来源：ACS Publications
The AM2Pn2 (A= Ca, Sr, Ba, Yb, Mg; M = Zn, Cd, Mg; and Pn = N, P, As, Sb, Bi) family of Zintl phases has been known as thermoelectric materials and has recently gained much attention for highly promising materials for solar absorbers in single-junction and tandem solar cells. In this paper, we will, from first principles, explore the entire family of AM2Pn2 compounds in terms of their ground-state structure, thermodynamic stability, and electronic structure. We also perform photoluminescence spectroscopy on bulk powder and thin film samples to verify our results, including the first measurements of the band gaps of SrCd2P2 and CaCd2P2. The AM2Pn2 compounds exhibit broad stability, are mostly isostructural to CaAl2Si2 (P3̅m1), and cover a wide range of band gaps from 0 to beyond 3 eV. This could make them useful for a variety of purposes, for which we propose several candidates, such as CaZn2N2 for tandem top cell solar absorbers and SrCd2Sb2 and CaZn2Sb2 for infrared detectors. By examining the band structures of the AM2Pn2, we find that Mg3Sb2 has the most promise as a thermoelectric material due to several off-Γ valence band pockets, which are unique to it among the compositions studied here.
Here, we have systematically studied the phase stability and electronic band structure of the AM2Pn2 compounds in a wide range of compositions, using first-principles calculations, finding that the majority of compositions studied here are stable and isostructural and that these possess a wide range of band gaps. The band gap generally increases as Pn mass decreases; while bismuthides are mostly metallic, certain nitrides have band gaps greater than 3 eV. We compare the results to experimental literature and complement them with new experimental results. Our work can be used to understand well-established AM2Pn2 compounds, suggest new AM2Pn2 compounds to synthesize, and suggest specific applications for certain chemistries.