Second harmonic generation from tetraphenylethylene functionalized graphdiyne

Abstract

The nonlinear optical (NLO) properties of two-dimensional (2D) layered materials have received extensive attention for their promising application prospects in the field of optoelectronics. Among these materials, 2D carbon materials have been pushed to the research hotspot thanks to their unique chemical and electronic structures. However, the exploration of second harmonic generation is currently limited to sp2 hybridized 2D carbon materials, while the research on multi-hybridized carbon atomic materials is relatively rare. Here, we report the observation of optical second harmonic from tetraphenylethylene-graphdiyne (TPE-GDY), a fully conjugated fluorescent 2D material composed of sp and sp2 hybridized carbon atoms based on the TPE unit. TPE-GDY is mixed with polyvinylpyrrolidone (PVP) to prepare TPE-GDY/PVP nanocomposite films, which further improves the stability of TPE-GDY. Cotton effect and favorable SHG response have been observed from these composite films. Our research enriches the material system in the field of NLO effects and opens up broad prospects for functional and potential applications of 2D graphdiyne materials.