Assembling fullerenes in conjugated macrocycles with molecular van der Waals heterojunction for diode rectification

Abstract

Controllable assembly and alignment of fullerenes is of fundamental importance in improving the optoelectronic device performance. Here, we found that conjugated macrocycles, 3B2A and 4B2A, could function as donors encapsulating electron-deficient fullerene to form a molecular-scale p–n junction, which enables fast electron transfer and enhanced exciton dissociation for current rectification. These self-assembled donor-acceptor host-guest systems significantly enhances the loading content of fullerene and prevents its aggregation with aid of the effective host-guest interaction. Thus formed molecular-scale van der Waals heterojunctions between the conjugated macrocycle and fullerene can effectively rectify the current density of the sandwiched diode devices, leading to a typical WORM memory behavior with ON/OFF ratio up to 104. More importantly, this deformation can be recovered by thermal annealing to turn the non-volatile memory device to the initial ON state. We proposed that this extraordinary diode rectification effect was due to the synergistic combination of electron-transfer and the physical deformation of host-guest complex under electric field. These findings will open a new avenue to develop high-performance molecular van der Waals heterojunctions for high-density data storage technology.