摘要
Flexible photodetector(PD)arrays have the potential to replace the rods and cones in the retina,converting external light signals into electrical signals and offering hope for blind patients to regain vision.However,issues like discontinuous electrode surfaces and incompletely crystallized perovskites can cause cracks and degrade the performance of flexible PDs during repeated bending,hindering their development and applications.In this study,we employ a combination of radio frequency magnetron sputtering and angular ion beam polishing to achieve an ultrathin,ultrasmooth platinum(Pt)electrode film(UTPF)with a thickness of less than 10 nm.Building on this,a vapor deposition method with dynamically regulated evaporation rates is developed to obtain a dense-gradient PbI_(2)precursor.This funnel-shaped vertical structure precursor facilitates the penetration of CH_(3)NH_(3)I solution,ultimately resulting in a dense and uniform perovskite film with large grains and strong interfacial bonding with UTPF.The results indicate that the flexible PD arrays exhibit excellent optoelectronic performances,characterized by high sensitivity,detectivity and a large on/off current ratio.Furthermore,benefitting from their exceptional flexibility and electrical stability,the devices retain 92.53%of the original photocurrent after 4000 bending cycles at large angles.Notably,the integrated 10×10 flexible PD arrays demonstrate good uniformity in dark current and photocurrent,along with high imaging resolution,showing the reliable imaging capabilities of the flexible arrays and their potential applications in artificial retina.
柔性光电探测器(PD)阵列能够将光信号高效转换为电信号,展现出在人工视网膜等生物电子领域替代感光功能的重要潜力.然而,在反复弯曲过程中,柔性PD易产生裂纹,导致光电性能退化,限制其实际应用.本研究采用射频磁控溅射结合角离子束抛光,制备出厚度小于10纳米的超薄、超光滑铂电极薄膜作为高稳定性导电基底.基于此,进一步开发了一种动态调控蒸发速率的气相沉积方法,成功构建出具有密度梯度漏斗状的PbI_(2)前驱体薄膜,有效促进CH_(3)NH_(3)I溶液在薄膜中的渗透与转化过程.所得钙钛矿薄膜晶粒大、致密性高、形貌均匀,并与超薄超平整的铂电极形成优异界面耦合.柔性PD器件表现出高达19.48×10^(12)Jones的探测率、6.87×10^(4)的开/关电流比,且在经历4000次大角度弯折后仍保持92.53%的初始光电流响应.此外,柔性PD阵列在均匀性和高分辨成像能力方面表现出色,展示出其在高可靠性视觉仿生系统中的广阔应用前景.
基金
supported by the National Natural Science Foundation of China(62375081,U22A20138,52372146,62090035,52221001,and 52402181)
the National Key R&D Program of China(2022YFA1204300 and 2022YFA1402501).
