Unique Photoelectric Properties and Defect Tolerance of Lead-FreePerovskite Cs3Cu2I5with Highly Efficient Blue Emission

The lead-free copper-based halide perovskite Cs3Cu2I5is a promisingmaterial that can overcome the toxicity and instability of lead-based halideperovskites, thereby affording remarkable performance in thefield of optoelectronics.Cs3Cu2I5perovskite exhibits blue emission with a very high photoluminescencequantum yield (PLQY). First-principles calculations were used herein to theoreticallyexpound the origins of the high PLQY of Cs3Cu2I5: (i) the low symmetry of Cs3Cu2I5breaks the forbidden transition and enables the transition process; (ii) the largetransition matrix and high transition rate increase the probability for radiativerecombination of Cs3Cu2I5; (iii) the good defect tolerance broadens the path forthermal relaxation and radiative recombination. The high transition rate and good defect tolerance account for the high-efficiencyPLQY of the lead-free copper-based perovskite, Cs3Cu2I5.

Automated summary

Cs3Cu2I5, a lead-free copper-based halide perovskite, exhibits blue emission with high PLQY. The high-efficiency PLQY of Cs3Cu2I5 is attributed to its low symmetry, large transition matrix, high transition rate, and good defect tolerance.