Efficient Singlet Fission in Loose Packing Benzodipyrrolidone Thin Films

Singlet fission (SF) hold immense potential in efficient solar energy conversion on account of the vital role in alleviation of thermalization loss for high-energy photons. Although tremendous effort and progress have been made, the application of such a potential process in practical photovoltaic devices remains a formidable task. Therefore, exploitation of efficient SF molecular systems and in-depth study of their excitonic dynamics are of great importance to the implementation of photovoltaic application. Herein, we have developed a series of benzodipyrrolidone (BDPP) derivatives and delved into the SF dynamics in these loose packing thin films using time-resolved spectroscopy and morphology analyses. Results illustrate that efficient triplet formation could be achieved in all these loose packing thin films with a distinct crystallographic form and intermolecular packing mode. Suitable excited state energy levels, strong absorption in the blue-green light region, and excellent stability render BDPP as a robust SF molecular system targeted to practical utilization.