Sensitized thulium blue upconversion emission in Nd3+/Tm3+/Yb3+ triply doped lead and cadmium germanate glass excited around 800 nm

Synthesis and properties of PbGeO3 nanostructures

“…Germanates, as an important group of inorganic compounds, are very few in nature. During the past decade, there has been increased interest in the synthesis of germanates due to their specific magnetic [4], mechanical [5], sensing [6], photocatalytic [7], electrical [8], and optical properties [9][10][11]. Among them, lead germanate including Pb 2 Ge 3 O 8 [9], Pb 5 Ge 3 O 11 [12,13], PbGeO 3 [10,14], have been fabricated by different methods such as pulsedlaser deposition [6] and high temperature sintering [12][13][14], which exhibit optical, dielectric, and ferroelectric properties.…”

Magnetic and optical properties of NaGdF4:Nd3+, Yb3+, Tm3+ nanocrystals with upconversion/downconversion luminescence from visible to the near-infrared second window

“…In this process one Nd 3+ photon loses energy and populates the 4 I J (J = 11/2, 13/2) states while the other one gains energy and is excited to the high energy 4 G 7/2 or 4 G 9/2 states followed by nonradiative relaxation to 4 I 9/2 and 4 I 11/2 states, and as a result the UC of Nd 3+ takes place [42,43]. On the other hand, an energy transfer (ET 1 in Scheme 1) from Nd 3+ to nearby accumulator Yb 3+ ions occurs through a pair of transitions [38,39]: Nd 3+ : 4 F 3/2 -4 I 11/2 and 4 I 9/2 ; Yb 3+ : 2 F 7/2 -2 F 5/2 . The Yb 3+ ions in the 2 F5/2 state radiatively relax to the 2 F 7/2 state generating a broad band around 980 nm.…”

“…The Yb 3+ ions in the 2 F5/2 state radiatively relax to the 2 F 7/2 state generating a broad band around 980 nm. Subsequently, the energies at the 2 F 5/2 state of Yb 3+ are transferred to the 4f-electron which is at the 3 F 4 excited state of Tm 3+ resulting in the Tm 3+ : 3 F 4 -1 G 4 , 1 G 4 -1 D 2 and 1 I 6 transition (ET 2 in Scheme 1) [38,40]. From the 1 G 4 and 1 D 2 levels, the Tm 3+ ions transfer to 3 H 6 and 3 H 5 states leading to UC blue light emission centered at 475 and 542 nm, respectively.…”

“…Figure 3 demonstrates the absorption spectrum of NaGdF 4 :Nd 3+ (3 mol%), Yb 3+ (2 mol%), Tm 3+ (0.2 mol%) in the range 500-1,000 nm. There are three main absorptions in the NIR range around 960 nm (Yb 3+ ), 870 nm (Nd 3+ ) and 800 nm due to Nd 3+ and Tm 3+ ions corresponding to Nd 3+ : 4 I9/2-( 4 F5/2, 2 H 9/2 ) and Tm 3+ : 3 H 6 -3 F 4 transitions [38]. The spectrum shows multiple absorption peaks assigned to the f-f transitions of Nd 3+ from the ground 4 I 9/2 state to the excited states and has an intense absorption near 800 nm.…”

Investigation of energy transfer and frequency upconversion in Er3+/Ho3+ co-doped tellurite glasses

“…In recent years, blue, green or red upconversion emissions luminescence have been obtained by doping glasses with Tm 3+ , Er 3+ , Ho 3+ , Nd 3+ , etc., both at low and room temperature [4][5][6][7], respectively. It is well known that energy transfer was one of the most important upconversion mechanisms and had widely used to achieve more efficienct laser action by co-doping some sensitizer ions into laser materials [8][9][10]. According to previous studies [11,12], upconversion emission luminescence can be easily obtained from Er 3+ , or Ho 3+ doped glass system, and also have the same green (∼548 nm) and red (∼660 nm) upconversion emission bands.…”