Ytterbium dopant-manipulated neuromorphic behavior for wavelength-dependent dual-modal photodetection

Integrating sensing and neuromorphic functions within a single low-power platform remains a key challenge in optoelectronic device design. We report a dual-modal perovskite photodetector by incorporating YbCl3 as a dopant, which simultaneously achieves neuromorphic behavior and conventional optoelectronic properties. Systematic characterizations of doping manipulation reveal that 0.5% YbCl3 can optimally modulate film crystallinity, enhance carrier transport, and tune charge dynamics. Notably, the 0.5% doped device exhibited distinct wavelength-dependent photoresponse, and hallmarks of depression-like neuromorphic behavior are were observed under pulsed 905 nm light excitation. This behavior is clearly supported by negative photoconductivity, gradual baseline modulation, and a prolonged post-illumination tail. However, these adaptive current dynamics are absent under 635 nm light illumination; the device instead demonstrated enhanced photoresponse, with responsivity increasing from 0.45 to 0.73 A/W and detectivity from 1.4 × 1012 to 5.1 × 1012 Jones. This spectral contrast originates from the wavelength-dependent activation of Yb3+-related trap states, confirmed by photoluminance measurements. These findings position YbCl3 doping as a versatile strategy for advancing perovskite photodetectors toward dual-modal photodetection, with ongoing studies exploring broader applicability.