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A Direct Bandgap Copper–Antimony Halide Perovskite
- Vargas, Brenda, Ramos, Estrella, Pérez-Gutiérrez, Enrique, Alonso, Juan Carlos, Solis-Ibarra, Diego
- Journal of the American Chemical Society 2017 v.139 no.27 pp. 9116-9119
- copper, geometry, humidity, lead, oxidation, semiconductors, solar cells, thermal stability
- Since the establishment of perovskite solar cells (PSCs), there has been an intense search for alternative materials to replace lead and improve their stability toward moisture and light. As single-metal perovskite structures have yielded unsatisfactory performances, an alternative is the use of double perovskites that incorporate a combination of metals. To this day, only a handful of these compounds have been synthesized, but most of them have indirect bandgaps and/or do not have bandgaps energies well-suited for photovoltaic applications. Here we report the synthesis and characterization of a unique mixed metal ⟨111⟩-oriented layered perovskite, Cs₄CuSb₂Cl₁₂ (1), that incorporates Cu²⁺ and Sb³⁺ into layers that are three octahedra thick (n = 3). In addition to being made of abundant and nontoxic elements, we show that this material behaves as a semiconductor with a direct bandgap of 1.0 eV and its conductivity is 1 order of magnitude greater than that of MAPbI₃ (MA = methylammonium). Furthermore, 1 has high photo- and thermal-stability and is tolerant to humidity. We conclude that 1 is a promising material for photovoltaic applications and represents a new type of layered perovskite structure that incorporates metals in 2+ and 3+ oxidation states, thus significantly widening the possible combinations of metals to replace lead in PSCs.