Lead-free perovskite Cs2AgBiBr6${\mathrm{Cs}}_2{\mathrm{AgBiBr}}_6$ manifests great potential in developing high-performance, environmentally friendly, solution-processable photodetectors (PDs). However, due to the relatively large energy bandgap, the spectrum responses of Cs2AgBiBr6${\mathrm{Cs}}_2{\mathrm{AgBiBr}}_6$ PDs are limited to the ultraviolet and visible region with wavelengths shorter than 560 nm. In this work, a broadband Cs2AgBiBr6${\mathrm{Cs}}_2{\mathrm{AgBiBr}}_6$ PD covering the ultraviolet, visible, and near infrared (NIR) range is demonstrated by incorporating titanium nitride (TiN) nanoparticles that are prepared with the assistance of self-assembled polystyrene sphere array. In addition, an atomically thick Al2O3${\mathrm{Al}}_2{\mathrm{O}}_3$ layer is introduced at the interface between the Cs2AgBiBr6${\mathrm{Cs}}_2{\mathrm{AgBiBr}}_6$ film and TiN nanoparticles to alleviate the dark current deterioration caused by nanoparticle incorporation. As a result, beyond the spectrum range where Cs2AgBiBr6${\mathrm{Cs}}_2{\mathrm{AgBiBr}}_6$ absorbs light, the external quantum efficiency (EQE) of the TiN nanoparticle incorporated Cs2AgBiBr6${\mathrm{Cs}}_2{\mathrm{AgBiBr}}_6$ PD is enhanced significantly compared with that of the control, displaying enhancement factors as high as 2000 over a broadband NIR wavelength range. The demonstrated enhancement in EQE arises from the photocurrent contribution of plasmonic hot holes injected from TiN nanoparticles into Cs2AgBiBr6${\mathrm{Cs}}_2{\mathrm{AgBiBr}}_6$. This work promotes the development of broadband solution-processable perovskite PDs, providing a promising strategy for realizing photodetection in the NIR region.

中文翻译：

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无铅钙钛矿 Cs2AgBiBr6 光电探测器检测氮化钛等离子体热空穴驱动的近红外光

无铅钙钛矿Cs 2 AgBiBr 6${\mathrm{Cs}}_2{\mathrm{AgBiBr}}_6$在开发高性能、环保、可溶液加工的光电探测器（PD）方面表现出巨大的潜力。然而，由于Cs 2 AgBiBr 6${\mathrm{Cs}}_2{\mathrm{AgBiBr}}_6$ PDs具有较大的能带隙，其光谱响应仅限于波长小于560 nm的紫外和可见光区域。在这项工作中，通过掺入借助自组装聚苯乙烯球阵列制备的氮化钛（TiN）纳米颗粒，演示了覆盖紫外、可见和近红外（NIR）范围的宽带Cs 2 AgBiBr 6 PD 。${\mathrm{Cs}}_2{\mathrm{AgBiBr}}_6$此外，在Cs 2 AgBiBr 6薄膜和TiN纳米颗粒之间的界面处引入原子厚的Al 2 O 3${\mathrm{Al}}_2{\mathrm{O}}_3$层，以减轻由纳米颗粒掺入引起的暗电流劣化。结果，在Cs 2 AgBiBr 6吸收光的光谱范围之外，掺入Cs 2 AgBiBr 6 PD的TiN纳米粒子的外量子效率（EQE）与对照相比显着增强，表现出高达2000的增强因子在宽带近红外波长范围内。EQE 的增强源于从 TiN 纳米颗粒注入Cs 2 AgBiBr 6的等离子体热空穴的光电流贡献。这项工作促进了宽带可溶液加工的钙钛矿PD的发展，为实现近红外区域的光电检测提供了一种有前景的策略。${\mathrm{Cs}}_2{\mathrm{AgBiBr}}_6$${\mathrm{Cs}}_2{\mathrm{AgBiBr}}_6$${\mathrm{Cs}}_2{\mathrm{AgBiBr}}_6$${\mathrm{Cs}}_2{\mathrm{AgBiBr}}_6$