Ternary blend strategy in benzotriazole-based organic photovoltaics for indoor application

Organic photovoltaics (OPVs) suitable for application in indoor lighting environments can power a wide range of internet of things (IoT) related electronic devices. The ternary structure has huge advantages in improving the photovoltaic performance of OPVs, including broadening the light absorption, improving the charge transport, manipulating the energy loss (E_loss) and so on. Herein, we use wide-bandgap photo-active materials, including the benzotriazole-based polymer donor (J52-F), chlorinated polymer donor (PM7) and A₂-A₁-D-A₁-A₂-structured acceptor (BTA3), to construct ternary OPVs for indoor light applications. Benefitting from the introduction of PM7 as the third component in J52-F:BTA3-based blend, a gratifying PCE of 20.04% with a high V_OC of 1.00 V can be obtained under the test conditions with an illumination of 300 lx from an LED lighting source with a color temperature of 3000 K. The excellent device performance is inseparable from the matched spectrum, enhanced light absorption and the reduced E_loss, while the improved charge transport capability and suppression of carrier recombination also play an indelible role. Our work shows a potential material system to meet the requirement of devices applied under indoor light. Moreover, these findings demonstrate that designing multi-component OPVs is indeed a feasible way to further improve the performances of the photovoltaic energy conversion system for indoor applications.