ABSTRACT
Energy level alignment (ELA) at donor (D) -acceptor (A) heterojunctions is essential for understanding the charge generation and recombination process in organic photovoltaic devices. However, the ELA at the D-A interfaces is largely underdetermined, resulting in debates on the fundamental operating mechanisms of high-efficiency non-fullerene organic solar cells. Here, we systematically investigate ELA and its depth-dependent variation of a range of donor/non-fullerene-acceptor interfaces by fabricating and characterizing D-A quasi bilayers and planar bilayers. In contrast to previous assumptions, we observe significant vacuum level (VL) shifts existing at the D-A interfaces, which are demonstrated to be abrupt, extending over only 1-2 layers at the heterojunctions, and are attributed to interface dipoles induced by D-A electrostatic potential differences. The VL shifts result in reduced interfacial energetic offsets and increased charge transfer (CT) state energies which reconcile the conflicting observations of large energy level offsets inferred from neat films and large CT energies of donor - non-fullerene-acceptor systems.
ABSTRACT
On-demand initiation of dual- and multi-component microreactions inside liquid marbles (LMs) was developed by coalescing contacting patchy LMs containing separate reagents through CO2-induced wetting transition of the interface between the LMs.
Subject(s)
Carbon Dioxide/chemistry , Polymethacrylic Acids/chemistry , Polystyrenes/chemistry , Bromine/chemistry , Ferricyanides/chemistry , Hydrophobic and Hydrophilic Interactions , Iodine/chemistry , Particle Size , Phenol/chemistry , Polymethacrylic Acids/chemical synthesis , Polystyrenes/chemical synthesis , Potassium Permanganate/chemistry , Starch/chemistry , Sulfates/chemistry , WettabilityABSTRACT
A choline phosphate (CP) modified surface is designed to resist protein adsorption due to its zwitterionic properties and simultaneously promote cell adhesion though its universal interaction with phosphate choline (PC) headgroups of the cell membrane. This work provides a new approach to obtain a cell-adhesive surface with a non-biofouling 'background', which has a potential for tissue engineering.
