Growth and optical spectroscopy of KPb2Cl5 crystal containing Mn2+

KPb2Cl5:Mn2+ crystal with sizes of centimeters has been successfully grown by a modified Bridgman method. The electronic spectra of Mn2+ in the title compound have been measured at different temperatures and compared, revealing that the red emission observed at 10 and 77 K in the spectral range from 500 to 800 nm, which vanishes at room temperature, is associated with the radiation from Pb2+ ions with adjacent defects whereas the orange-red emission in the spectral range from 530 to 680 nm can be undoubtedly attributed to the spin forbidden transition 4T1g (4G) → 6A1g(6S) of Mn2+. The electronic excitation spectra are interpreted in a strong crystal field scheme with the use of the Tanabe–Sugano diagram. Good agreement with the experimental spectroscopic data is obtained with the use of crystal field splitting parameter 10Dq = 7902 cm−1, Racah parameters B = 618 cm−1, and C = 3549 cm−1.

Graphical abstractThe electronic spectra of KPb2Cl5:Mn2+ have been interpreted in the strong crystal field scheme with use of the Tanabe–Sugano diagram by assuming Mn2+ occupies the Oh site symmetry with approximation.Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► We employed the modified Bridgman method to grow the crystal KPb2Cl5 containing Mn2+ into centimeter sizes with good optical properties. ► The low temperature optical spectroscopy of Mn2+ in the title compound has been investigated and interpreted with the use of the Tanabe–Sugano diagram. ► It gives insight into the assignment of transition metal optical spectroscopy interpreted with the aid of Tanabe–Sugano energy matrices.