An electrode design rule for high performance top-illuminated organic photovoltaics

Abstract

We show that for organic photovoltaics supported on a low workfunction reflective electron-extracting electrode, a hole-blocking layer is not required.

Enhanced stability and efficiency in hole-transport-layer-free CsSnI3 perovskite photovoltaics

“…Corroborating evidence for n-type doping is provided by HRXPS of the same films (Figure 6b), which shows that the binding energy of the Sn 3d orbitals in SnCl2 is increased by 0.4-0.5 eV when incorporated in a PC61BM film, consistent with partial electron transfer from the SnCl2 to the PC61BM. Based on a bandgap of 1.3 eV 11,15,25 the energy of the conduction band edge of CsSnI3 is 3.6 eV below the vacuum level, which is considerably shallower in energy than the LUMO of PC61BM at 3.78 eV 31 below the vacuum level, and so there is unlikely to be a barrier to electron extraction across this interface either with or without SnCl2 doping of the PC61BM layer. Figure 7 shows the performance of CsSnI3 PPV devices without encapsulation and tested in ambient air at a humidity of 25% under constant 1 sun simulated solar illumination.…”

Work Function-Tunable Amorphous Carbon–Silver Nanocomposite Hybrid Electrode for Optoelectronic Applications

“…On the other hand, the electronic quality of the interfaces is another primary factor that determines the device performance and stability, which depends on the WF, interface energy-level alignment, Fermi-level pinning, the strength of electric dipole at the interface, and electronic defect states at the interface. , The mismatch in energy-level alignment and high density of defect states at the device interface give rise to charge carrier accumulation and joule heating, eventually leading to device degradation . Thus, well-aligned energy levels between the electrode and semiconductor Fermi level are extremely important to achieve an efficient and balanced charge transport across the electrode/semiconductor interface.…”