Unique Photoelectric Properties and Defect Tolerance of Lead-Free Perovskite Cs₃Cu₂I₅ with Highly Efficient Blue Emission

Abstract

The lead-free copper-based halide perovskite Cs 3 Cu 2 I 5 is a promising material that can overcome the toxicity and instability of lead-based halide perovskites, thereby affording remarkable performance in the field of optoelectronics. Cs 3 Cu 2 I 5 perovskite exhibits blue emission with a very high photoluminescence quantum yield (PLQY). First-principles calculations were used herein to theoretically expound the origins of the high PLQY of Cs 3 Cu 2 I 5 : (i) the low symmetry of Cs 3 Cu 2 I 5 breaks the forbidden transition and enables the transition process; (ii) the large transition matrix and high transition rate increase the probability for radiative recombination of Cs 3 Cu 2 I 5 ; (iii) the good defect tolerance broadens the path for thermal relaxation and radiative recombination. The high transition rate and good defect tolerance account for the high-efficiency PLQY of the lead-free copper-based perovskite, Cs 3 Cu 2 I 5 .

Optoelectronic performance of perovskite Cs2KMI6 (M = Ga, In) based on high-throughput screening and first-principles calculations

“…To maintain the structure stabilities of Cs 2 KMI 6 (M = Ga, In) during the growth process, the following conditions should be satisfied according to the thermodynamic equilibrium conditions: 46 . 46 The calculated formation energy of Cs 2 KGaI 6 and Cs 2 KInI 6 are À13.54 eV and À13.82 eV, respectively, which are consistent with the corresponding values (À13.5 eV and À13.0 eV) in the Materials Project database. 30 Furthermore, we analyzed all experimentally synthesized binary and ternary compounds corresponding to perovskites Cs 2 KMI 6 (M = Ga, In), and calculated the stable chemical potential regions with these phases.…”

“…This indicates Table 1 The Goldsmith's tolerance factor (t) and octahedral factor (m) of Cs 2 KMI 6 (M = Ga, In); the optimized lattice parameters, unit cell volume, K-halogen and M-halogen bond lengths of double perovskites Cs 2 KMI 6 (M = Ga, In) based on the PBE functional that they are ductile materials with great application potential in foldable photovoltaic materials. 45 To further evaluate the thermal stability of perovskites, we calculated the phase stability diagram 46,47 based on the firstprinciples methods. To maintain the structure stabilities of Cs 2 KMI 6 (M = Ga, In) during the growth process, the following conditions should be satisfied according to the thermodynamic equilibrium conditions: 46 .…”

Lead-free all-inorganic halide double perovskite materials for optoelectronic applications: progress, performance and design

“…136,147 The calculated stable chemical potential region of Cs 2 CuSbCl 6 and Cs 4 CuSb 2 Cl 12 verifies the feasibility of their synthesis in theory. 144,145 Considering their successful synthesis, our theoretical conclusions on thermal stability are consistent with the experimental results. 34,38 To understand their electronic properties, the band structures and density of states (DOS) of Cs 2 CuSbCl 6 and Cs 4 CuSb 2 Cl 12 perovskites are shown in Fig.…”

“…136,147 The calculated stable chemical potential region of Cs 2 CuSbCl 6 and Cs 4 CuSb 2 Cl 12 verifies the feasibility of their synthesis in theory. 144,145 Considering their successful synthesis, our theoretical conclusions on thermal stability are consistent with the experimental results. 34,38…”

“…38 To access the thermodynamic stabilities of Cs 2 CuSbCl 6 and Cs 4 CuSb 2 Cl 12 , the thermodynamic equilibrium conditions were examined, which allowed us to determine the chemical potential window for the growth of the corresponding materials. [144][145][146] The constraints to be satisfied to avoid formation of other chemicals are summarized in Table 4. Further, the chemical potential window for the thermal equilibrium growth of Cu-based perovskites is plotted in Fig.…”