Kim Hyun-Tak, Lee Kangmin, Jin Wonjoo, Um Han-Don, Lee Minsoo, Hwang Eunhye, Kwon Tae-Hyuk, Seo Kwanyong
Department of Chemistry, Ulsan National Institute of Science and Technology (UNIST), Ulsan, Republic of Korea.
Department of Energy Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan, Republic of Korea.
Sci Rep. 2018 Nov 19;8(1):16974. doi: 10.1038/s41598-018-35356-w.
Molecularly engineered Ir(III) complexes can transfer energy from short-wavelength photons (λ < 450 nm) to photons of longer wavelength (λ > 500 nm), which can enhance the otherwise low internal quantum efficiency (IQE) of crystalline Si (c-Si) nanowire solar cells (NWSCs) in the short-wavelength region. Herein, we demonstrate a phosphorescent energy downshifting system using Ir(III) complexes at short wavelengths (300-450 nm) to diminish the severe surface recombination that occurs in c-Si NWSCs. The developed Ir(III) complexes can be considered promising energy converters because they exhibit superior intrinsic properties such as a high quantum yield, a large Stokes shift, a long exciton diffusion length in crystalline film, and a reproducible synthetic procedure. Using the developed Ir(III) complexes, highly crystalline energy downshifting layers were fabricated by ultrasonic spray deposition to enhance the photoluminescence efficiency by increasing the radiative decay. With the optimized energy downshifting layer, our 1 cm c-Si NWSCs with Ir(III) complexes exhibited a higher IQE value for short-wavelength light (300-450 nm) compared with that of bare Si NWSCs without Ir(III) complexes, resulting in a notable increase in the short-circuit current density (from 34.4 mA·cm to 36.5 mA·cm).
分子工程化的铱（III）配合物可以将短波长光子（λ < 450 nm）的能量转移到长波长光子（λ > 500 nm），这可以提高晶体硅（c-Si）纳米线太阳能电池（NWSCs）在短波长区域原本较低的内量子效率（IQE）。在此，我们展示了一种使用铱（III）配合物在短波长（300 - 450 nm）下的磷光能量下移系统，以减少c-Si NWSCs中发生的严重表面复合。所开发的铱（III）配合物可被视为有前景的能量转换器，因为它们具有优异的固有特性，如高量子产率、大斯托克斯位移、在晶体薄膜中的长激子扩散长度以及可重复的合成程序。使用所开发的铱（III）配合物，通过超声喷雾沉积制备了高度结晶的能量下移层，以通过增加辐射衰减来提高光致发光效率。通过优化的能量下移层，我们带有铱（III）配合物的1 cm c-Si NWSCs与没有铱（III）配合物的裸硅NWSCs相比，在短波长光（300 - 450 nm）下表现出更高的IQE值，导致短路电流密度显著增加（从34.4 mA·cm²增加到36.5 mA·cm²）。
