Research on perovskite photodetectors with thickness controlling spectral response

Spectral selective photodetection is vital to a number of emerging areas, including artificial intelligence, computer vision and biosensing. The Charge Collection Narrowing (CCN) concept, standing out from several fabulous strategies to achieve filter less narrowband photodetection, has been paid abundant attention by virtue of its simple principle that can be easy to implement to make active layer thick enough properly. In order to figure out how the thickness of active layer affects spectral response, a series of perovskite photodetectors with different perovskite precursor solution concentrations are fabricated in this work. Besides, an additive of Rhodamine B is applied in perovskite solution so as to observe the variation of spectral response with thickness intuitively. It is found that the introduction of Rhodamine B makes spectral response more sensitive to the changes of the thickness of perovskite film. This work demonstrates that thicker active layer results in narrower spectral response of external quantum efficiency (EQE) and the Rhodamine B can accelerate the spectral narrowing, which provides a reference to the further research on narrowband photodetectors.