Lin Jin-Tai, Hu Yu-Kai, Hou Cheng-Hung, Liao Chen-Cheng, Chuang Wei-Tsung, Chiu Ching-Wen, Tsai Ming-Kang, Shyue Jing-Jong, Chou Pi-Tai
Department of Chemistry, National Taiwan University, Taipei, 10617, Taiwan.
Research Center for Applied Science, Academia Sinica, Taipei, 11529, Taiwan.
Small. 2020 May;16(19):e2000903. doi: 10.1002/smll.202000903. Epub 2020 Apr 20.
Tin-based perovskite, which exhibits narrower bandgap and comparable photophysical properties to its lead analogs, is one of the most forward-looking lead-free semiconductor materials. However, the poor oxidative stability of tin perovskite hinders the development toward practical application. In this work, the effect of pseudohalide anions on the stability and emission properties of single-layer 2D tin perovskite nanoplates with chemical formula TEA SnI (TEA = 2-thiophene-ethylammonium) is reported. The results reveal that ammonium thiocyanate (NH SCN) is the most effective additive in enhancing the stability and photoluminescence quantum yield of 2D TEA SnI (23 ± 3%). X-Ray photoelectron spectroscopic investigations on the thiocyanate passivated TEA SnI nanoplate show less than a 1% increase of Sn signal upon 30 min exposure to air under ambient conditions (298 K, humidity ≈70%). Furthermore, no noticeable decrease in emission intensity of the nanoplate is observed after 20 h in air. The SCN passivation during the growth stage of TEA SnI is proposed to play a crucial role in preventing the oxidation of Sn and hence boosts both stability and photoluminescence yield of tin perovskite nanoplates.
锡基钙钛矿具有比其铅基类似物更窄的带隙和相当的光物理性质，是最具前瞻性的无铅半导体材料之一。然而，锡钙钛矿较差的氧化稳定性阻碍了其向实际应用的发展。在这项工作中，报道了拟卤化物阴离子对化学式为TEA₂SnI₄（TEA = 2-噻吩乙铵）的单层二维锡钙钛矿纳米片的稳定性和发射性质的影响。结果表明，硫氰酸铵（NH₄SCN）是提高二维TEA₂SnI₄稳定性和光致发光量子产率（23±3%）最有效的添加剂。对硫氰酸盐钝化的TEA₂SnI₄纳米片进行的X射线光电子能谱研究表明，在环境条件（298 K，湿度≈70%）下暴露于空气中30分钟后，Sn信号增加不到1%。此外，在空气中放置20小时后，未观察到纳米片发射强度有明显下降。有人提出，在TEA₂SnI₄生长阶段进行SCN钝化在防止Sn氧化方面起着关键作用，从而提高了锡钙钛矿纳米片的稳定性和光致发光产率。
