Stimuli Responsive Electronic Reconfiguration in Benzo ghi perylene TCNQ Donor Acceptor Crystalline Networks

Abstract

Template assisted crystal engineering provides a powerful strategy for constructing ordered networks tailored to organic electronic applications. We introduce a solution based strategy to fabricate crystalline needle like arrays of charge transfer complexes CTCs between electron donating benzo ghi perylene BP and electron accepting TCNQ. Well defined square crystals of BP polymorphs were employed as templates for the spatially controlled anisotropic growth of CTC needle like arrays. By tuning concentration and deposition rates, we modulated BP crystal dimensions and hence controlled the growth of needle networks mimicking the template spatial scale. In solution, these free standing flexible meshes were detached from the BPs and redeposited onto variable substrates, while the BP templates remain undissolved, enabling repeated fabrication cycles. CTC formation induces an electronic redistribution with thermally reversible modulation of characteristic electronic states. Such transformation modifies the BP luminescence character while bare BP exhibits a strong green emission, it is quenched in the presence of TCNQ and replaced by a weaker blueish CTC emission, establishing a charge transfer mediated photonic response. Our study provides a combination of crystal engineering with microspectroscopic insights offering a highly sensitive handle for elucidating charge redistribution and modulation of electronic states in CTC upon external stimul