Optoelectronic devices for light or spectral signal detection are desired for use in a wide range of applications, including sensing, imaging, optical communications, and in situ characterization. However, existing photodetectors indicate only light intensities, whereas multiphotosensor spectrometers require at least a chip-level assembly and can generate redundant signals for applications that do not need detailed spectral information. Inspired by human visual and psychological light perceptions, the compression of spectral information into representative intensities and colours may simplify spectrum processing at the device level. Here, we propose a concept of spectrum projection using a bandgap-gradient semiconductor cell for intensity and colour perception. Bandgap-gradient perovskites, prepared by a halide-exchanging method via dipping in a solution, are developed as the photoactive layer of the cell. The fabricated cell produces two output signals: one shows linear responses to both photon energy and flux, while the other depends on only photon flux. Thus, by combining the two signals, the single device can project the monochromatic and broadband spectra into the total photon fluxes and average photon energies (i.e., intensities and hues), which are in good agreement with those obtained from a commercial photodetector and spectrometer. Under changing illumination in real time, the prepared device can instantaneously provide intensity and hue results. In addition, the flexibility and chemical/bio-sensing of the device via colour comparison are demonstrated. Therefore, this work shows a human visual-like method of spectrum projection and colour perception based on a single device, providing a paradigm for high-efficiency spectrum-processing applications.

用于光或光谱信号检测的光电器件需要用于广泛的应用，包括传感、成像、光通信和原位表征。然而，现有的光电探测器仅指示光强度，而多光电传感器光谱仪至少需要芯片级组件，并且可以为不需要详细光谱信息的应用生成冗余信号。受人类视觉和心理光感知的启发，将光谱信息压缩为代表性强度和颜色可以简化设备级别的光谱处理。在这里，我们提出了使用带隙梯度半导体单元进行强度和颜色感知的光谱投影的概念。带隙梯度钙钛矿是通过浸入溶液中的卤化物交换方法制备的，被开发为电池的光敏层。所制造的电池产生两个输出信号：一个输出信号显示对光子能量和通量的线性响应，而另一个仅取决于光子通量。因此，通过组合两个信号，单个设备可以将单色和宽带光谱投影为总光子通量和平均光子能量（即强度和色调），这与从商业光电探测器和光谱仪获得的结果非常一致。在实时变化的光照下，所准备的设备可以立即提供强度和色调结果。此外，还通过颜色比较展示了该设备的灵活性和化学/生物传感。因此，这项工作展示了一种基于单个设备的类似人类视觉的光谱投影和颜色感知方法，为高效光谱处理应用提供了范例。