The Properties of Sprayed Nanostructured P‐Type CuI Films for Dye‐Sensitized Solar Cells Application

Abstract

In our experiments, we provide a new approach for depositing CuI (inorganic compound) thin films using the mister atomizer technique. The CuI solution was sprayed into fine droplets using argon as a carrier gas at different solution concentrations. The solution sprayed was 50 ml for all samples with substrate temperature constant at 50°C during the deposition process. The result shows that the CuI thin film properties strongly depend on its precursor concentration. The structural properties were characterized by XRD with strong (111) orientation shows for all the CuI thin films. FESEM images revealed that all the CuI thin films deposited were uniform with the existence of nanostructured CuI particle. The EDX measurement confirms the existence of Cu:I in the films. The nanostructured CuI will improve the penetration of p-type between the mesoporous matrix of TiO2thin film. Promising conductivity value of about 10° S cm−1was obtained for CuI thin films deposited by this new deposition method. Low transmittance of below 50% was observed for all CuI thin films. The band gap energy obtained here was between 2.82 eV and 2.92 eV which is much smaller than the reported band gap which is 3.1 eV.

Suppression of Grain Boundary Scattering in Multifunctional p‐Type Transparent γ‐CuI Thin Films due to Interface Tunneling Currents

“…This distinct grain structure and the gaps between the grains result in a high density of grain boundaries in the thin films, respectively. Such a granular structure is often reported for CuI thin films grown with various deposition methods and is also common for CuI thin films used in optoelectronic devices, where grain boundary effects should therefore also be expected. Even epitaxial thin films grown on crystalline substrates, for example, ZnO show (well‐oriented) rotational domains such that grain boundary effects should also be present and can limit the performance of devices especially for lateral transport.…”

“…The first one who fabricated transparent conductive CuI as early as 1907 was Karl Bädeker using a iodization routine for copper thin films, making it the first transparent conductive material discovered. In recent times, there are reports on γ‐CuI thin films grown via reactive sputtering of Cu‐targets, RF‐DC‐sputtering of γ‐CuI targets, thermal evaporation, atomizer techniques, metal–organic chemical vapor deposition, laser‐assisted molecular beam epitaxy, the Bädeker iodization routine, pulsed laser deposition, a solid iodination method, or coating techniques . The highest reported mobility in γ‐CuI thin films is 25 cm 2 V −1 s −1 for thermally evaporated films, most other reports also observe rather high mobilities for p‐type thin films in the range of 10 cm 2 V −1 s −1 in combination with high carrier densities above 10 18 cm −3 .…”

Cuprous iodide - a p-type transparent semiconductor: history and novel applications

“…Nanostructured CuI thin films prepared using spray technique, solving CuI in acetonitrile, were reported in Refs. . For a substrate temperature of 110 °C, CuI thin films showed zinkblende structure with (111) preferred orientation and a typical grain size of 35 nm .…”

Highly efficient organic solar cells based on a robust room-temperature solution-processed copper iodide hole transporter

“…The direct band gap can be extracted by plotting (αhν) 2 versus photon energy and extrapolating to intersect with the abscissa ( Figure S3). The optical band gap was found to be 2.96 eV which is lower than what was previously reported (3.1 eV) [38]. The work Table 1 The detailed parameters of X-ray photoelectron spectroscopy of solution-processed CuI film ( $12 nm).…”