School for Engineering of Matter, Transport and Energy, Arizona State University, Tempe, AZ 85287, USA.
Nanoscale. 2015 Oct 28;7(40):17109-15. doi: 10.1039/c5nr04879f.
Owing to their strong photon emission, low excitonic binding energies, and nearly-ideal band offset values for water splitting reactions, direct gap quasi-2D gallium chalcogenides are potential candidates for applications in energy harvesting, optoelectronics, and photonics. Unlike other 2D materials systems, chemical functionalization of gallium chalcogenides is still at its seminal stages. Here, we propose vapor phase pyridine intercalation technique to manipulate optical properties of gallium chalcogenides. After functionalization, the excitonic dynamics of quasi-2D GaSe change significantly as evidenced by an increase in integrated PL intensity and emergence of a new emission feature that is below the band edge. Based on our DFT calculations, we attribute these to formation of bound exciton complexes at the trap sites introduced by chemical reaction between pyridine and GaSe. On the contrary, pyridine functionalization does not impact the optical properties of GaTe, instead treats GaTe surface to prevent oxidization of tellurium atoms. Overall, results suggest novel ways to control properties of gallium chalcogenides on demand and unleash their full potential for a range of applications in photonics and optoelectronics.
由于其强的光子发射、低的激子束缚能以及对于水分解反应近乎理想的能带偏移值，直接带隙准二维镓硫属化物是用于能量收集、光电和光子学的潜在候选材料。与其他二维材料体系不同，镓硫属化物的化学功能化仍处于起步阶段。在这里，我们提出了蒸气相吡啶插层技术来操纵镓硫属化物的光学性质。功能化后，准二维 GaSe 的激子动力学发生了显著变化，表现为 PL 强度的积分增加和新的发射特征出现在能带边缘以下。基于我们的 DFT 计算，我们将其归因于吡啶与 GaSe 之间的化学反应在陷阱位置形成束缚激子复合物。相反，吡啶功能化不会影响 GaTe 的光学性质，而是在 GaTe 表面形成保护层以防止碲原子的氧化。总的来说，结果表明了一种新颖的按需控制镓硫属化物性质的方法，并释放了它们在光子学和光电学领域的各种应用中的全部潜力。
