A relationship between reported experimental band gaps (solid) and DFT-calculated binding energies (gas) is established, for the first time, for each of the four ten-membered lead (or tin) trihalide perovskite solar cell semiconductor series examined in this study, including CH3 NH3 PbY3 , CsPbY3 , CH3 NH3 SnY3 and CsSnY3 (Y=I(3-x) Brx=1-3 , I(3-x) Clx=1-3 , Br(3-x) Cl x=1-3 , and IBrCl). The relationship unequivocally provides a new dimension for the fundamental understanding of the optoelectronic features of solid-state solar cell thin films by using the 0 K gas-phase energetics of the corresponding molecular building blocks.
Keywords: DFT calculations; band gap and binding energy; halide perovskite semiconductors; hydrogen bonding; structure-activity property relationships.
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