Fig. 3: Photoelectric characteristics of CsPbI3:Ho3+- PbS QDs heterojunction.

TEM images of PbS QDs (a) and CsPbI₃:Ho³⁺—PbS QDs (b). c HR-TEM image of CsPbI₃:Ho³⁺—PbS QDs. d Emission spectra of CsPbI₃:Ho³⁺ PQDs and CsPbI₃:Ho³⁺ - PbS QDs. e PL lifetime of CsPbI₃:Ho³⁺ PQDs and CsPbI₃:Ho³⁺—PbS QDs at 692 nm. f I-V curves of CsPbI₃:Ho³⁺ PQDs and CsPbI₃:Ho³⁺—PbS QDs. UPS curves of CsPbI₃:Ho³⁺ PQDs (g) and PbS QDs (h). The Fermi level of CsPbI₃:Ho³⁺ PQDs and PbS QDs are -4.29 eV and -5.18 eV, respectively. i Schematic illustration of the each layer in PDs