Self‐Assembled Molecule‐Assisted Simplified Processing of High‐Performance Solar Cells and Light‐Emitting Diodes

State‐of‐the‐art, high‐performance solar cells and light‐emitting diodes normally rely on tedious layer‐by‐layer sequential deposition of carrier transport layer and light‐absorbing/emitting layers, which is not cost‐effective. Several recent exciting works have demonstrated surprising breakthroughs in terms of simplified processing of these optoelectronic devices. Upon the incorporation of carbazole phosphonic acid molecules and their derivatives into precursor ink beforehand, charge‐selective contact could spontaneously self‐assemble at the buried interface between the conducting substrate and photoactive layer, which results in the construction of simplified‐structured devices that yield comparable optoelectronic performances to the conventionally fabricated devices with full architectures. Herein, the recent groundbreaking advancement of high‐performance optoelectronic devices fabricated via a convenient codeposition technique is summarized, with particular emphasis on elucidating the chemical mechanism of self‐assembly mode and highlighting the unique advantages of this strategy on crystallization regulation, targeted defect passivation, carrier dynamics modulation, and comprehensive device performance improvement. Finally, the associated challenges are critically discussed and the future research directions are insightfully proposed, which can revolutionize the pathway toward constructing highly efficient optoelectronic devices in a cost‐effective manner and setting forward to future commercialization.