A new scheme for significant enhancement of the second order nonlinear optical response from molecules to ordered aggregates

Abstract

How to achieve maximum nonlinear optical (NLO) properties from the molecular to the macro block is very crucial to the development of nonlinear optical materials, which is the impetus of the present work. Buckybowls present large first hyperpolarizability ascribed to noncentrosymmetric charge distribution due to the curved shape of the system. The role of their packing pattern in maximizing the NLO response of buckybowl aggregates is investigated. In (corannulene)₁₀ and (sumanene)₁₀ aggregates, the first order hyperpolarizabilities (β₀) per molecule are enhanced 5.59 and 6.21 times with respect to a single entity respectively. For a larger buckybowl, C₃₆H₁₂, the β₀ value per molecule of its pentamer reaches 191.4 × 10⁻³⁰ esu which is much higher than conventional dipolar or octupolar NLO chromophores ones. The cohesive coupling among electric dipoles in packing of buckybowls is responsible for significant enhancement of the nonlinear optical response of the aggregates, which could pave the way for designing large 2nd order NLO materials with a good balance of nonlinearity, transparency, and stability.