Integrated heterostructure of PZT/CdS containing the synergistic effect between heterojunction structure and ferroelectric polarization for photoelectrochemical applications

Abstract

Ferroelectric photoelectrodes such as Pb(Zr0.2Ti0.8)O3 (PZT), with the high built-in electric for the separation of photoexcited carriers, are ideal candidates for photoelectrochemical (PEC) water splitting. However, the large bandgap and the poor conduction have limited the PEC performance of PZT photoelectrodes to date. To conquer these intrinsic drawbacks, we proposed the designed photoelectrode based on ferroelectric PZT film and surface decoration of discontinuous CdS nanoparticles toward enhanced PEC water splitting. More specifically, the ferroelectric PZT substrate with a spontaneous ferroelectric polarization could effectively segregated the charge carriers that generated in the bulk of photoelectrode. Meanwhile, the electron-hole pairs near the interface of PZT film and CdS nanoparticle could be effectively separated and transferred on account of the resulted p-n junction. Besides, the limitations of PZT include wide band gap and poor conductivity can be conquered by decorated CdS nanoparticles, which not only play as an electron conductor to trap photoinduced electrons transferred from PZT but also enhance the solar light harvesting own to their narrow band gap. The as-prepared photoelectrodes exhibited an enhanced photocurrent density (at 0 V vs. Ag/AgCl), which was 11 times than that of pure PZT films. This work may provide a new strategy toward the rational design of high performance ferroelectric-based photoelectrodes.