Effects of 10 MeV Al⁴⁺ ions irradiation on fluorine-doped tin oxide substrates for photovoltaic device applications

Abstract

The effects of 10 MeV Al4+ ions irradiation on structural, surface morphological, optical and electrical properties of fluorine-doped tin oxide (FTO) substrates are presented for solar cell applications. The ions irradiation changes the surface morphology, average roughness, interface width, roughness exponent, and several other fractal parameters of the FTO surfaces. The UV–visible transmittance measurement shows an enhancement of transmittance in the ions irradiated substrates up to 95%. The electrical properties such as mobility, work-function, sheet resistance, and resistivity are also modified due to ions irradiation. In order to have functional applications of these ions irradiated substrates, we fabricated organic solar cells on these ions irradiated and pristine FTO substrates. The device performances are significantly improved for the case of ions irradiated FTO substrate in comparison to the pristine one. Thus, better device performance due to effective changes in physical properties suggests that the ions irradiated FTO substrates can be used as better electrodes for organic and hybrid photovoltaic device applications.

Microstructural, Optical, and Work Function Tuning of Fullerene (C60) Modified Zinc Oxide Films for Optoelectronic Devices

“…Where, W tip , W film , V cpd , and q are the work function of the AFM tip, the work function of specimen substrates, contact potential difference, and the elementary charge, respectively. 3 The value of the work function of the tip was 5.00 eV which was kept constant throughout all the measurements. The estimated value of V cpd is changed from 611-532 mV on varying the…”

“…Further, increasing the doping concentration of C 60 viz., 0.25-0.50 wt% surface roughness along with other microstructural defects are reduced compared to pristine ZnO films, and thus, a downward shift in Fermi energy levels is observed. 3,50 Hence, it is clear from the above discussions that the incorporation of C 60 into ZnO may tailor the various deep or shallow energy levels which may subsequently cause a shift in the Fermi energy level positions. 18 Figure 6 presents the electrical conductivity (σ) measured by the four-probe method of the pristine and C 60 modified ZnO films.…”

“…The observed values of V cpd are 611 mV, 553 mV, 532 mV, and 567 mV for ZnO, ZnC1, ZnC2, and ZnC3 films, respectively. Since the work function is the difference between the vacuum level to the Fermi level 3,46. Thus, a change in work function subsequently may cause a shift in the position of Fermi energy levels of ZnO films modified with C 60 at different concentrations (see, Fig.5e).…”

“…1,2 MOSs can even be heavily doped to act as conductors with very low resistivity, some of them are known as transparent conducting oxides such as fluorine-doped tin oxide, indium-doped tin oxide, etc. 3 Based on the charge transport properties, MOSs can be characterized as either n-type viz. TiO 2 , SnO 2 , In 2 O 3 , ZnO, etc.…”