Plasmonic CsPbBr3-Au nanocomposite for excitation wavelength dependent photocatalytic CO2 reduction

ABSTRACT The optoelectronic performance of CsPbBr3 nanocrystal (NC) has been dramatically limited by the severe charge carrier recombination and its narrow light absorption range, which are anticipated to be resolved via coupling with plasmonic Au nanoparticle (NP). In view of this, CsPbBr3-Au nanocomposite is fabricated and further employed as a concept model to study the electronic interaction between perovskite NC and Au NP for the first time. It has been found that the excitation-wavelength dependent bidirectional carrier transfer behavior exists in CsPbBr3-Au nanocomposite. Upon illumination with visible light (λ >420 nm), photo-generated electrons in CsPbBr3 can inject into Au with an electron injection rate and efficiency of 2.84 × 109 s−1 and 78%, respectively. The boosted charge separation is further translated into a 3.2-fold enhancement in CO2 photocatalytic reduction activity compared with pristine CsPbBr3. On the other hand, when solely exciting Au NP with longer wavelength light (λ >580 nm), the localized surface plasmon resonance (LSPR) induced hot electrons in Au NPs can transfer to CsPbBr3 NC and further participate in photocatalytic reaction towards CO2 reduction. The present study provides new insights into preparing plasmonic nanostructure to enhance the performance of perovskite based optoelectronic devices.