Stathis Aristeidis, Bouza Zoi, Papadakis Ioannis, Couris Stelios
Department of Physics, University of Patras, 26504 Patras, Greece.
Institute of Chemical Engineering Sciences (ICE-HT), Foundation for Research and Technology-Hellas (FORTH), 26504 Patras, Greece.
Nanomaterials (Basel). 2022 Jan 1;12(1):152. doi: 10.3390/nano12010152.
In the present work the impact of in situ photoreduction, by means of ultraviolet (UV) irradiation, on the nonlinear optical response (NLO) of some graphene oxide (GO), fluorographene (GF), hydrogenated fluorographene (GFH) and graphene (G) dispersions is studied. In situ UV photoreduction allowed for the extended modification of the degree of functionalization (i.e., oxidization, fluorination and hydrogenation), leading to the effective tuning of the corresponding sp/sp hybridization ratios. The nonlinear optical properties of the studied samples prior to and after UV irradiation were determined by means of the Z-scan technique using visible (532 nm), 4 ns laser excitation, and were found to change significantly. More specifically, while GO's nonlinear optical response increases with irradiation time, GF and GFH present a monotonic decrease. The graphene dispersions' nonlinear optical response remains unaffected after prolonged UV irradiation for more than an hour. The present findings demonstrate that UV photoreduction can be an effective and simple strategy for tuning the nonlinear optical response of these graphene derivatives in a controllable way, resulting in derivatives with custom-made responses, thus more suitable for different photonic and optoelectronic applications.
在本工作中，研究了通过紫外线（UV）照射进行原位光还原对一些氧化石墨烯（GO）、氟化石墨烯（GF）、氢化氟化石墨烯（GFH）和石墨烯（G）分散体的非线性光学响应（NLO）的影响。原位UV光还原能够对官能化程度（即氧化、氟化和氢化）进行扩展修饰，从而有效调节相应的sp/sp杂化比。利用Z扫描技术，采用可见光（532 nm）、4 ns激光激发，测定了UV照射前后所研究样品的非线性光学性质，发现其发生了显著变化。更具体地说，虽然GO的非线性光学响应随照射时间增加，而GF和GFH则呈现单调下降。经过超过一小时的长时间UV照射后，石墨烯分散体的非线性光学响应未受影响。目前的研究结果表明，UV光还原可以成为一种有效且简单的策略，以可控方式调节这些石墨烯衍生物的非线性光学响应，从而得到具有定制响应的衍生物，因此更适合不同的光子和光电子应用。
