Self-assembled hierarchical nanostructured perovskites enable highly efficient LEDs via an energy cascade

• المؤلفون الرئيسيون: Veldhuis, Sjoerd Antonius, Martinez-Sarti, Laura, Chandran, Bevita, Chirvony, Vladimir S., Lo, Alencious Shu-Zee, So, Jinkyu, Soci, Cesare, Grätzel, Michael, Bolink, Henk J., Mathews, Nripan, Mhaisalkar, Subodh Gautam, Chin, Xin Yu, Perumal, Ajay, Bruno, Annalisa, Yantara, Natalia
• مؤلفون آخرون: School of Materials Science and Engineering
• التنسيق: مقال
• اللغة: English
• منشور في: 2018
• الموضوعات: Energy Cascade; Perovskites
• الوصول للمادة أونلاين: https://hdl.handle.net/10356/88171; http://hdl.handle.net/10220/44602

Metal halide perovskites have established themselves as extraordinary optoelectronic materials, exhibiting promise for applications in large area illumination and displays. However, low luminescence, low efficiencies of the light-emitting diodes (LEDs), and complex preparation methods currently limit further progress towards applications. Here, we report on a new and unique mesoscopic film architecture featuring the self-assembly of 3D formamidinium lead bromide (FAPbBr3) nanocrystals of graded size, coupled with microplatelets of octylammonium lead bromide perovskites that enables an energy cascade, yielding very high-performance light-emitting diodes with emission in the green spectral region. These hierarchically structured perovskite films exhibit photoluminescence quantum yields of over 80% and LEDs associated with record high efficiencies in excess of 57.6 cd A−1 with an external quantum efficiency above 13%. Additionally, due to low turn-on voltages (~2.2 V) the LEDs have power efficiencies exceeding 58 lumens per Watt, obtained without any light-outcoupling structures.