(a) The schematic device structure of an inverted PSC with an ITO/TiOx/P3HT:PCBM/PEDOT:PSS/metal electrode, and the P3HT, PCBM, and TiOx chemical structures. (b) Energy level diagram of the inverted PSC. (c) UV-vis absorption spectra of the TiOx, P3HT, and PCBM films. (d) AFM topographic images (5-μm × 5-μm) of the TiOx films on the ITO substrate.
The J-V characteristics of I-PSCs. (a) The effect of white light on the recovery of the kink shape. (b) The effect of light irradiation at different wavelengths (i.e., red, green, blue, and UV light). (c) The effect of UV irradiation time. (d) The changes in efficiency, FF, (inset) Voc, and Jsc with UV irradiation time.
(a) The schematic system of EIS measurement. The ITO/TiOx/Au structure was measured for impedance analysis. (b) The Bode plot and (c) Nyquist plot of ITO/TiOx/Au measured by EIS before and after UV irradiation. An equivalent circuit (inset) corresponding with the EIS results is also shown.
(a) The WF variations of the TiOx layer with increasing UV exposure time. (b) High binding region of UPS spectra of bare ITO, ITO/TiOx (w/o, w/UV), and P3HT:PCBM film.
(a) Jphoto response of the TiOx layer with UV on/off cycles and schematic device structure (inset). The dotted line shows the input signal during UV light activation and deactivation. (b) Investigation of the photocurrent saturation time with continuous UV irradiation. The trap site filling rate was gradually decreased and saturated after 10 min of UV irradiation.
(a) The energy diagram of the ITO/TiOx interface before UV irradiation. The EB between ITO and TiOx hinders the charge transport of the device. Here, qΦITO, qXTiOx, and EF° represent the WF of ITO and the LUMO and Fermi level of the TiOx layer, respectively. There are many trap sites between the LUMO and EF° of TiOx. (b) The energy diagram of the ITO/TiOx composite after UV irradiation. The width of EB became narrow after UV irradiation, which results in the tunneling of charges through the ITO/TiOx interface. The WF of TiOx (qΦ°TiOx) before UV irradiation changed to the value of qΦ′TiOx after UV irradiation, which resulted in a change in the WF difference (ΔE) between ITO and TiOx from ΔE° to ΔE′.
Photovoltaic parameters of I-PSCs irradiated with white light at different wavelengths (i.e., red, green, blue, and UV) and for different UV irradiation times.
Article metrics loading...
Full text loading...