Bright up-conversion photoluminescence of Bi4−xErxTi3O12 ferroelectric thin films

Abstract

The up-conversion (UC) photoluminescence and ferroelectric properties of Bi4−xErxTi3O12 (BErT) thin films were studied in terms of annealing temperature and Er3+ doping concentration. The thin films were prepared by chemical solution deposition method. There are two green emission bands centered at 527 and 548 nm, and a red emission band centered at 663 nm in UC luminescence spectra measured under a 980 nm laser excitation at room temperature, which correspond to the radiative transitions from 2H11/2, 4S3/2, and 4F9/2 to 4I15/2, respectively. The quenching concentration of Er3+ ions for green emission was as high as 20 mol % for Bi3.2Er0.8Ti3O12 thin films. The large Er3+ quenching concentration and efficient energy transfer between two neighboring Er3+ ions result in the improved UC emission. The dependence of UC emission intensity on pumping power indicated a two-photon UC emission process in the thin films. The combination of UC emission and ferroelectricity was realized in the capacitors of Pt/Bi3.25Er0.75Ti3O12/Pt/TiO2/SiO2/Si. The UC photoluminescent BErT ferroelectric thin films could be potentially applied to integrated optoelectronic devices.

Enhanced up-conversion photoluminescence and dielectric properties of Er- and Zr-codoped strontium bismuth niobate ceramics

“…The dominant UC green emission bands ranging from 510 to 530 nm and from 530 to 580 nm regions are assigned to the intra-4f 2 H 11/2 -4 I 15/2 and 4 S 3/2 -4 I 15/2 electronic transitions of Er 3 þ ion, respectively. The weak UC red emission band, situating at around 630-690 nm region, arises from the 4 F 9/2 -4 I 15/2 transition of Er 3 þ ion [14][15][16][17][18][19][20][21][22]. In fact, the intense UC green photoluminescence of SBNx can be easily observed by the naked eye at room temperature as shown in the inset of Fig.…”

Upconversion luminescence, ferroelectrics and piezoelectrics of Er Doped SrBi4Ti4O15

“…When Er 3+ concentration surpasses 0.1 mol, the cross relaxation between 2 H 11/2 and 4 I 15/2 is enhanced, which contributes to the concentration quenching for green emission. 47 This is why the red color dominant emission can be obtained when the Er 3+ concentration surpasses 0.1 mol. In a UC process, it is known that photoluminescence intensity is approximately proportional to the power of pumping laser, I∝P n , where I and P are the luminescence intensity and laser power, n is the number of photons involved in the pumping mechanism.…”

“…The high concentration of Er 3+ ions can increase the ions number of absorbing pumping source and promote the energy transfer between neighboring Er 3+ ions excited to intermediate energy level, which is important to get higher upconversion efficiency when excited by 980 nm laser. 47 The inset at left side of Fig. 2 shows a simplified energy level diagram of the green upconversion emissions for the Er 3+ doped SBT ferroelectric oxide.…”

“…However, these types of pervoskite oxides have chemical and physical stability but low emission efficiency due to their low solubility of trivalent rare earth ions. 41 [45][46][47][48] In this case, after activator or/and sensitizer ions substitutions, Bi 4 Ti 3 O 14 thin films show novel UC properties while retaining strong ferroelectric functions, which has potential applications in future integrated optoelectronic devices. So is of interest and significance to study UC properties of rare earth doped BLSFs oxides with big number of m (= 4) such as SBT, which including SrTiO 3 and Bi 4 Ti 3 O 12 units.…”

Optical thermometry based on the upconversion luminescence from Er doped Bi7Ti4TaO21 ferroelectric ceramics

“…However, in order to achieve multifunctional optoelectronic device by combination the UC luminescence and the ferroelectricity, some Er 3? doped ferroelectric materials has been systematically studied [10][11][12]. Among them, Bismuth layer structured ferroelectric (BLSFs) have been investigated extensively, because of their high Tc, relatively high dielectric constant and a low loss [13][14][15].…”