Intrinsic Optical Properties and Divergent Doping Effects of Manganese(II) on Luminescence for Tin(II) Phosphite Grown from a Deep-Eutectic Solvent

This is the first study on the ionothermal synthesis,
intrinsic
photoluminescence (PL), and dopant effects for tin­(II) phosphite,
a stereochemically active 5s2 lone-pair-electron-containing
compound, the fundamental properties of which have rarely been explored
before. In a new deep-eutectic solvent, single-phased products of
SnHPO3 (1) and Sn1–xMnxHPO3 (2) have been achieved in high yield. The crystalline powder of 1 is nonenantiomorphic, with an intense second-harmonic generation
comparable to that of potassium dihydrogen phosphate. Under UV excitation,
it unexpectedly emits white PL, an important intrinsic property never
discovered in tin­(II) oxysalts. Electron paramagnetic resonance hyperfine
splitting characteristic of manganese has been detected on 2 and a three-pulse electron-spin-echo envelope modulation technique
implemented to locate its corresponding location in the inorganic
host. On the basis of temperature-dependent PL and lifetime measurements,
the incorporated Mn2+ uncommonly acts as a sensitizer in
enhancing white emission until extremely low temperatures, in which
it would resume its normal role as an activator to give out characteristic
orange light.

本研究系首次对锡(II)亚磷酸盐的离子热合成、固有光致发光（PL）以及掺杂效应进行探讨，锡(II)亚磷酸盐是一种具有立体化学活性的5s2孤对电子化合物，其基本性质鲜有深入研究。在新型的深共熔溶剂中，成功实现了SnHPO3（1）和Sn1–xMnxHPO3（2）的单相产物，且产率较高。化合物1的晶体粉末为非手性结构，其二次谐波产生强度与磷酸二氢钾相当。在紫外激发下，意外地发出白色PL，这一重要的固有性质在锡(II)氧酸盐中尚未被发现。在化合物2中检测到了锰的电子顺磁共振超精细分裂特征，并采用三脉冲电子自旋回波包络调制技术定位其在无机基质中的对应位置。基于温度依赖性PL和寿命测量，掺杂的Mn2+在极低温度下罕见地充当敏化剂以增强白色发射，而在极低温度下，它将恢复其作为激活剂发出特征橙色光的正常角色。