Rivera Medina Martha Judith, Di Mario Lorenzo, Kahmann Simon, Xi Jun, Portale Giuseppe, Bongiovanni Giovanni, Mura Andrea, Alonso Huitrón Juan Carlos, Loi Maria Antonietta
Photophysics & Optoelectronics group, Zernike Institute of Advanced Materials, University of Groningen, Nijenborgh 4, 9747 AG, Groningen, The Netherlands.
Departamento de Materia Condensada y Criogenia. Instituto de Investigaciones en Materiales. Universidad Nacional Autónoma de México. Ciudad Universitaria, A.P. 70-360, Coyoacán, 04510, Mexico City, Mexico.
Nanoscale. 2023 Apr 6;15(14):6673-6685. doi: 10.1039/d3nr00087g.
Here we demonstrate blue LEDs with a peak wavelength of 481 nm, with outstanding colour purity of up to 88% (CIE coordinates (0.1092, 0.1738)), an external quantum yield of 5.2% and a luminance of 8260 cd m. These devices are based on quasi-2D PEA(CsMA)PbBr, which is cast from solutions containing isopropylammonium (iPAm). iPAm as additive assist in supressing the formation of bulk-like phases, as pointed out by both photophysical and structural characterization. Additionally, the study of the excitation dynamics demonstrates a hindering of the energy transfer to domains of lower energy that generally undermines the performance and emission characteristics of blue-emitting LEDs based on quasi-2D perovskites. The achieved narrow distribution of quantum well sizes and the hindered energy transfer result in a thin film photoluminescence quantum yield exceeding 60%. Our work demonstrates the great potential to tailor the composition and the structure of thin films based on Ruddlesden-Popper phases to boost performance of optoelectronic devices - specifically blue perovskite LEDs.
在此，我们展示了峰值波长为481 nm的蓝色发光二极管，其具有高达88%的出色色纯度（CIE坐标(0.1092, 0.1738)）、5.2%的外量子效率和8260 cd/m²的亮度。这些器件基于准二维PEA(CsMA)PbBr，它由含有异丙基铵（iPAm）的溶液浇铸而成。如光物理和结构表征所指出的，iPAm作为添加剂有助于抑制块状相的形成。此外，激发动力学研究表明，能量向较低能量域的转移受到阻碍，这通常会削弱基于准二维钙钛矿的蓝色发光二极管的性能和发射特性。所实现的量子阱尺寸窄分布以及受阻的能量转移导致薄膜光致发光量子产率超过60%。我们的工作证明了基于Ruddlesden-Popper相来调整薄膜的组成和结构以提高光电器件——特别是蓝色钙钛矿发光二极管——性能的巨大潜力。
