In recent years, metal halide perovskite materials have attracted wide attention in the fields of photovoltaics (PVs), light-emitting diodes (LEDs) and photodetectors (PDs) due to their excellent light absorption[1−6], adjustable bandgaps and long carrier diffusion length. Compared with commercial Si and GaN photodetectors, perovskite photodetectors (PPDs) present wider light detection range, higher sensitivity and higher external quantum efficiency (EQE)[7−9]. PDs are divided into two types: wide-bandgap detectors and narrow-bandgap detectors, and their functions correspond to different wavelength ranges. The traditional detectors (Si, GaN, InAs PDs) need low-temperature environment for their operation[10, 11], and it is difficult to perform simultaneous detection to short-wavelength and long-wavelength light, thus limiting their development, while the adjustable bandgaps of perovskites enable them to sense photons of short-wavelength and long-wavelength at once efficiently[12]. Moreover, perovskites can be made via a facile solutionprocessing, making PPDs more favorable in fabrication of large-area and flexible devices[13−17]. The development and application of PPDs are worthy of discussing. Visible light communication (VLC) is a wireless communication technology (Fig. 1), which uses visible light (300–900 nm) as the information carrier to transmit information within a certain distance[18−20]. It has the advantages of high response speed, security, low energy cost and electromagnetic interference resistance[21]. Gao et al.[22] reported that CsPbIxBr3–x photodetector simultaneously possessed high sensitivity and fast response by engineering device and film quality (Fig. 2(a)). CsPbIBr2 photodetector had a detectable limit of ~21.5 pW/cm2 and a response time of 21 ns. Moreover, the photoresponse characteristics can keep for 2000 h. The photodetector was integrated into the VLC system (Fig. 1), and successfully realized the transmission of text and audio signals. PPDs present specific responses to red, green and blue light, which is similar to the light-receiving vertebral body of human retina. Lin et al. [23] used a PPD with a microcavity structure to realize detection to different colors without using external filters, thus realizing full-color image restoration (Fig. 2(b)). The detection degree (D*) of the device reached 1013 Jones, the linear dynamic range (LDR) was 154 dB, and the response time was 580 ns, which were better than those of human retina. Fan et al.[24] made hemispherical FAPbI3 nanowire arrays by using a template method, which is almost impossible for traditional commercial semiconductors. And the bionic eye has been successfully assembled by using hemispherical nanowire detector arrays (Fig. 2(c)). The density of nanowire detectors on bionic eyes is much higher than that of photoreceptors in human retina, so higher image resolution can be achieved. Self-driven flexible PDs have attracted interests because they can be applied to wearable and portable devices[25−28]. The traditional planar photodetector is not satisfactory in both photoelectric and mechanical properties, and its structure needs to be improved to make it more suitable for flexible devices. Li et al.[29] reported a Cs0.05(FA0.85MA0.15)0.95Pb(I0.85Br0.15)3 PD with inverse opal structure, which can enhance light capture and improve carrier transport. The PD presented a high responsivity of 473 mA/W. What’s more, the detector had good mechanical properties, and the photocurrent maintained after 500 bending tests. The flexible device can detect sunlight from 5am to 7pm (Fig. 2(d)). At present, the infrared PD technology becomes mature. Owing to the limited detection range of Si and GaN PDs, the development and application of UV–visible light detection is required. Perovskite fabrication is simple, and perovskite has advantages in structure tuning. PPDs will present breakthroughs in the near future.

中文翻译：

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金属卤化物钙钛矿光电探测器的应用

近年来，金属卤化物钙钛矿材料由于具有优异的光吸收[1-6]、可调节的带隙和长载流子等优点，在光伏（PVs）、发光二极管（LEDs）和光电探测器（PDs）领域引起了广泛关注。扩散长度。与商用硅和氮化镓光电探测器相比，钙钛矿光电探测器（PPDs）具有更宽的光探测范围、更高的灵敏度和更高的外量子效率（EQE）[7-9]。PD分为宽带隙探测器和窄带隙探测器两种，其功能对应不同的波长范围。传统探测器（Si、GaN、InAs PDs）的工作需要低温环境[10, 11]，难以同时检测短波长和长波长光，从而限制了它们的发展，而钙钛矿的可调带隙使它们能够同时有效地感知短波长和长波长的光子[12]。此外，钙钛矿可以通过简单的溶液加工制备，使 PPD 更适合制造大面积和柔性器件[13-17]。PPDs的发展和应用值得讨论。可见光通信（VLC）是一种无线通信技术（图1），它以可见光（300~900 nm）为信息载体，在一定距离内传输信息[18-20]。具有响应速度快、安全、能耗低、抗电磁干扰等优点[21]。高等人[22] 据报道，CsPbIxBr3-x 光电探测器同时具有工程设备和薄膜质量的高灵敏度和快速响应（图 2（a））。CsPbIBr2 光电探测器的可检测限约为 21.5 pW/cm2，响应时间为 21 ns。此外，光响应特性可以保持2000小时。光电探测器集成到VLC系统中（图1），成功实现了文本和音频信号的传输。PPDs对红光、绿光和蓝光呈现特异性反应，类似于人类视网膜的受光椎体。林等人。[23]使用具有微腔结构的PPD实现对不同颜色的检测，无需使用外部滤光片，从而实现全彩图像恢复（图2（b））。该设备的检测度（D*）达到1013 Jones，线性动态范围（LDR）为154 dB，响应时间为580 ns，优于人类视网膜。范等人。[24] 使用模板方法制作了半球形 FAPbI3 纳米线阵列，这对于传统的商业半导体来说几乎是不可能的。通过使用半球形纳米线探测器阵列已成功组装仿生眼（图2（c））。仿生眼上纳米线探测器的密度远高于人类视网膜中的光感受器，因此可以实现更高的图像分辨率。自驱动柔性 PD 引起了人们的兴趣，因为它们可以应用于可穿戴和便携式设备[25-28]。传统的平面光电探测器无论是光电性能还是机械性能都不尽如人意，需要对其结构进行改进，使其更适用于柔性器件。李等人[29] 报道了具有反蛋白石结构的 Cs0.05(FA0.85MA0.15)0.95Pb(I0.85Br0.15)3 PD，这可以增强光捕获并改善载流子传输。PD 呈现出 473 mA/W 的高响应度。更重要的是，该探测器具有良好的机械性能，经过500次弯曲试验后仍能保持光电流。柔性设备可以检测早上 5 点到晚上 7 点的阳光（图 2（d））。目前，红外PD技术已经成熟。由于 Si 和 GaN PD 的检测范围有限，需要开发和应用紫外-可见光检测。钙钛矿制造简单，钙钛矿在结构调整方面具有优势。PPDs将在不久的将来出现突破。柔性设备可以检测早上 5 点到晚上 7 点的阳光（图 2（d））。目前，红外PD技术已经成熟。由于 Si 和 GaN PD 的检测范围有限，需要开发和应用紫外-可见光检测。钙钛矿制造简单，钙钛矿在结构调整方面具有优势。PPDs将在不久的将来出现突破。柔性设备可以检测早上 5 点到晚上 7 点的阳光（图 2（d））。目前，红外PD技术已经成熟。由于 Si 和 GaN PD 的检测范围有限，需要开发和应用紫外-可见光检测。钙钛矿制造简单，钙钛矿在结构调整方面具有优势。PPDs将在不久的将来出现突破。