Near infrared light‐induced photocurrent in NaYF4:Yb3+, Er3+/WO2.72 composite film

Abstract Spectral conversion technology based on NaYF 4 :Yb 3+ , Er 3+ upconversion nanoparticles was extensively used to improve photovoltaic conversion efficiency of solar cells. However, the response mismatch between absorption of semiconductors and upconversion luminescence (UCL) limits the application of spectral conversion technology. Nonstoichiometric WO 2.72 nanoparticles display the broad absorption from visible to near‐infrared region due to the presence of oxygen vacancy, which is overlapped with the UCL of NaYF 4 :Yb 3+ , Er 3+ nanoparticles. Thus, the combination between NaYF 4 :Yb 3+ , Er 3+ nanoparticles, and nonstoichiometric WO 2.72 provides a possibility for designing a novel UCL spectral converted solar cells. In this work, composite film consisted of NaYF 4 :Yb 3+ , Er 3+ nanoparticles, and WO 2.72 nanofibers was prepared. The UCL of NaYF 4 :Yb 3+ , Er 3+ /WO 2.72 film was decreased in contrast to pure NaYF 4 :Yb 3+ , Er 3+ nanoparticles due to energy transfer from NaYF 4 :Yb 3+ , Er 3+ nanoparticles to WO 2.72 nanofibers. The NaYF 4 :Yb 3+ , E 3+ /WO 2.72 film exhibits the photocurrent generation upon the 980 nm excitation. This novel UCL spectral converted solar cells based on the broad absorption of defects in the WO 2.72 host will provide a novel view for photovoltaic devices.