Achieving high efficiency and long-term device stability is a vital issue for the commercialization of organic–inorganic hybrid perovskite solar cells (PeSCs). In this work, phenylethylammonium iodide (PEAI)-induced bilateral interface engineering was developed to improve the device efficiency and stability of methylammonium lead triiodide (MAPbI3)-based PeSCs. Introducing PEAI onto a poly­(3,4-ethylenedioxythiophene):poly­(styrene sulfonate) (PEDOT:PSS) layer modifies the surface properties of PEDOT:PSS and facilitates the formation of a high-quality perovskite active layer with enlarged grains on PEDOT:PSS. PEA+ in PEAI–PEDOT:PSS also alters the work function of PEDOT:PSS, leading to a reduction in the energy difference between the PEDOT:PSS and MAPbI3 perovskite layers, which decreases the energy loss during charge transfer. Additionally, depositing PEAI onto three-dimensional (3D) perovskite yields a two-dimensional/three-dimensional (2D/3D) stacked structure for the perovskite active layer. Because the two-dimensional (2D) top layer acts as a capping layer to prevent water penetration, the stability of the perovskite active layer is significantly enhanced. A PeSC device fabricated based on this combination exhibits enhanced power conversion efficiency (PCE) and an extended device lifetime compared to a pristine PeSC. Under high-humidity conditions (75 ± 5%), the PEAI-treated PeSC retains 88% of its initial power conversion efficiency (PCE) after 100 h. In contrast, a pristine PeSC device loses over 99% of its initial PCE after only 25 h under the same conditions.

Doping serves as a vital strategy for tuning electronic and optoelectronic properties of semiconductors. Compared to organic semiconductors, the understanding and optimization of the doping process in halide perovskite semiconductors is still in its infancy. Nonetheless, there is a continuous surge in doping these semiconductors for performance enhancement. This perspective discusses the central role of dopants in organic and halide perovskite-based semiconductors used for energy conversion devices, particularly solar cells and thermoelectrics. We summarize various p-and n-type dopants explored for modifying the active layer in organic and perovskite devices, highlighting their challenges and limitations. Understanding doping-induced changes in electronic properties and their ramifications on device performance is essential for improving the device performance.

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Molecular doping is the key to enabling organic electronic devices, however, the design strategies to maximize doping efficiency demands further clarity and comprehension.