Perovskite Bifunctional Device with Improved Electroluminescent and Photovoltaic Performance through Interfacial Energy‐Band Engineering. Issue 33 (24th June 2019) - Xie, Jiangsheng
Abstract: Currently, photovoltaic/electroluminescent (PV/EL) perovskite bifunctional devices (PBDs) exhibit poor performance due to defects and interfacial misalignment of the energy band. Interfacial energy‐band engineering between the perovskite and hole‐transport layer (HTL) is introduced to reduce energy loss, through adding corrosion‐free 3, 3′‐(2, 7‐dibromo‐9 H ‐fluorene‐9, 9‐diyl) bis( n, n ‐dimethylpropan‐1‐amine) (FN‐Br) into a HTL free of lithium salt. This strategy can turn the n‐type surface of perovskite into p‐type and thus correct the misalignment to form a well‐defined N–I–P heterojunction. The tailored PBD achieves a high PV efficiency of up to 21.54% (certified 20.24%) and 4.3% EL external quantum efficiency. Free of destructive additives, the unencapsulated devices maintain >92% of their initial PV performance for 500 h at maximum power point under standard air mass 1.5G illumination. This strategy can serve as a general guideline to enhance PV and EL performance of perovskite devices while ensuring excellent stability. Abstract : A type of perovskite bifunctional device (PBD) with high photovoltaic (PV) and electroluminescence (EL) performance is developed. Interfacial energy‐band engineering between the perovskite and hole‐transport layer (HTL) is performed to turn the n‐type surface of the perovskite into p‐type and also correct the misalignment to form a well‐defined n–i–p heterojunction.