Ternary Inclusion Co‐Crystals for Efficient Photothermal Conversion and Solar‐Driven Water Evaporation

Abstract Organic co‐crystal engineering offers a convenient and efficient platform for preparing photothermal conversion (PTC) materials. However, current donor–acceptor (D–A) co‐crystals generally have medium photothermal performance. Here, an inclusion co‐crystal strategy is presented, i.e., host–guest encapsulation of small acceptor inside donor‐type macrocycle's cavity, to enhance PTC efficiency through the promotion of D–A binding. A naphthyl‐sidewall Tröger's base (TB[2]) molecular box donor is elaborately designed, which can encapsulate electron‐deficient 7,7,8,8‐tetracyanoquinodimethane (TCNQ) to form a 1:2 ternary inclusion charge‐transfer (CT) co‐crystal via the synergism of multiple noncovalent forces. Under 808 nm laser irradiation (0.7 W cm ⁻² ), the PTC efficiency of co‐crystals is as high as 94.3%. The co‐crystals are further introduced into the porous polymer of polyurethane (PU) to prepare an interfacial evaporator (TB‐TCNQ@PU) for solar‐driven water evaporation. Under 1 Sun irradiation, a high‐water evaporation rate of 1.746 kg m ⁻² h ⁻¹ and a prominent solar‐to‐vapor efficiency of 93.8% are achieved. This work opens new avenues for the efficient PTC materials.