A second-order nonlinear optical dendronized hyperbranched polymer containing isolation chromophores: achieving good optical nonlinearity and stability simultaneously

Large nonlinear optical (NLO) coefficient and good stability, two essential factors to evaluate second-order NLO materials, are difficult to be achieved in one molecule simultaneously. Herein, by utilizing the concept of “isolation chromophore”, “isolation group” and dendritic structure, a dendritic molecule D-NS and a dendronized hyperbranched polymer DHP-NS are prepared to investigate their structure-property relationship. For the small dendritic molecule D-NS, it exhibits a high d₃₃ value of 140 pm/V. But this value can be easily dropped when the temperature is higher than 50 °C, which extremely limits its real application. After introducing D-NS into a dendronized hyperbranched polymer chains, the obtained DHP-NS also shows a high d₃₃ value of 101 pm/V, but much better stability than D-NS. Even when its thin film was heated to 120 °C, no obvious decay can be observed in the d₃₃ value of DHP-NS. This work demonstrates an effective strategy to realize both large NLO effect and good stability simultaneously.