Recent Progress in Design of Organic Electro‐optic Materials with Ultrahigh Electro‐optic Activities†

Abstract

Comprehensive SummaryRationally designed organic electro‐optic (OEO) materials demonstrate ultra‐large electro‐optic (EO) activities, affording inorganic‐organic hybrid photonic devices with low drive voltage, large bandwidth, low energy consumption, and small footprint. OEO materials hold the potential to achieve EO coefficients (r33) over 1000 pm/V. Over the past decade, however, the best performance of OEO materials is limited to 300—600 pm·V−1. This is partly because of the concern of increasing dipole moment and optical loss due to the redshifted absorbance of high hyperpolarizability chromophores. Recent advance of theory‐guided design enables the OEO materials to achieve greatly enhanced hyperpolarizability and EO activity with dipole moment and propagation loss within acceptable constraints. Simultaneously, progress in hybrid device designs has greatly shortened the length of modulating waveguide, which resulted in significantly reduced sensitivity to propagation loss from redshifted absorption of OEO materials. Driven by theory‐guided design method, several high‐performance OEO materials have been presented with greatly enhanced EO coefficients beyond 1000 pm·V−1. This brief review summarizes the strategies to improve the EO activity including molecular engineering and hyperpolarizability, highlights the recent great progress in design of high‐performance OEO materials, and discusses the problems needed to be solved in application for current OEO materials.