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Lead‐Free Organic–Inorganic Hybrid Perovskites for Photovoltaic Applications: Recent Advances and Perspectives

“…Ternary bismuth halides have emerged as interesting functional materials closely related Pb halide perovskites for photovoltaic applications, especially given the significantly reduced toxicity of Bi. A few investigations of crystal structures, optical, dielectric, and quantum physical properties on Bi‐based perovskite films, Cs 3 Bi 2 I 9 or MA 3 Bi 2 I 9 , have been actually done previously; however, no report was made on solar cells application . Johansson et al reported and successfully fabricated A 3 Bi 2 I 9 (A = MA or Cs) perovskites and first integrated them into photovoltaic devices with the structure of MA 3 Bi 2 I 9 , Cs 3 Bi 2 I 9 , and MA 3 Bi 2 I 9 Cl x , respectively .…”

White light emission in low-dimensional perovskites

“…36,56 In <111>-oriented perovskites, the presence of three undercoordinated halides at the organic/inorganic interface further ease structural distortions and coordination rearrangements, suggesting that should also be prone to broadband emission. Being based on trivalent cations Sb 3+ and Bi 3+ , 57,58 they also present some differences compared to the previous two perovskite types (e.g. the PL is usually more red-shifted), although only few examples are available.…”

Bandgap engineering of a lead-free defect perovskite Cs3Bi2I9through trivalent doping of Ru3+

“…[19][20][21] At room temperature, Cs 3 Bi 2 I 9 exhibits a distorted and defect-modulated hexagonal perovskite structure, in which a pair of [BiI 6 ] 3À octahedral share faces to form a [Bi 2 I 9 ] 3À bioctahedra, and every third layer of the octahedral Bi sites is depleted for charge neutrality, resulting in a zerodimensional (0D) molecular salt crystal structure (space group P6 3 /mmc). 22 The 0D structure with separated [Bi 2 I 9 ] 3À bioctahedra leads to low carrier mobility and therefore poor charge transport, which might be more benecial for optical properties, rather than photovoltaic applications. [23][24][25] For instance, colloidal Cs 3 Bi 2 I 9 nanocrystals have shown unique absorption spectra arising from the 0D crystal structure, with a very high excitonic binding energy of 300 meV.…”