Efficient Near‐Infrared Emission of Ce³⁺–Nd³⁺ CoDoped (Sr_0.6Ca_0.4)₃(Al_0.6Si_0.4)O_4.4F_0.6 Phosphors for c‐Si Solar Cell

Abstract

Ce3+, Nd3+ codoped (Sr0.6Ca0.4)3(Al0.6Si0.4)O4.4F0.6 phosphors were synthesized through the high‐temperature solid‐state reaction method. Luminescence spectra, absorption spectra, and decay lifetimes of these samples have been measured to prove the energy‐transfer process from Ce3+ to Nd3+. Under UV and blue light excitation, (Sr0.6Ca0.4)3(Al0.6Si0.4)O4.4F0.6:Ce3+,Nd3+ phosphors exhibit near‐infrared (NIR) emission, mainly peaking at 1093 nm and secondarily at 916 nm. The NIR emission matches well with the band gap of c‐Si. Results of this work suggest that the (Sr0.6Ca0.4)3(Al0.6Si0.4)O4.4F0.6:Ce3+, Nd3+ phosphors have potential application as down‐shifting luminescent convertor for enhancing the photoelectric conversion efficiency of c‐Si solar cell.

A review on the structural dependent optical properties and energy transfer of Mn4+ and multiple ion-codoped complex oxide phosphors

“…44 As shown in Fig. 22a, the three absorption bands A (200-290 nm), B (290-420 nm), and C (420-550 nm) of the phosphors in the UV-vis absorption spectra can be attributed to the host lattice absorption, charge transfer transition of Mn 4+ -O 2-, and spinallowed transitions 4 A 2g / 4 T 1g and 4 A 2g / 4 T 2g of the Mn 4+ ions, respectively. 116 The absorption intensity of bands A and C decrease, but that of band B is enhanced with elevated Al 3+ concentrations, which indicates that the absorption intensity of the phosphor powder is enhanced in the ultraviolet light range, but reduced slightly in the blue light range.…”

“…9a and b illustrate the excitation spectra of Mn 4+ and emission spectra of Er 3+ in Mn 4+ and/or Er 3+ codoped samples with various doping concentrations. The two broad and intense excitation bands (monitored at Mn 4+ 710 nm emission) correspond to the spin-allowed transitions 4 A 2g / 4 T 1g and 4 A 2g / 4 T 2g of Mn 4+ (Fig. 9a).…”

“…It is well known that most of the energy of the solar spectrum is concentrated at wavelengths beyond 900 nm including UV-visible (UV-vis) and NIR light, which cannot be absorbed by the current crystalline silicon solar cells with high efficiency. [1][2][3][4] Converting the energy of the solar spectrum at wavelengths beyond 900 nm into the range located 900-1100 nm, which matches the maximum spectral response of the absorption of crystalline silicon, is an important alternative approach to improve the energy conversion efficiency of crystalline silicon solar cells. Recently, much attention has been paid to developing Mn 4+ -doped phosphors because Mn 4+ usually shows sharp line emissions in the red-infrared (IR) region due to its unique 3d 3 electron congurations.…”

“…5e-g show the emission spectra of Mn 4+ and multiple ions Nd 3+ /Er 3+ /Yb 3+ codoped CZGO with different doping concentrations of Ln 3+ ions, respectively. Upon excitation at 313 nm, the NIR emissions of Nd 3+ /Er 3+ /Yb 3+ such as the emission peaks at 900 and 1075 nm are assigned to the 4 monotonously decreases with an increase in the content of Ln 3+ , which indicates energy transfer occurs from Mn 4+ to Nd 3+ / Er 3+ /Yb 3+ .…”

“…Under excitation of NUV to visible light ranging from 250 to 550 nm, the Mn 4+ ions are excited into their charge transfer or excited states of 4 T 1g and 4 T 2g , which then rapidly relax to the metastable state of 2 E g of the Mn 4+ ions. The energy transfer occurs via Mn 4+ : 2 E g + Nd 3+ : 4 I 9/2 / Mn 4+ : 4 A 2g + Nd 3+ : 4 F 9/2 , 4 F 7/2 , 4 S 3/2 or Mn 4+ : 2 E g + Yb 3+ : 2 F 7/2 / Mn 4+ : 4 A 2g + Yb 3+ : 2 F 5/2 . The NIR emissions at 896 and 1064, 1540, and 980 nm are generated by the radiative transitions of the Nd 3+ : 4 F 3/2 , Er 3+ : 4 I 13/2 and Yb 3+ : 2 F 5/2 levels, respectively.…”