Mishra Aditya, Bose Riya, Zheng Yangzi, Xu Weijie, McMullen Reema, Mehta Abhas B, Kim Moon J, Hsu Julia W P, Malko Anton V, Slinker Jason D
Department of Materials Science and Engineering, The University of Texas at Dallas, 800 West Campbell Rd., Richardson, TX, 75080-3021, USA.
Department of Physics, The University of Texas at Dallas, 800 West Campbell Rd., Richardson, TX, 75080-3021, USA.
Adv Mater. 2022 Aug;34(31):e2203226. doi: 10.1002/adma.202203226. Epub 2022 Jun 28.
The 0D cesium lead halide perovskite Cs PbBr has drawn remarkable interest due to its highly efficient robust green emission compared to its 3D CsPbBr counterpart. However, seizing the advantages of the superior photoluminescence properties for practical light-emitting devices remains elusive. To date, Cs PbBr has been employed only as a higher-bandgap nonluminescent matrix to passivate or provide quantum/dielectric confinement to CsPbBr in light-emitting devices and to enhance its photo-/thermal/environmental stability. To resolve this disparity, a novel solvent engineering method to incorporate highly luminescent 0D Cs PbBr nanocrystals (perovskite nanocrystals (PNCs)) into a 3D CsPbBr film, forming the active emissive layer in single-layer perovskite light-emitting electrochemical cells (PeLECs) is designed. A dramatic increase of the maximum external quantum efficiency and luminance from 2.7% and 6050 cd m for a 3D-only PeLEC to 8.3% and 11 200 cd m for a 3D-0D PNC device with only 7% by weight of 0D PNCs is observed. The majority of this increase is driven by the efficient inherent emission of the 0D PNCs, while the concomitant morphology improvement also contributes to reduced leakage current, reduced hysteresis, and enhanced operational lifetime (half-life of 129 h), making this one of the best-performing LECs reported to date.
零维铯铅卤化物钙钛矿CsPbBr₃因其与三维CsPbBr₃相比具有高效稳定的绿色发光特性而备受关注。然而，要将其卓越的光致发光特性优势应用于实际发光器件仍颇具挑战。迄今为止，CsPbBr₃仅被用作高带隙非发光基质，用于在发光器件中钝化CsPbBr₃或为其提供量子/介电限制，并提高其光/热/环境稳定性。为了解决这一差距，设计了一种新颖的溶剂工程方法，将高发光性的零维CsPbBr₃纳米晶体（钙钛矿纳米晶体（PNCs））掺入三维CsPbBr₃薄膜中，在单层钙钛矿发光电化学电池（PeLECs）中形成有源发射层。观察到，对于仅含7%（重量）零维PNCs的三维-零维PNC器件，其最大外量子效率和亮度从仅含三维的PeLEC的2.7%和6050 cd/m²显著提高到8.3%和11200 cd/m²。这种提高主要是由零维PNCs的高效固有发射驱动的，同时伴随的形貌改善也有助于降低漏电流、减少滞后现象并延长工作寿命（半衰期为129小时），使其成为迄今为止报道的性能最佳的LEC之一。
