 84 Detailed information on various upconversion and downconversion materials that can be used for solar cell can be found in Ref.…”