Electronegativity explanation on the efficiency-enhancing mechanism of the hybrid inorganic–organic perovskite ABX ₃ from first-principles study

Abstract

Organic-inorganic hybrid perovskites play an important role in improving the efficiency of solid-state dye-sensitized solar cells. In this paper, we systematically explore the efficiency-enhancing mechanism of ABX 3 (A = CH 3 NH 3 ; B = Sn, Pb; X = Cl, Br, I) and provide the best absorber among ABX 3 when the organic framework A is CH 3 NH 3 by first-principles calculations. The results reveal that the valence band maximum (VBM) of the ABX 3 is mainly composed of anion X p states and that conduction band minimum (CBM) of the ABX 3 is primarily composed of cation B p states. The bandgap of the ABX 3 decreases and the absorptive capacities of different wavelengths of light expand when reducing the size of the organic framework A, changing the B atom from Pb to Sn, and changing the X atom from Cl to Br to I. Finally, based on our calculations, it is discovered that CH 3 NH 3 SnI 3 has the best optical properties and its light-adsorption range is the widest among all the ABX 3 compounds when A is CH 3 NH 3 . All these results indicate that the electronegativity difference between X and B plays a fundamental role in changing the energy gap and optical properties among ABX 3 compounds when A remains the same and that CH 3 NH 3 SnI 3 is a promising perovskite absorber in the high efficiency solar batteries among all the CH 3 NH 3 BX 3 compounds.

Impact of a Spun-Cast MoOx Layer on the Enhanced Moisture Stability and Performance-Limiting Behaviors of Perovskite Solar Cells

“…This behavior is also seen for the I 3d signals (see Figure f). The I 3d peaks of the perovskite shift from 630.82 to 630.98 eV for the 3d 5/2 orbital and from 619.32 to 619.48 eV for the 3d 3/2 component after MoO x deposition. , This could be attributed to the donation of a lone pair of electrons from the lower electronegativity of Pb and I ions to the higher electronegative O species. , Figure g,h shows the top view scanning electron microscopy (SEM) images of the perovskite without and with the spun-cast MoO x (0.02 M) layer, respectively. The surface morphologies of perovskite capped with different concentrations of MoO x are also presented in Figure S1.…”

“…25,26 This could be attributed to the donation of a lone pair of electrons from the lower electronegativity of Pb and I ions to the higher electronegative O species. 27,28 Figure 2g,h shows the top view scanning electron microscopy (SEM) images of the perovskite without and with the spun-cast MoO x (0.02 M) layer, respectively. The surface morphologies of perovskite capped with different concentrations of MoO x are also presented in Figure S1.…”

Perovskite photonic crystal photoelectric devices

“…B presents a metal cation (Pb 2þ , Sn 2þ , or Eu 2þ ), and X is a halide anion (typically Cl À , Br À , and I À , or mixtures thereof). 9,10 They exhibit excellent performance for various optoelectronic applications, for example, solar cells (SCs), [11][12][13][14][15][16][17][18][19][20] light-emitting diodes (LEDs), 6,8,[21][22][23][24][25][26][27][28] photodetectors (PDs), [29][30][31][32][33][34] phototransistors, 35 and lasers. [36][37][38][39][40][41][42] The first demonstration of metal halide perovskite materials concerned organic-inorganic (MA þ , FA þ ) metal halide perovskites by Weber in the 1970s.…”

Numerical simulation of MASnI3/CuI heterojunction based perovskite solar cell

“…For metal cation (B), toxic Pb or replacement of Pb with the metal ions. Theoretical and experimental studies shows that narrower band gap of 1.3 eV for MASnX3 makes it more promising perovskite in comparison of band gap of 1.55 eV for MAPbX3 under wider visible spectrum range [7,8]. In planar heterojunction configuration an alternate of Pb-free, Sn-based perovskite layer has been used in solar cells [9].…”