Elpasolite structures based on A2AgBiX6 (A: MA, Cs, X: I, Br): Application in double perovskite solar cells

Organic-inorganic hybrid perovskites have emerged as high-performance semiconductors for optoelectronic applications in recent years. Nevertheless, their stability and toxicity issues demonstrate considerable challenges. Double perovskites have lately been introduced as a promising lead-free alternative, and the Cs2AgBiBr6 composition has amazing potential to substitute current lead-containing absorbers due to its high stability and non-toxicity. Herein, Cs2AgBiBr6, MA(2)AgBiBr(6), and MA(2)AgBiI(6) films are synthesized in a one-step solution base route and incorporated into a perovskite solar cell. Structural characterizations confirm the formation of single-phase cubic double perovskite structure for Cs2AgBiBr6 and MA(2)AgBiBr(6), and orthorhombic crystalline phase for MA(2)AgBiI(6). The concentration of 0.5 M and annealing at 250 degrees C for 10 min for Cs2AgBiBr6 or at 100 degrees C for 10 min for MA(2)AgBi(Br or I)(6) is the optimized parameter for successful deposition of these films. By examining the UV-Vis absorption and PL spectra, it is found that the Cs2AgBiBr6 exhibits a direct bandgap of 2.16 eV, and MA(2)AgBiBr(6) and MA(2)AgBiI(6) feature indirect optical bandgaps of 2.00 and 1.64 eV, respectively. Also, the solar cells based on Cs2AgBiBr6, MA(2)AgBiBr(6), and MA(2)AgBiI(6) absorbers show power conversion efficiencies (PCE) of about 1.16%, 0.20%, and 0.31%, respectively. Thus, the potential of double perovskite as an absorber material is demonstrated. This research reveals the new route for the emerging category of perovskites with considerable potential for optoelectronic applications.

Automated summary

Organic-inorganic hybrid perovskites have shown high performance as semiconductors in optoelectronic applications, but face challenges in stability and toxicity; Double perovskites like Cs2AgBiBr6 have been introduced as promising lead-free alternatives due to high stability and non-toxicity; Solar cells based on double perovskite absorbers demonstrate potential with Cs2AgBiBr6 showing the highest power conversion efficiency.