Antimony doped lead-free double perovskites (Cs₂NaBi_1−xSb_xCl₆) with enhanced light absorption and tunable emission

Abstract

Recently, the compositional engineering of lead-free halide double perovskite materials (A2B+B3+X6) has attracted increasing research interests in terms of potential optoelectronic applications. Herein, antimony ions (Sb3+) are introduced to manipulate...

Isolated [SbCl6]3– Octahedra Are the Only Active Emitters in Rb7Sb3Cl16 Nanocrystals

“…The Sb-doped NC counterparts, in turn, have been reported to have lower PLQY values (∼20% in the case of Cs 2 NaInCl 6 and Cs 2 KInCl 6 , ∼40% for Rb 3 InCl 6 , and 8% for Cs 2 SnCl 6 ) caused by the undercoordinated surface Cl – ions generating nonradiative defect states. , Such Sb-doped systems are characterized by the presence of [SbCl 6 ] 3– octahedra governing their optical properties since they behave as both sensitizers and recombination centers. More specifically, Sb-doped metal halides reported so far are characterized by (i) analogous near-UV absorption features originating from the parity allowed, although spin forbidden, 1 S 0 → 3 P 0 and 1 S 0 → 3 P 1 transitions of the [SbCl 6 ] 3– octahedra and (ii) PL emission stemming from self-trapped excitons recombining in the Sb centers, with high PLQY values, large Stokes shifts, and long emission lifetimes (microsecond time scale). − ,− , …”

“…Lead halide perovskites nanocrystals (NCs) have emerged as promising materials for various optoelectronic applications because of their bright and narrow photoluminescence (PL) emission. − However, their poor stability, mainly against humidity and more in general against polar solvents, and the intrinsic toxicity of Pb 2+ limit their commercial application. , For these reasons, extensive efforts are being devoted to seek alternative nontoxic metal halide NC systems with analogous optical features and possibly higher stability. − Among the systems discovered and investigated so far, Sb-doped metal halides are particularly promising, as some of them have been demonstrated to feature high PL quantum yield (PLQY) in both the bulk and nanoscale. − For example, Sb-doped bulk Cs 2 NaInCl 6 and Cs 2 KInCl 6 double perovskite systems exhibit a blue-green emission with PLQY values of ∼80% and 90%, respectively. ,,, Similarly, Sb-doped bulk Rb 3 InCl 6 and Cs 3 InCl 6 and their hydrated counterparts (namely, Rb 2 InCl 5 (H 2 O) and Cs 2 InCl 5 (H 2 O)) feature a bright PL emission in the green or yellow with PLQY as high as 95%. ,− In addition, Cs 2 SnCl 6 powders, when doped with Sb 3+ ions, exhibit a broadband orange-red emission and a PLQY of 37%, and Sb 3+ doped Cs 2 ZnCl 4 crystals show a near-infrared emission with a 70% PLQY . The Sb-doped NC counterparts, in turn, have been reported to have lower PLQY values (∼20% in the case of Cs 2 NaInCl 6 and Cs 2 KInCl 6 , ∼40% for Rb 3 InCl 6 , and 8% for Cs 2 SnCl 6 ) caused by the undercoordinated surface Cl – ions generating nonradiative defect states. , Such Sb-doped systems are characterized by the presence of [SbCl 6 ] 3– octahedra governing their optical properties since they behave as both sensitizers and recombination centers.…”

“…More specifically, Sb-doped metal halides reported so far are characterized by (i) analogous near-UV absorption features originating from the parity allowed, although spin forbidden, 1 S 0 → 3 P 0 and 1 S 0 → 3 P 1 transitions of the [SbCl 6 ] 3− octahedra and (ii) PL emission stemming from self-trapped excitons recombining in the Sb centers, with high PLQY values, large Stokes shifts, and long emission lifetimes (microsecond time scale). [19][20][21][22][23][24][26][27][28]33 While several Sb-doped systems have been synthesized and carefully studied, not much is known about pure (not doped) antimony chloride based materials. 14−16,34−37 In this regard, two compounds have been reported so far, namely, Cs 3 Sb 2 Cl 9 (known since the 1980s and nonemissive at RT) 16,38−40 PL lifetimes being of the order of microseconds.…”

Sb-Doped Metal Halide Nanocrystals: A 0D versus 3D Comparison

“…Among the different dopants, Sb 3+ cations are particularly interesting, as they confer highly efficient optical emission properties to bulk DPs. − For example, several works have demonstrated that Sb-doping of Cs 2 NaInCl 6 DP bulk crystals yields a bright, broad (full width at half-maximum of 80 nm) emission centered at ∼450 nm with a PL quantum yield (PLQY) of ∼80%. ,, Similarly, Noculak et al synthesized both Cs 2 NaIn 1– x Sb x Cl 6 and Cs 2 KIn 1– x Sb x Cl 6 powders, exhibiting blue and green emission, respectively, with PLQY as high as ∼90% …”

Electrical and chemical properties of vacancy-ordered lead free layered double perovskite nanoparticles

“…6,7 In order to overcome the toxicity and the stability issues, it is inevitable to explore lead-free perovskites. Although many lead-free perovskite structures were reported, it is important to note that some lead-free perovskites contain other toxic elements, 8–10 however they demonstrate interesting and applicable optical properties which are essential to explore. One of the candidates to replace the lead is the trivalent metal B( iii ) based perovskites with the general formula A 3 B( iii ) 2 X 9 , that creates a two-dimensional layered structure.…”